title: Effect of three types of light-curing units on 5-year colour changes of light-cured composite.
abstract: The purpose of this study was to determine colour changes in a composite cured with tungsten-halogen, light-emitting diode (LED) or a plasma arc after 5 years. Five specimens 10 mm in diameter and 2 mm in height were prepared using Hybrid (Clearfil AP-X) composite for each test group. The corresponding specimens were cured with a tungsten-halogen curing light, a LED unit or with a plasma arc. Specimens were stored in light-proof boxes for 5 years after the curing procedure to avoid further exposure to light and stored in 37 degrees C in 100% humidity. Colorimetric values of the specimens immediately after curing and after 5 years were measured using colorimeter. The DeltaE*( ab ) values varied significantly depending on the curing unit used (p < 0.001). Curing time did not affect the colour changes of the specimens (p = 0.4). The results of this study suggest that composite materials undergo measurable changes due to the curing unit exposure.
authors.affiliation: Department of Prosthodontics, Faculty of Dentistry, Selcuk University, Konya, Turkey.
authors.forename: Onjen
authors.initials: O
authors.lastname: Tak
authors.forename: Subutay Han
authors.initials: SH
authors.lastname: Altintas
authors.forename: Nilgun
authors.initials: N
authors.lastname: Ozturk
authors.forename: Aslihan
authors.initials: A
authors.lastname: Usumez