牙本质与复合树脂压缩蠕变行为匹配性的实验研究

Suitability between human dentine and resin-composite′s compressive creep behaviour:an in vitro study

目的研究人牙本质与复合树脂在相同实验条件下蠕变行为的匹配性。方法收集离体人磨牙切削制作圆柱体形态的牙本质试件20个,采用随机数表法随机分为D300与D50两组,每组10个试件。制作圆柱形复合树脂试件20个,采用随机数表法随机分为R300与R50组两组,每组10个。分别对D300与R300组的试件施加300 N载荷、D50与R50组施加50 N载荷至7200 s,每5秒记录1次应变,绘制应变-时间曲线并提取最大蠕变应变,使用两独立样本的t检验进行组间比较,检验水准为双侧α=0.05。结果牙本质与复合树脂在实验条件下均表现出一定的蠕变行为,且蠕变曲线形态有差异。300 N载荷下牙本质最大蠕变应变为(2.953±1.099)%,复合树脂最大蠕变应变为(1.370±0.069)%,二者差异具有统计学意义(t=4.54,P<0.001);50 N载荷下牙本质最大蠕变应变为(1.490±0.348)%,复合树脂最大蠕变应变为(0.483±0.105)%,二者差异具有统计学意义(t=8.76,P<0.001)。结论相同实验条件下,相同载荷时牙本质蠕变较复合树脂蠕变明显。

Objective To evaluate the suitability between human dentine and resin-composite′scompressive creep behavior under in vitro circumstances. Methods Twenty human dentine specimenswere fabricated using molars free from fracture and irregularities in shape,and were then divided randomlyinto two groups,with ten specimens in each group. Twenty resin-composite specimens were prepared in adental laboratory and divided randomly into two groups,with ten specimens in each group. Specimens wereloaded for 7200 s under a constant compressive load of 300 and 50 N,respectively. After the dataacquisition of compressive creep tests,the time-strain curves were drawn and the maximum creep strainwas observed. Statistical analysis was performed using independent-samples t-test at a significance level of0.05. Results Under the same in vitro testing conditions,creep behaviour was observed in both humandentine and resin-composite,yet the trend of the strain-time curves was different. Under the constant loadof 300 N,the maximum creep strain of human dentine was（2.953 ± 1.099）%,significantly higher thanthat of the resin-composite（1.370 ± 0.069）%（t = 4.54,P 〈0.001）. Under the constant load of 50 N,themaximum creep strain of dentine was（1.490 ± 0.348）%,significantly higher than that of the resin-composite（0.483 ± 0.105）%（t = 8.76,P 〈0.001）. Conclusion Under the same in vitro testing conditions,the compressive creep occurred in human dentine was significantly higher than that in resin-composite.