Analysis of the rotational position of the maxillary first permanent molar in normal occlusion and Class II, division 1 malocclusion

Marisa Helena Zingaretti JUNQUEIRA, Karyna Martins VALLE-COROTTI, Daniela Gamba GARIB, Ricardo Brandão VIEIRA, Flavio Vellini FERREIRA

Objective: The purpose of this study was to evaluate and compare the rotational position of maxillary first permanent molars (U6) in subjects in the permanent dentition presenting normal occlusion and Class II, division 1 malocclusion. Methods: Casts of 60 subjects with normal occlusion (Group 1, mean age 15.1 years) and 120 with untreated Class II, division 1 malocclusion (Group 2, mean age 15.5 years) were evaluated. The maxillary dental casts were scanned and the position of maxillary molars was analyzed using three angular measurements and one linear measurement, named indicators 1, 2, 3 and 4, respectively. The mesiopalatal rotation of maxillary first molars was evidenced by an increase in the values of indicators 1 and 4 and decrease in the indicators 2 and 3. Comparisons between groups were performed using Student´s t test for measurements with normal distribution and by the Mann-Whitney test for non-normal distribution, at p<0.05. Results: Statistically significant differences were found between Groups I and II for all indicators, on both right and left sides. Conclusion: It was concluded that individuals with Class II, division 1 malocclusion present greater mesiopalatal rotation of the maxillary first molars.

Keywords: Molar rotation. Normal occlusion. Class II Division 1. Orthodontics.

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