Cone Beam Computerized Tomography Measurement of Alveolar Ridge at Posterior Mandible for Implant Graft Estimation

Damaging the inferior alveolar nerve (IAN) is the most serious complication when harvesting an autogenous graft from posterior mandible. The objective of this study was to use cone beam computerized tomography (CBCT) to measure dimensions of the alveolar ridge in the posterior mandible for estimation of a safe graft size, and then analyze how it is related to the gender, age, and dentition status of subjects. CBCT scans were screened to include 59 subjects without interfering pathologies. Alveolar height was measured from the alveolar crest to superior border of IAN and also to the inferior border of the mandible. Alveolar width (from buccal to lingual cortical plates) and buccal bone thickness (from buccal cortical plate to mandibular molar mesial root buccal surface) were measured at the coronal, middle, and apical thirds divided from the alveolar crest to the IAN. It was found that males and dentate sites had larger alveolar dimensions than did females and edentulous sites, respectively. Bone volume did not correlate significantly with age. Buccal bone thicknesses increased from coronal to apical and from the first to the third molar generally. A larger bone graft could be harvested from male than female patients, with a mean harvestable graft dimension (height × width in mm) for male was 15.5 × 3.2, and for female was 14.1 × 2.9. In conclusion, males and dentate arches demonstrate larger alveolar volumes than do females and edentulous regions, respectively. Larger alveolar grafts can be harvested from males compared to the females. Age does not seem to affect alveolar dimension/graft volume.