J Oral Maxillofac Surg 67:1234-1238, 2009 A Preferable Technique for Protecting the Inferior Alveolar Nerve: Coronectomy Dogan Dolanmaz, DDS, PhD,* Gulsun Yildirim, DDS, PhD,† Kubilay Isik, DDS, PhD,‡ Korhan Kucuk, DDS, PhD,§ and Adnan Ozturk, DDS, PhD¶ Purpose: The aim of this study was to evaluate the effectiveness of coronectomy for teeth whose root apices are very close to the inferior alveolar canal. Patients and Methods: The 43 patients of this study needed removal of their lower third molar, whose root apices were very close to the inferior alveolar canal. These patients underwent 47 coronectomies. Results: The mean follow-up period was 9.3 months (range, 1 to 48 months). The mean total amount of root movement was 3.4 mm at 6 months, 3.8 mm at 12 months, and 4.0 mm at 24 months. Conclusions: The technique of coronectomy is defined as removing the crown of a tooth but leaving the roots untouched, so that the possibility of nerve damage is reduced. Coronectomy is a preferable technique for patients who run a risk of injury to the inferior alveolar nerve during third molar surgery. © 2009 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 67:1234-1238, 2009 The removal of erupted, partially impacted, or totally impacted third molars is still one of the most com- monly applied oral surgery operations. The procedure is not particularly difficult, but can lead to several complications, including damage to the inferior alve- olar and lingual nerves. Damage to the inferior alveo- lar nerve when extracting lower third molars is often caused by the intimate relationship between the nerve and the roots of the teeth. The technique of coronectomy was proposed as a means to remove the crown of a tooth while leaving the roots (which may be intimately related to the inferior alveolar nerve) untouched, so that the possibility of nerve damage is reduced. 1,2 Patients and Methods Forty-three patients (20 women and 23 men, aged between 18 and 38 years) who needed removal of 47 lower third molars whose root apices were too close to the inferior alveolar canal were included in the study. They underwent coronectomies to re- move the crown of a tooth, leaving its roots in situ to reduce the risk of damage to the inferior alveolar nerve. The application of this technique was based on radiographic features in routine preoperative dental orthopantomographs. Three radiological fea- tures were accepted as indicators of the proximity of roots to the inferior alveolar canal: diversion of the canal, darkening of a root, and interruption of the canal walls. 3 All patients were thoroughly informed about the surgical technique. Patients who had sys- temic disorders or who were more predisposed to local infection were excluded. Operations were performed under local anesthesia. A conventional mucoperiosteal flap with a releasing incision was raised and retained with a retractor. Coronectomy involved transsection of the tooth 2 to 3 mm below the enamel of the crown into the den- tine. So as not to mobilize the roots, the crown was totally transected from the roots, without applying high forces. After removal of the crown of the tooth, the remaining root fragments were reduced with burs, so that the remaining roots were at least 2 mm below the crest of the lingual and buccal plates in all places. The socket was then irrigated with saline, and the mucoperiosteal flap was replaced with sutures. *Associate Professor, Department of Oral and Maxillofacial Sur- gery, Faculty of Dentistry, Selcuk University, Konya, Turkey. †Assistant Professor, Department of Oral and Maxillofacial Sur- gery, Faculty of Dentistry, Selcuk University, Konya, Turkey. ‡Resident, Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Baskent University, Ankara, Turkey. §Resident, Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, Selcuk University, Konya, Turkey. ¶Professor, Department of Oral and Maxillofacial Surgery, Fac- ulty of Dentistry, Ankara University, Ankara, Turkey. Address correspondence and reprint requests to Dr Yildirim: Dis ¸ Hekimlig ˘i Fakültesi Cerrahi AD, Selçuk Universitesi, 42080 Kampüs Selçuklu, Konya, Turkey; e-mail: ozgulsun@yahoo.com © 2009 American Association of Oral and Maxillofacial Surgeons 0278-2391/09/6706-0013$36.00/0 doi:10.1016/j.joms.2008.12.031 1234