Department of Operative Dentistry, Faculty of Dentistry, Cairo, Egypt.
Oper Dent. 2009 Nov-Dec;34(6):725-31. doi: 10.2341/09-012-L.
The current study aimed to determine the effect of preheating resin composite to three different temperatures on the cuspal movement and gap formation at the tooth/restoration interface.
Fifty extracted, sound human upper premolars were subjected to standardized MOD cavity preparations. Five groups of 10 premolars each were restored with either 1) Tetric Ceram HB, 2) a layer of Tetric Flow followed by Tetric Ceram HB, 3-5) preheated composite to 37 degrees C, 54 degrees C and 68 degrees C, respectively, using a chair-side preheating device (Calset thermal assist unit). Cuspal movement was calculated by measuring the intercuspal distance between the indexed cusp tips before restoration 5 minutes and 24 hours after composite curing using a stereomicroscope. The teeth were sectioned longitudinally and examined under a stereomicroscope connected to a digital camera and image analysis software to detect gap formation.
Group 2 showed the least cuspal movement at 5 minutes and 24 hours and the highest gap area, while Groups 4 and 5 showed the highest cuspal movement at 5 minutes and 24 hours. Group 3 had the least gap area.
Preheating resin composite to temperatures higher than 37 degrees C increases cuspal movement. The adaptation and gap area of preheated resin composite to 37 degrees C and 54 degrees C improved, but it did not change with resin composite preheated to 68 degrees C.
本研究旨在确定将树脂复合材料预加热至三种不同温度对牙尖运动和牙体/修复体界面间隙形成的影响。
将 50 颗提取的、健康的人上颌前磨牙进行标准化 MOD 窝洞制备。每组 10 颗前磨牙，分别用以下材料修复：1）Tetric Ceram HB，2）一层 Tetric Flow 后再用 Tetric Ceram HB，3-5）使用椅旁预热设备（Calset 热辅助装置）将复合材料分别预热至 37°C、54°C 和 68°C。使用立体显微镜在修复前 5 分钟和复合树脂固化后 24 小时测量指数牙尖之间的牙尖间距，计算牙尖运动。将牙齿纵向切割，使用连接到数字相机和图像分析软件的立体显微镜检查，以检测间隙形成。
第 2 组在 5 分钟和 24 小时时牙尖运动最小，间隙面积最大，而第 4 组和第 5 组在 5 分钟和 24 小时时牙尖运动最大。第 3 组的间隙面积最小。
将树脂复合材料预加热至高于 37°C 的温度会增加牙尖运动。预加热至 37°C 和 54°C 的树脂复合材料的适应性和间隙面积得到改善，但预加热至 68°C 的树脂复合材料的适应性和间隙面积没有变化。
