Physical Properties of Filled Chemically Initiated Silorane Biomaterials

A chemical initiation, which was used for the polymerization of filled silorane resins, was found to be biocompatible. The studied resin systems were composed of liquid monomer, ground silorane polymer, and glass at varying concentrations. The amount of chemical initiator was dependent on the identity and amount of solids. Objective: The goal of this project is to optimize the handling and polymerization time of this silorane material. Methods: Hardness of the resulting material was determined using the Gillmore needle test (1lb pass/fail). Mechanical tests, including flexure strength and elastic modulus, were measured for neat light-cured silorane (control,NLC) and filled chemically cured silorane (FCC). Sample beams (2x2x25mm) were prepared. The LC specimens were irradiated with a dental lamp for 2min then removed from glass molds. The CC samples were placed in glass molds, allowed to harden, and then removed from molds after 45min. Samples were stored for 24hrs, and then the samples were then tested on a mechanical tester (EnduraTEC ELF 3300, Bose, Eden Prairie, MN) at a loading rate of 3.7mm/min. FTIR spectroscopy was used to compare the degree of cure between the NLC and FCC. Results: In the FTIR spectroscopy results there was no dramatic difference from the neat chemically initiated to the filled material. The results of the flexural strength of FCC1(25.52±1.52) is roughly half that of the NLC(55.0±5.0); while the modulus of FCC1(1.63±0.08) was more similar to NLC(2.21±0.16). The range for the handling time was found to be between 8 and 20min depending on the amount of initiator used. Conclusion: It was found that an appropriate chemical initiation system used with differing fillers and the handling/curing time tuned appropriately. Supported in part by NIH-NIDCR Grant T32 DE07294, NIH-NIDCR Grant R21 DE 018336 and DOD Grant W81XWH.