Histological Changes in Alveolar Bone After Onlay Augmentation Using the Casing Method

Numerous studies on alveolar bone augmentation have been reported. However, it remains challenging to obtain favorable new bone, especially for onlay bone augmentation. For successful onlay bone augmentation, it is necessary to use a graft material with high bone-forming activity and wound stabilization. We performed onlay bone augmentation on the buccal surface of mandibular alveolar bone in dogs, using a polyethylene terephthalate (PET) case (Casing method). The aim of this study was to histologically examine the feasibility of Casing method for external onlay bone augmentation. Beagle dogs were selected for this study. At 12 weeks after tooth extraction, a PET case was placed on the buccal surface of mandibular alveolar bone and filled with a mixture of hydroxyapatite and β-tricalcium phosphate (β-TCP) particles (volume ratio 1:1) impregnated with crushed autogenous bone (superfine bone powder) suspended in plasma. At 4, 8, and 16 weeks after bone graft, nondecalcified sections were histologically examined. At 4 weeks, new bone formation on the particle surfaces was observed on the original bone side of the PET case. At 16 weeks, bone formation was observed in almost all areas inside the case. The percentage of the augmented area (including new bone and particles surrounded by new bone; was significantly greater at 16 weeks (85.7% ± 6.0%) than at 4 weeks (10.5% ± 4.8%) or 8 weeks (69.6% ± 15.6%). The results of this study suggest that onlay bone augmentation using the Casing method has considerable potential to yield histologically favorable new bone formation. Anat Rec, 301:1148-1158, 2018. © 2018 Wiley Periodicals, Inc.