Bone quality and quantity of the anterior maxillary trabecular bone in dental implant sites.

OBJECTIVES: The aim of this study was to investigate the characteristics of implant sites on the edentulous alveolar ridge in the anterior maxilla. We studied the bone quantity and quality of implant sites at the anterior maxilla using CT images for the 33 implant sites on patients who underwent dental implant therapy in our Department since 2006. MATERIALS AND METHODS: Computed tomography (CT) images of 33 patients (20 women: 13 men) encompassing 33 implant sites were chosen and examined. The recipient sites for implant placement were determined based on CT data using an implant planning software (Simplant 11.0). The mean bone density values in Hounsfield unit (HU) were recorded using Simplant for both the simulated implant areas and the trabecular bone width. We classified the edentulous alveolar ridge and bone quality according to a classification based on Lekholm and Zarb (1985). RESULTS: Incisors had higher bone densities than canines. Women had lower bone densities than men. Canines displayed greater trabecular bone density and alveolar bone widths than incisors. No maxillary sites were judged to have a bone quality of 1 in this group. Quality 3 accounted for 69.7% of the total samples. CONCLUSIONS: An assessment of bone quality in the anterior alveolar ridge may well reflect age-related systemic pathological conditions and should be used in dental implant treatment planning to avoid associated risk factors.

Histologic evaluation of human alveolar sockets treated with an artificial bone substitute material.

This study involved a histologic, enzyme histologic, immunohistologic, and three-dimensional microstructure evaluating the extent of osteogenesis and repair in the human alveolar extraction socket achievable with an artificial bone substitute. After tooth extraction in 7 patients, extraction sockets were filled with Mastergraft (15% hydroxyapatite, 85% ß-tricalcium phosphate complex). Radiomicrographs and histologic examinations were performed on samples obtained during dental implant placement procedure. On micro-computed tomography, new bone was observed in all collected samples, and osteogenesis was observed to have taken place around the artificial bone substitute. Histologically, active osteogenesis was found throughout the region observed. Addition of new bone around the Mastergraft was observed, and osteoblast-like cells were present. Cells that had partially invaded the artificial bone included tartrate-resistant acid phosphate-positive and CD34-positive cells. These findings indicate that the Mastergraft artificial bone induced osteogenesis in the jawbone and seemed effective for repairing bone defects.

Bone formation in a rat calvarial defect model after transplanting autogenous bone marrow with beta-tricalcium phosphate.

In the present study, we evaluated the osteogenic potential of an autogenous bone marrow graft combined with beta-tricalcium phosphate (beta-TCP) in a rat calvarial bone defect model. The bone marrow harvested from the tibia of 7-week-old rats was grafted autogenously in a calvarial defect together with beta-TCP (=BTG group, n=16) or without beta-TCP (=BG group, n=16). Groups of animals were also treated with beta-TCP alone (=TG group, n=16) and control animals (n=8) received no graft implanted into the defect. We then observed the process of bone formation by histology, enzyme histochemistry and immunohistochemistry. Five days after grafting, in the BTG and BG groups, cell proliferation and osteogenic differentiation were observed. From 5 to 10 days after surgery, active Runx2, osteopontin (OPN), and TRAP- positive cells appeared in the BTG and BG groups. New bone formation started in the defect in both the BTG and BG groups. At 30 days after grafting, the BTG group showed new bone development and replacement of beta-TCP to fill the bone defect. New bone formation in the BTG group was significantly greater than in the BG group (P<0.01). The TG group showed no marked bone formation in the defect. The combination graft of bone marrow with beta-TCP showed marked bone formation in rat calvarial defects. Our results indicate that the combination grafts of bone marrow with beta-TCP may be an effective technique for repairing bone defects Beta-TCPgraft (TG) group.