Vertical bone augmentation with titanium granule blocks in rabbit calvaria.

Prior research has shown that titanium-based grafts can support bone regeneration in localized defects. However, no prior work had resolved whether these materials can be used for vertical bone augmentation or whether granule size and color influence osteoconductive outcomes. Established methods typically focus on horizontal bone growth or small-volume defects. This gap motivated investigations into whether titanium granule blocks could achieve vertical augmentation and whether granule characteristics affect bone formation. It was already known that titanium is biocompatible and can serve as a scaffold for bone ingrowth. Yet, the role of granule size and color in vertical augmentation remained unclear. This uncertainty drove the need for controlled in vivo studies using animal models. The study aimed to bridge this knowledge gap by evaluating bone formation outcomes in rabbit calvaria. The research focused on whether vertical augmentation is feasible and whether granule properties influence osteoconductive performance.

The aim of this research was to assess the potential of titanium granule blocks for vertical bone augmentation in rabbit calvaria. The specific problem addressed was whether these blocks could support new bone formation in a vertical direction. The motivation stemmed from the lack of data on how granule size and color affect bone regeneration in such contexts. The study sought to determine if any differences exist between white and grey titanium granules in promoting bone growth. The researchers also wanted to evaluate whether small or large granules influence osteoconductive outcomes. The study focused on whether vertical augmentation is possible with this material. The experimental design aimed to compare multiple granule types under controlled conditions. The findings could inform clinical applications of titanium grafts in dental and skeletal reconstruction.

The study involved 11 rabbits, with four titanium blocks implanted per skull according to a randomized scheme. Each block was made from compressed titanium granules, categorized into four types: small grey, large grey, small white, and large white granules. The blocks were standardized in preparation and implantation. After a 12-week healing period, the animals were euthanized, and samples were taken for analysis. Histological examination and μCT scanning were used to assess bone formation and graft integration. The researchers measured bone area (BA) in the grafted regions using histomorphometric techniques. The study compared BA values across all four groups to detect differences in bone ingrowth. The experimental setup allowed for direct comparisons between granule types and sizes. The study focused on vertical augmentation and osteoconductive properties of the grafts.

The results showed that bone formation occurred in all groups, with the titanium granules maintaining their volume over the 12-week period. Histological and μCT analyses confirmed successful bone regeneration across all four groups. In the entire grafted area, no statistically significant differences were observed between the groups. The lowest 1/4 BA in contact with the skull showed that groups A and C had the highest mean BA. Group A (small grey granules) presented significantly higher BA than group D (large white granules) with a p-value of 0.049. No significant differences were found between groups A, B, and C. Large granules showed less bone ingrowth compared to small granules, regardless of color. The grafted area was not fully filled with new bone, suggesting bone migration from the cortical side.

The authors concluded that vertical bone augmentation is feasible using titanium granule blocks in rabbit calvaria. The study found that all granule types supported bone formation, with no overall differences in the entire grafted area. However, small granules showed better bone ingrowth than large granules, regardless of color. The highest BA was observed in group A, with small grey granules showing better performance than large white granules. The results suggest that granule size influences osteoconductive outcomes more than color. The study did not find differences between small white and grey granules. Bone formation appeared to occur mainly from the cortical side, indicating contact osteogenesis. These findings may guide future clinical applications of titanium granule blocks in bone augmentation.