In vitro degradation of mineralized collagen-based composite as GTR membrane

Objectives: The technique of guided tissue regeneration (GTR) has been developed for the regeneration of periodontal tissues and bone around natural teeth and dental implants. The aim of this study is to investigate the biodegradability and mechanic behavior of a novel mineralized hydroxyapatite/collagen/poly (lactic acid) composite as GTR membrane in vitro. Methods: For the preparation of the nHAC/PLA membrane, powders of nHAC made by the method were added into poly (lactic acid) (PLA) solution. The membranes were produced by a thin film solvent casting procedure. Thermogravimetric analysis was conducted to evaluate the change of the inorganic component in the samples. Morphology of samples were checked by scanning electron microscopy. The elastic modulus and maximum tensile strength of samples before and after degradation in vitro was measured. Results: The higher the molecular weight of the PLA was, the lower the weight loss was. With the increase of the nHAC: PLA ratio, the weight loss increased. The higher the nHAC/PLA ratios are, the higher the increases of weight percentages of HA in the membranes are. From the SEM, the longer the degradation term, the more aggragations of crystals on the surface of membrane. The higher the nHAC/PLA ratios, the more aggregation of crystals. Conclusions: On the basis of the results of the study, It can be concluded that the GTR membrane have a good mechanic property, can help the bone formation by increase the local concentration of Ca²⁺ and PO³²⁺, and help the integration of the membrane with the surrounding tissue.