Evaluation of the Relationship between Mandibular Third Molars and Adjacent Second Molars - Panoramic Radiography vs. CBCT

BACKGROUND Negative effects of third molars (3Ms) on the periodontal conditions of adjacent second molars (2Ms) depending on the level of impaction are quite common. Radiographic evaluation is of great importance in such cases. Therefore, the purpose of this study was to compare the efficacy of panoramic radiography (PR) and cone-beam CT (CBCT) images to determine the amount of bone loss on the distal side of 2Ms in relation to mandibular 3Ms. METHODS Radiographic data of 491 patients selected consecutively from the database were scanned. After applying the exclusion criteria, PR and CBCT images of a total of 97 patients were analyzed. The chi-square test was used to determine whether there was a relationship between the independent variables. The measurement of the agreement between PRs and CBCTs was calculated using Cohen's kappa coefficient. RESULTS 97 patients (47 females and 50 males) aged between 18-67 years (33.79±12.23 years) were included in this study. Most of the patients were in their 20s (41.2%). Moderate agreement was found between measurements made using PR and CBCT to determine bone loss in the distal side of the 2M. While bone loss was recorded in 53.7% of the teeth as a result of measurements made with PRs, this prevalence was determined as 61.5% in measurements made with CBCTs. (κ=0.448; P<0.001). There was no difference in terms of bone loss according to gender and location, while the highest rate of bone loss was observed in individuals aged 50 and over. In addition, a maximum bone loss was detected when 3M's position was horizontal and Class III / Level C according to Winter and Pell & Gregory classifications, respectively. CONCLUSIONS In individuals with 3M teeth, it is critical to use radiographs at regular intervals to monitor the periodontal status of 2M teeth, even in the absence of symptoms. In cases where severe bone loss is observed or suspected to be severe, CBCT provides detailed information and facilitates the clinician in planning any intervention.