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CBCT-Based Evaluation of Correlation Between Impacted Mandibular Third Molar, Lingual Bone Morphology and Inferior
Kirandeep Kaur1, Balwinder Singh2, Tejinder Kaur1
1Department of Oral and Maxillofacial Surgery, Sri Guru Ram Das Institute of Dental Sciences and Research Amritsar (Punjab), Amritsar, India.
Aim And Objective:
To evaluate the correlation between the position of inferior alveolar nerve canal and the angulation of impacted mandibular third molars. Also, the bone width and shape of the mandible at impacted third molar region determined precisely from CBCT cross-sectional images.
Material And Methods:
CBCT data of the impacted mandibular third molar of 89 patients were included in the study where an initial radiographic assessment demonstrated overlap/close proximity of the impacted mandibular third molar and inferior alveolar nerve canal. Using cross-sectional views and adjusting the position in panoramic view, the outline of the inferior alveolar canal was done and its buccolingual position was assessed. All the scans were taken using Carestream 9300 with 5/5 segment FOV size and operated at 75 kV and 8 mA. Scans were evaluated by two Oral and Maxillofacial Radiologist on same computer (Intex®CoreTMi7-8700 CPU @3.20 GHz, 64-bit operating system with 32.0 GB memory, with use of software CS 3D imaging v 3.8.7), and following parameters were noted: type of impaction, relative position of the mandibular canal, bone contact, shape of mandible, space, width of cortical bone, apex canal distance, width and height of the canal. All the data were analyzed statistically.
Result:
Class I position A impactions were found in majority of the cases, where the position of inferior alveolar canal was inferior and lingual to the impacted third molar (61.4%) and the result was statistically significant. 81% of inferior alveolar canal showed bone contact. Of these, 72.8% of the canal exhibit lingual bone contact, inferior to impacted third molar, and the results were statistically significant. Mesioangular impactions were most common in mandible having lingual and inferior position of the IAN canal (67.5%). The morphology of mandible at third molar region was observed as round (63%), lingual concave (25%) and lingual extended (12%) and was significantly associated with the type of impacted third molar. The space and the width of the lingual cortex were significantly associated with type of impactions (p = 0.016 and p = 0.036, respectively).
Conclusion:
The type of impacted tooth, morphology of the mandible and location of the IAN canal can be precisely determined on CBCT which can help the surgeon to predict any damage to the canal and to prevent sequelae of numbness.
