Preclinical alveolar ridge preservation using small-sized particles of bone replacement graft in combination with a gelatin cryogel scaffold.

BACKGROUND: Particulate anorganic bovine bone matrix (ABBM) is extensively used for alveolar ridge preservation (ARP). This study evaluates the potential of ABBM/gelatin cryogel scaffold of regular (250 to 1,000 μm) and small (50 to 100 μm) particles for ARP.

METHODS: ABBM was either condensed in a gypsum ring to simulate filling of ABBM in a defect or incorporated into a gelatin cryogel scaffold to disperse ABBM. Condensed regular-sized or small-sized ABBM (rABBM or sABBM) (± bone morphogenetic protein [BMP]-2) were subcutaneously implanted in rats to evaluate biocompatibility and osteogenic potential. Experimental extraction sockets were surgically created on the maxillary ridges of rats and were unfilled (control), filled with rABBM/gelatin, or sABBM/gelatin cryogel scaffold. The socket fill and dimensional changes of the ridge were evaluated by microcomputed tomography imaging and histology.

RESULTS: Condensed sABBM showed acceptable biocompatibility but significantly lower interparticle distance (IPD) and porosity (P < 0.001) compared with rABBM, whereas rABBM/gelatin and sABBM/gelatin cryogel scaffold showed similar IPD and porosity. Osteogenesis took place in rABBM/gelatin and sABBM/gelatin-treated extraction sockets showed osteogenesis at 8 weeks and had increased ridge width and reduced ridge discrepancy compared with the control sites. sABBM/gelatin scaffold significantly increased socket fill and reduced ridge discrepancy at 4 weeks, increased ridge width at 8 weeks, and reduced buccal ridge height resorption at both 4 and 8 weeks (P < 0.05 for all).

CONCLUSIONS: Osteoconductivity was suppressed in condensed sABBM, even after adding BMP-2. By dispersing sABBM in a gelatin cryogel scaffold, sABBM/gelatin showed a greater potential in promoting socket fill, reducing buccal ridge atrophy, and providing equivalent ridge stability compared with rABBM/gelatin.