In Vivo Evaluation of Porous Implants: Alpha-Tricalcium Phosphate Cement and Polymers Obtained by Different Manufacturing Processes.

This study introduces a comparative in vivo evaluation of four synthetic biomaterials with distinct resorption profiles-double-setting alpha-tricalcium phosphate (α-TCPdp), α-TCPdp combined with a lactic-co-glycolic acid and poly(isoprene) copolymer (PLGA/PI), and two 3D-printed polymers, acrylonitrile butadiene styrene (ABS) and polyamide (PA)-for reconstruction of critical-sized mandibular defects in rabbits. Twenty animals were divided into four groups (n = 10 defects each) and evaluated at 30, 60, and 120 days post-implantation through clinical, radiographic, histopathological, and scanning electron microscopy analyses. All implants exhibited excellent biocompatibility, osseointegration, and absence of adverse tissue reactions. ABS and PA promoted significantly greater early bone neoformation compared to α-TCP-based cements, whereas α-TCPdp and α-TCPdp + PLGA/PI underwent gradual bone replacement via surface degradation and creeping substitution. The addition of PLGA/PI reduced the inflammatory response without compromising osteoconductivity. SEM analysis, enhanced by an adapted decalcification protocol, confirmed continuous bone ingrowth and intimate bone-implant contact. This work provides the first direct comparison of α-TCPdp and polymer-based implants in a mandibular critical defect model, highlighting the potential of both absorbable and non-absorbable biomaterials for customized craniofacial reconstruction.