RESUMO
OBJECTIVE: To conduct a comparative study between two techniques for assessment of alveolar bone loss. MATERIALS AND METHODS: Absolute and relative techniques were evaluated. The sample consisted of 16 radiographs supposed to meet a single criterion: The reference points applied (Cementum-enamel junction (CEJ) alveolar bone crest and root apex) should be visible. Bone height was measured in the selected radiographs as the percentage of root length through both techniques. Data were submitted to the Statistical Package for Social Science software. Results obtained by both methods were converted into bone loss index values and then categorized. Sensitivity and specificity of the relative technique, compared to the absolute technique, were calculated. Wilcoxon test and the Bland and Altman's method were employed for comparisons. Significance level was set at 5%. RESULTS: For the absolute and relative techniques, means of bone loss index were respectively of 4.81 (±2.25) and 4.75 (±1.80). Bone loss index ≥6 (alveolar bone loss ≥50%) was found in 5 (31.2%) teeth, in the absolute technique, and in 4 (25%) teeth, according to the relative technique. There was no statistically significant difference between both methods (P>0.05). According to the Bland and Altman's method, it was verified a bias of 0.06, and limits of upper and lower agreement of, respectively, 1.58 and -1.45. Sensitivity of 0.8 and specificity of 1 were found for the relative technique compared to the absolute one. CONCLUSION: There was no significant difference between the techniques evaluated, and the relative technique was found to be reliable for measuring alveolar bone loss.