Optimal combination of 3-component photoinitiation system to increase the degree of conversion of resin monomers

Abstract

Objectives: This study investigated the optimal combination of 3-component photoinitiation system, consisting of CQ, p-octyloxy-phenyl-phenyl iodonium hexafluoroantimonate (OPPI), and 2-dimethylaminoethyl methacrylate (DMAEMA) to increase the degree of conversion of resin monomers, and analyze the effect of the ratio of the photoinitiator to the co-initiator. Materials and Methods: Each photoinitiators (CQ and OPP) and co-initiator (DMAEMA) were mixed in three levels with 0.2 wt.% (low concentration, L), 1.0 wt.% (medium concentration, M), and 2.0 wt.% (high concentration, H). A total of nine groups using the Taguchi method were tested according to the following proportion of components in the photoinitiator system: LLL, LMM, LHH, MLM, MMH, MHL, HLH, HML, HHM. Each monomer was polymerized using a quartz-tungsten-halogen curing unit (Demetron 400, USA) for 5, 20, 40, 60, 300 sec and the degree of conversion (DC) was determined at each exposure time using FTIR. Results: Significant differences were found for DC values in groups. MMH group and HHM group exhibited greater initial DC than the others. No significant difference was found with the ratio of the photoinitiators (CQ, OPPI) to the co-initiator (DMAEMA). The concentrations of CQ didn' t affect the DC values, but those of OPPI did strongly. Conclusions: MMH and HHM groups seem to be best ones to get increased DC. MMH group is indicated for bright, translucent color and HHM group is good for dark, opaque colored-resin.

Evaluation of Surface Roughness of Composite, Compomer and Carbomer After Curing Through Mylar Strip and Glycerin: A Comparative Study

“…The degree of polymerization is influenced by parameters such as filler content, color, initiator, light intensity, and curing time. [12][13][14] In the present study 3 different restorative materials, namely a hybrid composite, a polyacid modified composite resin, and a nanofiller integrated glass ionomer carbomer, were examined to see the effect of different curing conditions on surface roughness. The intensity of the LED and curing time was kept the same as in the aforementioned factors affecting the polymerization capacity.…”

Effect of glycerin on the surface hardness of composites after curing

“…Therefore, the measurement for surface hardness of composites was used for evaluating the quantity of OIL formation in this study. The degree of polymerization is affected by many factors such as initiator, 8,9 filler content and size, color, light intensity, curing time. 10 OIL formation is also affected by these factors.…”