INFLUENCE OF FACIAL AND OCCLUSAL CHARACTERISTICS ON GUMMY SMILE IN CHILDREN: A CASE – CONTROL STUDY

Objectives: To determine the association between occlusal and soft tissue characteristics to the presence of gummy smile (GS) in a pediatric population with inter-transitional mixed dentition.
Methods: This case-control study was performed with a probabilistic sample of 163 children in inter-transitional mixed dentition. Cases were 37 children with GS, and controls were 126 children without GS. Occlusal variables were assessed through clinical examination, and soft tissue variables were assessed through photograms. Reliablity tests (Kappa and ICC) were done (>0.87). The association between malocclusion, gender, and types of smile was assessed using a Chi square test. Comparison of quantitative variables in smile groups was made by the Student t-test. A multivariate binary logistic regression analysis to determine the influence of variables related to GS was performed
Results: Class II malocclusion, short upper lip at smile and short clinical crown, are risk factors for gingival smile (OR = 10.4 CI(3.07-34.95), 2.1 CI(1.44-3.13) and 2.5 IC(1.34-4.54) respectively); lower facial height was a protective factor against GS (OR = 0.76 CI(0.669-0.858).
Conclusions: Class II malocclusion is a risk factor for the presence of gingival smile. Other occlusal and soft tissue variables associated to gingival smile are short upper lip and short incisor clinical crown.