Dentogingival display through lip border movements: Report of the Committee on Research in Fixed Prosthodontics of the American Academy of Fixed Prosthodontics

Statement of problem Dentists strive to create natural looking teeth for their patients. However, much of the research on esthetic dentistry has used artificial and computer-generated images to establish esthetic norms. Altered images are helpful in determining personal preferences but may be misleading for natural norms. Purpose The purpose of this report from the Committee on Research in Fixed Prosthodontics of the American Academy of Fixed Prosthodontics was to establish an evidence base for clinical guidelines on lip mobility and the visibility of oral tissues. Material and methods A systematic search was conducted to collect data on the lip border movements and the visibility of teeth and gingiva of human participants. Results One thousand and ninety-six articles were processed, and, based on inclusion criteria, 48 articles were reviewed. The findings determined that the upper lip lengthens with age resulting, at rest, in less display of the maxillary teeth and more of the mandibular arch. When evaluating the maxillary incisal edge position at rest, the canines are the most reproducible. Women tend to display more gingiva in a social smile than men, but this may not be so for a true smile of joy. Both the middle and lower facial thirds should be evaluated to detect a maximal smile. Care must be taken not to classify a person incorrectly as having a low smile line because they could still have a potential to show gingiva. Conclusions Evidence-based clinical guidelines are offered to reduce the risk of esthetic failures.