Effect of gingival phenotype on the maintenance of periodontal health: An American Academy of Periodontology best evidence review

BACKGROUND: Gingival thickness, keratinized tissue width, and bone morphotype are three important parameters used to categorize periodontal phenotypes. These elements all play an important role in the maintenance of periodontal health. The aim of this review is to explore the importance of converting thin phenotype into a thick phenotype for periodontal health maintenance. METHODS: Three clinically relevant focused questions were defined to understand the role of gingival phenotype around teeth. 1) What are the factors affecting gingival phenotype (e.g., age, sex, dental arch, race, crown forms, etc.)? 2) Is there a difference between thin versus thick gingival phenotype in terms of gingival health? 3) Does the conversion of gingivae from a thin to thick gingival phenotype in sites without mucogingival defects help with periodontal health maintenance? RESULTS: Extensive electronic and manual literature search identified a total of 1,129 citations. After title, abstract, and full-text screenings, 30 articles were included in the present review. Twenty-five studies met the inclusion criteria and provided data for focused question 1. It was found that periodontal phenotype varies among different individuals and different areas of the mouth within the same individual. Asian individuals tend to have thinner gingival phenotype compared with white subjects. Eleven studies met the inclusion criteria for the focused question 2. Prevalence and severity of gingival recession was higher at the sites with thin gingiva compared with the sites with thicker gingiva. No studies provided data for focused question 3. CONCLUSIONS: Available evidence indicates that subjects with thin and narrow gingiva tend to have more gingival recession compared with those with thick and wide gingiva. Currently, there is no published evidence to support conversion of thin to thick gingival phenotype in sites without gingival recession or mucogingival deformity.