The Effectiveness of Microwave Sterilization on the Hardness of Silicone and Acrylic Based Soft Reliners

Objective. This study evaluated the effect of microwave sterilization on the hardness of silicone and acrylic based relining materials. Material and Method. Acrylic resin specimens were fabricated and the resilient materials (GC Extra soft and Trusoft) were bonded to these specimens, which acted as a denture base. The specimens were divided into 6 groups (n=10); i.e. 3 groups of silicone and 3 groups of acrylic liner specimens. The specimens were stored in artificial saliva and were exposed to 5min and 15min microwave sterilization per cycle per day for 45 days. The control group was not exposed to any sterilization. Pre-treatment and post treatment hardness reading (Shore A) of the resilient materials were taken at 0, 15, 30 and 45days respectively. Data was analyzed statistically with one-way analysis of variance and independent sample t test. Results. The analysis revealed that, the mean hardness of the silicone relining material sterilized for 15min had significant increase of 5.81% than that of the specimens sterilized for 5mins.The mean hardness of acrylic relining material after 5 min of sterilization had significant increase of 39.09% than the of the control group . Acrylic relining material showed deterioration at 15min of sterilization on the 1 day. Conclusion. Based on the st results, it can be assumed that silicone resilient relining material was resilient after being submitted to the experimental conditions, with no detrimental effect caused by microwave sterilization. However, acrylic relining material showed distortion for 15 min sterilization and it emphasizes that 15min sterilization regime canot be advised for acrylic liners.