1 Glossary

1.1 Domain Terms

2 Introduction

2.1 Purpose

Nearly one out of every two American adults age 30 and over have periodontal disease, according to recent findings from the Centers for Disease Control and Prevention (CDC).[1] The purpose of this project is to review the 41565005 |Periodontitis (disorder)| hierarchy and to evaluate and integrate requests from the American Academy of Periodontology (AAP) Classification System for Periodontal Diseases with existing 2556008 |Periodontal disease (disorder)| content in SNOMED CT^® (SCT).

2.2 Audience and stakeholder domain

The audience for this document includes all standards terminology leaders, implementers and users but is especially targeted at stakeholders involved in the practice of dentistry or concerned with oral health conditions including the American Academy of Periodontology, the Dentistry Specialty Interest Group (Dental SIG), and users of SNODENT the American Dental Association’s Systematized Nomenclature of Dentistry.

A further significant audience are the SNOMED CT authors who are tasked with implementing the recommended specification.

2.2.1 Input from stakeholders

Between the initiation of this project in 2012 and July 2015, there were over 50 requests related to periodontitis submitted to the SNOMED CT International Request Submission (SIRS) System. During that time, input related to specific concepts was also elicited from the American Academy of Periodontics representative to the SNODENT Committee and the Dentistry Specialty Interest Group (Dental SIG).

In late August 2015, after the better part of this document had been completed, an additional 84 requests related to periodontal dentistry were submitted to SIRS and are being added/evaluated for the January 2016 Release. These requests are resulting in ongoing changes in the 41565005 |Periodontitis (disorder)| hierarchy which are taken into account in this document to some degree.

2.2.2 Degree of consensus on the statement of problem

There is generally agreement that as classification systems evolve, new content needs to be added and some outdated content needs to be retired. There is consensus that, like classification systems, SNOMED CT is a work-in-progress that requires ongoing modification to its content. In addition to updating the |Periodontitis (disorder)| content, some request submissions also indicate that there is a need to clarify the concept model and the naming conventions to avoid ambiguity and duplication.

With respect to the degree of consensus on the type of content that should be added or retired, the classification system that is the basis for a significant number of the requests being addressed was developed during the International Workshop for a Classification of Periodontal Diseases and Conditions (IWCP) October 30th – November 2nd 1999.  It is sometimes referred to as The American Academy of Periodontology (AAP) 1999 Classification System and also as the IWCP 1999 Classification. The consensus that the content is needed is substantiated by the international authorities developing it. Correctly representing the intended meaning of the content in SNOMED CT may require additional consensus.

2.3 Impact of new July 2015 Editorial Policy guidance on recommendations

The July 2015 SNOMED CT Editorial Guide (section 6.1.3.17 Multisystem disorders) introduced changes to editorial policy that significantly impact recommendations made in this document. The July 2015 SNOMED CT international Release also included the addition of a substantive amount of new periodontal content.

This document had been largely completed prior to July 31, 2015. Therefore, although some changes were made to the document to reference the new changes to policy and content, many of the document’s observations and recommendations were impacted by the policy changes and the addition of new concepts and may no longer be applicable. However, the recommendations related to editorial policy and to specific SNOMED CT concepts should still be useful in helping to refine the new editorial policies as well as the periodontal content related to those policies.

3 Statement of the problem or need

3.1 Summary of problem or need, as reported

Content Tracker artf226141 – Periodontitis (disorder) hierarchy and periodontal disease:

Review the existing |Periodontitis (disorder)| hierarchy and alignment of new content requests from the American Academy of Periodontology (AAP) Classification System for Periodontal disease with existing SNOMED CT content.

3.2 Summary of requested solution

3.2.1 Review the existing |Periodontitis (disorder)| hierarchy

Review of the existing |Periodontitis (disorder)| hierarchy will require normal quality assurance processes which include;

1. Review of FSNs for ambiguity and duplicates.

2. Review of Descriptions for appropriate synonymy.

3. Evaluation of the Concept Model and review of concept definitions for consistency to ensure correct representation of meaning and correct classification.

4. Review for partitioning, completeness and for removal of outdated content.

Additionally, because |Periodontitis (disorder)| is a subtype of |Periodontal disease (disorder)|, the integrity of this concept definition also requires review.

3.2.2 Specific requests for content to be added or retired

The general request to review the existing |Periodontitis (disorder)| hierarchy was accompanied a request for the alignment of new content requests from the American Academy of Periodontology (AAP) Classification System for Periodontal Disease which will be undertaken with Section 3.2.1. Additionally, two specific content requests were addressed with artf226141 on the contact tracker.

3.2.2.1 Add “Aggressive periodontitis (disorder)”

Analysis of this initial request for the addition of “Aggressive periodontitis (disorder)” led to further questions regarding several existing SNOMED CT concepts which are now outdated in AAP including:

1. Juvenile periodontitis (which has generalized and localized subtypes)
2. Prepubertal periodontitis (which has generalized and localized subtypes)
3. Early-onset periodontitis (which has generalized and localized subtypes)
4. And possibly Rapidly progressive periodontitis

3.2.2.2 Retire |Refractory periodontitis (disorder)|

This concept has been retired from the AAP classification system and it was requested that it also be retired in SNOMED CT. 

3.3 Statement of problem as understood

3.3.1 Review the existing |Periodontitis (disorder)| hierarchy

During the time which has elapsed since the original project request, a number of new concepts have been added in the |Periodontitis (disorder)| hierarchy and ongoing addition of content in this hierarchy continues for January 2016. Additionally, new editorial policy guidance was introduced in August 2015 which impacts this content. The new and existing content will require review for consistency in the following areas:

3.3.1.1 Naming conventions and unambiguous Fully Specified Names (FSNs)

The |Periodontitis (disorder)| hierarchy contains some naming conventions which are new as of the July 2015 Release which will need to be evaluated in the context of existing naming conventions. In particular, use of “co-occurrent with” in concept FSNs and Descriptions is a recent development to SNOMED CT.

Patterns currently in use in the |Periodontitis (disorder)| hierarchy include:

1. Periodontitis associated with <X disorder> 
2. Periodontitis co-occurrent with < X disorder> (new pattern)
3. Periodontitis co-occurrent and due to <X disorder> (new pattern)
4. Periodontitis due to <X disorder> 
5. <X disorder> of peritonitis (disorder)

3.3.1.2 Descriptions

Descriptions will also require review for appropriate synonymy. For example, should “Periodontitis co-occurrent with <X disorder>” have the synonym “Periodontitis associated with < X disorder>”?

Example:

1. 710927004 |Periodontitis co-occurrent with cyclical neutropenia (disorder)|
   Synonym: Periodontitis associated with cyclical neutropenia
   
   
2. 703149000 |Periodontitis associated with cyclical neutropenia (disorder)| also exists as a separate concept.

3.3.1.3 Concept Model and Concept Definitions

The meaning of the prevalent patterns for the FSNs needs to be clearly understood so that the Concept Model for this content can be clarified and consistently applied. This is particularly true for the “Periodontitis co-occurrent with <X disorder> (disorder)” patterns discussed in Section 3.3.1.1 where new Editorial Guidance (released in August 2015) indicates, that for this pattern, both <Periodontitis> and <X disorder>  should be assigned as supertypes.

New guidance in the July 2015 Editorial Guide - Section 6.1.3.17.1 on Disorder combinations:

In this section, the guidance states that the “X co-occurrent with Y” pattern in an FSN implies “Simple co-occurrence” and that the default modeling pattern for this content is to:

Assign each participating disorder as a supertype (or ensure that each participating disorder is present in the ancestor tree following classification).

This guidance has significant implications for periodontal diseases being added to SNOMED CT.  For example, it means that periodontal diseases referred to in the AAP Classification System under Periodontitis as a Manifestation of Systemic Diseases, are actually being assigned an IS_A relationship to Periodontitis and an IS_A relationship to the systemic disease that they are a manifestation of.

Example: 709469005 |Periodontitis co-occurrent with Down syndrome (disorder)|

It is assumed that this concept was added to represent the disorder shown below in the AAP Classification System of Periodontal Diseases:

From: Armitage GC. Development of a Classification System for Periodontal Diseases and Conditions. Annals of Periodontology 1999 (4)

A review of the literature suggests that “Down syndrome-associated periodontitis” is referring to a periodontal condition that is present in a patient with Down’s syndrome. Under the new Editorial Guidance, 709469005 |Periodontitis co-occurrent with Down syndrome (disorder)| is modeled as a subtype of 41565005 |Periodontitis (disorder)| and of 41040004 |Complete trisomy 21 syndrome (disorder)| and has the following concept definition in the July 2015 Release:

This concept, which was represented in The AAP Classification as “Periodontitis associated with Down Syndrome”, is now actually a type of Down Syndrome in SNOMED CT with associated morphologic abnormalities that include not only inflammation but also trisomy.

This is problematic because in the AAP Classification System and in the literature, the primary disorder for the concept now represented in SCT as |Periodontitis co-occurrent with Down Syndrome (disorder)| is actually “Periodontitis”. While the IS_A relationship to |Periodontitis (disorder)| appears to be correct, the IS_A relationship to 41040004 |Complete trisomy 21 syndrome (disorder)| requires further review. With an IS_A relationship to |Periodontitis (disorder)| and an IS_A relationship to 41040004 |Complete trisomy 21 syndrome (disorder)|, the FSN for the concept actually means Periodontitis and |Complete trisomy 21 syndrome (disorder)|.

Other aspects of the Concept Model that will require clarification related to the naming patterns identified in Section 3.3.1.1 include use of the |Due to|, |Associated with| and |Has definitional manifestation| attributes.

3.3.1.4 Partitioning, Completeness and Outdated Content

Ideally, the partitioning of the |Periodontitis (disorder)| hierarchy would mirror the partitioning in the AAP Classification System for Periodontal Diseases. However, a more detailed analysis (offered in Section 3.4.3) illustrates that this objective may have limitations within the SNOMED CT Concept Model.

The hierarchy also requires review for whether there are missing subtypes of |Periodontitis (disorder)| as well as whether there are currently inappropriate subtypes. A detailed comparison between the American Academy of Periodontology Classification System for Periodontal Disease and the SNOMED CT |Periodontitis (disorder)| hierarchy is provided as a starting point for this exercise (Appendix B - Analysis of SNOMED CT Coverage of the American Academy of Periodontology Classification of Periodontal Disease.) This comparison will also address the specific requests raised in artf226141 to add “Aggressive periodontitis (disorder)” to replace several previous terms which exist in SNOMED CT and to retire |Refractory periodontitis (disorder)| which has been retired from the AAP Classification System.

3.4 Detailed analysis of reported problem, including background

3.4.1 Naming conventions and unambiguous Fully Specified Names (FSNs)

The Editorial Guide Section 4.5.2.1 “Terminology structure: coded meanings” states:

The central component of SNOMED CT must be coded meanings. Each code must have a single clear and unambiguous meaning.

The use of “co-occurrent with” in concept FSNs and descriptions represents a fairly recent change in SNOMED CT and a further review of these patterns is indicated to ensure that they are unambiguously conveying the meaning of the clinical content they intend to represent.

Some prevalent FSN patterns currently in use (with examples of existing concepts) include:

1. Periodontitis associated with <X disorder>
   Example: 703149000 |Periodontitis associated with cyclical neutropenia (disorder)|
2. Periodontitis co-occurrent with <X disorder> (new pattern)
   Example: 710927004 |Periodontitis co-occurrent with cyclical neutropenia (disorder)
3. Periodontitis co-occurrent and due to <X disorder> (new pattern)
   Example: 710096000 |Periodontitis co-occurrent and due to histiocytosis syndrome (disorder)|
4. Periodontitis due to <X disorder>
   Example: 709472003 |Periodontitis due to Papillon-Lefèvre syndrome (disorder)|
5. <X disorder> of peritonitis (disorder)
   Example: 235984009 |Abscess of suppurative peritonitis (disorder)|

In the July 2015 Release, 15 FSNs in the |Periodontitis (disorder)| hierarchy have “co-occurrent”.

As of August 2015, an additional 19 SIRS requests for “co-occurrent with” content in the Periodontal Dentistry domain are being added or are under consideration for the January 2016 Release.

Examples:

SIRS Request ID: 601538 - Retire 95212006|Pregnancy gingivitis (disorder)| and add Gingivitis co-occurrent with pregnancy

SIRS Request ID: 601537 - Retire 700240005|Gingivitis associated with menstrual cycle (disorder)| and add Gingivitis co-occurrent with menstrual cycle

A general review of the meaning of co-occurrence suggests that the meaning can differ depending on the definition used and the context in which it is used. A few common definitions include:

1. Co-occurrence - the fact of two things happening at the same time[2]
2. Co-occurrence - an event or situation that happens at the same time as or in connection with another[3]
3. Co-occurrence - the temporal property of two things happening at the same time; "the interval determining the coincidence gate is adjustable"[4]

Additionally, a review of the literature indicates that it can be difficult to clearly define what “co-occurrence” and related constructs mean in a clinical context. “Co-occurrence” is often used in conjunction with the term “comorbid”. Wikipedia addresses the issue of comorbidity and co-occurrence in a bit more detail than most other sources but the definitions still vary. [5]

In medicine, comorbidity is the presence of one or more additional disorders (or diseases) co-occurring with a primary disease or disorder; or the effect of such additional disorders or diseases. The additional disorder may also be a behavioral or mental disorder.

In medicine, the term "comorbid" can be either medical condition(s) existing simultaneously but independently with another condition; or it can indicate a related medical condition or conditions.  

      The term "comorbid" has three definitions:

1. 1.  to indicate a medical condition existing simultaneously but independently with another condition in a patient (this is the older and more "correct" definition)
   2.  to indicate a medical condition in a patient that causes, is caused by, or is otherwise related to another condition in the same patient (this is a newer, nonstandard definition and less well-accepted)[6]
   3.  to indicate two or more medical conditions existing simultaneously regardless of their causal relationship[7]

The most consistent aspect of most definitions/uses of “co-occurrence” appears to be a temporal association between two things. A significant question related to comorbidity in medicine is whether the comorbid conditions are temporally related but are otherwise independent of one another or whether the two conditions are somehow clinically related. The paper “Defining Comorbidity: Implications for Understanding Health and Health Services”[8] attempted to study the meaning of comorbidity and states,

Comorbidity is most often defined in relation to a specific index condition,[9] as in the seminal definition of Feinstein: “Any distinct additional entity that has existed or may occur during the clinical course of a patient who has the index disease under study.”[10] 

A key question when representing disorder combinations in SNOMED CT is whether one of the disorders is the primary disorder (or index condition). Therefore, the distinction between the use of “co-occurrence with” and “associated with” for SNOMED CT disorder combinations requires further review in the context of the disorders being represented.

