Kích thước giải phẫu định khu vùng răng cối lớn thứ nhất hàm dưới trên conebeam CT

The aim of the study is to determine the distances to lower alveolar canal from anatomical structures in the region of the first lower molars in Vietnamese on CBCT. Subjects and methods: The study was conducted on 166 patients who had exposured using CBCT indicated by dentists in Nguyen Trai Dental CT Central, HoChiMinh City, from October 2015 to June 2016. The CBCT digital images were captures using Picasso Trio (Ewoo Vatech, Korea). CBCT digital images were displayed on the 14 inches flat monitor, at 1366 x 768 pixel resolution with EzImplant CD viewer software. The positions of the first lower molars were recorded. The images needed measured were converted to the original status (reset all action) with the magnification of 1.5 times. In the axial plane, the origin of coordinate axis was moved to the middle of each root of the first lower molars, so that the sagittal section line following buccal-lingual direction divided the root into relative same two parts. In the sagittal plane, the sagittal section line was adjusted following the axis of each root. In the coronal plane, some lines were drew and the needed dimensions were measured. Results: For the first lower molars with two roots, the distances from the mesial and distal apices to lower alveolar canal were 6.41±2.67 mm, 5.82±2.79 mm, respectively. For the first lower molars with three roots, the distances from the mesial and distal apices to lower alveolar canal were 7.02±2.16 mm, 6.89±2.26 mm, 8.02±2.33 mm respectively. Conclusion: Older the patient, longer the distances from lower alveolar canal to the root apices. There were significant differences about the distances from lower alveolar canal to some anatomical structures, that male distances were longer than female ones.