Mineralization processes in demineralized bone matrix grafts in human maxillary sinus floor elevations

Abstract

For reconstruction of the severely resorbed lateral maxilla for dental implant placement, one of the successful procedures is to elevate the maxillary sinus floor by implanting demineralized bone matrix (DBM). We studied bone formation in DBM grafts in the lateral maxilla in humans by means of histology and histomorphometry. Six months after grafting, at the time of dental implantation biopsies were taken from the grafted areas of seven patients. All biopsies contained mineralized matrix (MM) in the grafted area. At close inspection, three types of mineralization were found. First, lamellar biomineralization was seen in and near the maxillary host bone. Second, remineralization was observed in some particles that probably had not been completely demineralized. In the area connecting the graft and host bone, where woven bone was formed against DBM particles, a third mechanism was detected. In this case many dotlike foci of remineralization appeared close to the bone-DBM interface. The remineralized DBM and woven bone were both subsequently remodeled. Bone formation was most active in the area adjoining the maxillary host bone. We conclude that in human sinus floor elevation, allogenic DBM increases mineralized tissue volume by osteoconduction that is supported by the remineralization processes. Osteoinduction by this material seems questionable.

Tissue-engineered composite scaffold of poly(lactide-co-glycolide) and hydroxyapatite nanoparticles seeded with autologous mesenchymal stem cells for bone regeneration

“…Scaffolds serve primarily as osteoconductive moieties, since new bone is deposited by creeping substitutions from adjacent living bone (Groeneveld et al, 1999). HA/PLLA composites have shown some advantages in mechanical property, biocompatibility, and osteoconductivity (Hong et al, 2005).…”

“…These results indicate that tissue engineering technology, where polymer scaffolds are pre-seeded with autologous bone marrow mesenchymal cells cultured in vitro, could improve the osteoconductivity of biomaterials. In addition to osteoconductivity, scaffolds can serve as delivery vehicles for cytokines such as BMPs, insulin-like growth factors (IGFs), and transforming growth factors (TGFs), which transform recruited precursor cells from the host into bone matrix producing cells (Groeneveld et al, 1999), thereby providing osteoinduction. In our research, we seeded rabbit MSCs to the g-HA/PLGA scaffold by bovine collagen, and BMP-2 was added as follows.…”

Porous alginate/poly(ε-caprolactone) scaffolds: preparation, characterization and in vitro biological activity

“…Suitable pore size guarantees the migration and proliferation of osteoblasts and mesenchymal cells, as well as the diffusion of factors and vascularization (34)(35)(36), while the total porosity improves the connection of the implant biomaterial with the surrounding natural bone (37). The pore sizes which better sustain bone mineralization appear to be approximately 100-200 μm (38) while the optimal total scaffold porosity is considered to be the one ranging between 80-90% (39) .…”

Investigation of formation processes of porous biocompatible materials based on silicon doped and undoped ?-calcium-phosphate and hydroxyapatite

“…Skafold služi pre svega kao osteokonduktivni moiti dok se nova kost formira u procesu spustitucije iz susednog živog koštanog tkiva. 83 Pored obezbeđivanja osteokonduktivnosti, skafoldi mogu da služe i kao nosači citokina, kao što su koštani morfogenetski proteini (BMPs), insulinu slični faktori rasta (IGFs) i transformišudi faktori rasta (TGFs), koji menjaju obnovljene prekursorske delije iz tkiva domadina u delije koje stvaraju koštanu matricu, obezbeđujudi tako osteoinduktivnost. Konačno, proces osteogeneze se inicira tako što se skafoldi pre implantacije zasade delijama koje de formirati nove centre za formiranje kosti, kao što su osteoblastne i mezenhimalne delije koje imaju potencijal da memorišu poreklo.…”

“…Konačno, proces osteogeneze se inicira tako što se skafoldi pre implantacije zasade delijama koje de formirati nove centre za formiranje kosti, kao što su osteoblastne i mezenhimalne delije koje imaju potencijal da memorišu poreklo. 83 Genetski transformisane delije koje pokazuju osteokontuktivna svojstva takođe mogu biti korišdene u ovu svrhu. Kombinacija skafolda, citokina i delija u cilju stvaranja ex vivo tkivne konstrukcije predstavlja hipotezu koja bi trebala da obezbedi efikasniju koštanu regeneraciju u in vivo uslovima u poređenju sa samom matricom biomaterijala.…”