Investigation of bone marrow stromal cells in bone regeneration and osseointegration of dental implants: an in vitro and preclinical study in rabbits

Abstract

The aim of this research will be to investigate the osseointegration of titanium dental implants of nano-hydroxypatite surface (UNITITE® Compact, SIN Implantes, Brasil) biofunctionalized with bioglass (BSF18, Vetra®) installed in maxillary sinus area previously grafted with synthetic bioactive biomaterial (F18, Vetra®) associated with bone marrow stromal cells or with a biomaterial composed of a mixture of hydroxyapatite and beta-tricalcium phosphate (HA², SinBone®). To test the hypotheses, this project will be divided into two studies. In the first study, BMSCs will be obtained from the bone marrow of 5 rabbit tibiae and submitted to cell isolation and processing in vitro. The analysis of osteogenic capacity will be performed by adipogenic, osteogenic and chondrogenic differentiation, as well as a cellular characterization and mesenchymal cells differentiation by alizarin red test and flow cytometry to determine the clusters of differentiation. After BMSCs demonstrate osteogenic potential, the cells will be plated and prepared into to the particles of the biactive glass biomaterial (F18, Vetra®) to perform a pre-clinical regenerative use of graft into defects created in the maxillary sinus of rabbits. A investigation of BMSCs adhesion and proliferation with F18® particles by SEM images will be investigate. In the second study, a total of 32 rabbits will be submitted into bilateral access to the maxillary sinus floor membrane to perform elevation and insertion of bone grafts with the following groups: 1) SinBone®; 2) F18®; 3) F18® + SinBone®; 4) F18® + BMSCs; 5) blood clot. An absorbable collagen membrane will be adjusted over the bone window in all groups (Collagen Pericardium®, Bionnovation, Brasil). After 30 and 60 days, biopsies of the grafted areas and absorbable collagen membrane absorbable will be collected and the grafted defects will be submitted to titanium dental implants placement (UNITITE®) associated or not with a biofunctionalization by BSF18 bioglass (Vetra®). The animals will be euthanized 15 days after the dental implant placement. Biopsies of the grafted areas will be analyzed by histometric descriptive and immunohistochemistry of proteins, such as, osteocalcin, BMP-2 and alkaline phosphatase. Areas with implants will be analyzed by microCT and histometry to analyze bone-implant contact (%BIC) and bone area between the implant threads (%BBT). The topographic characterization of the implant surfaces will be investigated by SEM images, chemical composition by EDS, contact angle measurements and by atomic force microscopy. (AU)