Immunohistochemical evaluation of bone repair using micro-hydroxyapatite and nano-hydroxyapatite associated with beta-tricalcium phosphate: A study in rat calvaria.

• Grant number: 25/05819-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2025
• End date: March 31, 2026
• Field of knowledge: Health Sciences - Dentistry - Oral and Maxillofacial Surgery
• Principal Investigator: Daniela Ponzoni
• Grantee: Maria Eduarda Asman Gonçalves
• Host Institution: Faculdade de Odontologia (FOA). Universidade Estadual Paulista (UNESP). Campus de Araçatuba. Araçatuba , SP, Brazil

Abstract

Among the numerous biomaterials used in grafting techniques for bone rehabilitation and subsequent dental implant therapy, biphasic ceramics have shown promise as a viable option. The different physicochemical properties of biphasic ceramics affect the time and quality of new bone formation through variations in porosity, particle size, and different concentrations of hydroxyapatite and beta-tricalcium phosphate. The objective of the present study is to evaluate bone repair of critical cavities in the calvaria of rats using two particulate biphasic ceramics, namely micro and nano hydroxyapatite combined with beta-tricalcium phosphate, at different concentrations, through immunohistochemical analysis. For this, 72 male Wistar rats will be selected, randomly divided into four groups according to the biomaterials tested: blood clot (BC); GenPhos® with a 70/30 concentration (GP) containing micro-hydroxyapatite; Blue Bone® with an 80/20 concentration (BB) containing nano-hydroxyapatite; and BioOss® (BO). The animals will undergo the creation of a 5mm critical defect in the calvaria using a trephine drill in the central region of the parietal bone. After grafting, all defects will be covered with a resorbable membrane (Green Membrane®). After 7, 14, and 28 days, the animals will be euthanized in each group, with 6 animals per analysis time. Finally, the specimens will be processed by histological methods and sent for immunohistochemical analysis, followed by a comparison between the evaluated groups, which will be conducted using Sigma Plot 12.0 software, with a significance level of P<0.05. (AU)