Interestingly, prior to the newly added July 2015 Editorial Guidance (Section 6.1.3.17 Multisystem disorders), the only SNOMED CT editorial guidance that included the word “co-occurrence” pertained to the attribute |Associated with (attribute)|. This guidance persists in the July 2015 SNOMED CT^® Editorial Guide Section 6.1.2.3 on the |Associated with (attribute)| which states:

This attribute asserts an interaction between two concepts beyond simple co-occurrence in the patient. | ASSOCIATED WITH | represents a clinically relevant association between concepts without either asserting or excluding a causal or sequential relationship between the two.

This guidance implies that “simple co-occurrence” between two concepts is a more general phenomena than a “clinically relevant association” between two concepts and that “simple co-occurrence” would not be sufficient to warrant a concept definition that includes 47429007 |Associated with (attribute)|.

The new July 2015 Editorial Guidance on Disorder Combinations (Section 6.1.3.17.1) suggests that “simple co-occurrence” is used when two disorders co-occur temporally but a causal relationship between them cannot be asserted.

The guidance also states:

For simple co-occurrence of X and Y, construct an FSN of the form:

“X co-occurrent with Y”

Assign each participating disorder as a supertype (or ensure that each participating disorder is present in the ancestor tree following classification).

A potential problem with this guidance is that the notion that one of the two disorders is the primary disorder is completely lost and this may result in a shift in meaning for some disorder combinations.

The existing guidance as well as the new guidance will be relevant for developing recommendations related to FSNs with “co-occurrent” as well as for Descriptions and for Concept Definitions.

3.4.2 Descriptions

Descriptions for concepts in the |Periodontitis (disorder)| hierarchy will require review for appropriate synonymy.

As noted, the Editorial Guide (Section 6.1.2.3) states that “|Associated with| represents a clinically relevant association beyond simple co-occurrence”.  The new editorial guidance (Section 6.1.3.17.1) also states that “X co-occurrent with Y” means “simple concurrence”. On this basis, the synonym “Periodontitis associated with <X disorder>” is more specific than the FSN “Periodontitis co-occurrent with <disorder>” and should not be allowed per the July 2015 Editorial Guide Section 7.4.3 Narrower synonyms:

If a synonym is more specific than the FSN this is an error, since it does not have the same meaning. Concepts with synonyms more specific than the FSN are considered ambiguous, since they could have the general meaning of the FSN or the specific meaning of the erroneously attached synonym.

Example:

710927004 |Periodontitis co-occurrent with cyclical neutropenia (disorder)|

Synonym: Periodontitis associated with cyclical neutropenia

All but one of the 14 concepts with the pattern “Periodontitis co-occurrent with <disorder>” have a synonym of “Periodontitis associated with <disorder>”.

Additionally, one concept with “due to” in its FSN has a more general “associated with” synonym.

3.4.3 Concept Model and Concept Definitions

Clear understanding of, and consensus on, the meaning of FSN naming patterns is essential for content in the |Periodontitis (disorder)| hierarchy so that Concept Model guidance is clear and is applied consistently across concept definitions. As discussed in Section 3.3.1.3, the new editorial guidance for “X co-occurrent with Y” is that the default modeling pattern for this content is to: “Assign each participating disorder as a supertype (or ensure that each participating disorder is present in the ancestor tree following classification).”

Consistent with this guidance, the prevalent approach for modeling “Periodontitis co-occurrent with <X disorder >” includes an |IS_A| relationship to <Periodontitis> and an |IS_A| relationship to <X disorder>.

Example: (July 2015 release)

710926008 |Periodontitis co-occurrent with familial neutropenia (disorder)| has the parents shown:

If this concept is taken in the context of the AAP concept which it is intended to represent, the concept added in SNOMED CT as 710926008 |Periodontitis co-occurrent with familial neutropenia (disorder)| is classified in AAP under “Periodontitis as a Manifestation of Systemic Disease.” In AAP, this category is for “destructive periodontal disease that is a manifestation of certain systemic diseases”[11]. The concept in SNOMED should mirror the AAP meaning and be a subtype of |Periodontitis (disorder)| but not of the “Systemic Disease” that it is a manifestation of.

“Periodontitis co-occurrent with familial neutropenia” represents a shift in meaning from “Periodontitis as a manifestation of familial neutropenia”. Per the meaning conveyed for this concept in the AAP Classification, the IS_A relationship to |Periodontitis (disorder)| is correct but the IS_A relationship to |Familial neutropenia (disorder)| is not.

3.4.3.1 Concept Model for disorders that include combinations of “Periodontitis” and “<X disorder>”  

The modeling of Periodontitis concepts that include a reference to an additional disorder (<X disorder>) should be determined by the meaning of the concept. A discussion of some of the critical patterns in the periodontitis hierarchy and the editorial guidance related to naming and modeling these patterns is presented here.

1.) Periodontitis co-occurrent with <X disorder> (meaning “simple co-occurrence” - where the co-occurrence represents only temporal overlap between the two disorders and no causation is implied and neither disorder is the primary disorder)

Following new guidance in the July 2015 Editorial Guide:

Periodontitis co-occurrent with <X disorder> would be modeled as:

Sufficiently Defined

=== 41565005 |Periodontitis (disorder)| + |<X> (disorder)|

And would have a concept definition that is equivalent to:

Periodontitis AND <X disorder> which would also be modeled as:

Sufficiently Defined

=== 41565005 |Periodontitis (disorder)| + |<X> (disorder)|

Periodontitis co-occurrent with <X disorder> is a new pattern in SNOMED as of the July 2015 Release. The July 2015 Editorial Guide provides guidance for this pattern (Section 6.1.3.17.1 on Disorder combinations) which suggests that “simple co-occurrence” is used when two disorders co-occur (temporally) but no causal relationship between them is asserted.

Section 6.1.3.17.1 on Disorder combinations also states:

While the editorial guidance does not explicitly state that assigning each disorder as a supertype allows the concept to be Sufficiently Defined, it appears that the majority of this content is being given a definition status of Sufficiently Defined on this basis.

As modeled, from a clinical standpoint, the meaning of Periodontitis co-occurrent with <X disorder> could be interpreted as “<X disorder>” receiving equal billing to “Periodontitis” where neither disorder is the primary disorder. Thus, 710926008 |Periodontitis co-occurrent with familial neutropenia (disorder)| would be equivalent in meaning to |Familial neutropenia co-occurrent with periodontitis (disorder)|. While this interpretation might be appropriate for a concept like 262688009 |Cortex laceration and contusion (disorder)|, it is not necessarily appropriate for 710926008 |Periodontitis co-occurrent with familial neutropenia (disorder)|.

For a pattern like Periodontitis co-occurrent with <X disorder>, it is not clear why two disorders that simply co-occur, without any assertion of a clinical association between the two disorders, would warrant the creation of a new SCT concept that represents the disorder combination as a single disorder. Additionally, the AAP Classification System does indicate a clinical association between periodontitis and the disorders that are combined with periodontitis. Therefore, this pattern is not necessarily correct for representing the AAP disorders because it represents a shift in meaning.

Finally, guidance in Section 6.1.3.17.1 of the Editorial Guide - on Disorder Combinations states:

Many clinically useful disorder labels refer to disorder combinations. Current guidance on how to approach combinations attempts to achieve consistency by simplifying the available options for both modelling and FSN construction. Identifying and documenting clinically significant disorder combinations is generally motivated by a desire to represent one of the following associations:

Simple co-occurrence

Causation (1: where the causal disorder is no longer necessarily present)

Causation (2: where the causal disorder is necessarily still present)

Temporal sequencing (without necessary implication of causation)

The concern with the above guidance is that it states that documenting “clinically significant disorder combinations” is motivated by a desire to represent one of the four associations shown above. However, the first option of “simple co-occurrence” does not actually represent the fact that the association between the two disorders is clinically significant.

If the intent is to represent a clinically significant association between two temporally co-occurring disorders that stops short of causation, then Periodontitis co-occurrent and associated with <X disorder> would better represent this meaning. This would be a subtype of Periodontitis associated with <X disorder> and of Periodontitis co-occurrent with <X disorder> (if there was a clinical indication to create these patterns.)

Even if the pattern Periodontitis co-occurrent and associated with <X disorder> was introduced, it is still suggested that Periodontitis should be the primary disorder which is impacted by <X disorder> in a clinically significant way that falls short of definite causation. Therefore, the following model would be suggested for this pattern:

Periodontitis co-occurrent and associated with <X disorder> (where <X disorder> is present simultaneously with and has clinical significance for Periodontitis, the primary disorder) would be suggested to be modeled as:

Primitive

<<< 41565005 |Periodontitis (disorder)|:

        47429007 |Associated with (attribute)| = |<X> (disorder)|

The above pattern is not represented in the new model for “Disorder combinations” and it also cannot be Sufficiently Defined using the Concept Model for the |Associated with (attribute)| because the “co-occurrence” (present at the same time) aspect cannot be fully captured using |Associated with (attribute)| and an IS_A relationship to <X disorder> would be incorrect.

(Note: The addition of a new attribute in the |Associated with| role hierarchy (e.g., a “Co-occurrent with” attribute) could be considered as a means to represent a co-occurrent disorder associated with Periodontitis. The “co-occurrent attribute” could be used to represent a clinically relevant association to a disorder that neither asserts nor excludes a causal relationship, but instead asserts that the co-occurrent disorder is necessarily present at the same time as the primary disorder. This would be similar to 255234002 |After (attribute)| which is used to represent a clinically relevant association to a disorder that, per Editorial guidance, “neither asserts nor excludes a causal relationship, it instead emphasizes a sequence of events.”)

2.) Periodontitis associated with <X disorder> (In the past, this pattern was generally used when there was a clinically relevant association between two disorders that neither asserted nor excluded a causal relationship, and <X disorder> may or may not be present simultaneously with Periodontitis, the primary disorder)

Sufficiently Defined

=== 41565005 |Periodontitis (disorder)|:

        47429007 |Associated with (attribute)| = |<X> (disorder)|

The new July 2015 Editorial Guidance for Disorder combinations (6.1.3.17.1) does not appear to include an option for the meaning previously conveyed using |Associated with|: a clinically relevant association between two disorders beyond simple co-occurrence in the patient without either asserting or excluding a causal or sequential relationship between the two.

In the new model, Causation is either asserted or excluded. There is no middle ground.

However, the option to represent “associated with” still persists in the July 2015 SNOMED CT® Editorial Guide Section 6.1.2.3 on |Associated with (attribute)| which states:

This attribute asserts an interaction between two concepts beyond simple co-occurrence in the patient. | ASSOCIATED WITH | represents a clinically relevant association between concepts without either asserting or excluding a causal or sequential relationship between the two.

On researching the meaning of the AAP concepts classified under “Periodontitis as a Manifestation of Systemic disease”, the pattern Periodontitis associated with <X disorder> seems to more accurately capture the intended AAP meaning than Periodontitis co-occurrent with <X disorder>.

3.) Periodontitis due to <X disorder> (where Periodontitis is the primary disorder caused by <X disorder>, and <X disorder> may or may not be still be present)

This is consistent with the Causation 1 pattern in the new model. According to both the new and existing Concept Model guidance, Periodontitis due to <X disorder> would be modeled: 

Periodontitis due to <X disorder>

Sufficiently Defined

=== 41565005 |Periodontitis (disorder)|:

                  42752001 |Due to (attribute)| = |<X> (disorder)|

The new guidance provided for this pattern mirrors existing guidance (Editorial Guide Section 6.1.2.5) for |Due to (attribute)|:

This attribute is used to relate a | Clinical finding | directly to its cause. If a clinical finding merely predisposes to or worsens another disorder, rather than causing it directly, then the more general attribute | ASSOCIATED WITH | is used instead.

Of note, it may be challenging to assess existing or newly submitted content that uses “associated with” and determine when the FSN should include causation (e.g., |Due to (attribute)|).

Example:

416729007 |Neutropenia associated with acquired immunodeficiency syndrome (disorder)|

The new editorial guidance provides this legacy concept as an example of a concept that would meet the new criteria for the Causation 1 pattern (e.g., the meaning is |Neutropenia due to acquired immunodeficiency syndrome (disorder)|.)

It is not necessarily correct that this concept can be interpreted as “Neutropenia due to AIDS”. As the abstract below demonstrates, neutropenia associated with AIDS may be associated with antiretroviral medication. Thus, the safer interpretation is to keep the “associated with” relationship which asserts that there is a clinical association between the patient’s neutropenia and the fact that the patient has AIDS but does not assert the absolute cause of the neutropenia. Changing the existing FSN would be a shift in meaning. Of note, the primary disorder for this concept is Neutropenia. This is not a kind of AIDS and does not have an IS_A relationship to AIDS.

4.) Periodontitis co-occurrent and due to <X disorder> (Periodontitis due to <X disorder> AND <X disorder> is necessarily still present)

This is consistent with the Causation (2) pattern in the new model and should be modeled as:

Periodontitis co-occurrent and due to <X disorder>

Sufficiently defined

=== 41565005 |Periodontitis (disorder)| + |<X> (disorder)|:

         42752001 |Due to (attribute)| = |<X> (disorder)|

New editorial guidance on Causation (2) pattern:

Interestingly, this guidance mentions a “causal disorder” which would seem to imply that one of the two disorders is the “caused disorder” (or the primary disorder). This was the case for Causation pattern 1 (the “X due to Y” pattern) which had a caused disorder (X) and a causal disorder (Y) and guidance was to only assign the caused disorder (X) as a parent. However for the “X co-occurrent and due to Y” pattern, guidance is to assign both disorders as a parent. For the same reasons cited for the other “co-occurrent with” patterns, it is suggested that assigning the causal disorder (Y) as a parent concept for “X co-occurrent and due to Y” is incorrect.

Modeled using current guidance:

Periodontitis co-occurrent and due to <X disorder> would be modeled as:

Sufficiently defined

=== 41565005 |Periodontitis (disorder)| + |<X> (disorder)|:

         42752001 |Due to (attribute)| = |<X> (disorder)|

That means it would be modeled the same way (same meaning) as:

<X disorder> co-occurrent with Periodontitis, due to <X disorder>.

