Conservative Dentistry Department, Faculty of Oral and Dental Medicine, Delta University for Science and Technology, Gamasa, Egypt.
Conservative Dentistry Department, Faculty of Dentistry, Mansoura University, Mansoura, Egypt.
BMC Oral Health. 2023 Jan 31;23(1):57. doi: 10.1186/s12903-023-02770-0.
The pre-cure temperature is considered an important parameter that affects the polymerization kinetics and the properties of composite restoration. As dissension exists about the effect of storing composite restorative materials in refrigerator, this study aimed to assess the effect of shelf-storage temperature on degree of conversion (DC) and microhardness of three composite restorative materials with different matrix systems.
Three commercially-available composite restorative materials were used in this study; an Ormocer-based composite (Admira Fusion, Voco GmbH), a nanoceramic composite, (Ceram.X SphereTEC One, Dentsply Sirona GmbH), and a nanohybrid composite (Tetric N-Ceram, Ivoclar Vivadent AG). Regarding DC and microhardness tests, 60 disc-shaped composite specimens for each test were randomly divided into 3 groups (n = 20) according to the restorative material used. Each group was divided into 2 subgroups (n = 10) according to the composite storage temperature; stored at room temperature or stored in the refrigerator at 4°-5 °C. DC was evaluated using a Fourier-transform infrared spectrometer coupled to an attenuated total reflectance accessory. Microhardness was evaluated using micro-Vickers hardness tester under a load of 50 g with a dwell time of 10 s. The results were analyzed by ANOVA, post-hoc LSD, and independent t-tests at a significance level of p < 0.05.
Regarding DC test all groups showed statistically significant differences at both storage temperature. The Ormocer-based composite had the highest mean values. There was a statistically significant difference between all room-stored groups and their corresponding groups stored at refrigerator (p < 0.05). For microhardness test, all groups exhibited also statistically significant differences at both storage temperatures with the Ormocer-based composite having the highest mean values. A statistically significant difference between both room-stored and refrigerator-stored groups has been observed also (p < 0.05).
Refrigeration of resin-composite might have a deleterious effect on DC and microhardness of the tested composite restorative materials with different matrix systems. Moreover, the differences in the formulations of composite matrix have a potential impact on DC and microhardness.
预固化温度被认为是影响复合修复聚合动力学和性能的重要参数。由于对于将复合修复材料储存在冰箱中对其性能的影响存在争议，本研究旨在评估储存温度对三种具有不同基质系统的复合修复材料的转化率（DC）和显微硬度的影响。
本研究使用了三种市售的复合修复材料；一种基于奥莫克的复合材料（Admira Fusion，Voco GmbH）、一种纳米陶瓷复合材料（Ceram.X SphereTEC One，Dentsply Sirona GmbH）和一种纳米杂化复合材料（Tetric N-Ceram，Ivoclar Vivadent AG）。对于 DC 和显微硬度测试，根据使用的修复材料，将 60 个圆盘状复合试件随机分为 3 组（n=20）。每组根据复合储存温度进一步分为 2 个亚组（n=10）；室温储存或在 4-5°C 的冰箱中储存。使用傅里叶变换红外光谱仪结合衰减全反射附件评估 DC。在 50g 载荷下用微维氏硬度计，保持时间为 10s，评估显微硬度。使用方差分析、事后 LSD 和独立 t 检验在 p<0.05 的显著性水平下对结果进行分析。
对于 DC 测试，所有组在两种储存温度下均显示出统计学上的显著差异。基于奥莫克的复合材料具有最高的平均值。所有室温储存组与相应的冰箱储存组之间存在统计学上的显著差异（p<0.05）。对于显微硬度测试，所有组在两种储存温度下均显示出统计学上的显著差异，基于奥莫克的复合材料具有最高的平均值。还观察到室温储存组和冰箱储存组之间存在统计学上的显著差异（p<0.05）。
树脂基复合材料的冷藏可能对不同基质系统的测试复合修复材料的 DC 和显微硬度有有害影响。此外，复合材料基质的配方差异对 DC 和显微硬度有潜在影响。
