Coronectomy: A technique to protect the inferior alveolar nerve

Mandibular Third Molar Impaction: Review of Literature and a Proposal of a Classification

“…CBCT scan should be also accomplished for detailed surgery planning in cases when C2 or C3 relation to the mandibular canal is expected on two-dimensional radiographs (Figure 2A, B). Some authors are recommending to perform coronectomy of impacted wisdom tooth if roots are surrounding the mandibular canal because there is high risk or inferior alveolar nerve injury [33,74,75]. In contrast, it was considered that in cases when wisdom tooth position is ≥ 3 mm away from the mandibular canal, there is no risk to damage mandibular canal during surgical extraction (Figure 3).…”

Notes on coronectomy

“…In addition, if CBCT confirms that the mandibular third molar roots are distinct from the ID canal (Figs 3a and 3b) or inextricably involved with the IAN canal (Figs 3c and 3d) the surgeon may elect to ensure mobilisation of the roots is prevented by extended sectioning of the crown from the roots, but this technique may be associated with increased risk to the lingual nerve. 9 CBCT has provided an additional indication for elective coronectomy, which is when there is loss of the lingual cortex (identified in 30% of cases) and IDC buccally with a mandibular third molar root apex 'sandwiched' in between (Fig. 4).…”

“…6 The patient must also be aware that there is a risk of early and late infection that will necessitate the removal of the roots, which in most cases occurs once control study and one retrospective study. [6][7][8][9][10][11][12][13] Three of the six articles investigate the fate of third molars deemed at high risk on a DPT radiograph that have been coronected. [7][8][9] The remaining three articles compare the techniques of coronectomy versus complete removal of the high risk third molar tooth.…”

“…[6][7][8][9][10][11][12][13] Three of the six articles investigate the fate of third molars deemed at high risk on a DPT radiograph that have been coronected. [7][8][9] The remaining three articles compare the techniques of coronectomy versus complete removal of the high risk third molar tooth. 6,10,11 Interestingly, Dolanmaz et al 11 did not have a high risk control group for comparison as they deemed this unethical.…”

“…This cut is then lateralised to create a narrow horizontal groove in the tooth just below the ACJ. The depth of this cut needs to be into the pulp then lateralised but no more than the length of the fissure bur so has to avoid perforation of the lingual cortical plate, the distal and mesial confines of the tooth (in other studies the whole crown is sectioned from the roots, eg Pogrel et al) 9 5. A small elevator instrument such as a Coupland No.…”