<X disorder> AND Periodontitis, due to <X disorder>

or

Periodontitis AND <X disorder>, due to <X disorder>

Also, the concept definition guidance does not identify which parent disorder should be grouped with the |Due to| attribute for classification:

41565005 |Periodontitis (disorder)|:

         42752001 |Due to (attribute)| = |<X> (disorder)|

OR

|<X> (disorder)|:

         42752001 |Due to (attribute)| = |<X> (disorder)|

Clearly <X disorder> due to <X disorder> would not make sense which further validates the idea that the primary disorder is Periodontitis and that Periodontitis is an appropriate supertype but <X disorder> is not.

5.) The pattern “X disorder after Y disorder” does not exist in the |Periodontitis (disorder)| hierarchy as of the July 2015 Release. Therefore, this pattern is not assessed in this document.

Summary

• A number of issues have been raised related to new guidance on Disorder Combinations.
• The patterns Periodontitis co-occurrent with <X disorder> and Periodontitis co-occurrent and due to <X disorder> represent a shift in meaning from the original AAP content.
• Some problem patterns identified in this section should not be fully defined.
• Changes to existing FSNs may represent a shift in meaning.

3.4.4 Partitioning, Completeness and Outdated Content  

3.4.4.1 Partitioning

Partitioning of the |Periodontitis (disorder)| hierarchy should ideally mirror the partitioning in the AAP Classification System for Periodontal Diseases. This Classification System evolved from a classification system that was first developed in 1989 at the World Workshop in Clinical Periodontics and was later simplified at the 1st European Workshop in Periodontology and again at the 1996 World Workshop in Periodontics.

Mirroring the AAP Classification System is not straightforward for several reasons which include but are not limited to:

1. Complexities and nuances of some AAP terms which prohibit them from being sufficiently defined with the SNOMED CT Content Model. This particularly impacts some of the top-level terms which, as primitives, will not subsume their intended subtypes from the AAP Classification System. Adding these “groupers” as primitive and asserting their AAP subtypes manually also has limitations (outside of the scope of this document but related to the impact of intermediate primitive parents on the concept definitions of their stated subtypes.)
2. The body structure hierarchy, which provides the values for the 363698007 |Finding site (attribute)| in the |Periodontal disease (disorder)| hierarchy, does not currently have a structure that fully represents the Periodontium and will subsume the body structures impacted by Periodontal disease.

3.4.4.2 Completeness and Outdated Content

The hierarchy also requires review for whether there are missing subtypes of |Periodontitis (disorder)| as well as whether there are currently inappropriate subtypes.

A detailed comparison between the American Academy of Periodontology Classification System for Periodontal Disease and the SNOMED CT |Periodontitis (disorder)| hierarchy is provided as a starting point for this exercise (Appendix B - Analysis of SNOMED CT Coverage of the American Academy of Periodontology Classification of Periodontal Disease) This comparison will also address the specific requests raised in artf226141 to add “Aggressive periodontitis (disorder)” to replace several previous terms which exist in SNOMED CT and, to retire |Refractory periodontitis (disorder)| which has been retired from the AAP Classification System

3.5 Subsidiary and interrelated problems

• “Artifact artf233786 : Alignment of Existing Content to "X with Y" and "X due to Y" patterns from "X associated with Y". Decisions this for this project may influence the “X co-occurrent with Y” concepts in the Periodontitis hierarchy where many of the concepts have “X associated with Y” synonyms.

• “Artifact artf235767 : Revision of existing content for ‘caused by’ pattern – part 1” (posted September 7, 2015). This appears to the first part of a multistep project to implement some of the new naming patterns also described in this document.

• Artifact artf6206 : Anatomy and Artifact artf231206 : Dental anatomy revisions” is related because changes to periodontal structures in the body structure hierarchy may be required to accurately model and define concepts in the 2556008 |Periodontal disease (disorder)| hierarchy.

• “Artifact artf6251 : HAS DEFINITIONAL MANIFESTATION” . This project is currently in the Elaboration Phase and the likely outcome for this project is that the Has Definitional Manifestation attribute will be retired. This attribute is used in some concept definitions in the |Periodontal disease (disorder)| hierarchy.

4 Risks / Benefits

This content is particularly relevant because of the prevalence of Periodontal disease (47% of Americans over 30 per CDC data[12]) and because a number of concepts impacted by this project are also in the 2015 SNOMED CT Core subset.

• 2556008 |Periodontal disease (disorder)|
• 41565005 |Periodontitis (disorder)|
• 21638000 |Acute periodontitis (disorder)|
• 5689008 |Chronic periodontitis (disorder)|
• 66383009 |Gingivitis (disorder)|
• 31642005 |Acute gingivitis (disorder)|
• 72621003 |Chronic gingivitis (disorder)|
• 20607006 |Gingivostomatitis (disorder)|

4.1 Risks of not addressing the problem

The risks of not addressing this issue include:

1. The |Periodontitis (disorder)| hierarchy may not be fit for purpose if:
   1. FSNs are ambiguous or do not accurately capture the meaning of the content they intend to represent
   2. Concept definitions are inconsistent
   3. Content is incomplete or outdated
      
      
2. The recently introduced “X co-occurrent with Y (disorder)” pattern has broader implications for SNOMED CT. This pattern is also being introduced in other hierarchies and clarifying the meaning and model of this pattern early in its introduction may avert the need to remodel (or possibly retire) this content in the future and may prevent unnecessary change for users and developers dependent on this content.

4.2 Risks of addressing the problem

The “X co-occurrent with Y (disorder)” pattern” which was recently introduced in the |Periodontitis (disorder)| hierarchy, is also being introduced in other hierarchies. Therefore, decisions related to the meaning and concept model for this content may require that content in other hierarchies is also remodeled (or possibly retired).

There are no significant additional risks to addressing the |Periodontitis (disorder)| hierarchy. Content in other disorder hierarchies should otherwise not be too significantly impacted by changes to this content. If a change is made to the body structure hierarchy, the impact of that change to other content modeled with those structures (e.g., procedures) needs to be assessed and monitored.

5 Requirements: criteria for success and completion

5.1 Criteria for success/completion

5.1.1 Consistent meaning, modeling and editorial policy

Address issues (outlined in this document) in the current naming and modeling of content in the |Periodontal disease (disorder)| and |Periodontitis (disorder)| hierarchies to ensure that naming conventions and the Concept Model for this domain represent this content unambiguously to ensure its usefulness for users.

5.1.2 Content completeness

A |Periodontitis (disorder)| hierarchy which is complete and includes FSNs and concept definitions which represent, as unambiguously as possible, the American Academy of Periodontology (AAP) 1999 Classification of Periodontal Diseases.

5.2 Strategic and/or specific operational use cases

5.2.1 1 Clear editorial policy development for this domain

Provide feedback on new Editorial Policy for naming conventions and the Concept Model for this domain as well as other domains that may be affected by similar issues (e.g., meaning and modeling of the “X co-occurrent with Y” pattern) to ensure that editorial policy preserves the integrity of the content. The |Periodontitis (disorder)| hierarchy is a good hierarchy for testing of policy because of its relatively limited scope.

5.2.1.1 Fit with Strategy

A sound and valued primary product [SNOMED CT] – Ensuring that Editorial Policy for this domain  allows for the creation of unambiguous content will be critical to achieving a quality product particularly (because of it high usage in the EHR).

5.2.2 |Periodontitis (disorder)| hierarchy consistent with AAP (IWCP) Classification

Work with Dentistry and anatomy redesign project SMEs to evaluate the recommended changes to the body structure hierarchy which may be required to more accurately represent this content.

Edit content in the |Periodontitis (disorder)| hierarchy and some |Periodontal disease (disorder) content (as outlined in this project) to retire outdated terms, add new terms and ensure that FSNs are unambiguous. A number of concepts which are currently sufficiently defined should be made primitive and a number of new requests would likely need to be added as primitive.

5.2.2.1 Fit with Strategy

Make it easier to use SNOMED CT for priority use cases – Based on prevalence and usage data, this content is likely to be heavily used in an EHR. The amount of content submitted in the dental and periodontal domain in the past year and the activity of the Dentistry Specialty Interest Group (Dental SIG) indicate an urgent need for this content. Improving this domain will facilitate semantic representation in this area and improve the accurate collection and sharing of periodontal health information.

6 Solution Development

6.1 Initial Design

6.1.1 Outline of initial design

6.1.1.1 Naming conventions and ambiguous Fully Specified Names (FSNs)

Proper review of the 2556008 |Periodontal disease (disorder)| hierarchy requires correct interpretation of editorial guidance related to the newly adopted naming patterns for “Disorders combinations” which contain “co-occurrent with <X disorder>”. The new guidance should be applied where it can appropriately capture the meaning of the AAP periodontal content in SNOMED CT. However, the patterns and guidance need to be carefully reviewed to ensure that they do not alter the meaning of the content or lead to ambiguity.

Concepts with the “Periodontitis co-occurrent with <X disorder>” pattern require review on the basis that their FSNs may not accurately capture the meaning of the AAP content, and that the synonym “Periodontitis associated with <X disorder>” is more specific in meaning than the FSN and therefore should not be used.

Review of the AAP definitions for periodontal terms that would be considered to be “Disorder combinations”, indicates that the periodontitis is the index condition or primary disorder in these combinations.

Resolution of this issue is important in light of incoming requests such as SIRS Request Id: 601537 to:

Retire 700240005 |Gingivitis associated with menstrual cycle (disorder)| and add Gingivitis co-occurrent with menstrual cycle.

Given that “associated with” synonyms are being added to many of the new “co-occurrent with” concepts, SIRS Request Id: 601537 could be interpreted as a request to retire one concept for a new concept that might be considered to be its duplicate.

As represented in the July 2015 Release, the existing concept 700240005 |Gingivitis associated with menstrual cycle (disorder)| appears to capture the intended meaning of the AAP Classification:

In the AAP Classification, “menstrual cycle-associated gingivitis” is classified under “Gingival diseases modi?ed by systemic factors”.

Menstrual cycle-associated gingivitis has the AAP definition (1): Pronounced inflammatory response of gingiva to plaque and hormones immediately prior to ovulation.

The AAP definition implies more than mere co-occurrence. At a minimum, it implies that the gingivitis is associated with the hormones of ovulation (a clinically relevant association).

Based on the AAP definition, the existing FSN 700240005 |Gingivitis associated with menstrual cycle (disorder)| is closer to the intended AAP meaning than the new request for “Gingivitis co-occurrent with menstrual cycle”. If subject matter experts from the AAP suggested that “due to” is the more appropriately represents the association, then that would warrant a new concept.

Solutions

1. Review all new and existing FSNs in the |Periodontitis (disorder)| hierarchy to ensure that the content accurately captures the AAP meaning. Some subtypes of 18718003 |Gingival disease (disorder)| and 2556008 |Periodontal disease (disorder)| (which are also in the AAP Classification) will also require review.
2. The patterns “Periodontitis co-occurrent with <X disorder>” and “Periodontitis co-occurrent with and due to <X disorder>” appear to represent a shift in meaning from the AAP representation of these disorder combinations and are not advised for the majority of this content if the intent is to represent the AAP meaning.
3. If retained, the two patterns above do not appear to meet criteria to be fully defined.
4. Further testing is recommended before new guidance in the editorial Guide Section 6.1.3.17.1 on Disorder combinations is implemented on a wider scale.
5. If two disorders simply co-occur, without any assertion of clinical relevance between the disorders, it is not clear that the creation of the combination of the two as a new disorder concept in SCT is warranted.
6. Use caution in retiring existing content that may already accurately represent AAP content.
7. Changes to existing FSNs should meet editorial criteria for minor FSNs changes. Some changes noted in the daily build (but not yet released), presumably related to the new guidance for Disorder combinations, represent a shift in meaning and should not be released.

Example: 103681000119108 |Restrictive strabismus due to Graves disease (disorder)|:

July 2015:

September 2015 daily build (not yet released): This represents a shift in meaning from the original FSN and should not be allowed.

Similar FSN changes in the Periodontitis hierarchy should not be permitted.

6.1.1.2 Descriptions

Solutions proposed for descriptions can be separated into solutions for concepts with the “X co-occurrent with Y” pattern and solutions for other specific concepts.

6.1.1.2..1         Descriptions for concepts with the “co-occurrent with” patterns for “disorder combinations”

Solutions

1. If the “Periodontitis co-occurrent with <X disorder>” pattern is retained, the synonym “Periodontitis associated with <X disorder>” is more specific than the FSN “Periodontitis co-occurrent with < X disorder>” and should not be allowed (based on Editorial Guidance already cited in Section 3.4.1.2 of this document).
2. The synonym “Periodontitis associated with <X disorder>” is more general than the FSN “Periodontitis co-occurrent with and due to <X disorder>” and should also be discouraged particularly in light of other concepts which might use the same <Periodontitis associated with <X disorder>” term as an FSN or Description.

6.1.1.2..2         Other Descriptions on specific concepts in the Periodontitis (disorder) hierarchy

For the July 2015 Release content, additional Descriptions for specific concepts in the |Periodontitis (disorder)| hierarchy (other than concepts with “co-occurrent” in their FSNs) were reviewed.

Solutions

Descriptions which should be reviewed with input from the Dentistry SIG (Q for SME) include:

1. “Chronic pericementitis”  and “Acute pericementitis” as Descriptions for:

• • 5689008 |Chronic periodontitis (disorder)|
  • 21638000 |Acute periodontitis (disorder)|

Based on Dorland’s Medical dictionary definition of Pericementitis: Inflammation of the    Pericementum (periodontal ligament), the descriptions with “pericementitis” are too specific for these two concepts and align more closely with the FMA definition of periodontium (as being the periodontal ligament). They could be added as separate concepts.

2. “Paradental cyst”, “Mandibular infected buccal cyst” and  Residual radicular cyst as Descriptions for 89988002 |Radicular cyst (disorder)|

• • “Paradental cyst” and  “Mandibular infected buccal cyst”

Per a 2011 article in Head and Neck Pathology[13], “Paradental cyst” and “Mandibular infected buccal cyst” appear to represent a separate entity from Radicular cyst and should be retired and added as a separate concept - Paradental cyst (disorder) with Synonyms: Mandibular infected buccal cyst and Mandibular inflammatory buccal cyst.

• • Residual radicular cyst

89988002 |Radicular cyst (disorder)| has a subtype 109608003 |Residual cyst (disorder)|. This implies that this concept has the same meaning as the synonym Residual radicular cyst on its parent 89988002 |Radicular cyst (disorder)|. If SMEs confirm this is a distinct concept, then the synonym is too narrow for 89988002 |Radicular cyst (disorder)| and the Description should be retired. If not, then 109608003 |Residual cyst (disorder)| should be retired as a duplicate for 89988002 |Radicular cyst (disorder)|.

