The Association of Childhood Obesity with Dental Crowding and Skeletal Malocclusion

Hypothesis and Objective: Children with obesity have precocious dental development, with researchers suggesting that this may lead to increased dental crowding. This study aims to test the hypothesis that children with obesity have greater mandibular incisor crowding. Methods: Subjects were recruited from the UIC College of Dentistry’s Orthodontic Clinic (n=105) and categorized into healthy, overweight or obese body mass index (BMI) as defined by the Center of Disease (CDC) for children and adolescents. OrthoCAD was used to measure mandibular intercanine distance and crowding. Skeletal classification was determined by Steiner's analysis of traced cephalograms. Descriptive statistics, Kruskal-Wallis test, Chi-squared test and Spearman’s rank correlation were employed to examine differences in dental crowding and skeletal classification by CDC BMI categories and BMI percentile. Results: 78 children with a mean age of 13.72 years (SD 2.01) met the inclusion criteria. Among the total sample, mean crowding measured 2.36mm (SD 2.67) and mean intercanine distance measured 28.20mm (SD 2.84). BMI categorization of the sample included, 25 obese (35%), 13 overweight (17%), 39 healthy (50%) and 1 underweight (1%). Furthermore, skeletal classification of the sample indicated, 31% Class I (24 subjects), 46% Class 2 (36 subjects) and 23% Class 3 (18 subjects). There was no significant association between BMI and lower incisor crowding. In contrast, there was an association between BMI and intercanine distance, with higher BMI children having larger intercanine widths, when controlling for sex and age (rho=0.40; p<0.001). Furthermore, there was no association between BMI category and skeletal classification. Conclusions: In our sample, there is no evidence of increased crowding nor greater likelihood of skeletal malocclusion with childhood obesity. Remarkably, wider intercanine distances were observed that could contribute to decreased crowding. Although the cause of increased intercanine distance is unclear, this may reflect overall greater mandibular growth. IRB and/or ACC Protocol #: 2017-1276 and 2017-0956