In vitro investigation of the effect of preheating, thermal cycling, and different chewing environment temperatures on the wear of dental composite resins

To determine the effect of different temperature on the wear amounts of dental composite material prepared in Pre-heating Temperature (PTG,60 degrees C) and Room Temperature (RTG,23 degrees C). To increase the Degree of conversion (%DC) in material by pre-heating process, and to investigate the effects of the employed method on the amount of wear. To evaluate the effect of %DC on the material's surface roughness.To evaluate the effect of thermal cycling on the material's surface roughness. Valux (TM) Plus, x-trafil and Charisma (R) Classic materials were polymerised in two groups: RTG and PTG. The mechanical loadings were applied simultaneously with different In vitro Chewing Environment Temperature (ICET). To perform the thermal cycle (ICET = 5/55 degrees C), 20,000 thermal cycles were applied simultaneously with 500,000 mechanical loading. Amounts of wear, hardness, %DC, and surface roughness were evaluated statistically by ANOVA. Amount of wear rate, and loss of filler particles at the wear zones were changed in different ICET conditions. Pre-heating process caused increase in %DC, surface roughness, and hardness value of all materials. The increase of %DC increased wear resistance in ICET = 5 degrees C, 35 degrees C, and 55 degrees C for x-trafil and Charisma (R) Classic. Moreover, the same pattern was recorded for the ICET = 5 degrees C for Valux (TM) Plus material. In Valux (TM) Plus, x-trafil and Charisma (R) Classic materials the maximum wear occurred in the RTG group at the ICET = 5 degrees C. Pre-heating and thermal cycling processes caused increase of the surface roughness values. For all materials the pre-heating process caused decrease of wear resistance in the ICET = 5/55 degrees C.