Physicochemical evaluation of gamma and microwave irradiated dental grafts

Abstract

Periodontological bone or dermal grafts are materials which are used in dentistry to regenerate lost tissue which can be obtained from a human or animal source. As a result, the possibility of disease transmission from the source to the patient is high. Therefore, sterilization of grafts before implanting to the patient got a significant importance due to the direct contact with blood. Sterilization process for dental materials can be done by three different methods, chemical gas, heat and radiation sterilization. Sterilization by radiation is an accepted official method due to its reliability and applicability to many materials. Radiation sterilization could have different advantages in comparison to the others. The application of radiation to materials in their final packages makes this method as the first option that comes to mind for sterilization. However, this method can have disadvantages like unwanted effects as crosslinking or chain breaking in the sterilized materials. The possibility of causing adverse effects of gamma irradiation has got consideration among companies and tissue banks. Radiation can have a lethal effect on microorganisms directly or indirectly. It affects microorganisms in a direct way by targeting DNA of microorganisms and affects indirectly by aiming the water in the microorganism cell and causes formation of free radicals. Therefore, radiation sterilization as gamma irradiation can be a reliable and effective sterilization method (Nguyen, H; A. F. Morgan, D 2007; Rooney, et al., 2008; Jeng, D. K. H 1987). Microwave irradiation as a very novel radiation sterilization method also got importance recently. In recent studies, microwave radiation showed a successful performance in killing gram positive and negative bacteria at 2 min of microwave irradiation at 900 W and 2450 MHz, respectively (Jeng, D. K. H 1987). This method can be hopeful, acceptable and promising sterilization method to be a good substitute for gamma radiation due to low cost and much easier application process in comparison to gamma radiation. The purpose of this study was to evaluate the effects of gamma radiation and microwave sterilization processes on the physicochemical features of periodontological grafts by applying different physicochemical analyses as organoleptic analyses, FTIR, SEM, TGA and SAXS. Based on the results, both gamma radiation and microwave sterilization were found potential and successful as sterilization methods with no significant physicochemical changes in the characteristic features of the irradiated grafts. Additionally, HBG1, MBG3, PBG1 coded grafts were found as the most compatible materials to gamma and microwave radiation sterilization.