Evaluation of the Ideal Implant Insertion Time in Human Bone Biopsies After Sinus Elevation Using a Combination of Autologous Bone and Graft Substitute.

PURPOSE: To evaluate the ideal implant insertion time in human bone biopsies after sinus elevation with a composite graft consisting of an equal amount of biomaterial and autologous bone, by comparing the bone regeneration obtained 4 to 5 months after surgery with that obtained after 6 to 8 months, and using the adjacent native bone as reference. MATERIALS AND METHODS: Twenty-six biopsy specimens of 11 patients were analyzed. Two groups were created depending on the time of implant insertion: group t1 at 4 to 5 months (n = 13) and group t2 at 6 to 8 months (n = 13). The same volume of grafted bone and native bone were analyzed for each biopsy with microcomputed tomography (microCT) and gene expression analysis. RESULTS: Statistically significant differences were found in bone mineral density (BMD), bone volume fraction, and trabecular separation (TbSp) between native and grafted bone in both groups, with higher grafted bone values, except for the variable TbSp, which was lower in the grafted bone. This decrease in TbSp in the grafted bone in both groups can be explained by the significant increase in trabecular thickness in group t2 and the trabecular number in group t1, compared with native bone. No significant differences were found between the two groups in the morphometric parameters and BMD of the grafted bone. Also, no significant changes in the messenger RNA (mRNA) levels of bone formation, bone resorption, and inflammatory markers were found between both groups, with the exception that alkaline phosphatase mRNA levels were significantly lower in group t1 relative to native bone. CONCLUSION: This composite graft showed no differences in three-dimensional microstructure, BMD, or at the molecular level between 4 to 5 months and 6 to 8 months of healing time. Thus, this time can be shortened to 4 months with the security of a grafted area of mature bone.

Gene expression and morphometric parameters of human bone biopsies after maxillary sinus floor elevation with autologous bone combined with Bio-Oss® or BoneCeramic®.

OBJECTIVES: Although the clinical success of Bio-Oss(®) and BoneCeramic(®) has been corroborated by histologic and histomorphometric findings, the biological events that occur during healing after maxillary sinus floor elevation (MSFE) are unknown. Here, we evaluated biopsies of grafted bone with a mixture of autologous bone and Bio-Oss(®) or BoneCeramic(®) after two different healing time periods to understand the molecular process underlying bone formation after MSFE. MATERIAL AND METHODS: Seven patients, following a bilateral split-mouth design model and needing a MSFE to allow implant placement, were recruited for this study. Right or left sinuses were grafted with autologous maxillary bone combined either with Bio-Oss(®) or BoneCeramic(®) , respectively. Twenty biopsies were taken at the time of implant insertion after 4-5 months or 6-8 months of MSFE, and analyzed by micro-computed tomography (microCT) and gene-expression analysis. RESULTS: MicroCT analysis revealed no differences in the morphometric parameters or BMD either after 4-5 months or 6-8 months of MSFE between Bio-Oss(®) and BoneCeramic(®) . At molecular level, a higher expression of bone forming gene Runx2 was observed after 4-5 months of MSFE in the Bio-Oss(®) compared with the BoneCeramic(®) group. CONCLUSIONS: Our results indicate that differences found at the molecular level between Bio-Oss(®) and BoneCeramic(®) are not translated to important differences in the 3D microstructure and BMD of the grafted bone.

Sinus graft with safescraper: 5-year results.

PURPOSE: In the procedure of sinus floor elevation, autogenous bone, allogenic grafts, and several other bone substitutes are used. However, autogenous bone is still considered the gold standard. Donor sites for autogenous bone are generally the iliac crest, oral cavity, calvarium bone, and tibia. In this work the experience with the use of a Safescraper device for harvesting of autogenous bone is reported and a decision-making algorithm for grafting in sinus floor elevation procedures is proposed. MATERIALS AND METHODS: Forty sinus augmentation procedures were performed in 34 patients. All sinuses were filled with a mixture of autogenous bone and bovine hydroxyapatite. A Safescraper device was used to harvest autologous bone from the maxillary area. Platelet-rich plasma was used to sustain bone placement. Sixty-five dental implants were placed at 4 months with a flapless procedure. A clinical and radiological 5-year retrospective case series of a cohort is reported. RESULTS: In all cases new bone formation was confirmed radiologically and implant placement was performed successfully. Analysis of samples obtained by biopsy with histology and microcomputed tomography showed the presence of mature bone. Healing problems were observed in only 1 case. CONCLUSIONS: Sinus augmentation with bone grafts obtained from oral cavity with a bone scraper device has the advantage of providing autogenous bone without the need for an extra surgical approach. This procedure yields satisfactory results in bone formation, implant survival, and patient satisfaction. When combined with a flapless approach for implant placement, a decrease in the morbidity of the entire process is achieved.