6.1.1.3 Concept Definitions

In addition to resolution of issues related to naming and modeling the “co-occurrent with” pattern, additional issues with the concept definitions for the |Periodontitis (disorder)| hierarchy require resolution related to the meaning of Periodontitis and Periodontium.

Meaning and Modeling of Periodontitis and Periodontium

6.1.1.3..1         Meaning of Periodontitis and Periodontium

The meaning of 41565005 |Periodontitis (disorder)|, 2556008 |Periodontal disease (disorder)| and Periodontium determine their appropriate SNOMED CT concept definitions.

American Academy of Periodontology Definitions (1):

Periodontal disease: Those pathologic processes affecting the periodontium; most often gingivitis and periodontitis.

Periodontitis: Inflammation of the supporting tissues of the teeth. Usually a progressively destructive change leading to loss of bone and periodontal ligament. An extension of inflammation from gingiva into the adjacent bone and ligament.

Periodontium: The tissues that invest and support the teeth including:

• gingiva
• alveolar mucosa
• cementum
• periodontal ligament
• alveolar and supporting bone

Foundational Model of Anatomy (FMA) Definition:

Periodontium: Skeletal ligament (organ) that connects a tooth to the maxilla or mandible. (has_exact_synonym: Periodontal ligament; Periodontal membrane) http://purl.obolibrary.org/obo/FMA_56665

The FMA definition of Periodontium is more restrictive than the AAP definition of Periodontium. Ideally, if SNOMED CT intends to represent AAP terminology, the AAP definitions should be followed. The modeling and meaning of |Periodontitis (disorder)| and 2556008 |Periodontal disease (disorder)| are very dependent on the meaning of “Periodontium” and the modeling of the five body structures included in the AAP definition of Periodontium:

• gingiva: (113279002 |Gingival structure (body structure)|)
• alveolar mucosa: (~5560003 |Alveolar ridge mucous membrane structure (body structure)|)
• cementum: (80541002|Cementum structure (body structure)|)
• periodontal ligament: (245775004 |Periodontal ligament (body structure)|)
• alveolar and supporting bone: (~129143008 |Structure of alveolar process (body structure)|)

Additional body structures (to the 5 shown above) may be required to represent these 5 structures that define the periodontium (will require input from the anatomy experts).

Unless the SNOMED CT concept definitions for Periodontal diseases include anatomical structures consistent with the AAP definitions of Periodontitis and Periodontium, the hierarchy and meaning will most likely not align with the AAP meaning.

Additionally, although periodontal diseases appear to include disorders of the periodontium (e.g., gingivitis and periodontitis), Dentistry SIG input (Q for SME) is required to determine whether 66383009 |Gingivitis (disorder)| should be a subtype of 41565005 |Periodontitis (disorder)|. In particular, does “Gingivitis” mean inflammation that is necessarily confined to the gingiva and does “Periodontitis” mean inflammation that includes the gingiva but necessarily also involves additional supporting tissues? In this case, 66383009 |Gingivitis (disorder)| would not be a subtype of 41565005 |Periodontitis (disorder)| and both concepts would likely need to be Primitive on the basis that SNOMED CT concept definitions in the Clinical Finding hierarchy cannot represent a disorder that includes  <X structure> as a finding site but specifically excludes <X₁ structure> as a finding site.

6.1.1.3..2         Concept Model for |Periodontal disease (disorder)| and |Periodontitis (disorder)|

In the July 2015 Release, 41565005 |Periodontitis (disorder)| and 2556008 |Periodontal disease (disorder)| are Sufficiently Defined with 363698007 |Finding site (attribute)| = 8711009 |Periodontal tissues structure (body structure)|. 

8711009 |Periodontal tissues structure (body structure)| does not adequately represent Periodontium as defined by the AAP because it does not subsume:

• 113279002 |Gingival structure (body structure)|
• 245775004 |Periodontal ligament (body structure)|
• 80541002 |Cementum structure (body structure)|
• 129143008 |Structure of alveolar process (body structure)|
• 5560003 |Alveolar ridge mucous membrane structure (body structure)|

Thus, 41565005 |Periodontitis (disorder)| and 2556008 |Periodontal disease (disorder)| should not be Sufficiently Defined because their concept definitions do not adequately represent their meaning (as described in Section 6.1.1.3..1). Although the AAP classification of Periodontal Diseases includes Gingival diseases, 2556008 |Periodontal disease (disorder)| as modeled with 363698007 |Finding site (attribute)| = 8711009 |Periodontal tissues structure (body structure)| will not subsume disorders of the gingiva because in the |Body structure (body structure)| hierarchy, 113279002 |Gingival structure (body structure)| is not a subtype of 8711009 |Periodontal tissues structure (body structure)|.

54308001 |Structure of gum and supporting structure of tooth (body structure)| might be better than 8711009 |Periodontal tissues structure (body structure)| for defining 41565005 |Periodontitis (disorder)| and 2556008 |Periodontal disease (disorder)|. However, |Structure of gum and supporting structure of tooth (body structure)| also does not include all structures of the periodontium.

Subtypes of 54308001 |Structure of gum and supporting structure of tooth (body structure)| include:

• 8711009 |Periodontal tissues structure (body structure)|
• 113279002 |Gingival structure (body structure)|
• 245775004 |Periodontal ligament (body structure)|

But NOT:

• 80541002 |Cementum structure (body structure)|
• 129143008 |Structure of alveolar process (body structure)|
• 5560003 |Alveolar ridge mucous membrane structure (body structure)|

Solutions:

1. 2556008 |Periodontal disease (disorder)| should have the same meaning as the AAP definition for Periodontal disease.

2. Coordination between SMEs in the Dentistry SIG and the Anatomy Redesign Project (Artifact artf6206) will be required to review whether a new body structure can be added to represent the Periodontium or whether Periodontium is an appropriate additional synonym for 54308001 |Structure of gum and supporting structure of tooth (body structure)| and whether the following concepts are appropriate to add as its subtypes:

• • 80541002 |Cementum structure (body structure)|
  • 129143008 |Structure of alveolar process (body structure)|
  • 5560003 |Alveolar ridge mucous membrane structure (body structure)|

3. A Body structure hierarchy that appropriately represents the Periodontium would allow 2556008 |Periodontal disease (disorder)| to be Sufficiently Defined so that it subsumes 18718003 |Gingival disease (disorder)| and other disorders that are consistent with the AAP definition for Periodontal disease. (Dentistry SIG input would be required to confirm this outcome is desired.)

4. Regardless of whether the suggested changes can be made in the body structure hierarchy, 54308001 |Structure of gum and supporting structure of tooth (body structure) appears to be a more appropriate value than 8711009 |Periodontal tissues structure (body structure)| for the current modeling of 2556008 |Periodontal disease (disorder)| and 41565005 |Periodontitis (disorder)|.

5. Based on AAP definitions of Periodontal disease and Periodontium, 266418006 |Gingival and periodontal disease (disorder)| is a duplicate for 2556008 |Periodontal disease (disorder)| and one of the two concepts should be retired as a duplicate. If Dental input (Q for SME) confirms this, then synonyms for the remaining concept should correctly capture its meaning. Currently, 2556008 |Periodontal disease (disorder)| has the synonym “Disease of supporting structures of teeth”. This may be too restrictive and may need to be changed to Disease of gingiva (gum) and supporting structures of teeth (or another definition suggested by the Dental SIG or literature review).

6. If an anatomical structure that represents the Periodontium is identified, Dental input (Q for SME) is required to ascertain whether 41565005 |Periodontitis (disorder)| can be fully defined using that structure. This will depend on SME input as to whether 66383009 |Gingivitis (disorder)| is an allowed a subtype of 41565005 |Periodontitis (disorder)| (see discussion Section 6.1.1.3..1). If not, |Gingivitis (disorder)| and |Periodontitis (disorder)| may need to be primitive (and would become intermediate primitives). In that case, their previously classified subtypes would require stated IS_A relationships to and |Gingivitis (disorder)| and |Periodontitis (disorder)|.

7. In the AAP classification for this content, Peritonitis appears to be the primary disorder. Thus, the AAP meaning for this content would be better represented by concept definitions which represent the disorder combinations as a subtype of |Periodontitis (disorder)| but NOT as a subtype of <X (disorder)>.

8. The patterns “Periodontitis co-occurrent with <X disorder>” and “Periodontitis co-occurrent with and due to <X disorder>” appear to represent a shift in meaning from the AAP representation of these disorder combinations and are not advised for the majority of this content if the intent is to represent the AAP meaning. Although the “Periodontitis co-occurrent with <X disorder>” pattern avoids stating a direct causal relationship between Periodontitis and <X disease>, the pattern “Periodontitis associated with <X disorder>” also avoids stating a direct causal relationship while better representing the true AAP meaning. If retained, the two “co-occurrent” patterns above do not appear to meet criteria to be fully defined.

9. Further testing is recommended before new guidance in the editorial Guide Section 6.1.3.17.1 on Disorder combinations is implemented on a wider scale.

10. If two disorders simply co-occur, without any assertion of clinical relevance between the disorders, it is not clear that the creation of the combination of the two as a new disorder concept in SCT is warranted.

11. Artf6251 project suggests that 363705008 |Has definitional manifestation (attribute)| which is used in some concept definitions in the |Periodontal disease (disorder)| hierarchy does not meet URU criteria and advocates for “removing the Has definitional manifestation attribute from approved use”. Until that time, it is suggested to change the definition status of Sufficiently Defined content in the |Periodontal disease (disorder)| hierarchy that uses this attribute to Primitive (e.g., 710927004 |Periodontitis co-occurrent with cyclical neutropenia (disorder)|).

6.1.1.4 Partitioning, Completeness and Outdated Content

Partitioning and Completeness

The AAP Classification System for Periodontal Diseases is a good starting model for partitioning of the 41565005 |Periodontitis (disorder)| (and 2556008 |Periodontal disease (disorder)| hierarchies) in SNOMED CT. A comparison between the American Academy of Periodontology Classification System for Periodontal Disease and the SNOMED CT |Periodontitis (disorder)| hierarchy| also serves as a reasonable starting point for an initial assessment of completeness.

Solution

1. Where possible, mirroring the AAP Classification System should be the objective while recognizing the may not be entirely possible for several reasons which include but are not limited to:
   1. Complexities and nuances of some AAP terms which prohibit them from being sufficiently defined with the SNOMED CT Content Model. This particularly impacts some of the top-level terms which, as primitives, will not subsume their intended subtypes from the AAP Classification System. Adding these “groupers” as primitive and asserting their AAP subtypes manually also has limitations (outside of the scope of this document but related to the impact of intermediate primitive parents on the concept definitions of their stated subtypes.)
   2. The body structure hierarchy, which provides the values for the 363698007 |Finding site (attribute)| in the |Periodontal disease (disorder)| hierarchy, does not currently have a structure that fully represents the Periodontium and will subsume the body structures impacted by Periodontal disease.

2. A fairly in depth assessment of the SNOMED CT representation of the full American Academy of Periodontology Classification of Periodontal Disease (shown below) is provided in Appendix B - Analysis of SNOMED CT Coverage of the American Academy of Periodontology Classification of Periodontal Disease.

From: Armitage GC. Development of a Classification System for Periodontal Diseases and Conditions. Annals of Periodontology 1999

Outdated Content

The artf226141 includes a few specific requests related to adding “Aggressive periodontitis (disorder)” to replace several previous terms which exist in SNOMED CT and also to retire |Refractory periodontitis (disorder)| which has been retired from the AAP Classification System.

At the 1999 International Workshop for a Classi?cation of Periodontal Diseases, it was decided to discard classi?cation terminologies that were age-dependent or required knowledge of rates of progression. Therefore, the highly destructive forms of periodontitis formerly considered under the umbrella of “Early-Onset Periodontitis” were renamed using the term “Aggressive Periodontitis.”

In the 1989 AAP and 1993 European classifications, “Early-Onset Periodontitis” (EOP) was used as a collective designation for a group of dissimilar destructive periodontal diseases that affected young patients (i.e., prepubertal, juvenile, and rapidly progressive periodontitis).

Based on this information, analysis of the initial request for the addition of “Aggressive periodontitis (disorder)” led to further questions regarding several existing SNOMED CT concepts which are now outdated in AAP including:

1. Juvenile periodontitis (which has generalized and localized subtypes)
2. Prepubertal periodontitis (which has generalized and localized subtypes)
3. Early-onset periodontitis (which has generalized and localized subtypes)
4. And possibly Rapidly progressive periodontitis

The original request for 449908004 |Aggressive periodontitis (disorder)| was added in January 2012.

However, the new AAP Classification System also included “Localized Aggressive Periodontitis” and “Generalized Aggressive Periodontitis” which were also requested in 2013 but the requests were closed in May 2015 as “Not accepted – usage below 50”:

• SIRS request ID 183501 Aggressive localized periodontitis (disorder)
• SIRS request ID 183549 for Aggressive generalized periodontitis (disorder)

In August 2015, 6 additional SIRS requests for even more granular subtypes (e.g., Localized moderate aggressive periodontitis (disorder) are being considered for addition in January 2016 as a subtypes of 449908004 |Aggressive periodontitis (disorder)|.

Solution:

Recommendations related to the addition and retirement of the specific AAP concepts discussed in artf226141 include:

1. Allow SIRS request ID 183501 Aggressive localized periodontitis (disorder) be added as Localized aggressive periodontitis (disorder) (to correspond more closely to the AAP term.)
   
   1. Add it as subtype of 449908004 |Aggressive periodontitis (disorder)|
   2. This is logical in light of the more granular terms being added
   3. The three concepts which are planned for addition in January 2016 would be subtypes:

2. Allow SIRS request ID 183549 Aggressive generalized periodontitis (disorder) be added as Generalized aggressive periodontitis (disorder) (to correspond more closely to the AAP term.)

1. 1. Add it as subtype of 449908004 |Aggressive periodontitis (disorder)|
   2. This is logical in light of the more granular terms being added
   3. The three concepts which are planned for addition in January 2016 would be subtypes:

The question of adding “Localized aggressive periodontitis (disorder)” and “Generalized aggressive periodontitis (disorder)” above was also posed by Jim Case to “The American Academy of Periodontology representative to the SNODENT committee” who agreed with the additions. Definitions for both terms are provided in the Glossary of Periodontal Terms (1).

