Evaluation of Bone Repair Using a New Biphasic Synthetic Bioceramic (Plenum(®) Oss(hp)) in Critical Calvaria Defect in Rats

SIMPLE SUMMARY: The search for regenerative treatments is one of the main objectives of researchers to find effective ways of repairing bone defects and forming areas of bone of sufficient quality and quantity which can receive osseointegrated implants to reconstruct areas affected by periodontal lesions and/or systemic diseases. Biphasic bioceramics are synthetic bone substitutes made of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP). These materials have osteoconductive properties and are chemically and structurally similar to bone matrix, providing better safety and predictability during guided bone regeneration. This study aimed to evaluate the bone repair process using a new biphasic bioceramic (Plenum(®) Oss(hp)—70HA: 30β-TCP) compared to a synthetic graft (Straumann(®) BoneCeramic™) in a critical defect in the calvaria of rats. It was observed that the new Plenum(®) Oss(hp) bioceramic, in the rat calvaria model, offered excellent safety and surgical predictability, being efficient in the bone repair process. Plenum(®) Oss(hp) behaved similarly to the commercial control (BoneCeramic™) and can be considered an effective option as a synthetic bone substitute in the dental clinic, especially for implantology. ABSTRACT: (1) Background: Biphasic bioceramics are synthetic bone substitutes that provide greater safety and better predictability in guided bone regeneration. This study aimed to evaluate the bone repair process using a new biphasic bioceramic of synthetic origin (Plenum(®) Oss(hp)—70HA: 30β-TCP) in critical calvarial defects. (2) Methods: seventy-four defects were created in rat calvaria and divided into two groups—Plenum(®) Oss(hp) (PO), right side, and Straumann(®) BoneCeramic™ (BC), left side. Euthanasia was performed at 7, 15, 30, and 60 days after surgery. (3) Results: Lower gene expression was observed for runt-related transcription factor 2 (RUNX2) and vascular endothelial growth factor (VEGF) and higher expression for Integrin Binding Sialoprotein (IBSP). The results correlated with moderate immunolabeling for osteocalcin (OCN) and slight immunolabeling for osteopontin (OPN) in the PO group. Histometry showed a greater amount of biomaterial remaining in the PO group at 60 days. The microtomographic analysis showed a lower density of bone connectivity and a greater thickness of the trabeculae for the remnants of the PO group. (4) Conclusions: the Plenum(®) Oss(hp) showed no differences compared to BoneCeramic™ and is therefore considered an effective option as a synthetic bone substitute in bone regeneration.