The Accuracy of Bone Assessment Distal to Lower Second Molars Using Panoramic Radiography: A Systematic Review and Meta-Analysis

Panoramic radiography (OPG) evaluates mandibular third molar impaction (MTMI). This systematic review aimed to investigate the diagnostic accuracy of OPG in detecting bone loss distal to the lower second molars. The associated bone loss with different impaction positions and the most prevalent positions of MTMI were investigated as secondary outcomes. In January 2023, PubMed, Scopus, and Cochrane were searched to identify studies published between January 2012 and January 2023. Two examiners blindly selected the eligible studies for data extraction and quality assessment. Of 427 studies, 8 were suitable for data extraction. All studies reported bone loss distal to the second molar using OPG, ranging from 4.9 to 62.9%. The most frequent position of MTMI is mesioangular. The distal bone loss in the vertical and horizontal positions is statistically significant compared to typically positioned third molars and those that are fully erupted or impacted, but in a normal orientation (p-value 0.005 and 0.02, respectively). Bone loss was not statistically significant in the mesioangular position compared to other impacted positions (p-value 0.14). The risk of bias ranges between 66 and 88%. Despite its limitations, OPG is still considered a valuable tool to assess bone loss distal to the lower second molar in cases of an impacted mandibular third molar.