Prevalence and factors associated with gummy smile in adolescents: a cross-sectional analysis

Abstract

Aim: To evaluate the prevalence and factors associated with gummy smiles in adolescents aged between 15 and 18 years attending high school. Methods: The cross-sectional and quantitative study was carried out during the Covid-19 pandemic, with 160 adolescents, from two public (A1) and two private (A2) schools chosen by lottery, divided into two groups: G1 (with gummy smile) and G2 (no gummy smile). A clinical examination was carried out on the adolescents, investigating the presence or absence of a gummy smile (GS), by analyzing the variables (interlabial distance at rest, upper incisor exposure at rest, smile arc, measurement from the subnasal to the upper lip philtrum, upper lip length, upper lip thickness, hypermobility and lower/middle third ratio). Means and dispersion were obtained, and the Chi-square association test was applied, to compare the results between A1 and A2 and between G1 and G2. Results: The prevalence of GS was 33.8% (=54). It was found that no statistically significant associations were found (p > 0.05), regarding the type of school and gender with the presence of GS in adolescents. There was no statistically significant difference (χ2 = 1.82; p = 0.07) between the groups and the age of adolescents. There was a significant association between the studied variables and GS (p < 0.05). Conclusion: The prevalence was high with a predominance of females. There were no statistically significant associations regarding the type of school and gender, but there was a significant association between gummy smile and lip dimensions.