The aim of the study is to evaluate the usefulness of cone-beam computed tomography (CBCT) in the assessment of the relationship between the cemento-enamel junction (CEJ) and bone crest of the anterior mandibular cortex. The study population comprised 39 males and 61 females, aged 18-71. A GENDEX GXCB-500 machine, i-CAT Vision and CorelDraw 9 software were used. The distances between the CEJ and bone crest at buccal and lingual sides of six anterior mandibular teeth were measured. Descriptive statistical methods, Student's t-test and ANOVA were used. The mean distance between the bone crest and CEJ was 2.32 mm ± 0.78 mm at the buccal and 2.52 mm ± 0.85 mm at the lingual side. It was found that in males aged over 50 years, the mean distance at the buccal side was 2.84 mm ± 0.79 mm and was significantly higher than in males aged 49 and less - 2.08 mm ± 0.41 mm. The mean distance at the lingual side was 3.28 mm ± 1.08 mm and was significantly lower in the age group of 49 years and less - 2.10 mm ± 0.41 mm. CBCT allows determining the distance between the CEJ and crestal bone margin at buccal and lingual sides. The data provide crucial information for planning orthodontic treatment, implant placement and periodontal therapy.