Histologic evaluation of alveolar ridge preservation using aseptically processed large-particle demineralized freeze-dried bone allograft: A case series.

Background

Demineralized freeze-dried bone allograft (DFDBA) is widely utilized in alveolar ridge preservation (ARP). However, limited human histologic evidence exists characterizing early healing associated with aseptically processed large-particle DFDBA. Both graft processing methodology and particle size may influence regenerative healing dynamics, graft integration, and tissue maturation.

Methods

Three systemically healthy patients underwent ARP following tooth extraction using aseptically processed large-particle DFDBA (850-2000 µm) and dense polytetrafluoroethylene (d-PTFE) membrane coverage. Core biopsies were harvested at implant placement after 13-17 weeks of healing. Histologic and histomorphometric analyses were performed to evaluate graft integration, newly formed bone, residual graft particles, connective tissue, cellular repopulation, and tissue mineralization patterns.

Results

All specimens demonstrated active bone formation, graft integration, and cellular repopulation of residual DFDBA particles. Newly formed bone was observed in close apposition to graft particles, consistent with ongoing remodeling and incorporation at the graft-host interface. Mean vital bone formation was approximately 34%, while mean mineralization approached 90%. Residual graft particles remained present at all sites and demonstrated varying degrees of integration into newly formed tissue. Cone beam computed tomography (CBCT) evaluation demonstrated regions of reduced radiopacity suggestive of incomplete mineralization; however, histologic and histomorphometric analyses demonstrated highly mineralized regenerated tissue, highlighting differences between radiographic appearance and tissue maturity during early healing.

Conclusion

Within the limitations of this exploratory case series, aseptically processed large-particle DFDBA demonstrated early healing characterized by graft integration, cellular repopulation of graft particles, vital bone formation, mineralized tissue development, and progressive remodeling following alveolar ridge preservation. Histologic and histomorphometric findings obtained at 13-17 weeks provide direct human evidence regarding early healing patterns associated with a graft configuration defined by both aseptic processing methodology and large particle size. Mean vital bone formation of approximately 35% and mean 90% mineralization were observed during this early healing interval, and all sites demonstrated sufficient clinical development to permit subsequent implant placement. PLAIN LANGUAGE SUMMARY When a tooth is removed, the surrounding bone naturally shrinks during healing, which can make future dental implant placement more difficult. One way to reduce this bone loss is alveolar ridge preservation, in which a bone graft is placed into the extraction socket. This study evaluated early healing following ridge preservation using an aseptically processed human donor bone graft composed of relatively large particles. Three healthy patients received the graft after tooth extraction. Approximately 13-17 weeks later, small bone samples were collected during routine implant site preparation and examined microscopically. In all cases, new bone formation was observed, and the graft particles showed evidence of integration with the surrounding tissue. Many particles were repopulated with living bone cells, indicating active remodeling. Although radiographs suggested that healing was still ongoing, microscopic analysis demonstrated a high degree of mineralization within the regenerated tissue. Within the limitations of this small case series, these findings provide insight into early healing patterns associated with this graft material and support further investigation in larger clinical studies.