Anatomically unpredictable, the mandibular third molar must be evaluated on the basis of its root formation. Wellformed crowns are often supported by fused, short, severely curved, or malformed roots. Most teeth can be successfully treated endodontically, regardless of anatomic irregularities, but root surface volume in contact with bone is what determines long-term prognosis. The clinician may find a single canal that is wide at the neck and tapers to a single apical foramen. Access is gained through the mesial aspect of the crown. Distally angulated roots often permit less extension of the access cavity. Difficult accessibility in the arch occasionally can be simplified by the use of engine-mounted files on reciprocal handpieces. All caries, leaking restorations, and pulpal calcifications should be removed and replaced with adequate temporary restoration. If the tooth is in heavy occlusal function, full cuspal protection is indicated postendodontically (Burns RC, Buchanan LS. Tooth Morphology and Access Openings. Part One: The Art of Endodontics in Pathway of Pulp, 6th Ed. p. 164).
Keywords: micro-computed tomography, micro-ct, marco versiani, micro-computer tomography, high resolution x-ray tomography, dental anatomy, root canal anatomy