Evaluation of Mandibular Lingual Concavity in Premolar and Molar Region Using ConeBeam Computed Tomography (CBCT)

Background: Implant therapy has become an integral part of dental practice. However, surgical accidents and complications by placing implants may occur. So knowledge of bone morphology is mandatory for correct implant direction. The aim of this study was to evaluate the morphological parameters of mandibular concavities using Cone-beam Computed Tomography. Methods: In this study, 100 cone-beam computed tomography images were assessed on cross-sectional view. The mandible morphology 2 mm above the inferior alveolar canal was classified into the convex (C), parallel (P) and undercut (U) type, based on the presence of lingual concavity and the shape of alveolar ridge. The prevalence of each group and the lingual concavity characters, including the depth and the angulation were determined by the measurements of selected anatomic landmarks. Data analysis was performed through SPSS26 and using Pearson correlation, t- test and Chi-Square test. The significance level was set at 0.05. Results: One hundred subjects (mean age: 38.89± 12.10, range of 19-63 years) were studied. The U type was the most prevalent, accounting for 51% of the study population. The mean undercut depth and angulation at the level 2 mm above the inferior alveolar canal were respectively 3/22 ± 0.92 mm and 50.42 ±4.75 degree. Concavity depth and its angle showed no significant correlation with age, gender, edentulous area and type of ridge. Conclusion: The anatomic location and the degree of the lingual concavity presented in this article added more information about implant treatment planning at mandibular premolar and molar regions.