Morphology of third mandibular molars – an in vivo cone beam computed tomography study in Lower Silesia

Abstract Background Understanding the root and canal morphology of mandibular third molars (MTMs) is crucial for anatomical characterization of human dentition and effective endodontic treatment. This study investigates the number of roots, canal configurations, and the prevalence of C-shaped canals in MTMs using Cone Beam Computed Tomography (CBCT). Objectives To analyse root number, sex-related differences, canal configurations, and the prevalence of C-shaped canals in MTMs. Methods This cross-sectional study analysed CBCT scans of 261 MTMs from patients aged 18 and over according to Vertucci’s classification. Data were collected at the X-Ray Diagnostic Laboratory of Wrocław Medical University from January to April 2022. Statistical analyses included chi-squared tests with Bonferroni correction ( p < 0.05). Effect size was assessed using Cohen’s “w” (0.172) with test power of 0.64 at an alpha level of 0.05. Results Most MTMs had two roots (79.69%), followed by three roots (11.81%) and a single root (8.43%). Two-rooted teeth were more frequent in males (87.27%) than in females (74.17%, p = 0.027). Type I was the predominant root canal configuration in all categories. C-shaped canals were present in 5.36% of teeth, predominantly in single-rooted teeth (71.43%) and females (92.86%). Interobserver agreement was excellent (κ = 0.83), with an overall agreement of 91.7%. Intraobserver agreement was κ = 0.84 and κ = 0.86. Conclusions This study highlights variations in anatomical diversity of MTMs, emphasizing clinical importance of CBCT for accurate diagnosis and treatment planning, expanding anatomical knowledge. Findings underscore the prevalence of C-shaped canals and sex-related differences in root structure.