Color Distribution and Visual Color Assessment of Human Gingiva and Mucosa: A Systematic Review of the Literature

Purpose: This study undertook a systematic overview of the literature on the description and visual measurement of gingival color. Materials and Methods: Two research questions were formulated. The first addressed the description of gingival color, while the second aimed at visual color measurement techniques. An electronic search was performed in 22 literature databases. The electronic search was complemented by hand searching. The retrieved articles were independently reviewed by two members of the research team. The levels of evidence of the articles were classified following the guidelines of the Oxford Centre for Evidence-Based Medicine. Results: Of the nine articles retrieved by the two searches, six applied to the first question, two applied to the second question, and one applied to both questions. Three articles were published in Japanese and dealt with the color of gingival and alveolar mucosa. The clinical studies showed that the intraoral tissues of younger persons are of a lighter color. Evidence levels were no higher than 4. Conclusion: Studies on the description of gingival color used a narrative approach. Studies on visual gingival color measurement had diverse aims, methods, and parameters. It is impossible to compare or even combine their outcomes in a scientifically meaningful manner. Since none of the investigations used a controlled or randomized design, they represent low levels of evidence.