Inter-radicular distance between the maxillary second premolar and the first molar

Abstract

The aim of this study was to evaluate the effect of the curvature of mesiobuccal root of the maxillary first molar in the space between the maxillary second premolar and the first molar, which is the preferred site for mini-implant placement. In this study, cone-beam computed tomography (CBCT) data of 85 patients (36 male, 49 female; 14-38 years old) were used to measure the mesiobuccal root length of the maxillary first molar and the distance from the cementoenamel junction (CEJ) to the most curved point of the mesiobuccal root of the maxillary first molar. The interradicular distance between the maxillary second premolar and the first molar, and the buccolingual width of alveolar bone and cortical bone thickness at the plane 4-, 6-, and 8-mm apical to the CEJ were also measured. The length of the mesiobuccal root of the maxillary first molar was 11.2 ± 1.1 mm, and the distance from CEJ to the most curved point was 6.4 ± 0.7 mm, which was about 57.4% of the root length. The interradicular distances were almost same at the 4- and 6-mm planes, but increased significantly between the 6- and 8-mm planes. Although the buccolingual widths of the alveolar bone was increased apically, cortical bone thicknesses were not different among the 4-, 6-, and 8-mm planes. The interradicular distance does not increase between the 4-mm and 6-mm planes from CEJ because of the presence of the curvature of the mesiobuccal root of maxillary first molar.