Evaluation of Outcome Following Coronectomy for the Management of Mandibular Third Molars in Close Proximity to Inferior Alveolar Nerve

Abstract

IntrOductIOnSurgical extraction of impacted mandibular third molar is one of the most commonly performed day care procedure in Oral and Maxillofacial Surgery either for therapeutic or prophylactic purpose. It is often associated with complications like pain, swelling, trismus, dry socket, bleeding and infection, which are typically temporary in nature. However, the most concerning complication is temporary or permanent damage to the Inferior Alveolar Nerve (IAN) resulting in paresthesia, hypoesthesia or dysesthesia of the lower lip, teeth, gingiva and skin over the chin, which significantly affects the quality of life of the patient [1].Ahmed C et al., reports that the common risk factors for the IAN damage includes advanced age and difficult impaction but the most important one is the proximity of the root to the IAN canal [2]. The incidence of IAN injury following mandibular third molar extraction is 0.41% to 8.1% for temporary altered sensation and 0.014% to 3.6% for permanent nerve damage [3]. But the incidence increases up to 20% to 36% in high risk cases as defined by radiographic signs described by various authors [4,5] which includes alteration in the root structure (darkening, narrowing, root deflection, bifid apex or overlapping over the nerve canal) or alteration in the inferior alveolar canal features (obliteration of radio opaque line, deflection or narrowing of the inferior alveolar canal). In these cases the nerve injury may occur either due to the instrumentation or due to crushing and tearing of the nerve by the root during tooth elevation [4].Various approaches have been proposed to decrease damage to the IAN in high risk cases, which comprises coronectomy and leaving the roots behind, staged surgical removal of the third molar [6], modified coronectomy and grafting [7], orthodontic aided extrusion [8] and pericoronal ostectomy [9]. Staged tooth removal was proposed to minimize the late post-operative risk of infection of retained roots, but requires two surgical interventions and the amount of root migration is unpredictable. Modified coronectomy with grafting was advocated for restoring the periodontal health of the second molar. Orthodontic aided extrusion of the third molar is technique sensitive, time consuming, expensive and unpredictable procedure. Applied coronectomy to prevent IAN damage was first proposed by Ecuyer and Debien [10] in 1984. In spite of numerous studies supporting the effectiveness of coronectomy, the procedure remains controversial due to the possibilities of infection and other odontogenic pathology arising from the roots left behind [11]. The aim of present study was to evaluate the outcome after coronectomy of mandibular third molars in terms of complications encountered during or after the procedure, temporary or permanent IAN injury, infection rate and other associated morbidity.

Alternative approach to prevent inferior alveolar nerve injury in lower third molar surgery: A pilot study on coronectomy

“…Some studies have reported 0% nerve injury with coronectomy. [ 10 20 , 21 ] In our study, none of the patients had IAN injury.…”

Coronectomy - An alternative approach to remove impacted teeth in oncological patients

“…In addition, after coronectomy the cut pulp is cover by a hematic clot, which represents a biological dressing. The roots must be left at 3mm below the crest cortical bone to allow osseous formation over the roots ( 14 , 15 ). The vital remained roots heal without problems ( 13 ).…”

“…Although coronectomy is a relatively simple procedure, the lack of experience or guidelines is one of the main causes of failure ( 15 , 19 ). Moreover, Monaco et al ( 19 ) observed that surgeons with greater expertise presented lower incidence of complications.…”

“…Moreover, Monaco et al ( 19 ) observed that surgeons with greater expertise presented lower incidence of complications. Furthermore, it is necessary to explain the patients the advantages and reasons for indicating coronectomy as many are reluctant to accept leaving the roots ( 15 ). In our experience, for the success of coronectomy is fundamental that the remnant root must be left completely covered by a mucosal flat to avoid local infection.…”

Mandibular Third Molar Postoperative Complications – A Brief Review

“…The use of local anesthetic has also been implicated in the injuries of the inferior dental nerve and its related paresthesia. 16,17…”