Aim: Buccal bone thickness is an important factor in implant treatment, bone health after tooth extraction, apical surgery, and esthetic outcomes. We evaluated the distance from the mandibular premolar and molar teeth apices to the buccal cortical bone in southeastern Anatolian people using cone-beam computed tomography (CBCT). Methodology: This retrospective study was performed in 461 posterior teeth (220 premolars, 241 molars) of 133 patients (62 females, 64 males) at Dicle University, Faculty of Dentistry, Department of Oral and Maxillofacial Radiology. Data were analyzed using Student's t-tests and Tukey HSD tests. Results: The mandibular buccal bone was thicker in men than in women, but the difference was not statistically significant (p>0.05). The thinnest point of the mandibular buccal bone was measured in women as 2.431 mm and in men as 2.491 mm in the first premolar teeth. The thickest point of the mandibular bone was measured in women as 7.940 mm and in men as 7.859 mm in the distal roots of mandibular second molar teeth. For the mandibular first and second premolars, there was no significant difference in buccal bone thickness among the 10-29-, 30-49-, and 50-69-year age groups. The difference between the first and second molar mesial and distal roots of the age groups was significant at the level of buccal root thickness (p<0.05). Conclusions: It is important to examine buccal bone thickness (with CBCT) before surgical dental procedures for appropriate implant planning and surgical endodontic treatment.