Comparison of two bone substitutes of bovine origin in the repair of critical defects in rat calvaria

• Grant number: 24/23856-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2025
• End date: December 31, 2025
• Field of knowledge: Health Sciences - Dentistry - Oral and Maxillofacial Surgery
• Principal Investigator: Daniela Ponzoni
• Grantee: Talita Gracielen Lima da Silva
• Host Institution: Faculdade de Odontologia (FOA). Universidade Estadual Paulista (UNESP). Campus de Araçatuba. Araçatuba , SP, Brazil

Abstract

Guided bone regeneration (GBR) is an essential technique in implantology, used for decades to promote new bone formation in defect areas. Among the biomaterials used, xenogeneic grafts, such as those of bovine origin, stand out for their biocompatibility and osteoconductive properties. The low resorption rate and possible osteoinductive limitation of existing biomaterials have driven the development of new options, such as Extra Graft®, which combines hydroxyapatite and collagen, bypassing the failure in osteoconduction and osteoinduction of the others. The objective of the present study will be to evaluate the bone repair of critical defects in rat calvarias filled with two bone substitutes based on hydroxyapatite and bovine collagen (Extra Graft® and Bio-Oss Collagen®), covered by a collagen membrane (Green Membrane®), through histological, histomorphometric, microtomographic and birefringence test analyses. Fifty-four male Wistar rats will be selected and randomly divided into three groups according to the biomaterials tested: blood clot (BC); Bio-Oss Collagen® (BO), as a positive control; and Extra Graft® (EG). The animals will undergo the protocol of creating a critical 5 mm defect in the calvaria, grafting with the studied bone substitutes, and covering all defects with a resorbable membrane (Green Membrane®). After 7, 14, and 28 days, the animals will be euthanized in each group, containing 6 animals per analysis time. Two specimens from each group and period will be analyzed by microtomography. All specimens will subsequently be decalcified for histomorphometric analysis. Quantitative analyses of the newly formed bone and qualitative analyses of the repair will be performed, with subsequent comparison between the evaluated groups. (AU)