Pre-operative assessment of impacted mandibular third molar and inferior alveolar canal using orthopantomograhpy and cone beam computed tomography

Mahmuda Akter,Gokul Chand Kundu,Samir Banik,Md Wares Uddin,Ashik Abdullah Imon,Quazi Billur Rahman

doi:10.3329/bsmmuj.v9i4.30536

Abstract

<p class="Abstract">The aim of this study was to assess the proximity and relation of impacted mandibular third molar and inferior alveolar canal on orthopantomogram and cone beam computed tomography (CBCT). Sixty impacted mandibular third molars having close proximity with the inferior alveolar canal were included. CBCT images were done to determine the exact location and relationship of impacted third molar tooth and inferior alveolar canal. We assessed the radiographic signs from orthopantomogram, the course of inferior alveolar canal and proximity to the third molar tooth in CBCT. The buccal course of inferior alveolar canal was most frequently detected (n=36) in CBCT findings. The impacted lower third molar roots were 55% contact with the inferior alveolar canal and 45% separate from the canal. On orthopantomogram, the following signs were strongly correlated with actual contact: Superimposed relationship between the third molar and the inferior alveolar canal. CBCT is useful as a presurgical planning in patients with impacted mandibular third molar showing close proximity to the inferior alveolar canal.</p>

Highlights

The extraction of lower third molar is most common surgical procedure in maxillofacial surgery
Several clinical studies have shown the specific radiographic signs detected in panoramic radiographs which shows close relationship between the inferior alveolar canal and mandibular third molars.[4]
Sixty patients who consulted with impacted mandibular third molars whose panoramic radiographs show a close approximate between inferior alveolar canal and the mandibular third molars were included in the study

Summary

Introduction

The extraction of lower third molar is most common surgical procedure in maxillofacial surgery. There is a chance of temporary inferior alveolar nerve injury increases due to close approximation between third molar and inferior alveolar canal is observed radiologically. Assessment of third molar position and establish the anatomical relationship of with the inferior alveolar canal preoperatively is important for reducing the risk of nerve injury. Two dimensional panoramic radiographs provide limited information about the relationship between the inferior alveolar canal and the mandibular third molars, cortication of the inferior alveolar canal and the detailed anatomy of the third molar. If the panaromic radiographs indicates there is a close relationship between the third molar and the mandibular canal, supplement investigation using CT may be recommended to verify.[1,6,7] CT are higher radiation dose and financial cost in compare to panaromic view.[8]

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Conclusion