Radiographic examination precedes removal of a mandibular third molar or third molar extraction if there is wisdom molar pain or wisdom molar inflammation. The radiographic image (CBCT) contributes to the treatment plan, herein the decision for removal of the tooth. Ideally, the radiographic examination of mandibular third molars should provide information about the tooth itself, the surrounding bone, the neighbouring tooth and related anatomical structures. Parameters that should be assessed are state of impaction, root development, angulation of the tooth, number of roots, root morphology, related pathology and, most importantly, the relation between the tooth/roots and the mandibular canal, and a sufficient image should display the whole third molar and the mandibular canal in the region.

Since CBCT images can display the examined volume in all anatomical planes, and the examiner is able to scroll through the sub-millimetre image slices, it may be assumed that more detailed information is offered than in 2D imaging. When an overprojection of the mandibular canal by the roots of the third molars is seen in the traditional 2D images, it is expected that CBCT can reveal the exact relationship between the third molar and the mandibular canal in cross-sectional image sections.

Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4277437/