How the Perception of the Most Pleasing Nasolabial Angle Has Changed throughout the Years: a systematic review of literature

Background: Harmonious and esthetic facial profile is confidently one of the important goals to be achieved at the end of orthodontic treatment. The perception of beauty and attractiveness is vastly influenced by media and thus, can change with trends over time. The aim of this study is to assess the nasolabial angle in facial profiles perceived as attractive; and whether or not the perception of the most pleasing nasolabial angle has changed through time. Methods: We performed a systematic review of literature using three different search engines (PubMed, Scopus, and Embase), based on terms ?esthetics?, ?beauty?, ?attractive?, ?facial profile?, ?cephalometry?, ?cephalometric analysis?, ?nasolabial angle?, and ?soft tissue?. Our selection criteria were comprised of studies indicating facial attractiveness by a panel of at least 10 judges, evaluated the cephalometric characteristics and stated the preferred nasolabial angle. Results: The search results revealed 470 related articles of which 226 full texts matched our inclusion criteria. Among these, 20 studies investigated nasolabial angle as a conducive factor. The maximum amount of reported nasolabial angle was 123 degrees, which belonged to a sample of Italian women in 2010; while the minimum was 84 degrees, representing the profile preference for African-Americans in 1995. Conclusion: It can be concluded that the most pleasing lip position and subsequently nasolabial angle is influenced by variables, including observer and subject?s gender, level of professional education, culture, and ethnic background. As for the measure of nasolabial angle, since 1979 to date, the trend has had its peaks and troughs and no distinctive pattern of change was found. In general, it seems that more obtuse nasolabial angle is perceived to be more pleasing.