Radiographic Findings in Relationship between Mandibular Lesion and Mandibular Canal

Abstract

Findings of mandibular canal close to mandibular lesions (46 cases and 53 places in total), obtained by panoramic radiography and computed tomography, were examined. The mandibular lesions extended between premolar and mandibular ramus region and were well-defined by radiolucency in panoramic radiographic findings. The 46 lesions in this study were finally diagnosed as ameloblastoma in two cases, radicular cyst in nine cases, residual cyst in one case, primordial cyst in six cases, dentigerous cyst in 23 cases and simple bone cyst in five cases.
The results are as follows:
1. In panoramic radiographic findings, conditions of mandibular canal were classified as seven types according to the relation to the lesion and the displacement of the mandibular canal. In 16 of 53 places, mandibular canal was displaced and overlapped at the bottom of the radiolucency, whereas in 15 places mandibular canal did not appear.
2. In axial CT images based on 3-mm thick-slices, in 38 out of 46 cases mandibular canal was welldefined. In I6 of 38 cases mandibular canal was buccolingually displaced
3. In the MPR (multiplanar reformation) images reconstructed from axial CT, the positions of mandibular canal to the lesion were classified as six types. In 30 of 53 places, mandibular canal was positioned below the lesion.
4. In nine places, MPR images showed the mandibular canal below the radiolucency as panoramic radiographic images did.