3-Dimensional Radiographic Analysis Of Mandibular Homonym Premolars Using CBCT

To evaluate the 3-dimensional radiographic characterizations of mandibular homonym premolars (MHPs) using cone beam computed tomography (CBCT). CBCT images of 124 patients with MHPs were collected. The 3-dimensional radiographic characterizations of the MHPs were evaluated using NNT software, including the number, position, direction of torsion, bilateral symmetry, relationship to adjacent teeth and associated complications. The gender and age differences of these radiographic characterizations were analyzed. A total of 241 MHPs were found in the mandibular premolar regions. Most of the patients with MHPs were adolescent males (10∼20 years). The majority type of MHPs was single (41.94%), and most of the MHPs were located lingually within the mandibular premolar regions. 66.94% of the MHPs were asymmetrically distributed. Males were primarily asymmetrically distributed, whereas females were more symmetrically distributed, with statistically significant differences (P<0.05). According to the analysis of the 3D spatial position of the CBCT, the MHPs were located on the lingual side of the mandibular basal bone (90.87%), and the torsion angle was predominant >45° (57.26%), the axial angle was dominant (29.84%), and the axial position was usually orthogonal (73.86%). Most of the patients had adjacent teeth affected by the MHPs (57.26%). There were gender and age differences in the occurrence characteristics of MHPs. MHPs had certain 3-dimensional spatial positional distribution characteristics. CBCT can accurately analyze the positional distribution of MHPs.