Determining an average distance from the external mandibular cortex to the inferior alveolar canal using cone beam computed tomography (CBCT) imaging: An aid to harvesting mandibular ramus autogenous grafts.

Abstract

OBJECTIVES: To provide average measurements relating the external mandibular cortex (EMC) to the inferior alveolar canal (IAC) using CBCT. METHODS: 100 CBCT images from UWC Dental hospital patient database were analysed using CBCT software (NewtomVGi Image works Corps) to produce coronal slices at four defined points along the IAC. Each point was measured from the IAC to the outer aspect of the mandibular buccal cortex and to the alveolar ridge crest (edentulous mandibles) or buccal cortical plate crest (dentate mandibles). The paired t-test was used to analyse right and left side measurements in order to test for differences in right and left side means. RESULTS: A mean width of 5.891mm (±1.09) from the IAC to the EMC in the horizontal plane and a mean height of 13.068mm (±2.963) from IAC to the alveolar crest or buccal cortical plate was demonstrated. Mean height was lower in edentulous mandibles (11.142mm in females; 13.490mm in males) than in dentate mandibles (12.916mm in females; 14.102 in males). There was no significant difference in width values. Height values were greater in males (14.102mm) than in females (12.916mm), being marginally significant (p-value of 0.00948:p<0.05). CONCLUSIONS: These measurements are clinically applicable when harvesting mandibular autogenous block grafts.