上颌第三磨牙根管形态：Maxillary Third Molar

Loss of the maxillary first and second molars is often the reason for considering the third molar as a strategic abutment. The other indication for endodontic treatment and full coverage is a fully functioning mandibular third molar. Careful examination of root morphology is important before recommending treatment. Many third molars present adequate root formation; and given reasonable accessibility, there is no reason why they cannot remain as functioning dentition after endodontic therapy. The radicular anatomy of the third molar is completely unpredictable, and it may be advisable to explore the root canal morphology before promising success. As an alternative to conventional hand instrumentation, the use of engine-mounted files in reciprocating handpieces may simplify the problem of accessibility. Precurving instruments helps guide them through tortuous canals. For visual and mechanical convenience the access may be overextended slightly with the knowledge that full coverage is mandatory. All caries, leaking restorations, and pulpal calcifications must be removed prior to instituting treatment. Some third molars will have only a single canal, some two, and most three. The orifice openings may be made in either a triangular arrangement or a nearly straight-line (Burns RC, Buchanan LS. Tooth Morphology and Access Openings. Part One: The Art of Endodontics in Pathway of Pulp, 6th Ed. p. 150.