Transverse features of subjects with sucking habits and facial hyperdivergency in the mixed dentition.

INTRODUCTION The aim of this study was to analyze the transverse characteristics of subjects with sucking habits and hyperdivergency in the mixed dentition. METHODS The test group consisted of 80 subjects with sucking habits and hyperdivergency in the intermediate mixed dentition, and it was compared with a control group of 185 subjects. The prevalence rate of posterior crossbite was recorded. Maxillary and mandibular intercanine and intermolar widths, and anterior and posterior transverse interarch discrepancies were measured on the dental casts. The statistical comparisons between the test and control groups were performed with independent sample t tests and chi-square tests (P <.05). RESULTS The prevalence rate of posterior crossbite in the test group was significantly greater (52%) than in the control group (14%) (P <.001). The test group had significantly smaller maxillary intermolar and intercanine widths and significantly greater posterior transverse discrepancy (P <.01). No significant differences were found for mandibular intermolar and intercanine widths or anterior transverse discrepancy. CONCLUSIONS Prolonged sucking habits and hyperdivergency in the mixed dentition were associated with narrow maxillary intermolar and intercanine widths, increased posterior transverse discrepancies, and increased prevalence of posterior crossbites.