Guanghua School of Stomatology, Hospital of Stomatology, Sun Yat-sen University, Guangdong Engineering Research Center of Technology and Materials for Oral Reconstruction, Guangdong Provincial Key Laboratory of Stomatology, Guangzhou, China.
Department of Radiation Oncology, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou, China.
Dent Mater. 2020 Mar;36(3):366-376. doi: 10.1016/j.dental.2020.01.003. Epub 2020 Jan 23.
To evaluate and compare the viscoelastic properties of dentine and resin-based dental materials by bulk compressive test and the Burgers model.
Sound dentine, three resin composites as well as a resin-based cement were prepared into cylindrical specimens (n = 8). A bulk compressive creep test was applied with a constant load of 300 N (23.9 MPa) for 2 h, followed by another 2 h recovery. The maximum strain, creep stain, percentage of recovery and permanent set was measured using a linear variable displacement transducer. The viscoelastic properties were characterized via the Burgers model, and the instantaneous elastic, viscous as well as elastic delayed deformation were separated from the total strain. Data were analysed via ANOVA (or Welch's Test) and Tukey (or Games-Howell Test) with a significance level of 0.05.
Sound dentine presented the lowest maximum strain, creep strain, permanent set and the highest percentage of recovery, followed by 3 resin composites with comparable parameters, while the cement showed a significantly higher maximum strain, permanent set and lower percentage of recovery (p < 0.001). The Burgers model presented acceptable fits for characterization viscoelastic processes of both dentine and resin-based dental materials. Viscous and elastic delayed strain of dentine was significantly lower than those for tested materials (p < 0.001) with the highest instantaneous elastic strain percentage. Similar viscous and delayed strain was found among the 4 resin-based materials (p > 0.05).
Sound dentine exhibited superior creep stability compared to resin-based dental materials. The viscous deformation in sound dentine could be ignored when loading parallel to dentine tubules.
通过体压缩试验和伯格模型评估和比较牙本质和树脂基牙科材料的粘弹性。
制备健康牙本质、三种树脂复合材料和一种树脂基水泥的圆柱形试件（n=8）。在恒定载荷 300N（23.9MPa）下进行体压缩蠕变试验 2 小时，然后再恢复 2 小时。使用线性可变位移传感器测量最大应变、蠕变应变、恢复百分比和永久变形。通过伯格模型来描述粘弹性特性，从总应变中分离出瞬时弹性、粘性和弹性延迟变形。数据采用方差分析（或 Welch 检验）和 Tukey（或 Games-Howell 检验）进行分析，显著性水平为 0.05。
健康牙本质的最大应变、蠕变应变、永久变形最小，恢复百分比最大，其次是 3 种具有相似参数的树脂复合材料，而水泥的最大应变、永久变形明显更高，恢复百分比更低（p<0.001）。伯格模型对牙本质和树脂基牙科材料的粘弹性过程具有良好的拟合度。牙本质的粘性和弹性延迟应变明显低于测试材料（p<0.001），瞬时弹性应变百分比最高。4 种树脂基材料之间发现了相似的粘性和延迟应变（p>0.05）。
健康牙本质与树脂基牙科材料相比，具有更好的蠕变稳定性。当载荷平行于牙本质小管时，可以忽略健康牙本质中的粘性变形。
