Dental dimethacrylate-based nanohybrid composite Kalore GC: Kinetic study of its light-curing

摘要

Objective This study investigated the light-curing kinetic of the novel dental dimethacrylate-based nanohybrid composite (Kalore GC). Its organic matrix consists of a high molecular weight monomer called DX 511 as well as the known dimethacrylate monomers bisphenol A ethyl dimethacrylate (Bis-EMA) and urethane dimethacrylate (UDMA). Methods Four properties were measured: degree of conversion (DC), depth of curing (DOC), polymerization shrinkage (S) and glass transition temperature (T g ) versus curing time. These properties were measured by spectroscopic imaging in Attenuated Total Reflection (ATR-FT-IR), scrape test, density measurements and dynamic mechanical thermal analysis (DMTA), respectively. Results After 10s of light curing, the DC was 2.50%, DOC 1.86 mm and S 1.48%. The composite cured for 10s showed two T g; 56.4?°C and 112.8?°C. At this stage, the maximum rate of polymerization was noticed. The curing, however, continued with much lower and decreased rate for up to 100s. There, a maximum DC of about 40% and a maximum DOC of about 3.5 mm were observed. T g values were raised to 59.5 and 102.3?°C, respectively. Conclusions Within the condition of this study, the optimum curing time of Kalore GC seems to be 100?s. The composite light-cured up to 300?s showed two T g, indicating that this compound still contained unreacted double bonds of C=C and macroradicals, which continued to cure upon heating in DMTA.