Effect of different light-curing devices and aging procedures on composite knoop microhardness

• Main Authors: Fernanda Regina Voltarelli, Claudia Batitucci dos Santos-Daroz, Marcelo Corrêa Alves, Alessandra Rezende Peris, Giselle Maria March
• Format: Article
• Language: English
• Published: Sociedade Brasileira de Pesquisa Odontológica 2009-12-01
• Series: Brazilian Oral Research
• Subjects: Dental materials; Hardness tests; Dental curing lights; Dental stress analysis
• Online Access: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1806-83242009000400019

The aim of this study was to evaluate the effect of light-curing devices (Halogen/HAL, Light Emitting Diodes/LED, Argon Laser/LAS and Plasma Arc/PAC) and aging procedures (Mechanical Cycling/MC, Thermal Cycling/TC, Storage/S, MC+TC and MC+TC+S) on the micro-hardness of bottom/B and top/T surfaces of 2-mm-high composite resin cylinders. The Knoop microhardness test (25 g, 20 s) on both B and T was performed before and after each aging procedure. For B and T, before aging procedures, PAC showed reduced polymerization effectiveness when compared with HAL. In the T, after TC, PAC and LAS had also showed reduced polymerization effectiveness when compared to HAL and LED. For all light-curing devices, MC+TC+S and S affected the Knoop microhardness values. In the B, no difference could be observed among the aging procedures for PAC. From all light-curing units, PAC may have rendered composites of reduced quality and the storage aging procedures were the most harmful to the polymer hardness.