3. Retire 49965002 |Juvenile periodontitis (disorder)| as Outdated with a “Replaced by” association to 449908004 |Aggressive periodontitis (disorder)|.

Posed by Jim Case to “The American Academy of Periodontology representative to the SNODENT committee” who agreed with this action.

4. Retire 235007003 |Early onset periodontitis (disorder)| as Outdated with a “Replaced by” association to 449908004 |Aggressive periodontitis (disorder)|.

Posed by Jim Case to “The American Academy of Periodontology representative to the SNODENT committee” who agreed with this action.

5. Retire 2624008 |Prepubertal periodontitis (disorder)| as Ambiguous concept (rather than Outdated) - Possibly equivalent to 699785004 |Periodontitis as manifestation of systemic disease (disorder)|, 5689008 |Chronic periodontitis (disorder)| or 449908004 |Aggressive periodontitis (disorder)|.

Posed by Jim Case to “The American Academy of Periodontology representative to the SNODENT committee” who agreed with the suggestion to retire as Outdated with a “Replaced by” association to 449908004 |Aggressive periodontitis (disorder)|. However later review indicates that, although this term is “outdated” it appears it was not actually replaced by a single term and therefore the suggestion here is to retire it as ambiguous.

“The 1989 classification contained a category termed “Prepubertal Periodontitis” which had localized and generalized forms. The category was originally developed to accommodate those rare situations in which children with primary teeth had severe periodontal destruction. It is now known that most of the patients who have been given the diagnosis of generalized prepubertal periodontitis actually had one of a variety of systemic conditions that interfere with resistance to bacterial infections. Such conditions include leukocyte adherence deficiency, congenital primary immunodeficiency, hypophosphatasia, chronic neutrophil defects, or cyclic neutropenia. Under the new classification system, such patients would be placed under the heading of “Periodontitis as a Manifestation of Systemic Diseases” … Prepubescent children who have periodontal destruction without any modifying systemic conditions would, depending on a variety of secondary features, fit under the categories of “Chronic Periodontitis” or “Aggressive Periodontitis” in the new classification.[14]

6. Retire 75891001 |Rapidly progressive periodontitis (disorder)| as Ambiguous - Possibly equivalent to 5689008 |Chronic periodontitis (disorder)| and Generalized Aggressive Periodontitis (needs to be added as per #2 above)

Posed by Jim Case to “The American Academy of Periodontology representative to the SNODENT committee” who agreed with the suggestion to retire as Outdated with a “Replaced by” association to 449908004 |Aggressive periodontitis (disorder)|. However later review indicates that, although this designation has been discarded, “Patients who were formerly classified as having Rapidly Progressive Periodontitis will, depending on a variety of other clinical criteria, be assigned to either the “Generalized Aggressive Periodontitis” or “Chronic Periodontitis” categories.[15]

7. Retire 235008008 |Refractory periodontitis (disorder)| as Reason not stated.

In the 1989 classification, a separate disease category was devoted to Refractory Periodontitis. This heterogeneous group of periodontal diseases refers to instances in which there is a continuing progression of periodontitis in spite of excellent patient compliance and the provision of periodontal therapy that succeeds in most patients. Because of the diversity of clinical conditions and treatments under which periodontal therapy fails to arrest the progression of periodontitis, workshop participants were of the opinion that “Refractory Periodontitis” is not a single disease entity.

The question of retiring 235008008 |Refractory periodontitis was posed by Jim Case to “The American Academy of Periodontology representative to the SNODENT committee” who felt it should be retired with no “Replaced by” association because Refractory was applied to all types of periodontitis which failed to respond to treatment. It was not a unique type of disease.

8. Retire 74797001 |Adult periodontitis (disorder)| as Outdated with a “Replaced by” association to 5689008 |Chronic periodontitis (disorder)|.

Although this concept was not included with artf 226141, review of the new AAP Classification indicates this should be retired because at the 1999 Workshop, the age-dependent nature of the adult periodontitis designation created problems and workshop participants decide to adopt a nonspecific term “Chronic Periodontitis” to characterize this constellation of destructive periodontal diseases.[16]

The same will probably be required for the subtypes of 74797001 |Adult periodontitis (disorder)|:

Retire 93462002 |Generalized adult periodontitis (disorder)| as Outdated with a “Replaced by” association to 707251008 |Generalized chronic periodontitis (disorder)| (new in 2015)

Retire 93164008 |Localized adult periodontitis (disorder)| as Outdated with a “Replaced by” association to 707252001 |Localized chronic periodontitis (disorder)| (new in 2015)

9. Obtain Feedback from the Dental SIG as to whether the following concepts are duplicates

402441007 |Oral involvement by mucous membrane pemphigoid (disorder)|

235023003 |Oral cicatricial pemphigoid (disorder)|    

10. 173599005 |Acute necrotizing ulcerative gingivostomatitis (disorder)| is not always of bacterial origin but is modeled with 246075003 |Causative agent (attribute)| = 409822003 |Superkingdom Bacteria (organism)| which needs to be removed from the definition.

6.1.2 Significant design or implementation decisions / compromises

There are four significant implementation decisions for this project:

1. Whether the Dental SIG will be in agreement with the AAP definitions for Periodontal Disease, Periodontitis and Periodontium (presented in Section 6.1.1.3..1)
2. Whether to continue the use of “co-occurrent with” in FSNs in this domain or whether it should be disallowed (this is suggested) because it shifts the meaning of the AAP content
3. Whether the Periodontium can be represented as a body structure in a manner that mirrors its meaning in Periodontology
4. Whether the groupers used in the AAP system classification can be used in SNOMED CT. Some will be able to be added as primitive and others should not be added at all. The risk benefit ratio of the intermediate primitive groupers needs to be taken into account on a case by case basis as this work is completed.

6.1.3 Evaluation of design

Criteria used to evaluate the design(s) include: 1. Representation of periodontal content with unambiguous FSNs 2. Accurate concept definitions and 3. Correct hierarchical inferences

6.1.3.1 Exceptions and Problems

In addition to the 4 issues already raised in Section 6.1.2 the proposed solutions are highly related to the outcome of subsidiary and interrelated projects described in Section 3.5 which are tied to policies being developed by the Event Condition and Episode Project Group.

6.1.3.2 Design Strengths

The recommended solutions should more accurately align the meaning of Periodontitis content in with the meaning of the content in the AAP Classification which it is intended to represent.

6.1.3.3 Design Weaknesses

The recommended solutions advocate for retaining the pattern “Periodontitis associated with <X disorder>” which is interpreted by some to be ambiguous. However, without this compromise, disorders which are actually clinically related may be represented as merely co-occurrent.

6.1.3.4 Design Risks

7 Recommendation

7.1 Detailed design final specification

The recommended solutions are outlined in Section 6 which provides a solution for each issue addressed. Additionally, critical aspects of this project and the proposed solutions were presented to the IHTSDO CTP cohort.

Final specification will rely, in part, on the outcome of subsidiary and interrelated projects described in Section 3.5 which are tied to policies being developed by the Event Condition and Episode Project Group. After this document had been largely developed, some new policies were released in the July Editorial Guide. Therefore, some of the solutions suggested in this document are proposed after the issue has already been decided. Additionally, during the development of this document, the bulk of the content related to this project has been added for the January 2015 Release. None the less, significant aspects of the proposed solutions and the guidance in Appendix B can still be considered.

8 Quality program criteria

8.1 Quality metric 1

8.2 Quality metric 2

8.3 Quality metric 3

9 Project Resource Estimates

The |Periodontitis (disorder)| hierarchy had 55 concepts as of the July 2015 Release. However, on August 19, 2015, there were 83 new SIRS requests related to Periodontal Dentistry (Batch Id 601382). Over 70 of the new requests are for new concepts which will more than double the size of the hierarchy. The rate of ongoing change in this hierarchy made it difficult to assess the true project scope and resources. Scope will also depend on the degree of acceptance of recommendations in this document.

|Periodontal disease (disorder)| is also impacted by this project because the decisions related to the modeling of 2556008 |Periodontal disease (disorder)| may affect its subtype |Periodontitis (disorder)| and may also impact 66383009 |Gingivitis (disorder)| and 266418006 |Gingival and periodontal disease (disorder)|.

9.1 Scope of construction phase

The Elaboration phase of this document has provided a fairly complete review of concepts in the |Periodontitis (disorder)| hierarchy (based on the July 2015 release) which correspond to the AAP Classification System for Periodontal Disease. (See Appendix B - Analysis of SNOMED CT Coverage of the American Academy of Periodontology Classification of Periodontal Disease.) The scope of the Construction phase of this project will require review of nearly every concept definition in the |Periodontitis (disorder)| hierarchy. The proposed solutions are detailed in the Solutions Development section of this document (Section 6). As noted earlier, the construction phase of this project appears to be occurring simultaneously with the development of this Inception – Elaboration document.

9.2 Projection of remaining overall project resource requirements

9.2.1 Expected project resource requirement category

This is not a fast track project. The project should not require project management. The project resource requirement is classed as SMALL – less than 1 person year. The implementation could take place over one release.

9.2.2 Expected project impact and benefit

The project impact is MEDIUM – significant improvement to a minority but high profile use case.

Concepts in this project, including 2556008 |Periodontal disease (disorder), 41565005 |Periodontitis (disorder)|, and 66383009 |Gingivitis (disorder)| are in the 2015 NLM SNOMED CT Core subset. This content is heavily used in diagnoses which heightens the urgency of representing it correctly and of addressing issues to decrease unnecessary change for users.

The benefit of the |Periodontitis (disorder)| hierarchy project is to ensure that the fully specified names and concept definitions accurately represent the clinical meaning of periodontal disorders when used in a clinical record.

9.2.3 Indicative resource estimates for construction, transition and maintenance:

Construction and transition phase:  The estimate is that between 150-300 new and existing concepts related to |Periodontitis (disorder)| and possibly to |Gingivitis (disorder)| will require review and editing. Editing of this content in SNOMED CT is ongoing while this document is being developed. Therefore, resource estimates for completing the project are difficult. Normally, concepts of this nature requiring complete review (for clinical meaning, concept definition modeling, evaluation for duplication, and accuracy of synonymy) could be expected to take several hours per concept. A rough estimate for 250 concepts (at 2 hours per concept) would be 3-4 months of an FTE. If content is reviewed by a second editor an additional 1 month of an FTE might be needed.

Maintenance phase: A large number of concepts (~80) related to |Periodontitis (disorder)| were submitted for the January 2015 Release. However, these appear to have been submitted as part of the ongoing project which may be nearing completion. This is not anticipated to be an area where there will be a significant number of submissions on an ongoing basis. 

10 Appendix A - Descendants of |Periodontitis (disorder)| in the July 2015 International Release

11 Appendix B - Analysis of SNOMED CT Coverage of the American Academy of Periodontology Classification of Periodontal Disease

The following is a detailed analysis of the state of SNOMED CT coverage of content from the American Academy of Periodontology Classification of Periodontal Disease. This assessment is based on the July 2015 Release. There are ongoing changes to Periodontology content in SNOMED CT as this document is being written. While there has been some attempt to mention these ongoing changes (since the July release), they are generally being treated as out of scope for this document.         

NOTE: FOR APPENDIX B, REPRODUCING THE  FORMATTING OF THE ORIGINAL WORD DOCUMENT WAS NOT POSSIBLE IN CONFLUENCE. INFORMATION IS LOST BECAUSE THE COMBINATION OF INDENTATIONS AND NUMBERING REPRESENTED IN THE WORD DOCUMENT CANNOT BE REPRODUCED HERE. PLEASE REFERENCE THE ATTACHED WORD DOCUMENT FOR APPENDIX B.artf226141_Periodontitis_Combined_Inception_Elaboration_Phase_v0.x.docx IHTSDO-720 - Getting issue details... STATUS

Key

• Blue: Terms from the AAP Classification presented in the hierarchical arrangement as shown by AAP
• Orange: SNOMED CT concepts corresponding to the AAP terms or suggested as possible options. If presented after a comment relating to a SIRS request, the content is either being added for the January 2016 Release or under consideration for addition.
• MISSING: Highlights AAP terms not found in the July 2015 Release. However, many are being added for January 2016 and this is generally noted with the missing term as well.
• Black: Comments related to the terms presented, their meaning in AAP and SNOMED CT and their presentation in SNOMED CT.
• Q: Questions posed for consideration by editors, reviewers or SME from the Dental SIG usually highlighting areas of concern or inconsistency.
• Note: SIRS – Concepts/content preceded by this Note represent additions to this document that include requests for content changes submitted to SIRS after August 19^th, 2015 that may be incorporated in the January 2016 Release.

Of note: The AAP Definitions included in this document are from the American Academy of Periodontology. Glossary of Periodontal Terms (4th ed. Chicago, Ill.: American Academy of Periodontology, 2001) which provides definitions for many of the terms covered here. Because the origin of these terms is the AAP Classification of Periodontal diseases, this Glossary is a useful reference for editors working in this area. Some of the AAP definitions are included below (followed by the reference (1). However, including all definitions was out of scope.

1. Gingival Diseases

18718003 |Gingival disease (disorder)|

Q for SME: This is NOT currently a subtype of 2556008 |Periodontal disease (disorder)|. Should it be? (This relates to the larger anatomy issue of what constitutes the Periodontium and how it will be addressed in SNOMED CT.)

1. Dental plaque-induced gingival diseases

707237008 |Gingival disease due to dental plaque (disorder)| (Synonym: Dental plaque induced gingival disease)

In July 2015, |Gingival disease due to dental plaque (disorder)| is Sufficiently Defined and has no subtypes. None of the existing SNOMED CT (SCT) concepts below, which are classified as “Dental plaque-induced gingival diseases” in AAP the AAP Classification System, are subtypes of |Gingival disease due to dental plaque (disorder)| in SNOMED CT.

1. Gingivitis associated with dental plaque only – MISSING

If this concept is added in SCT it cannot be Sufficiently Defined because the “only” aspect cannot be represented in the definition. The same is true for the two subtypes.

Note: SIRS ID 601467: 713245008 |Gingivitis due to dental plaque (disorder)| (Added August 24, 2015) - probably in an attempt to represent this concept.

(AAP Definition (1): PLAQUE-INDUCED Gingivitis: Gingival inflammation resulting from dental plaque)

1. without other local contributing factors - MISSING
2. with local contributing factors (See VIII A) – MISSING

Note: SIRS ID 601468: Gingivitis due to dental plaque with local contributing factors (disorder) - In Process

The two new SCT concepts above do not capture the AAP restriction that this is Gingivitis associated with dental plaque only.

