ANATOMICAL RELATIONSHIP BETWEEN MANDIBULAR THIRD MOLAR ROOTS AND MANDIBULAR CANAL IN PANORAMIC RADIO-GRAPHY AND CT SCANS

: Background: Inferior alveolar nerve (IAN) injuries are the third common complication after infections and alveolar osteitis during third molars (M3s) extraction. The most common cause of IAN injuries, is the proximity of M3 apices with mandibular canals, so the pre-operative radiographic views (such as common or advanced techniques) are outmost important to detect the proximity, number and position of M3s roots, and mandibular canal branches. the aim of this study was to assay the exact detection of relationship between M3s and mandibular canals in panoramic views and CT-Scans Method and Material: 165 panoramic radiographs were assessed to detect the proximity signs between M3 and mandibular canals. 9 patients (with 18 teeth) were detected and CT scan was obtained. Results: In panoramic views of 18 teeth, we could see root darkening in 11 cases, interruption of white lines in 11 teeth, deflected root in 6 of them and canal divergence in 4 cases. In CT scan views 12 teeth (%66/6) showed the association with mandibular canals and the 6 other teeth, in spite of significant proximity signs in panoramic views, did not have any relation with the canal. The associated teeth were mostly seen in women, left side and mesioangular and most of the canals placed in lingual side to root apices. Conclusion: Admittedly, the IAN injuries are complication during M3s extraction. So we have to use the pre-operative radiographs for exact detection of anatomical proximities. If the proximity signs between M3s and mandibular canals are seen in panoramic radiographs, it is highly suggested to use advanced radiographic views such as tomography and CT scans.