PLA-based composite implants for mandibular fracture: towards bioresorbable solutions.

Abstract

Mandibular fractures are among the most common facial injuries requiring surgical intervention, traditionally treated using titanium plates and screws for rigid fixation. While effective, commonly used metallic fixation implants such as titanium and titanium-based alloys (e.g., Ti-6Al-4V), stainless steel, and cobalt-chromium alloys have been associated with complications including ion release, stress shielding due to elastic modulus mismatch, imaging artefacts, and, in certain clinical scenarios, the need for secondary removal surgeries, thereby increasing patient burden. To address these limitations, bioresorbable polymers have emerged as promising alternatives. In this study, poly (lactic acid) (PLA) was selected due to its biodegradability, biocompatibility, and renewability, and further modified with nano-hydroxyapatite (HAp) and modified chitosan (MCS) fillers to enhance flexibility and mechanical performance. Composite specimens of PLA/nHAp/MCS were fabricated using extrusion-injection molding and subjected to mechanical characterisation under a universal testing machine. Additionally, finite element (FE) analysis was employed to simulate mandibular fracture fixation, enabling preclinical assessment of load transfer, fracture stability, and implant performance. The results demonstrate the viability of PLA-based bio-composites for mandibular fracture fixation, highlighting their potential to reduce complications and eliminate the need for secondary surgeries. Cytotoxicity studies confirmed the nontoxic nature of the bio-composite on mouse fibroblast cell lines, even at higher concentrations.