Evaluation of Hard and Soft Tissue Responses to Four Different Generation Bioresorbable Materials-Poly-l-Lactic Acid (PLLA), Poly-l-Lactic Acid/Polyglycolic Acid (PLLA/PGA), Uncalcined/Unsintered Hydroxyapatite/Poly-l-Lactic Acid (u-HA/PLLA) and Uncalcined/Unsintered Hydroxyapatite/Poly-l-Lactic Acid/Polyglycolic Acid (u-HA/PLLA/PGA) in Maxillofacial Surgery: An In-Vivo Animal Study

Abstract

Bone stabilization using osteosynthesis devices is essential in maxillofacial surgery. Owing to numerous disadvantages, bioresorbable materials are preferred over titanium for osteofixation in certain procedures. The biomaterials used for osteosynthesis in maxillofacial surgery have been subdivided into four generations. No study has compared the tissue responses generated by four generations of biomaterials and the feasibility of using these biomaterials in different maxillofacial surgeries. We conducted an in vivo animal study to evaluate host tissue response to four generations of implanted biomaterial sheets, namely, PLLA, PLLA/PGA, u-HA/PLLA, and u-HA/PLLA/PGA. New bone volume and pertinent biomarkers for bone regeneration, such as Runx2, osteocalcin (OCN), and the inflammatory marker CD68, were analyzed, and the expression of each biomarker was correlated with soft tissues outside the biomaterial and toward the host bone at the end of week 2 and week 10. The use of first-generation biomaterials for maxillofacial osteosynthesis is not advantageous over the use of other updated biomaterials. Second-generation biomaterials degrade faster and can be potentially used in non-stress regions, such as the midface. Third and fourth-generation biomaterials possess bioactive/osteoconductivity improved strength. Application of third-generation biomaterials can be considered panfacially. Fourth-generation biomaterials can be worth considering applying at midface due to the shorter degradation period.