1. Gingival diseases modi?ed by systemic factors  - MISSING

 “Gingival disease modified by systemic factors” is a grouper that cannot be Sufficiently Defined. Also, it is easy to confuse with the separate AAP term “Gingival manifestations of systemic conditions” (See Section 1.B.5 below).  

1. associated with the endocrine system - MISSING

It is probably not advisable to add “Gingival disorder modified by (or associated with?) endocrine system”  because it is a “grouper” that cannot be Sufficiently Defined. The subtypes already exist in SNOMED and would have to be given stated IS_A relationships to 707237008 |Gingival disease due to dental plaque (disorder)| if the intent in SNOMED is to mirror the AAP classification.

1)     puberty-associated gingivitis

234991003 |Puberty gingivitis (disorder)| (It appears this concept is being retired for the January 2015 release.)

Note: SIRS ID 601539: 713218007 |Gingivitis co-occurrent with puberty (disorder)| (Added August 21, 2015)

AAP definition (1): PUBERTY-ASSOCIATED Gingivitis.: Pronounced inflammatory response of gingiva to dental plaque and hormones during the circumpubertal period.

It is suggested that the new concept Gingivitis co-occurrent with puberty (disorder) does not fully capture this meaning and that the concept definition of this new concept be reviewed (in particular the Parent and Interprets)

2)     menstrual cycle-associated gingivitis

  700240005 |Gingivitis associated with menstrual cycle (disorder)|

(However, it appears this concept is may be retired for the January 2015 release.)

Note: SIRS ID 601537: Retire 700240005|Gingivitis associated with menstrual cycle (disorder)| and add Gingivitis co-occurrent with menstrual cycle (disorder). – In Process

AAP definition (1): MENSTRUAL-CYCLE ASSOCIATED Gingivitis: Pronounced inflammatory response of gingiva to plaque and hormones immediately prior to ovulation.

It is suggested that the new concept Gingivitis co-occurrent with menstrual cycle (disorder) does not fully capture this meaning.(See Section 6.1.1.1 for discussion.)

3)     pregnancy-associated

a)     gingivitis

95212006 |Pregnancy gingivitis (disorder)| (exists but may be retired in Jan 2015)

Note: SIRS ID 601538: Retire 95212006|Pregnancy gingivitis (disorder)| and add Gingivitis co-occurrent with pregnancy (disorder) – In Progress

AAP definition (1): PREGNANCY-ASSOCIATED Gingivitis: Pronounced inflammatory response of the gingiva to dental plaque and hormones usually occurring during the second and third trimesters of pregnancy.

It is suggested that the new concept Gingivitis co-occurrent with pregnancy (disorder) does not fully capture this meaning.

b)     pyogenic granuloma - MISSING

Note: See SIRS ID: 601531 713249002 |Pyogenic granuloma of gingiva co-occurrent with pregnancy (disorder)| (Added August 24, 2015)

AAP definition (1): PREGNANCY-ASSOCIATED Pyogenic granuloma: A pyogenic granuloma resulting from dental plaque and hormones during pregnancy.

It is suggested that the new concept Pyogenic granuloma of gingiva co-occurrent with pregnancy (disorder) may not fully capture this meaning and that the concept definition of this new concept be reviewed. Suggest adding “Pyogenic granuloma of gingiva associated with pregnancy (disorder)” with Synonym Gingival pyogenic granuloma associated with pregnancy.

4)     diabetes mellitus-associated gingivitis

709147009 |Gingivitis co-occurrent with diabetes mellitus (disorder)|

AAP definition (1): DIABETES -ASSOCIATED Gingivitis: Inflammatory response of the gingiva to plaque aggravated by poorly controlled plasma glucose levels.

It is suggested that the new concept Gingivitis co-occurrent with diabetes mellitus (disorder) does not fully capture this meaning and that the concept definition of this new concept be reviewed (in particular, the IS_A relationship to 73211009 |Diabetes mellitus (disorder)|).

1. associated with blood dyscrasias

710786004 |Gingivitis due to disorder of cellular component of blood (disorder)

Q for SME: Should this be Gingival disorder associated with blood dyscrasia (disorder) or are they always gingivitis?

1)      leukemia-associated gingivitis

 705127009 |Gingivitis due to leukemia (disorder)|

AAP definition (1): LEUKEMIA-ASSOCIATED Gingivitis: Pronounced inflammatory response of the gingiva to plaque resulting in increased bleeding and enlargement subsequent to leukemia. Enlargement may be partially due to leukemic cell infiltration of the gingiva.

2)     other – MISSING Do not add      

1. Gingival diseases modi?ed by medications - MISSING  

The meaning of “modified by” cannot be represented in SNOMED unless it means “due to”. “Gingival disorder associated with medication (disorder)” would be acceptable to add and could still be a parent for the concepts below and could be Sufficiently Defined with 47429007 |Associated with (attribute)| = 410942007 |Drug or medicament (substance)|.

1. drug-in?uenced gingival diseases

708653004 | Gingival disease due to drug (disorder)| (new July 2015)

May not be identical in meaning to “Drug-influenced gingival disease”, but Gingival disease due to drug (disorder) is still a valid concept.

1) drug-in?uenced gingival enlargements

93434009 |Drug-induced gingival hyperplasia (disorder)|

2) drug-in?uenced gingivitis

709062008 |Gingivitis due to drug (disorder)|

Not sure that this is exactly correct or whether this should have been |Gingivitis associated with drug (disorder)| so that it would subsume the subtypes which were added with “associated with” which is more general than “due to”.

                          It does not have subtypes in the July Release, but in AAP it has subtypes:

a) oral contraceptive-associated gingivitis

702784001 |Gingivitis associated with oral contraceptive use (disorder)|

This concept is not subsumed by 709062008 |Gingivitis due to drug (disorder)| in SNOMED because 709062008 |Gingivitis due to drug (disorder)| is modeled with the more specific |Causative agent (attribute)| while 702784001 |Gingivitis associated with oral contraceptive use (disorder)| is modeled with the more general |Associated with (attribute)|. The subtleties in naming these concepts impacts how they are modeled and classify in the hierarchy.

AAP definition (1): ORAL CONTRACEPTIVE-ASSOCIATED Gingivitis: Pronounced inflammatory response of the gingiva to plaque and oral contraceptives.

b) other - MISSING   do not add 

1. Gingival diseases modi?ed by malnutrition

708512000 |Gingival disease due to malnutrition (disorder)| (Added January 2015)

“Due to” may have a different meaning here than “modified by”, but this content has already been added.

1. ascorbic acid-de?ciency gingivitis

705126000 |Gingivitis due to ascorbic acid deficiency (disorder)| (Added January 2015)

Note: SIRS Request (601436) 713231002 |Gingivitis co-occurrent with ascorbic acid deficiency (disorder)| (Added Aug 22, 2015) However, this concept was not added as a subtype of 708512000 |Gingival disease due to malnutrition (disorder)|

AAP definition (1): ASCORBIC ACID DEFICIENCY Gingivitis: Inflammatory response of the gingiva to plaque aggravated by chronically low ascorbic acid levels.

It is suggested that the new concept 713231002 |Gingivitis co-occurrent with ascorbic acid deficiency (disorder)| may not fully capture this meaning and that meaning and that “due to” or “associated with” would have been better. This concepts should also be reviewed for appropriateness of IS_A assertions.

Q for SME: How does this relate to the existing concept 705126000 |Gingivitis due to ascorbic acid deficiency (disorder)|? Are two concepts necessary and will users understand the difference in their meaning? It is suggested they are actually two different attempts to represent the same AAP concept. What is the true meaning?

1. other - MISSING   do not add

1. B. Non-plaque-induced gingival lesions

707606004 |Non-plaque induced gingival disease (disorder)| (Added for January 2015)

Added in SNOMED with a Text Definition: Gingival disease with an etiology other than dental plaque, such as bacterial, viral, fungal or genetic origin, due to systemic conditions, trauma, foreign body reactions, or other causes.

This concept is problematic in SNOMED because it is really of the type “X disorder not due to Y disorder” which cannot be Sufficiently Defined. Yet, as stated in its text definition, |Non-plaque induced gingival disease (disorder)| is intended to be the grouper (parent) for the concepts below (see AAP Classification table). But the concept is primitive and has no SCT subtypes. The existing SNOMED CT content below would need to be added as stated subtypes. However, this may present a problem in that just because “gingival disease is due to bacteria”, does not assert that it is necessarily also “not due to plaque”. These may not be correct IS_A relationships to assert in SNOMED based on these FSNs and may defeat the purpose of adding 707606004 |Non-plaque induced gingival disease (disorder)| which was intended as a grouper.

1. Gingival diseases of speci?c bacterial origin

708055005 |Gingival disease due to bacteria (disorder)|

1.  Neisseria gonorrhea-associated lesions - MISSING   

Note:  SIRS ID 601454: 713261005 |Gingivitis caused by Neisseria gonorrhoeae (disorder)| (Added August 24, 2015)

Q for SME: IN AAP, does this mean |Lesion of gingiva due to Neisseria gonorrhoeae (disorder)| or |Inflammation of gingiva due to Neisseria gonorrhoeae (disorder)| or |Infection of gingiva due to Neisseria gonorrhoeae (disorder)|? If so, the appropriate FSN should be added with appropriate synonyms and Sufficiently Defined.

1.  Treponema pallidum-associated lesions - MISSING   

Note: SIRS ID 601464: 713251003 |Gingivitis co-occurrent with infection by Treponema pallidum (disorder)| (Added August 24, 2015)

Q for SME: Does this mean |Lesion of gingiva due to Treponema pallidum (disorder)| or |Inflammation of gingiva due to Treponema pallidum (disorder)| or |Infection of gingiva due to Treponema pallidum (disorder)|? If so, the appropriate FSN should be added with appropriate synonyms and Sufficiently Defined.

Q for editor: Why does this concept use “co-occurrent” and the one above uses “caused by Neisseria gonorrhoeae”? It is suggested that if this term in AAP is restricted in meaning to gingivitis, this should still be |Gingivitis associated with infection by Treponema pallidum (disorder)| or |Gingivitis caused by Treponema pallidum (disorder)|.

1. streptococcal species-associated lesions - MISSING   

Note: SIRS ID 601462: Gingivitis co-occurrent with Streptococcal species (disorder) – In Progress

Q for SME: Does this mean |Lesion of gingiva due to Streptococcus (disorder)| or |Inflammation of gingiva due to Streptococcus (disorder)| or |Infection of gingiva due to Streptococcus (disorder)|? If so, the appropriate FSN could be added with appropriate synonyms and Sufficiently Defined.

Again, “co-occurrent” does not seem correct for this concept. Also the concepts with “co-occurent” cannot be subtypes of 708055005 |Gingival disease due to bacteria (disorder)| (their intended parent in AAP) because it is more specific in meaning.

1. Gingival diseases of viral origin

707129008 |Gingival disease due to virus (disorder)|

1. herpesvirus infections - MISSING

Q for SME: Why, in AAP, are the “Gingival diseases of speci?c bacterial origin” in the section above called “lesions” and the word lesion is not used here for viral diseases?

It is suggested that Infection of gingiva due to herpes simplex virus (disorder)| with synonym: Gingival infection due to herpesvirus could be added. Again, the issue of co-occurrent in the FSN below needs to be addressed.

1) primary herpetic gingivostomatitis

57920007 |Herpetic gingivostomatitis (disorder)| has Synonym: Primary herpetic gingivostomatitis

Note: SIRS ID 601458 Gingivitis co-occurrent with primary herpetic gingivostomatitis (disorder)

Q for editor and SME: 57920007 |Herpetic gingivostomatitis (disorder)| has a synonym: Primary herpetic gingivostomatitis. Is the synonym “Primary herpetic gingivostomatitis” may be too specific for |Herpetic gingivostomatitis (disorder)|? If so, the synonym should be retired and a new concept can be added to represent Primary herpetic gingivostomatitis. However, “Co-occurrent” means “simple co-occurrence” without suggestion of causation and that seems too general for the AAP representation where primary herpetic gingivostomatitis is classified as a “Gingival disease of viral origin”. This is really “First outbreak of gingivostomatitis due to herpes simplex virus (disorder) with synonym “Primary herpetic gingivostomatitis”.

2) recurrent oral herpes

235057006 |Recurrent oral herpes simplex infection (disorder)| (exists)

Note: SIRS ID 601460: 713252005 |Gingivitis co-occurrent with recurrent oral herpes (disorder)| (Added August 24, 2015)

Q for SME: Does the new FSN |Gingivitis co-occurrent with recurrent oral herpes (disorder)| correctly represent “recurrent oral herpes” as shown in the AAP Classification and definition?

AAP Definition (1): INTRAORAL RECURRENT Herpes simplex (listed as a subtype of HERPES (Herpetic Gingivostomatitis, H. Simplex): An attenuated form of herpes in which clusters of pinhead-sized vesicles occur on the attached keratinized mucosa. Commonly called cold sores or fever blisters

In the AAP classification, this is a subtype of “Gingival diseases of viral origin”. This implies more than mere co-occurrence, it implies causation. It seems that this is not Gingivitis co-occurrent with recurrent oral herpes, but rather that the disease that is being represented IS recurrent oral herpes affecting the gingiva.

Should this be represented as “Recurrent gingivostomatitis due to herpes simplex virus (disorder)” (with synonym: Recurrent herpetic gingivostomatitis)?

3) varicella-zoster infections - MISSING  

Note: SIRS ID 601466 – 713250002 |Gingivitis co-occurrent with varicella-zoster virus infection| (disorder) (Added August 24, 2015)

Q for SME: Based on how this concept is classified in AAP, as a subtype of “Gingival diseases of viral origin”, the relationship between VZ infection and gingivitis is more than mere co-occurrence, it implies causation. Also is it always manifested as gingivitis? Should this be added as Gingival infection due to due to varicella-zoster virus(disorder)? Or Gingivitis due to varicella-zoster virus (disorder)?

1. other - MISSING   do not add

1. Gingival diseases of fungal origin - MISSING   

Suggest adding Gingival disorder due to fungus (disorder) (Could also use “disease” in the FSN even though editorial guidance is to use “disorder” in the FSN.)

