Effectiveness of composite cure with pulse activation and soft-start polymerization

Abstract

The study investigated the effectiveness of composite cure with pulse activation and soft-start polymerization. A light-cure unit (BISCO VIP, BISCO Dental Products, Schaumburg, IL 60193, USA) that allowed for independent command over time and intensity was used. The six light-curing modes examined were: Control (C)-400 mW/cm 2 [40 seconds]; Pulse Delay I (PDI) -100 mW/cm 2 [3 seconds] → delay [3 minutes] → 500 mW/cm 2 [30 seconds]; Pulse Delay II (PDII) - 200 mW/cm 2 [20 seconds] → delay [3 minutes] → 500 mW/cm 2 [30 seconds]; Soft-start (SS) - 200 mW/cm 2 [10 seconds] → 600 mW/cm 2 [30 seconds]; Pulse Cure I (PCI) - 400 mW/cm 2 [10 seconds] → delay [10 seconds] → 400 mW/cm 2 [10 seconds] → delay [10 seconds] → 400 mW/cm 2 [20 seconds]; and Pulse Cure II (PCII) - 400 mW/cm 2 [20 seconds] → delay [20 seconds] → 400 mW/cm 2 [20 seconds]. Effectiveness of cure with the different modes was determined by measuring the top and bottom surface hardness of 2 mm thick composite (Z100) specimens using a digital microhardness tester (load=500 gf; dwell time=15 seconds). The effectiveness of cure of the bottom surface of the composite was also established by Fourier Transform Infrared (FTIR) spectroscopy using the KBr technique. Data obtained was analyzed using one-way ANOVA/Scheffe's post-hoc test (p