RESUMO
The main objective of this study was to quantify the transverse maxillary dimensions using orthodontic cast models of individuals with natural normal occlusion. Sixty-eight pairs of orthodontic models were evaluated with the respective posteroanterior radiographies of white adults (38 women and 30 men; mean age, 17 years and 5 months). The models were placed in Class I molar occlusion, and on each pair, 4 points were marked on the alveolar buccal ridge (2 on the premolar region and 2 on the molar), determining the upper and lower transverse interpremolar and intermolar dimensions. The variables analyzed in the 3 measurements, obtained from the cephalometric radiographies and the cast models, showed no statistical differences. The upper intermolar distance was 57.20 +/- 2.60 mm; the lower intermolar, 55.16 +/- 2.40 mm; the upper interpremolar, 42.17 +/- 2.19 mm, and the lower interpremolar; 39.67 +/- 1.77 mm. On the posteroanterior cephalograms, the maxillary width was 65.97 +/- 3.42 mm and the mandibular width was 87.92 +/- 4.60 mm. There was intraresearcher and interresearcher correlation. There was no sexual dimorphism. The method proposed in this study can predict the transverse maxillary dimension, applying the formula ym = 8.62 + 0.88xm (ym = expected upper intermolar distance, xm = lower intermolar distance) for the molar region, and ypm = 4.87 + 0.94xpm (ypm = expected upper interpremolar distance, xpm = lower interpremolar distance) for the premolar region.
