关键词: Ⅱ期牙周炎, 牙周病新分类, 诊断, AutoCAD, 骨吸收

Abstract: Objective    To apply AutoCAD software to measure alveolar bone loss boundaries and to preliminarily evaluate its feasibility as reference values for assisting the diagnosis of stage Ⅱ periodontitis. Methods    A retrospective analysis was conducted on clinical and radiographic data from 612 patients who underwent periapical radiography at the Department of Radiology，Stomatology Hospital of Shanxi Medical University between 2023 and 2024. A total of 1 272 teeth were included，comprising 116 central incisors，110 lateral incisors，106 canines，340 first premolars，330 second premolars，and 270 molars. AutoCAD software was used to precisely measure root length，as well as 15% and 33% of root length on periapical radiographs. In addition，the proportions of root length corresponding to distances of 1 mm and 2 mm apex to the cemento-enamel junction（CEJ）were calculated. For a representative case of mild periodontitis，20 periodontists independently assessed the degree of alveolar bone loss of the mandibular second premolar using three approaches：visual estimation by clinicians，AutoCAD-based measurement，and assessment based on the reference values established in this study. Results    In the maxilla，15% of root length for central incisors，lateral incisors，canines，first premolars，second premolars，buccal roots of molars，and palatal roots of molars was（2.35 ± 0.16）mm，（2.24 ± 0.16）mm，（2.83 ± 0.08）mm，（2.14 ± 0.18）mm，（2.15 ± 0.17）mm，（1.50 ± 0.23）mm，and（2.20 ± 0.15）mm，respectively，while the corresponding 33% values were（5.17 ± 0.35）mm，（4.93 ± 0.36）mm，（6.24 ± 0.19）mm，（4.70 ± 0.40）mm，（4.72 ± 0.37）mm，（3.31 ± 0.51）mm，and（4.83 ± 0.32）mm. The proportions of root length represented by 2 mm apex to the CEJ were（13 ± 1）%，（13 ± 1）%，（11 ± 0）%，（14 ± 1）%，（14 ± 1）%，（20 ± 3）%，and（14 ± 1）%，respectively. In the mandible，15% of root length for central incisors，lateral incisors，canines，first premolars，second premolars，first molars，and second molars was（2.13 ± 0.10）mm，（2.22 ± 0.12）mm，（2.72 ± 0.22）mm，（2.28 ± 0.16）mm，（2.26 ± 0.18）mm，（2.03 ± 0.16）mm，and（1.99 ± 0.19）mm，respectively，while the corresponding 33% values were（4.68 ± 0.21）mm，（4.88 ± 0.26）mm，（5.98 ± 0.47）mm，（5.01 ± 0.35）mm，（4.97 ± 0.40）mm，（4.48 ± 0.34）mm，and（4.38 ± 0.42）mm. The proportions of root length represented by 2 mm apex to the CEJ were（14 ± 1）%，（14 ± 1）%，（11 ± 1）%，（13 ± 1）%，（13 ± 1）%，（15 ± 1）%，and（15 ± 1）%，respectively. Case-based analysis showed that using visual estimation，10%（2/20）of clinicians made the diagnosis of stage Ⅰ periodontitis and 90%（18/20）made the diagnosis of stage Ⅱ periodontitis. In contrast，assessments based on AutoCAD-based measurements and the reference values established in this study demonstrated good inter-observer agreement among all clinicians，with intraclass correlation coefficients of 0.86 and 0.89，respectively，both supporting a diagnosis of stage Ⅱ periodontitis. Conclusion    AutoCAD-based reference values of 15% and 33% of root length measured on periapical radiographs may be used to assist the diagnosis of stage Ⅱ periodontitis. In contrast，a CEJ-to-alveolar crest distance greater than 2 mm as the criterion for deciding alveolar bone loss has limitations.

Key words: stage Ⅱ periodontitis, new classification of periodontal diseases, diagnosis, AutoCAD, bone loss