Biomaterials Research Group, School of Dentistry, University of Manchester, Higher Cambridge Street, Manchester M15 6FH, UK.
Dent Mater. 2012 Aug;28(8):928-35. doi: 10.1016/j.dental.2012.04.038. Epub 2012 May 30.
To determine the creep deformation of several "bulk-fill" resin-composite formulations in comparison with some other types.
Six resin-composites; four bulk-fill and two conventional were investigated. Stainless steel split molds (4 mm × 6 mm) were used to prepare cylindrical specimens for creep testing. Specimens were thoroughly irradiated with 650 mW cm(-2). A total of 10 specimens for each material were divided into two groups (n = 5) according to the storage condition; Group A stored dry at 37 °C for 24h and Group B stored in distilled water at 37 °C in an incubator for 24h. Each specimen was loaded (20 MPa) for 2h and unloaded for 2h. The strain deformation was recorded continuously for 4h. Statistical analysis was performed using a two-way ANOVA followed by one-way ANOVA and the Bonferroni post hoc test at a significance level of a = 0.05.
The maximum creep strain % ranged from 0.72% up to 1.55% for Group A and the range for Group B increased from 0.79% up to 1.80% due to water sorption. Also, the permanent set ranged from 0.14% up to 0.47% for Group A and from 0.20% up to 0.59% for Group B. Dependent on the material and storage condition, the percentage of creep strain recovery ranged between 64% and 81%. Increased filler loading in the bulk-fill materials decreased the creep strain magnitude.
Creep deformation of all studied resin-composites increased with wet storage. The "bulk-fill" composites exhibited an acceptable creep deformation and within the range exhibited by other resin-composites.
比较几种“块状填充”树脂复合材料与其他类型的树脂复合材料的蠕变变形。
研究了六种树脂复合材料；其中四种为块状填充型，两种为传统型。使用不锈钢分体模具（4mm×6mm）制备用于蠕变测试的圆柱形试件。试件用 650mW/cm²的光进行彻底照射。每种材料各制备 10 个试件，根据储存条件分为两组（n=5）；A 组在 37°C 下干燥储存 24 小时，B 组在 37°C 的孵育器中储存于蒸馏水中 24 小时。每个试件加载（20MPa）2 小时，卸载 2 小时。连续记录应变变形 4 小时。使用双因素方差分析（ANOVA） followed by 单向方差分析（one-way ANOVA）和 Bonferroni 事后检验进行统计分析，显著水平设为 a = 0.05。
A 组的最大蠕变应变范围为 0.72%至 1.55%，B 组的范围由于吸水而增加到 0.79%至 1.80%。此外，A 组的永久变形范围为 0.14%至 0.47%，B 组的范围为 0.20%至 0.59%。取决于材料和储存条件，蠕变应变恢复率在 64%至 81%之间。块状填充材料中填料负载的增加降低了蠕变应变幅度。
所有研究的树脂复合材料的蠕变变形都会随着湿储存而增加。“块状填充”复合材料表现出可接受的蠕变变形，并且在其他树脂复合材料表现出的范围内。
