Flexural Strength and Physical Changes of Dental Composite Resins after Extract Treatment

Abstract

Recently introduced composite resins for anterior or posterior tooth may improve physical strength and polymerization. It is also becoming important that biocompatible or biodegradable materials are used. In order to get a Korean admission for making or selling any dental resin’s material, the tests include flexural strength of composite resin and quantitative analysis after extract treatment. The purpose of this study was to test the effect of extract conditions such as extract time and temperature on the composite resins and then evaluate them by flexural strength, UV absorbance, and potassium permanganate consumption. Four commercial products, AELITETM Universal Light-Cured (Bisco, Schaumberg, IL USA), GRADIA DIRECT ANTERIOR (GC Corp., Tokyo, Japan), DenFilTM (Vericom, Anyang, Korea), and FiltekTM Z350 (3M ESPE, St. Paul, MN USA), were used for this study. Four conditions of the extract treatment were (121 ± 2oC, 1 ± 0.2 hr), (70 ± 2oC, 24 ± 2 hr), (50 ± 2oC, 72 ± 2 hr), and (37 ± 2oC, 72 ± 2 hr), respectively. The cured samples were examined using a Universal Testing Machine (Instron 3366, Instron Engineering Corporation, Canton, MA USA). After treatment, the elution for the quantitative analysis was measured using a UV-vis spectrophotometer (WPA S2100, Biochrom Ltd., Cambridge, UK). To quantify chemically reduced materials, the test of potassium permanganate reduction material (KMnO4-test) was required. From the present study, we concluded that the results indicated both extraction time and temperature affected the flexural strength, UV absorbance, and KMnO4-test of the dental composite resins. Overall, increasing extraction time weakened the composite resins while increasing extraction temperature heightened the flexural strength of the composite resins. The UVabsorbance was higher when the extract conditions were high temperature and short time duration then compared to low temperature and long time duration. In certain cases, KMnO4-test showed the extract time was more important than the extract temperature. These are cautiously expected that both extract temperature and time influence flexural strength; extract temperature is more significant to UV absorbed materials and extract time is more important in terms of chemically reduced materials.