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Temperature changes under demineralised dentin during polymerization of three restorative resin-based materials using QTH and LED units

Statement of the Problem: Light-curing of resin-based materials (RBMs) is associated with temperature increase in the pulp chamber, which may have a detrimental effect on the vital pulp. Moreover, adequate polymerization is a crucial factor in obtaining optimal physical properties and clinical performance of resin-based restorative materials. 
Introduction: The purpose of this invitro study was to compare the temperature rise under demineralized human tooth dentin during light polymerization and, degree of conversion (DC) of three different RBMs using QTH and LED units. 
Methods and Materials: Demineralized and undemineralized dentin disks were prepared from one-hundred and twenty extracted human molars. Temperature rise during light polymerization of three RBMs including one ormocer based composite resin (Ceram.X), one low-shrinkage silorane based composite (Filtek P90), and one giomer (Beautifil-II) was measured with a K-type thermocouple wire that was connected to a data logger under the dentinal discs.(n=12) DC of the materials also investigated using FTIR spectroscopy. Data were analyzed using three-way ANOVA, independent samples t-test, and post hoc Tukey test.(α = 0.05) 
Results: Temperature rise under demineralized tooth dentin disks was higher than that of undemineralized tooth dentin disks during polymerization of all restorative materials (p 0.05) 
Conclusion: While there was no significant differences between the amounts of DC, temperature rise under demineralized tooth dentin disks for silorane-based composite was higher than dimethacrylate-based restorative materials, specially with QTH unit.