Ultrasonic measurement of the effects of light irradiation and presence of water on the polymerization of self-adhesive resin cement.
Self-adhesive resin cements are useful in restorations because they reduce the number of clinical steps involved in the restoration process. This study evaluated, using ultrasonic measurements, the influence of light irradiation and the presence of water on the polymerization behavior and elastic modulus of a self-adhesive resin cement. A self-adhesive resin cement (RelyX Unicem 2 Automix) or a resin cement (RelyX ARC) was inserted into a transparent mold on a sample stage, and the presence of water and effect of light-irradiation were evaluated. The transit time of a sonic wave through the cement disk was divided by the specimen thickness to obtain the sonic velocity, and longitudinal and shear waves were used to determine the elastic modulus. When the resin cements were light-irradiated, the sonic velocity rapidly increased and plateaued at 2,500-2,700 m s-1. When the cements were not irradiated, the rates of increase in the sonic velocity were reduced. When water was applied to the sample stage, the sonic velocity was reduced. The elastic modulus values of the specimens ranged from 9.9 to 15.9 GPa after 24 h. The polymerization behavior of self-adhesive resin cements is affected by the polymerization mode and the presence of water.
Department of Operative Dentistry, Nihon University School of Dentistry, Tokyo, Japan.
Hirotaka
H
Takenaka
Department of Operative Dentistry, Nihon University School of Dentistry, Tokyo, Japan.
Hajime
H
Ouchi
Department of Operative Dentistry, Nihon University School of Dentistry, Tokyo, Japan.
Keiichi
K
Sai
Department of Operative Dentistry, Nihon University School of Dentistry, Tokyo, Japan.
Ryo
R
Kawamoto
Department of Operative Dentistry, Nihon University School of Dentistry, Tokyo, Japan.
Ryosuke
R
Murayama
Department of Operative Dentistry, Nihon University School of Dentistry, Tokyo, Japan.
Hiroyasu
H
Kurokawa
Department of Operative Dentistry, Nihon University School of Dentistry, Tokyo, Japan.
Masashi
M
Miyazaki
elastic modulus; moisture condition; polymerization reaction; self-adhesive resin cement; ultrasonic velocity