1. Candida-species infections

700455003 |Gingivitis due to Genus Candida (disorder)| (added July 2014)

1)     generalized gingival candidosis - MISSING  

1. linear gingival erythema

304984001 |Linear gingival erythema (disorder)|

Note: SIRS (ID 601451) for |Gingivitis co-occurrent with linear erythema of fungal origin (disorder)| - In Progress

AAP Definition (1): LINEAR GINGIVAL ERYTHEMA: A gingival manifestation of immunosuppression characterized by a distinct linear erythematous band limited to the free gingiva. The lesion does not predictably respond to plaque removal.

Q for SME: Based on the AAP definition, this is not co-occurrence. This is a Candidal infection that presents as erythema of the attached gingiva. The linear erythema of the Gingiva IS the disorder. Is the correct representation of this concept |Linear gingival erythema due to fungus (disorder)|? Synonym: linear erythematous gingivitis

1. histoplasmosis

702577006 |Gingivitis due to Histoplasma (disorder)|

1. other MISSING   do not add

1. Gingival lesions of genetic origin

707183006 |Gingival disease due to genetic disorder (disorder)| - Broader in meaning than the AAP term but that is okay this is only a grouper.

1. hereditary gingival ?bromatosis

109620006 |Hereditary gingival fibromatosis (disorder)|

Note: SIRS (ID 601439) 713230001 |Gingivitis co-occurrent with hereditary gingival fibromatosis (disorder)| (added August 22, 2015)

AAP Definition (1): Gingival FIBROMATOSIS: A diffuse, fibrous overgrowth of the gingiva; can be idiopathic, hereditary, or associated with drug administration

Q for SME: Based on the AAP definition, it appears that the request for |Gingivitis co-occurrent with hereditary gingival fibromatosis (disorder)| is not correctly capturing this disorder. It appears that this disorder in AAP is not co-occurrent with hereditary gingival fibromatosis, the disorder is hereditary gingival ?bromatosis and the concept is already in SNOMED CT.

1. other - MISSING no need to add

1. Gingival manifestations of systemic conditions - MISSING   

This appears to have similar meaning to Periodontitis as manifestation of systemic disease. These are gingival diseases with onset and progression affected by systemic diseases that affect immune function, inflammatory response and tissue organization (systemic diseases in which gingival disease is a frequent manifestation).

A similar grouper, 699785004 |Periodontitis as manifestation of systemic disease (disorder)|, was added in January 2014. It is primitive and has no subtypes in SNOMED (July 2015) but has many subtypes in AAP Classification (shown below). To serve the purpose it serves in AAP (as a grouper), it will be an Intermediate Primitive. The same would be true for the addition of |Gingival disease as manifestation of systemic disease (disorder)|.

The concept |Gingival disease associated with another disorder (disorder)| would be able to be sufficiently defined and if added would be a new Intermediate primitive, and would not subsume the concepts below. They would need to be added manually.

It is not clear that there is value to adding these groupers if the AAP subtypes shown below (e.g., “Gingival mucocutaneous disorder”) are not always and necessarily manifestations of systemic disease.  In that case, they would not have an IS_A to Gingival disease as manifestation of systemic disease (disorder) unless their FSNs included the phrase “Gingival mucocutaneous disorder as a manifestation of <X disease>”.

1. mucocutaneous disorders - MISSING  

Q for editor/SME: This appears to represent Gingival mucocutaneous lesion as a manifestation of systemic disease (disorder)? It cannot be Sufficiently Defined and per AAP classification it would be the parent of the subtypes below but would not subsume them so they would need to be manually assigned. It is probably okay to omit this grouper.

1) lichen planus - MISSING  

    235049008 |Oral lichen planus (disorder)| exists

   This concept above seems broader although it can involve gingiva.

Lichen planus is a chronic inflammatory disease that affects the skin and the mucus membrane. 

Note: SIRS ID 601440 713224001 |Gingivitis co-occurrent with lichen planus (disorder)| (Added August 22, 2015)

Q for SME: It appears that this disorder in AAP is not Gingivitis co-occurrent with lichen planus, rather it is a gingival manifestation of lichen planus. This should be named Gingival lichen planus (disorder) or Lichen planus of gingival mucosa (disorder) and also be a subtype of 235049008 |Oral lichen planus (disorder)|

2) pemphigoid

402441007 |Oral involvement by mucous membrane pemphigoid (disorder)|

Q1 for SME: the above concept has a synonym: Desquamative gingivitis due to pemphigoid. Is this too specific? Should it be a separate concept?

Q2 for SME: Is 235023003 |Oral cicatricial pemphigoid (disorder)| a duplicate of 402441007 |Oral involvement by mucous membrane pemphigoid (disorder)|?

Note: SIRS ID 601455: 713223007 |Gingivitis co-occurrent with pemphigoid (disorder)| (Added August 22, 2015)

AAP Definition (1): PEMPHIGOID (Cicatricial Pemphigoid, Benign Mucous Membrane Pemphigoid): A chronic vesiculobullous autoimmune disorder that primarily affects the mucosa in older females; characterized by a sub-basalar separation of epithelium from connective tissue; almost all cases have an oral involvement with the gingiva being the most favored site.

Q3 for SME: It appears that this disorder in AAP is not Gingivitis co-occurrent with pemphigoid, rather it is a gingival manifestation of pemphigoid. Should it be named something like:

Gingivitis due to pemphigoid (disorder), or Gingival mucosal involvement by pemphigoid (disorder) or Mucous membrane pemphigoid of gingiva (disorder)?

3) pemphigus vulgaris- MISSING

Q1 for SME: Are the concepts below too broad to represent this concept and are they duplicates?

                                        361211002 |Pemphigus minor (disorder)|

  361212009 |Oral pemphigus vulgaris (disorder)|

Note: SIRS ID 601456: 713253000 |Gingivitis co-occurrent with pemphigus    vulgaris (disorder)| (Added August 22, 2015)

Q2 for SME: It appears that this disorder in AAP is not Gingivitis co-occurrent with pemphigus vulgaris, rather it is a gingival manifestation of pemphigoid. Should it be named something like Gingivitis caused by pemphigus vulgaris (disorder) or Gingival mucosal involvement by pemphigus vulgaris (disorder) with Synonym: Gingival pemphigus vulgaris, or Pemphigus vulgaris of gingiva (disorder) with Synonym Gingival pemphigus vulgaris?

4) erythema multiforme - MISSING  

Note: SIRS request (ID 601438): 713229006 |Gingivitis co-occurrent with erythema multiforme (disorder)| (added August 22, 2015)

Q for SME: Same issue as for the concepts above. This is not co-occurrence with erythema multiforme. These are the oral lesions of erythema multiforme. Should the FSN be Erythema multiforme of gingiva (disorder) with Synonym Gingival erythema multiforme (disorder)| or Erythema multiforme gingivitis (disorder)?

5) lupus erythematosus - MISSING  

    707301001 |Lupus erythematosus of oral mucous membrane (disorder)|

Q1 for SME: Is this concept too broad to represent this?

Note: SIRS (ID 601453): 713225000 |Gingivitis co-occurrent with lupus erythematosus (disorder)| (Added August 22 2015)

Q2 for SME: Same issue as for the concepts above. This is not co-occurrence with lupus erythematosus, it is a gingival manifestation of lupus. Should the FSN be Lupus erythematosus of gingiva (disorder) with Synonym Gingival lupus erythematosus (disorder)|?

6) drug-induced -

                                       709062008 |Gingivitis due to drug (disorder)|

AAP Definition (1): DRUG-INFLUENCED Gingivitis.: Pronounced inflammatory response of the gingiva to plaque and drug(s).

7) other - MISSING  do not add

1. allergic reactions

91924004 |Allergic gingivitis (disorder)|

Note: New subtypes are being requested in SIRS as this document is being written.

1)     dental restorative materials - MISSING  

Note: SIRS ID 601434 Gingivitis caused by dental restorative material (disorder) – In Process

Q for SME: As requested, the concept above appears to be too general and not necessarily the result of an allergic reaction. It is missing the word “allergic”. Should the FSN be “Allergic gingivitis caused by dental restorative material (disorder)? This would be consistent with the way that the new additions below are requested which include “allergic” in their FSNs. Also, it seems that this concept is intended as a grouper and probably would not be used as a diagnosis in a record. Therefore, in order to subsume the subtypes in AAP, it might be best to assign it an FSN “Allergic gingivitis caused by dental material (disorder).

The three substances below are its subtypes of “dental material”. Therefore, the concept could be fully defined and would subsume the three concepts if they are also modeled with the substances shown

255922001 |Dental material (substance)|

468321001 |Dental amalgam mercury (physical object)|

256505003 |Nickel chromium dental material (substance)|

256511000 |Acrylic dental material (substance)|

a)     mercury

Note: SIRS ID 601397: Allergic gingivitis caused by dental mercury (disorder) – In Process

Q for SME:  Is Allergic gingivitis caused by dental amalgam mercury (disorder) better?

b)     nickel

Note: SIRS ID 601398: Allergic gingivitis caused by nickel (disorder) – In Process

Q for SME: This is really not gingivitis caused by any nickel substance. It is caused by the nickel in dental restorative materials. Would Allergic gingivitis caused by Nickel chromium dental material (disorder) be better or is it too specific?

  c)  acrylic

Note: SIRS ID 601396: 713236007 |Allergic gingivitis caused by acrylic dental material (disorder)| (Added August 22, 2015)

2)     reactions attributable to - MISSING  

In AAP this is a subtype of allergic reactions (above). Therefore, it appears that these are gingival allergic reactions attributable to specific causes in the same way that the three concepts added above were added as “allergic gingivitis due to dental restorative materials”. Therefore, this could be added as:

 Allergic gingivitis caused by substance (disorder)

The concepts below are being requested/added via SIRS for January 2016.

If added as requested below, these concepts could represent any type of allergic reaction, not necessarily an allergic reaction that involves the gingiva. As added, they will have no connection to periodontal diseases. It is suggested that the concepts below do not represent the AAP disorders but rather represent much more general reactions.

Q for Editor: Should the FSNs below include “Allergic gingivitis due to <X> (disorder)” or Adverse reaction to <X> involving the gingiva (disorder)?

a)  toothpastes/dentifrices

Note: SIRS (ID 601395): Adverse reaction to toothpaste and dentifrice (disorder) - In Process

b) mouthrinses/mouthwashes  

Note: SIRS (ID 601394): Adverse reaction to mouth rinse and mouthwash (disorder) - In Process

c) chewing gum additives

Note: SIRS (ID 601392): 713228003 |Adverse reaction to chewing gum additive (disorder)| (Added August 22, 2015)

d)     foods and additives

Note: SIRS ID 601393 Adverse reaction to food and additive (disorder) – In Process

e)     other MISSING no need to add

1. Traumatic lesions (factitious, iatrogenic, accidental)

282754004 |Gum injury (disorder)| - exists already in SCT

Q for editor: Consider changing this FSN to Injury of gingiva (disorder) and this might suffice.

The concept above is modeled with 116676008 |Associated morphology (attribute)| = 19130008 |Traumatic abnormality (morphologic abnormality)| but the subtypes below are not necessarily traumatic (in the same way that SNOMED uses this term). This probably cannot be resolved.

AAP Definition (1): LESION: I. An injury or wound. 2. Any single patch or area of morbid tissue. 3. A pathologic disturbance of a tissue, or organ, which results in impairment, loss of continuity, or loss of normal function of the part.

AAP Definition (1): TRAUMATIC Lesion: Self-inflicted (factitious), accidental, or iatrogenic injuries. They may manifest as recession, abrasions, ulcerations, lacerations, hums, edema, erythematous or white lesions, or combinations of several of these features.

Note: SIRS Request ID 601470: |Gingivitis due to traumatic injury (disorder)| (Added August 28, 2015)

Q for SME:  Based on the AAP definition of traumatic lesion, these injuries are not always inflammation. Therefore, “Gingivitis due to <X>” as added per the SIRS requests seems too specific. Should these FSNs use the pattern “Injury of gingiva caused by <X>” instead?

1. chemical injury MISSING

Note: SIRS ID: 601469 Gingivitis due to traumatic chemical injury (disorder)

AAP Definition (1): CHEMICALLY INDUCED Lesion: Results from local application of substances that may include aspirin, cocaine, pyrophosphates, detergents (e.g., sodium lauryl sulfate), smokeless tobacco, betel nut, and bleaching agents.

Q for SME: Would “Injury of gingiva caused by chemical (disorder)” be better than Gingivitis due to traumatic chemical injury (disorder)? (Consider modeling with 246075003 |Causative agent (attribute)| = 312415009 |Chemical categorized structurally (substance)| or leave primitive.)

1. physical injury MISSING

Note: SIRS ID: 601471 Gingivitis due to traumatic physical injury (disorder) – In Process

There is no way in SCT to model this concept as distinct from |Gingivitis due to traumatic injury (disorder)|

(If these concepts are retained, text definitions to help users understand the difference between Gingivitis due to traumatic injury (disorder) and Gingivitis due to traumatic physical injury (disorder) are indicated.)

1. thermal injury MISSING

Note: SIRS ID 601472: Gingivitis due to thermal injury (disorder) (Added August 28, 2015)

Q for SME: Is this always inflammation? Should this be Thermal injury of gingiva (disorder) or “Injury of gingiva caused by heat (disorder)”?

1. Foreign body reactions

449763003 |Foreign body gingivitis (disorder)|

Because the AAP definition describes a granulomatous reaction, “gingivitis” is probably acceptable in this FSN.

AAP Definition (1): FOREIGN-BODY REACTION: A granulomatous reaction around a foreign material within a tissue or organ; often characterized by giant cells. This may present as acute or chronic gingival inflammation and may produce tattoos; or red, red/white; or suppurative lesions.

1. Not otherwise speci?ed (NOS) MISSING do not add

A detailed analysis of the Gingival Disease section of the American Academy of Periodontology Classification of Periodontal Disease was provided above as an indicator of the type of effort that might be involved in the Construction Phase of this project if the AAP terms are to be accurately represented in SCT. While some analysis is provided for the remaining sections of the AAP Classification of Periodontal Disease, it is much less complete and will require further analysis in the Construction Phase. The next section of this document was also developed prior to the release of the new Editorial Guidance on Disorder Combinations and therefore may not be completely accurate. SIRS Requests related to this content were also being submitted as this document was being developed.

1. Chronic Periodontitis†

5689008 |Chronic periodontitis (disorder)| currently a subtype of 41565005 |Periodontitis (disorder)|

Chronic periodontitis is defined as inflammation of the gingiva extending into the adjacent attachment apparatus. The disease is characterized by loss of clinical attachment due to destruction of the periodontal ligament and loss of the adjacent supporting bone.

