Relationship between crown and root canal anatomy of four-rooted maxillary molar teeth.

This study aimed to determine the prevalence of four-rooted teeth and the corresponding crown, root and canal morphology in maxillary molars. Cone-beam computed tomographic images for 1200 patients were examined, and 1799 maxillary first molar (MFM) and 2123 maxillary second molar (MSM) teeth were evaluated. Statistical analyses were performed at a 5% significance level. Only three MFMs (0.17%) and 30 maxillary MSMs (1.41%) were four-rooted. The most common four-root type was the double palatal root. A higher proportion of four-rooted teeth were observed in men (P < 0.05), and a high percentage of root fusion was seen in these teeth. The palatal half of the crown was wider in teeth with double palatal roots. Although rarely encountered, the diagnosis and proper treatment of these teeth are very important for endodontic success.