Analysis of repair process of critical size defects filled with Bone Ceramic® associated to BMP2 in rats: a histometric and immunohistochemical study

Abstract

The loss of alveolar bone is a limitation for insertion of dental implants. This defect is usually caused by dentoalveolar trauma, traumatic exodontia, congenitally missing tooth, or maxillary and mandibular pathologies. Large bone defects may result in longer healing process, which decreases the success rate. Thus, biomaterials have been used to accelerate or allow the normal and complete repair of bone defects, decreasing the post-operative failure rate. BoneCeramic (Straumann®) is a 100%-synthetic bone substitute with morphology able to stimulate vital bone formation. It is composed by biphasic calcium phosphate (BCP), a mixing of 60% of hydroxyapatite (HA) and 40% of beta- tricalcium phosphate. Thus, the aim of this study is to evaluate the osteoconductive activity of hydroxyapatite and calcium beta triphosphate (Bone Ceramic - Straumann®) on repair of critical rats calvarial defects through histometric and immunohistochemical analyses. Forty-eight male adult rats will be divided into 3 groups (n=8) and euthanized at two different periods (14 and 28 days after surgery). A critic calvarial defect (5mm) will be created in each animal with a trephine bur according to the following groups: Control group (CO) (n=16) - bone defect reconstructed with clot; Group autogenous bone (AUT) (n=16) - bone defect reconstructed with autogenous bone harvested from calvaria, and Group Bone Ceramic (BC) (n=16) - bone defect reconstructed with alloplastic bone (Straumann ®). The bone tissue at the central area of the defect will be evaluated. Data will be analyzed and transformed from pixel to relative percentage value to minimize the size difference of the slides negative after hematoxylin and eosin staining (HE). ANOVA (p<0.05) will be conducted to compare the means of the different groups and experimental periods. In addition, immunohistochemical analysis will evaluate the different steps of bone repair using primary antibodies for RUNX 2, Osterix, Osteopontin and Osteocalcin.