To evaluate and compare the effect of different light-curing modes and different liners on cuspal deflection in premolar teeth restored with bulk filled or incrementally filled composite measured at different time intervals

AIM: The aim of this study is to evaluate and to compare the effect of different light-curing modes and different liners on cuspal deflection in premolar teeth restored with bulk filled or incrementally filled composite measured at different time intervals. MATERIALS AND METHODS: The study was divided into two parts (Part 1-different curing modes, Part 2-different liner) each with sixty extracted human upper premolar teeth with standardized large mesio-occlusal-distal cavities prepared. Each part was divided into two groups according to the composite used (Group A-Filtek Z350 XT, Group B-Sonic fill). Each group was then divided into three subgroups according to the light-curing modes (soft-start, pulse, and continuous curing mode) and liner (Filtek Z350 XT Flowable, Vitremer) used. The cuspal deflection was then measured with a digital micrometer gauge and subjected to statistically analysis using analysis of variance and Tukey's post hoc test. RESULTS: Sonic fill composite, resin-modified glass ionomer cement (RMGIC) liner and curing with soft-start/pulse curing mode had significantly lower cuspal deflection compared to Filtek Z350 XT, flowable liner, and continuous curing mode, respectively. CONCLUSION: Sonic fill composite, RMGIC liner under the restorations and composites cured with soft start/pulse curing mode resulted in reduced cuspal deflection.