Assessment of bone healing following enucleations of cysts with computed tomography

This prospective, controlled and randomized study was planned to evaluate bone regeneration by using allogenic bone graft and membrane after removal of large odontogenic cysts. Twenty-four patients with odontogenic cysts larger than 3 cm in diameter were selected and divided into two, as control and study groups. The control group was treated by enucleation and primary closure, whereas allogenic bone grafts ( Dynagraft Putty) and collagen membranes (Tutoplast Pericardium) were applied to the cavities of the study group after enucleation. CT scans were taken postoperatively on the tenth day and in the third, sixth and twelfth months to measure residual cavity volume and density of the newly formed tissue. Initial and remaining cavity volumes were compared on CT images and density was measured in Hounsfield units. Means and standard deviations were calculated for all variables in the groups. Comparison between the groups was carried out by Mann Whitney U statistical test, Similar results were observed in control and study groups. A progressive reduction in the volume of the cavities both with and without graft material was apparent. Findings for the mean density of the newly formed tissue in the third, sixth and twelfth postoperative months were also similar. The mean residual volume at each observation period did not show statistical differences between the groups. Twelfth month CT scans showed a significant increase in the average density of the newly formed bone in the mandible when compared to the maxilla. Results of this study suggest that using grafts doesn't contribute to increased bone regeneration and large cyst defects can regenerate spontaneously.