NHẬN XÉT ĐẶC ĐIỂM HÌNH THÁI ỐNG RĂNG DƯỚI VÀ MỐI LIÊN QUAN VỚI RĂNG HÀM LỚN THỨ 3 HÀM DƯỚI TRÊN PHIM CT CONEBEAM TẠI BỆNH VIỆN ĐẠI HỌC Y HÀ NỘI

Abstract

Objective: To evaluate the morphological characteristics of the mandibular canal (MC) and its relationship with the mandibular third molar on cone-beam computed tomography (CBCT) images at Hanoi Medical University Hospital in 2024. Methods: A cross-sectional descriptive study was conducted on 55 CBCT images of patients aged 25–44 years who had both mandibular third molars. The CBCT scans were obtained at Hanoi Medical University Hospital from March 2024 to June 2024. Patients underwent history taking, clinical examination, and CBCT imaging. Study variables included sex, MC morphology, buccolingual diameter of the MC, presence of bifid MC, classification of bifid MC morphology, position and number of mental foramina, and the relationship between the MC and the roots of the mandibular third molar according to Parant’s classification. Results: Among the 55 CBCT images, 25 were from female patients, a lower proportion than males (54.50%), and the difference between sexes was statistically significant. According to Carter and Keen’s classification, type I MC morphology was the most common, accounting for 60.91%. Type III MC morphology (bifid mandibular canal) accounted for 18.18%. Based on the classification by Langlais et al., types I and II were equally prevalent, each accounting for 35%, while type III accounted for 10% and type IV for 20%. The MC diameter was relatively similar on both sides of the mandible. The most common finding was a single mental foramen; no cases with three or four mental foramina were observed. The mental foramen was most frequently located below the root of the second premolar. The proportion of cases in which the MC was centrally located within the mandibular bone and separated from the apex of the mandibular third molar root accounted for 61.82%. Conclusion: The mean age of the patients was 30.65 ± 10.63 years, and the sex difference in this study was statistically significant. Type I MC morphology was the most prevalent, and bifid MC (type III) was also commonly observed. The MC diameter was relatively similar on both sides of the mandible. The mental foramen was most commonly located beneath the root of the second premolar. Most cases showed the MC centrally positioned within the mandible and separated from the apex of the mandibular third molar root.