Volumetric analysis of simulated alveolar cleft defects and bone grafts using cone beam computed tomography

Background: Cone beam computed tomography allows for a significantly lower radiation dose than conventional computed tomographic scans, with generation of accurate images of the maxillofacial skeleton. The authors investigated its accuracy in the volumetric analysis of alveolar cleft defects and simulated bone grafts. Methods: Five simulated alveolar clefts were created using a burr drill in three dry pediatric skulls and filled with simulated bone grafts. Pregrafting and postgrafting cone beam computed tomographic scanning of skulls was performed using specialized imaging software. The authors compared actual volumes of the simulated bone grafts obtained using a water displacement technique with scan-derived volumes of both the grafts and the defects. Results: The average of the five simulated bone grafts calculated by cone beam computed tomography scanning was 0.380 ml, which was lower than their mean volume of 0.392 ml calculated by water displacement. The percentage difference between measurements ranged from 2.9 to 8.6 percent (mean, 4.86 percent). The mean of the simulated defects of 0.399 ml derived from scanning was higher than the actual mean volume of 0.392 ml derived by water displacement. The mean difference in defect comparison was 2.52 percent. There was no statistically significant difference between real volume and scan-derived graft and defect volume. Conclusions: Cone beam computed tomography calculation of simulated alveolar cleft and bone graft volume is precise and accurate. The volume of bone graft needed to fill alveolar defects can be accurately predicted using volume measurements of the bony defect. These findings further validate its use in the perioperative assessment of alveolar grafting.