Analysis of Vertical changes after Maxillary onlay block graft

Objectives:In spite of rapid improvement of implant dentistry, implant installation on insufficient bone is still remained as a challenging topic. Onlay bone graft has advantage of solidity, can used widely for maintaining contour of bone and need of stability of reconstruction site even though it shows reduced capability of osteogenesis and slow revasculization compared to other bone graft methods. Methods:A Consecutive retrospective study was made on patients who had onlay bone grafts for augmentations of severely atrophied maxilla followed by placement of implants at Ewha Womans University from 2002 to 2009. Study was investigated as 1. Analysis of vertical height changes after autogenous block onlay bone graft on maxilla. 2. Analysis of peri-implant marginal bone changes of autogenous bone graft on maxilla. Bone graft and Implantation was done by one operator, and MKIII®, Replace Select®(Nobel biocare, Sweden), USII®, SSII® (Osstem, Korea) were used for implantation. For statistic evaluation, ANOVA analysis and t-test were used. Results:1. In autogenous onlay block bone graft on maxilla, mean augmentation height was 6.22mm. Mean resorption of grafted bone was 0.54mm(8.5%) at 3 months after surgery, 0.99mm(15.9%) at 6 months after surgery, so rate of resorption were lager in 3 months after surgery than that of 3 to 6 months after surgery. 2. The loss of peri-implant marginal bone grafted from ramus subsequently increased in premolar area followed molar and anterior area, while the iliac bone graft in anterior maxilla resulted in higher resorption than in molar area. Conclusions:Within the limit of this research , the resorption of iliac bone was larger than it of ramal bone with statistic significance. The marginal bone resorption of the iliac graft was significantly larger than that of ramus.