Effect of Cone beam Computed Tomography on Treatment Decision of Wisdom Tooth

Objective: This diagnostic accuracy study aimed to evaluate the relationship between mandibular third molars (M3) and mandibular canal (MC) using panoramic radiographs (PR) and cone-beam computed tomography (CBCT) and to assess the effect of CBCT on treatment decision. Materials and Methods: CBCT scans of 150 patients with close association between MC and M3 on PR were included in the study. The degree of superimposition, Buccolingual position (buccal, central and lingual) and physical relationship (separation, contact and involved) were measured on CBCT images. Fisher's Exact test was used to evaluate differences between PR and CBCT. Results: All M3 were directly superimposed on the MC on PR; however, CBCT showed separation from the canal in 10% of M3 roots. Evaluation of CBCT images revealed that the probability to observe an involvement was significantly higher when the MC was in the lingual position (57.6%) than in other positions. Conclusion: Three-dimensional imaging is very useful to clarify the true relationship between M3 and MC relative to two-dimensional panoramic images, and the clinician may decide to change the treatment plan based on CBCT images in patients with high risk. Nevertheless, PR can be considered an acceptable diagnostic method with low radiation dose compare with CBCT