Title Open Gingival Embrasures Between Maxillary Central Incisors (Black Triangles), Following Orthodontic Treatment in Adults
Clinical Question Open gingival embrasures between maxillary central incisors (black triangles), following orthodontic treatment in adults.
Clinical Bottom Line In 38% of adults, orthodontic treatment may lead to open gingival embrasures. Risk factors include: Alveolar bone to interproximal contact distance greater than 5.5 mm, short and incisally located post-treatment proximal contacts, divergent root angulations and triangular-shaped crown forms. (See Comments on the CAT below)
Best Evidence  
PubMed ID Author / Year Patient Group Study type
(level of evidence)
11500652Kurth/2001119 patients who had completed orthodontic treatment, were used for measurements and divided into 2 groups: Normal gingival embrasures and open gingival embrasures.Retrospective Cohort Study
Key resultsThe authors found the prevalence of post-treatment open gingival embrasures in adult orthodontic patients was 38%. The authors reported that “When mesial crown form, alveolar bone–interproximal contact, and interproximal contact–incisal edge variables are constant, a 1%; increase in root divergence increased the odds of an open gingival embrasure by 14% to 21%.” The retrospective study design precludes control of other treatment variables, such as the type of orthodontic movements, mechanics, periodontal status, etc.
Evidence Search PubMed was searched using the following terms- Orthodontics, open gingival embrasure, black triangle.
Comments on
The Evidence
The best research on this topic was a retrospective study by Kurth & Kokich in 2001. Intra-oral photographs of 119 patients who had completed orthodontic treatment, were used for measurements and divided into 2 groups: Normal gingival embrasures and open gingival embrasures. Measurements of pretreatment maxillary central incisor overlap and rotation, and post-treatment alveolar bone height, interproximal contact height, crown shape, root angulation, and embrasure area were obtained to determine whether there was an association between these factors and open gingival embrasures. The authors found the prevalence of post-treatment open gingival embrasures in adult orthodontic patients was 38%. The authors reported that “When mesial crown form, alveolar bone–interproximal contact, and interproximal contact–incisal edge variables are constant, a 1%; increase in root divergence increased the odds of an open gingival embrasure by 14% to 21%.” The retrospective study design precludes control of other treatment variables, such as the type of orthodontic movements, mechanics, periodontal status etc. The authors did not have a control group of untreated individuals in the same age range, to compare the prevalence of open gingival embrasures. The influence of age was not assessed.
Applicability These results are applicable to all adults undergoing orthodontic treatment
Specialty (General Dentistry) (Orthodontics) (Pediatric Dentistry)
Keywords Orthodontics, open gingival embrasure, black triangles, esthetics
ID# 338
Date of submission 11/20/2009
E-mail RajV@uthscsa.edu
Author Vishnu Raj, DDS
Co-author(s)
Co-author(s) e-mail
Faculty mentor
Faculty mentor e-mail
   
Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?)
None available
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Comments and Evidence-Based Updates on the CAT
(FOR PRACTICING DENTISTS', FACULTY, RESIDENTS and/or STUDENTS COMMENTS ON PUBLISHED CATs)
by Garrett Klingsporn (San Antonio, TX) on 04/12/2012
I conducted a Pubmed search on this topic in April 2012 and found a more recent publication: Pubmed ID 20136942. This is a narrative review of 42 articles dealing with open gingival embrasures following orthodontic treatment. The findings in this article parallel what was found in the previous article, in fact it is the first paper referenced. This article strengthens and enhances the conclusions of this CAT.