Does the use of CBCT prior to mandibular third molar surgery impact treatment planning?

Abstract

Purpose: To investigate whether cone-beam computed tomography (CBCT) alters the treatment decision for impacted third molar surgery (M3M) when the third molars demonstrate proximity to the inferior alveolar canal (IAC) on panoramic radiography (OPG) and to examine surgeons’ confidence in the various treatment options.

Methods: A retrospective study evaluating a series of randomized OPG and CBCT images and answering a set of questions regarding impacted M3M. The anatomical risk factors studied included proximity of M3M roots to the IAC, vertical relationship between the root of M3M and the IAC and interruption of the IAC cortex by M3M roots. The primary outcome variable was the treatment plan whether to observe, extract under local anesthesia, extract under general anesthesia or perform coronectomy. The secondary outcome variable was confidence in the proposed treatment plan. The Chi-square test was used to compare proportions and to test the differences in the treatment plan according to the studied independent variables. Binary logistic regression was used to determine the effect of anatomical factors. A P value < .05 was considered statistically significant.

Results: The study sample consisted of 132 impacted M3M from 71 patients. There were no significant differences in the proposed treatment plan when the imaging modalities (OPG and CBCT) were compared, P>.05. Examination of CBCT enabled detecting anatomical risk factors, P<.001. Binary logistic regression demonstrated the absence of IAC cortex interruption to be the most significant determinant towards planning for extraction on OPG (OR=3.1, P<.001.

Conclusions: The use of CBCT provides a better understanding of the anatomical relationship between the roots of M3M and the IAC. However, experienced surgeons dealing with impacted M3M with evidence of proximity to IAC on the OPG, can decide on the treatment modality without CBCT.