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

Abstract

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 1,000μm) and small (50 to 100μm) particles for ARP. 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. 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 8weeks 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 4weeks, increased ridge width at 8weeks, and reduced buccal ridge height resorption at both 4 and 8weeks (P<0.05 for all). 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.