Reduction of polymerization contraction stress for dental composites by two-step light-activation

被引:231
作者
Lim, BS
Ferracane, JL
Sakaguchi, RL
Condon, JR
机构
[1] Oregon Hlth & Sci Univ, Sch Dent, Dept Biomat & Biomech, Portland, OR 97201 USA
[2] Seoul Natl Univ, Coll Dent, Dept Dent Biomat, Seoul, South Korea
关键词
dental composite; polymerization contraction stress; shrinkage; two-step light-activation;
D O I
10.1016/S0109-5641(01)00066-5
中图分类号
R78 [口腔科学];
学科分类号
1003 ;
摘要
Objectives: The goal of this study was to assess the reduction of polymerization contraction stress of composites during a two-step light-activation process and to relate this reduction to the process of polymerization shrinkage and specimen thickness. Methods: Three test procedures were performed to compare two-step light-activation with delay with one-step continuous irradiation of composites: polymerization contraction stress using a closed-loop servohydraulic testing instrument, polymerization shrinkage by a mercury dilatometer, and degree of conversion by FTIR. For the one-step continuous curing method, the samples were light-activated for 60 s at 330 mW/cm(2). For the two-step curing method, a 5 s light exposure at 60 mW/cm(2) was followed by 2 min without light exposure, and then a second light exposure for 60 s at 330 mW/cm(2). The same light parameters were used for measurements of stress, shrinkage. and degree of conversion. Three composites, Heliomolar, Herculite and 2100 were evaluated. The contraction stress experiments were repeated with varying thickness for Herculite using the one-step and two different two-step techniques. Results: Polymerization contraction stress 10 min after light-activation was significantly reduced (P < 0.05) by the two-step method: 29.7% for Heliomolar, 26.5% for Herculite, and 19.0% for Z100. Total volumetric shrinkage and degree of conversion were not significantly different for composites cured by the two different techniques. Increasing the thickness of the composite sample reduced the measured contraction stress, especially for one of the two-step curing methods. Significance: A combination of low initial energy density followed by a lag period before a final high-intensity light irradiation provides a reduction of polymerization contraction stresses in dental composites. The stress reductions cannot be attributed to reductions in degree of conversion or unrestrained volumetric shrinkage. (C) 2002 Academy of Dental Materials. Published by Elsevier Science Ltd. All rights reserved.
引用
收藏
页码:436 / 444
页数:9
相关论文
共 39 条
[1]  
Bouschlicher M R, 2000, J Esthet Dent, V12, P23, DOI 10.1111/j.1708-8240.2000.tb00195.x
[2]  
Bouschlicher MR, 1997, AM J DENT, V10, P88
[3]   SYNTHESIS AND POLYMERIZATION OF NEW EXPANDING DENTAL MONOMERS [J].
BYERLEY, TJ ;
EICK, JD ;
CHEN, GP ;
CHAPPELOW, CC ;
MILLICH, F .
DENTAL MATERIALS, 1992, 8 (5-6) :345-350
[4]  
Carvalho RM, 1996, OPER DENT, V21, P17
[5]   The effects of adhesive thickness on polymerization contraction stress of composite [J].
Choi, KK ;
Condon, JR ;
Ferracane, JL .
JOURNAL OF DENTAL RESEARCH, 2000, 79 (03) :812-817
[6]   Reduction of composite contraction stress through non-bonded microfiller particles [J].
Condon, JR ;
Ferracane, JL .
DENTAL MATERIALS, 1998, 14 (04) :256-260
[7]   Assessing the effect of composite formulation on polymerization stress [J].
Condon, JR ;
Ferracane, JL .
JOURNAL OF THE AMERICAN DENTAL ASSOCIATION, 2000, 131 (04) :497-503
[8]   Visco-elastic parameters of dental restorative materials during setting [J].
Dauvillier, BS ;
Feilzer, AJ ;
De Gee, AJ ;
Davidson, CL .
JOURNAL OF DENTAL RESEARCH, 2000, 79 (03) :818-823
[9]   THE COMPETITION BETWEEN THE COMPOSITE-DENTIN BOND STRENGTH AND THE POLYMERIZATION CONTRACTION STRESS [J].
DAVIDSON, CL ;
DEGEE, AJ ;
FEILZER, A .
JOURNAL OF DENTAL RESEARCH, 1984, 63 (12) :1396-1399
[10]   Polymerization shrinkage and polymerization shrinkage stress in polymer-based restoratives [J].
Davidson, CL ;
Feilzer, AJ .
JOURNAL OF DENTISTRY, 1997, 25 (06) :435-440