Third molars: extraction or endodontics?
Fig. 1

A third mandibular molar was endodontically treated because of swelling and chronic pain upon chewing. After eight years, the tooth is healed and fully functional.

Third molars: extraction or endodontics?
Fig. 2

A third mandibular molar, used as an abutment for a removable partial denture in a 80 y/o patient, was endodontically treated more than ten years ago. Morphology quite unusual, one root, reported frequency 17% (Sidow et al., JOE 2000) At a seven-year recall, the periapical radiolucency disappeared.

Third molars: extraction or endodontics?
Fig. 3

Another third mandibular molar. Anatomical features are the most frequent for this tooth, two roots-three canals. Mesial canals were confluent, type II.

Third molars: extraction or endodontics?
Fig. 4

Mandibular third molars are often mesioinclinated, making endodontic access less difficult. On the other hand, maxillary third molars are distally inclinated, making access even more difficult than usual. In this particular case, however, a deep mesial carious lesion helped in accessing root canal anatomy. Endodontics was preferred upon extraction because of the risk of biphosphonate-related osteonecrosis of the jaw.

Third molars: extraction or endodontics?
Fig. 5

A good periapical radiograph would provide adequate information on the anatomy of third molar teeth and the surrounding structures; however, root dilacerations parallel to the x-ray beam would not always be apparent on the radiograph. CBCT should only be done when the conventional periapical radiographs fail to provide adequate information. “Cognitive deduction of the clinical picture and intelligent interpretation of radiologic information”(Krithikadatta, JOE 2010) should be the best way to understand the morphological features of third molars. Anyway, sometimes there are other concurrent indications for a CBCT, and this can show some interesting features.

Third molars: extraction or endodontics?
Fig. 6

Proximity of nerve structures:  over-instrumentation and extrusion of irrigants and/or obturation materials can lead to local injury to the alveolar nerve. In this case, paresthesia of the lip occurred after endodontic and restorative treatment of a third mandibular molar. Patient was referred for periapical surgery and symptoms subsided.


Endodontic treatment of third molars with varying root-canal morphology and difficult access can be challenging. Nevertheless, modern techniques and devices make third molar endodontics predictable. A comprehensive review upon this topic has been published by Ahmed in 2012.
The root canal morphology of third molars shows an increased likelihood for aberrations, such as dilacerations, C-shaped canals and unpredictable morphological features, that should be identified accurately before commencing endodontic treatment. Intelligent evaluation of clinical and radiographic data makes possible to understand the unpredictable anatomy of these teeth. Magnification and coaxial illumination allow the identification of canal orifices, along with the "Laws" postulated by Krasner and Rankow. The proximity of alveolar nerve, with respect to the apexes of third mandibular molars, suggests, even more than in usual cases, a safe irrigation technique, such as the use of side vented needles or negative pressure irrigation systems. Following these principles, extraction of third molar teeth, usually considered as a common dental procedure, should became more and more uncommon.


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