DefinePK

Abstract

OBJECTIVE: To evaluate the compressive strength of resin composites cured with a QTH lamp & LED unit at different exposure time. STUDY DESIGN: In Vitro Experimental study METHODOLOGY: Two composite materials were used in this study. Filtek Z250, (3M ESPE Dental products) and Filtek P60 (3M ESPE Dental products). For each composite 114 disc shaped samples were prepared (5mm in diameter and 2mm in thickness) by using stainless steel mold. The mold was packed with the bulk of resin composite by incremental technique. Each sample was cured through the polyester strip with either QTH unit or LED unit depending on samples grouping. Samples were irradiated for 20, 30 and 40 seconds. Nineteen specimens were prepared for each experimental group. Specimens were placed in artificial saliva for 24 hours after curing. Compressive strength was then determined in universal Instron Testing Machine. Data was analyzed by factorial design by Three Way ANOVA and post hoc Tukeys HSD test. Units RESULTS: Halogen light curing unit is more effective then LED unit in terms of compressive strength. Compressive strength was influenced by exposure time (20, 30 or 40 s) (p