Buccolingual Inclination of Posterior Teeth in Untreated Adults with Unilateral Tooth Loss: A CBCT Investigation

Abstract

Background: T o evaluate the buccolingual inclinations of posterior teeth in untreated adults with and without unilateral, partial edentulism by using CBCT images.
Methods: One hundred and one untreated adults (47 males, 54 females), who had CBCT images (average age: 49.79 years) participated in the study . T wo sub-groups of patients were considered: fully dentate patients and patients with loss only of the first molar. The images were oriented according to the long axis of the tooth and visualized in coronal slices. Dental landmarks were used to evaluate the buccolingual inclination of the second permanent maxillary and mandibular molars.Right mandibular second molars of the subjects with the first mandibular molar absent appeared to be approximately 1 4° more inclined in lingual direction than those of the other subjects. There was no significant difference related to gender.
Results: The buccolingual inclination of the second mandibular molar on the edentulous side is greater than the buccolingual inclination of the second maxillary molar on the edentulous side. The inclination of the second right mandibular molar shows a significant difference between the group of fully dentate patients and the group of patients with a first molar absent (p=0.001); the angle Ay(MMd2)r/MdP being more closed in partially toothed subjects (86.7°). In other words, only the second right mandibular molar has a more pronounced bucco-lingual inclination
Conclusion: There exists a significant increase of the lingual tilting of mandibular molars adjacent to the sites of the partial edentulism. Correction of this inclination will therefore be necessary to maintain a certain degree of Wilson's curve at the end of orthodontic treatment to meet physiological needs and stability .