In the landscape of cranioplasty procedures, composite cranial implants incorporating calcium phosphate cement (CPC) and 3D-printed titanium alloy have demonstrated advancements in surgical outcomes. Notably, the patient's bone gradually replaces the CPC, while the titanium component remains. Fully resorbable implants could hold promise for expanding applications in pediatric surgery and minimizing the necessity for revision surgeries. We propose the replacement of titanium with a resorbable, biocompatible, and 3D-printable polymer exhibiting appropriate mechanical properties and degradation rate.

While biological responses to individual materials have been extensively explored in the literature, the interaction within specific material combinations remains a less explored topic. Factors such as pH variations, known to influence osteoblast performance, may yield distinct responses. This in vitro study examines the degradation behavior of CPC - poly-L-lactic acid (PLLA) structures and evaluates the impact of degradation by-products on preosteoblastic cells.

We prepared samples in an implant-like design by molding CPC around a 3D-printed dense PLLA beam. Degradation tests were carried out in a physiologically relevant environment, enabling a concurrent assessment of cellular responses. A comprehensive array of techniques, including Scanning Electron Microscopy, Differential Scanning Calorimetry, X-Ray Diffraction, Inductively Coupled Plasma Optical Emission Spectroscopy, and pH monitoring, facilitated morphological, chemical, and thermal characterization of the solid samples and extracts. Culturing MC3T3 preosteoblastic cells with inserts containing the samples provided insights into the early stages of bone healing and the composite's osteoinductive potential. Analysis over time included measurements of cell viability by metabolic activity, progression towards osteoblastic differentiation by ALP expression and enzymatic activity, and matrix mineralization to evaluate the osteoblasts' differentiation efficacy. Early time points present discernible signs of preosteoblast differentiation into osteoblasts, and no contraindications for the use of the composite structures. This experiment serves as an exploration of candidate materials for novel resorbable cranial implants, encompassing assessments of degradation processes, potential material interactions, and the influence of degradation by-products on cell viability and osteogenic potential.