ABSTRACT
<p><b>OBJECTIVE</b>The aim of this study was to evaluate the changing of alveolar cleft bone volume before and after bone graft.</p><p><b>METHODS</b>11 complete unilateral alveolar cleft patients were scanned with dental CT before bone graft surgery and 3 months after surgery. Matlab7.0 software was used to calculate the bone volume of alveolar cleft before bone graft and bone bridge volume after bone graft. The method was clockwise identify the irregular area of alveolar cleft by several points at different vertical level, then calculated the irregular area of alveolar cleft and the volume of alveolar cleft using Matlab7.0 software. The volume of implant bone was evaluated with same method after 3 months surgery. The ratio of graft bone bridge volume and alveolar cleft volume was calculated.</p><p><b>RESULTS</b>The maximum ratio of bone bridge volume and alveolar cleft volume was 114.99%, the minimum ratio was 13.36%. The average ratio was 71.80%, coefficient variation was 47.987.</p><p><b>CONCLUSION</b>Bone bridge volume after bone graft is varying.</p>