Influence of Facial and Occlusal Characteristics on Gummy Smile in Children: A Case-Control Study

Abstract

Objective: To determine the association between occlusal and soft tissue characteristics with the presence of gingival smile (GS) in a pediatric population with inter-transitional mixed dentition. Material and Methods: Case-control study was performed with a probabilistic sample of 163 children in inter-transitional mixed dentition (age:8.8 years ±0.8). 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. Kappa test and intraclass correlation coefficient were done (0.87-0.96). 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 Student t test. A multivariate binary logistic regression was performed. Results: Class II malocclusion, short upper lip at smile and short incisor clinical crown, were risk factors for gummy smile (OR= 10.4, 95%CI 3.07-34.95, OR= 2.1, 95%CI 1.44-3.13 and OR= 2.5 95%CI 1.34-4.54 respectively). Lower facial height was a protective factor against GS (OR= 0.76; 95%CI 0.69-0.85). The logistic regression model explains 48% of GS variability. Conclusion: Class II malocclusion is considered a risk factor for gummy smile. Other variables associated to gummy smile were short upper lip and short incisor clinical crown. Clinicians should considered these aspects in clinical examination of each patient to provide an adequate diagnostic and plan of treatment to control and/or correct a GS.

Morphological differences in lower facial third soft tissues in children with and without gingival smile: A cross‐sectional comparative study

“…Research studies have been carried out in an attempt to show the factors related to GS development. Some factors related to the risk of gingival smile have been the enlarged length between the subnasal point and the incisal border of anterior‐superior teeth, the greater capacity to lift the upper lip while smiling, the increased OB and OJ, and the length of the upper central incisor clinic crown . Likewise, it has been found that class II malocclusion and the vertical anterior excess are factors that influence the presence of GS …”

“…Studies have been conducted on the presence of GS in adults, but few studies on children show what characteristics influence either the presence or absence of GS . Therefore, the objective of the present study was to describe the characteristics of lower facial height in children with and without GS, and describe their differences, as well as to determine if increased LFTH was directly related to GS.…”

“…A video was made of the individuals who met the selection criteria, according to the protocol described by Barbosa et al., with the purpose of obtaining images of the individuals both at rest and while smiling. The video camera was placed 70 cm from the individual in natural head position with the help of the cephalostat.…”

“…In the general population, GS are fairly common, with a prevalence of 26%, and are one of the most frequent reasons for dental appointments . Research has been conducted on the factors related to GS development, and has found that some of the factors associated with the presence of this type of smile are the enlarged distance from the subnasal point to the incisal edge of anterosuperior teeth, the class II malocclusion, lower facial vertical height excess, incisor labial inclination, increased overbite (OB) and overjet (OJ), thickness and length of the upper lip reduction, and a larger distance …”

“…Studies have been carried out on the presence of GS and its characteristics in adults, but there have only been a few published studies on characteristics of lower facial height in children with GS, and it is not clearly determined how lower facial height affects or perpetuates GS.…”