Compression of the Inferior Alveolar Canal by Mandibular Third Molar among Images Taken from Patients Visiting Dental Imaging Centres of Kathmandu: A Descriptive Cross-sectional Study.

Rinky Nyachhyon,Ujjwal Joshi,Pranay Sakya,Apeksha Mainali

doi:10.31729/jnma.7124

Abstract

Third molars are common teeth to be impacted. The position of mandibular third molar is such that it is in close contact with inferior alveolar canal which may lead to nerve damage during its removal. So, this study was conducted to find out the prevalence of compression of inferior alveolar canal by mandibular third molars. This descriptive cross-sectional study was conducted on images collected from Dental Imaging Centers of Nepal from 25th June 2020 to 15th February 2021 after obtaining ethical clearance from Nepal Health Research Council (Reference number: 2100). A convenience sampling method was used to collect 433 cone-beam computed tomography images showing the relation between the third molars and inferior alveolar canal. Data were analyzed using the Statistical Package for the Social Sciences version 16. Point estimate at 95% confidence interval was calculated along with frequency and proportion for the binary data. Out of 433 images, 135 (31.17%) (26.80-35.53 at 95% Confidence Interval) images showed compression of inferior alveolar nerve by mandibular third molar. The study result indicated that 16 (11.85%) buccally placed, 50 (37.03%) lingually placed and 69 (51.11%) inferiorly placed inferior alveolar canal were compressed by apices of mandibular third molars. The prevalence of compression of inferior alveolar canal by mandibular third molar was found to be similar to other studies done in similar settings. Compression of the canal was more evident when inferior alveolar canal is situated lingually.

Highlights

Third molars are common teeth to be impacted
In 200 (46.18%) inferior alveolar canal were in contact and in 98 (22.63%), inferior alveolar canal was separate from MM3 (Figure 1)
The study result indicated that 16 (11.85%) buccally placed, 50 (37.03%) lingually placed and 69 (1.11%) inferiorly placed inferior alveolar canal were compressed by apices of mandibular third molars

Summary

Introduction

Third molars are common teeth to be impacted. The position of mandibular third molar is such that it is in close contact with inferior alveolar canal which may lead to nerve damage during its removal. Mandibular third molars (MM3s) are last teeth to erupt in oral cavity, 40% of which fail to erupt, mainly due to lack of space.[1] They are associated with various complications like pericoronitis, odontogenic cyst, dental crowding.[1,2] MM3 roots can contact or penetrate into mandibular canal where inferior alveolar nerve is enclosed. This close relationship can damage inferior alveolar nerve during surgical procedures.[3,4,5,6] Damage is common when roots of MM3 lie in buccal and inferior position.[7]. OPG being two-dimensional cannot accurately determine number of roots, morphology, exact location of inferior alveolar nerve.[6,13,14] cone beam computed tomography (CBCT) provides three-dimensional volumetric data reconstruction and can illustrate buccolingual position of MM3 in relation to inferior alveolar canal without any distortion.[8,15,16]

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Conclusion