Potential new subtypes might include (J Periodontol 2000;71:856-858.):

Chronic periodontitis with slight to moderate loss of periodontal supporting tissue

Chronic periodontitis with advanced loss of periodontal supporting tissue

1. Localized (up to 30% of sites in the mouth are affected)

707252001 |Localized chronic periodontitis (disorder)|

1. Generalized (more than 30% of sites in the mouth are affected)

707251008 |Generalized chronic periodontitis (disorder)|

1. Aggressive Periodontitis

449908004 |Aggressive periodontitis (disorder)|

Addition of subtypes in this area is ongoing for the January 2015 release

1. Localized MISSING

Consider adding Localized aggressive periodontitis (disorder) as subtype of 449908004 |Aggressive periodontitis (disorder)|

1. Generalized MISSING

Consider adding Generalized aggressive periodontitis (disorder) as subtype of 449908004 |Aggressive periodontitis (disorder)|

1. Periodontitis as a Manifestation of Systemic Diseases

699785004 |Periodontitis as manifestation of systemic disease (disorder)|

This concept was added in January 2014 and is primitive and has no subtypes in SNOMED (as of July 2015) but has many subtypes in AAP Classification (shown below). To serve the purpose it serves in AAP (as a grouper), it would be an Intermediate Primitive in SNOMED CT.

Within the AAP Classification system, it seems to have a more specific meaning than can be ascertained from its SCT FSN. Consideration should be given to adding a text definition.

Periodontitis as manifestation of systemic disease seems to be periodontitis with onset and progression affected by systemic diseases that affect immune function, inflammatory response and tissue organization (systemic diseases in which periodontitis is a frequent manifestation).

A number of systemic factors have been documented as being capable of affecting the periodontium and/or treatment of periodontal disease. Systemic etiologic components may be suspected in patients who exhibit periodontal inflammation or destruction which appears disproportionate to the local irritants. The clinician should be aware of systemic conditions and/or drugs that may be contributing factors to periodontal diseases, and of steps necessary to evaluate them.[17]

Additionally, the issues raised earlier in this document related to the use of “co-occurrent” are equally relevant for the SNOMED CT concepts in the sections that follow but were not restated for each concept below. It is again suggested that for the majority of the FSNs below that represent “disorder combinations”, that “co-occurent” does not capture the intended clinical relevance between Periodontitis and the additional clinically associated (or at times causative) disorder.

1. Associated with hematological disorders

709557000|Periodontitis co-occurrent with hematologic disorder (disorder)| Synonym: Periodontitis associated with hematologic disorder

1. Acquired neutropenia

709608008 | Periodontitis co-occurrent with acquired neutropenia (disorder)| Synonym: Periodontitis associated with acquired neutropenia

This concept is not currently a subtype of 709557000|Periodontitis co-occurrent with hematologic disorder (disorder)|.

1. Leukemias

709471005 |Periodontitis co-occurrent with leukemia (disorder)|

1. Other

Q for SME: The concepts shown below are not currently subtypes of 709557000|Periodontitis co-occurrent with hematologic disorder (disorder). In AAP, they are subtypes of “Periodontitis associated with genetic disorders”. Should they also be subtypes here as they are also hematological disorders?

703148008 |Periodontitis associated with chronic familial neutropenia (disorder)|

703149000 |Periodontitis associated with cyclical neutropenia (disorder)|

710927004 |Periodontitis co-occurrent with cyclical neutropenia (disorder)| Synonym: Periodontitis associated with cyclical neutropenia (Duplicate of concept above?)

710735009 |Periodontitis co-occurrent with leukocyte adhesion deficiency (disorder)|

710096000 |Periodontitis co-occurrent and due to histiocytosis syndrome (disorder)|

709535007 | Periodontitis co-occurrent with infantile genetic agranulocytosis (disorder)|

1. Associated with genetic disorders

710903001 |Periodontitis co-occurrent with genetic disorder (disorder)|

1. Familial and cyclic neutropenia

These concepts are not currently subtypes |Periodontitis co-occurrent with genetic disorder (disorder)| in SNOMED CT. If the naming issues are resolved, they may be appropriate as subtypes.

703148008 |Periodontitis associated with chronic familial neutropenia (disorder)|

703149000 |Periodontitis associated with cyclical neutropenia (disorder)|

710927004 |Periodontitis co-occurrent with cyclical neutropenia (disorder)| Synonym: Periodontitis associated with cyclical neutropenia

1. Down syndrome

This concept is not currently a subtype of |Periodontitis co-occurrent with genetic disorder (disorder)| in SNOMED CT. It probably could be.

709469005 |Periodontitis co-occurrent with Down syndrome (disorder)|

1. Leukocyte adhesion de?ciency syndromes

This concept is not currently a subtype of |Periodontitis co-occurrent with genetic disorder (disorder)| in SNOMED CT. It probably could be.

710735009 |Periodontitis co-occurrent with leukocyte adhesion deficiency (disorder)|

1. Papillon-Lefèvre syndrome

This concept is not currently a subtype of |Periodontitis co-occurrent with genetic disorder (disorder)| in SNOMED CT. It probably could be.

709472003 |Periodontitis due to Papillon-Lefèvre syndrome (disorder)|

1. Chediak-Higashi syndrome

709465004 |Periodontitis co-occurrent with Chédiak-Higashi syndrome (disorder)|

1. Histiocytosis syndromes

710096000 |Periodontitis co-occurrent and due to histiocytosis syndrome (disorder)|

1. Glycogen storage disease

709561006 |Periodontitis co-occurrent with glycogen storage disease (disorder)|

1. Infantile genetic agranulocytosis

709535007 |Periodontitis co-occurrent with infantile genetic agranulocytosis (disorder)|

1. Cohen syndrome

709466003 |Periodontitis co-occurrent with Cohen syndrome (disorder)|

1. Ehlers-Danlos syndrome (Types IV and VIII)

709604005 |Periodontitis co-occurrent with Ehlers-Danlos syndrome type 4 (disorder)|

50869007 |Ehlers-Danlos syndrome, type 8 (disorder)| Synonym: Periodontitis associated with Ehlers-Danlos syndrome type VIII

1. Hypophosphatasia

709556009 |Periodontitis co-occurrent with hypophosphatasia (disorder)|

1. Other

1. Not otherwise speci?ed (NOS) MISSING Does not need to be added.

1. Necrotizing Periodontal Diseases

706984006 |Necrotizing periodontal disease (disorder)| (January 2015)

“Necrotizing ulcerative gingivitis (NUG) and necrotizing ulcerative periodontitis (NUP) are clinically identifiable conditions and, for now, AAP has placed both clinical conditions under the single category of “Necrotizing Periodontal Diseases.” This may be subject to change in the future.[18]

1. Necrotizing ulcerative gingivitis (NUG)

707792000 |Necrotizing ulcerative gingivitis (disorder)| (Added January 2015)

Definition. Necrotizing ulcerative gingivitis (NUG) is an acute infection of the gingiva. Where NUG has progressed to include attachment loss, it has been referred to as necrotizing ulcerative periodontitis (NUP).[19]

Q for SME: Are the following three SNOMED concepts duplicates?

707792000 |Necrotizing ulcerative gingivitis (disorder)|

409865002 |Vincent's disease (disorder)|

399050001|Acute necrotizing ulcerative gingivitis (disorder)|

Some sites mention chronic necrotizing ulcerative gingivitis, but others use the three terms interchangeably (e.g., the following site which was reviewed by The Columbia University College of Dental Medicine):

Necrotizing ulcerative gingivitis (NUG) is a condition affecting the gums that is caused by a bacterial infection. It is a form of periodontal (gum) disease. But unlike other forms, it typically develops quickly and causes moderate to severe pain. This condition used to be known as acute necrotizing ulcerative gingivitis (ANUG) and Vincent's disease, among other names. http://www.simplestepsdental.com/SS/ihtSSPrint/r.==/st.32219/t.33417/pr.3/c.357875.html

1. Necrotizing ulcerative periodontitis (NUP)

707320004|Necrotizing ulcerative periodontitis (disorder)| (Added January 2015)

47548009 |Necrotizing ulcerative gingivoperiodontitis (disorder)|

Q for SME: Are the two concepts above duplicates? Is the latter the old name?)

1. Abscesses of the Periodontium

83412009 |Periodontal abscess (disorder)|

1. Gingival abscess

109610001 |Parulis (disorder)| SIRS ID 601551 Synonym: Gingival abscess (Added August 24, 2015)

Q for SME: This is not a subtype of 83412009 |Periodontal abscess (disorder)| in SNOMED. Should it be (not sure at all on this)? Also, is this always infectious in etiology?  (If so, it is not currently modeled with 370135005 |Pathological process (attribute)| = 441862004 |Infectious process (qualifier value)| and should be. This may true for the abscesses below as well.)

1. Periodontal abscess

83412009 |Periodontal abscess (disorder)|

1. Pericoronal abscess

109631003 |Pericoronal abscess (disorder)|

1. Periodontitis Associated With Endodontic Lesions MISSING

This is probably not needed as a grouper in SNOMED as it has just one subtype.

1. Combined periodontic-endodontic lesions

235006007 |Periodontal and endodontic lesion (disorder)|

1. Developmental or Acquired Deformities and Conditions MISSING

With the exception of one concept in Section D (Occlusal trauma), this content was not in the July 2015 Release. However, that is changing as of August 19^th, 2015 when a number of these requests were received and may have been added to SNOMED. Where possible, the new SIRS Requests and their status have been noted.

1. Localized tooth-related factors that modify or predispose to plaque-induced gingival diseases/periodontitis MISSING probably not needed

For concepts below, it is not clear that the use of the plural is indicated.

1. Tooth anatomic factors

Note: SIRS Request Id: 601520: Periodontitis due to tooth anatomic factors (disorder)

1. Dental restorations/appliances 

Note: SIRS Request Id: 601514: Periodontitis due to dental appliances (disorder)

1. Root fractures

Note: SIRS Request Id:  601518: 713211001 |Periodontitis due to fracture of root of tooth (disorder)| (Added August 20, 2015)

1. Cervical root resorption and cemental tears

Note: SIRS Request Id 601512:  Periodontitis due to cemental tears (disorder) – In Process

Note: SIRS Request Id 601513:  713256008 |Periodontitis due to cervical root resorption (disorder)| (Added August 24, 2015)

1. Mucogingival deformities and conditions around teeth MISSING
   1. Gingival/soft tissue recession

4356008 |Gingival recession (disorder)| synonym: "Gingival soft tissue recession" (added late August 2015)

1. facial or lingual surfaces MISSING
2. interproximal (papillary) MISSING
3. Lack of keratinized gingiva

707219007 |Lack of keratinized gingiva (disorder)|

1. Decreased vestibular depth

Note: SIRS Request ID 601412: Decreased vestibular depth (finding) Requested as IS_A Oral cavity finding (finding).

Q for SME: The following two concepts are be too specific to represent this AAP term, but are they duplicates?

109793005 |Shallow vestibular depth after teeth loss (disorder)|

109794004 |Inadequate vestibular depth after teeth loss (disorder)|

1. Aberrant frenum/muscle position

109556002 |Aberrant insertion of frenum of tongue (disorder)|

1. Gingival excess
   1. pseudopocket

Note: SIRS ID 601432: Gingival excess due to pseudopocket (disorder) – In Process

1. inconsistent gingival margin

Note: SIRS ID 601475: Inconsistent gingival margin due to mucogingival deformity (disorder)

1. excessive gingival display

Note: SIRS ID 601552: Change FSN on concept 698275009|Gummy smile (finding) to Gingival excess on display of smile

1. gingival enlargement (See I.A.3.and I.B.4.)

Note: SIRS ID 601554: 441787004 | Hypertrophy of gingiva (disorder)| - Requests to add Synonyms Gingival excess-gingival enlargement, and Gingival soft tissue enlargement - Clarification of Request pending

1. Abnormal color MISSING
2.  Mucogingival deformities and conditions on edentulous ridges

 Note: SIRS Request Id 601495: Mucogingival deformity on edentulous ridge (disorder)

1. Vertical and/or horizontal ridge de?ciency

708494003 708494003 |Deficiency of alveolar ridge (disorder)| (Added Jan 2015)

1. Lack of gingiva/keratinized tissue

Note: SIRS Request Id 601498: Mucogingival deformity on edentulous ridge due to lack of keratinized gingiva (disorder)

1. Gingival/soft tissue enlargement
2. Aberrant frenum/muscle position

Note: SIRS Request Id 601496: Mucogingival deformity on edentulous ridge due to aberrant frenum/muscle position (disorder) - In Process

1. Decreased vestibular depth

Note: SIRS Request Id 601497: Mucogingival deformity on edentulous ridge due to decreased vestibular depth (disorder) - In Process

1. Abnormal color
2. Occlusal trauma

43043007 |Periodontal lesion due to traumatic occlusion (disorder)| Synonym: Acute traumatic periodontitis

AAP Definition (1): Occlusal trauma: Injury resulting in tissue changes within the attachment apparatus as a result of occlusal force(s).

Q1 for SME: Not all periodontal lesions are periodontitis. Is the synonym Acute traumatic periodontitis too specific for the FSN above or are all lesions related to traumatic occlusion considered to be inflammation?

Q2 for SME: SCT also has 109647001 |Occlusal trauma (disorder)| which is not related to periodontal disease in SCT. It has subtypes 109648006 |Primary occlusal trauma (disorder)|, 109649003 |Secondary occlusal trauma (disorder)|, and 109650003 |Localized secondary occlusal trauma (disorder)|.

Based on the AAP definition of Occlusal trauma above, is 109647001 |Occlusal trauma (disorder)| ever used to refer to changes that do not involve the periodontium? Is 43043007 |Periodontal lesion due to traumatic occlusion (disorder)| actually a duplicate for the existing concept 109647001 |Occlusal trauma (disorder)|?

1. Primary occlusal trauma

AAP Definition: Injury resulting in tissue changes from excessive occlusal forces applied to a tooth or teeth with normal support.

Note: SIRS ID 601517 Periodontitis due to primary occlusal trauma (disorder) (Added 8/20/15)

Q for SME: Is this a duplicate for 109648006 |Primary occlusal trauma (disorder)|?

1. Secondary occlusal trauma

AAP Definition: Injury resulting in tissue changes from normal or excessive occlusal forces applied to a tooth or teeth with reduced support.

Note: See SIRS Request Id: 601519 for Periodontitis due to secondary occlusal trauma (disorder) (Added 8/20/15)

Q for SME: Is this a duplicate for 109649003 |Secondary occlusal trauma (disorder)|?