Chen H Y, Manhart J, Kunzelmann K-H, Hickel R
Department of Restorative Dentistry, Dental School of the Ludwig--Maximilians-University, Goethe Street 70, Munich 80336, Germany.
Dent Mater. 2003 Nov;19(7):597-602. doi: 10.1016/s0109-5641(02)00110-0.
The magnitude and kinetics of polymerization contraction stress build-up may be potential predictors of bond failure of adhesive restorations. The present study determined these properties of seven commercial compomers (Dyract, Dyract AP, F2000 Rasant, Hytac, Compoglass F, Luxat, Glasiosite).
Polymerization shrinkage was generated by 40 s light curing the test materials (800 mW/cm2). The contraction force induced was recorded for 300 s at room temperature (23-24 degrees C) by means of a Stress-Strain-Analyzer (C factor=0.33). Maximum contraction stress (MPa), coefficient of near linear fit of contraction force/time (gradient) and relative force rate (%/s) of each material were compared with that of two hybrid composites (Tetric Ceram, Prodigy). The statistical analysis was conducted by ANOVA (alpha=0.05) and post hoc Tukey's test.
No statistically significant differences in the maximum stress between Glasiosite (2.27+/-0.06 MPa), Hytac (2.31+/-0.07 MPa) and Tetric Ceram (2.21+/-0.11 MPa), and between Compoglass F (2.60+/-0.18 MPa) and Prodigy (2.70+/-0.06 MPa) were found. The contraction stress of F2000 Rasant (3.41+/-0.09 MPa) and Luxat (3.33+/-0.08 MPa) were significantly highest, whilst Dyract exhibited the significantly lowest shrinkage stress (1.27+/-0.08 MPa) among the tested materials.
High contraction stress, early start of stress build-up and rapid contraction force development may lead to failure of bond to tooth structure. This study suggested that the contraction stress and kinetic behavior of compomers are generally similar to those of hybrid composites in a dry condition. Dyract might be superior in maintaining the bond with cavity walls compared to conventional hybrid composites in view of its low shrinkage stress.
聚合收缩应力积累的大小和动力学可能是黏结修复体黏结失败的潜在预测指标。本研究测定了七种市售复合体（Dyract、Dyract AP、F2000 Rasant、Hytac、Compoglass F、Luxat、Glasiosite）的这些特性。
通过对测试材料进行40秒光固化（800 mW/cm2）产生聚合收缩。借助应力应变分析仪（C因子=0.33）在室温（23 - 24摄氏度）下记录300秒内诱导产生的收缩力。将每种材料的最大收缩应力（MPa）、收缩力/时间的近似线性拟合系数（梯度）和相对力速率（%/秒）与两种混合型复合树脂（Tetric Ceram、Prodigy）进行比较。采用方差分析（α = 0.05）和事后Tukey检验进行统计分析。
未发现Glasiosite（2.27±0.06 MPa）、Hytac（2.31±0.07 MPa）和Tetric Ceram（2.21±0.11 MPa）之间以及Compoglass F（2.60±0.18 MPa）和Prodigy（2.70±0.06 MPa）之间在最大应力上有统计学显著差异。F2000 Rasant（3.41±0.09 MPa）和Luxat（3.33±0.08 MPa）的收缩应力显著最高，而Dyract在测试材料中表现出显著最低的收缩应力（1.27±0.08 MPa）。
高收缩应力、应力积累的早期开始和快速的收缩力发展可能导致与牙体结构的黏结失败。本研究表明，在干燥条件下，复合体的收缩应力和动力学行为通常与混合型复合树脂相似。鉴于Dyract的低收缩应力，与传统混合型复合树脂相比，它在维持与洞壁的黏结方面可能更具优势。
