Department of Restorative Sciences, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles 90089-7792, USA.
Dent Mater. 2011 Feb;27(2):109-13. doi: 10.1016/j.dental.2010.09.002. Epub 2010 Oct 8.
To evaluate in vitro the pre-cementation resistance of CAD/CAM inlays subjected to functional occlusal tapping.
An extracted tooth model (molar and premolar) with simulated bone and periodontal ligament was used to make a medium-size mesio-occlusal inlay preparation (molar). Immediate dentin sealing was applied to the prepared tooth. The corresponding inlays were fabricated with Cerec either using composite resin (Paradigm MZ100) or ceramic (e.max CAD and Mark II) blocks (n=14). A high marginal ridge was designed in order to generate hyper-occlusion. Pre-cementation occlusal tapping was simulated using closed-loop servo-hydraulics at 2 Hz, starting with a load of 40 N, followed by 80, 120, 160, 200, 240, and 280 N (10 cycles each). All samples were loaded until fracture or to a maximum of 70 cycles. Groups were compared using the life table survival analysis (p=0.016, Bonferroni method).
Survival probability was e.max CAD>MZ100>Mark II. None of the specimens survived the 70 cycles except for two e.max CAD inlays (survival: 14%).
Material selection has a significant effect on the risk of Cerec inlay fracture during pre-cementation functional occlusal tapping.
评估 CAD/CAM 嵌体在功能咬合敲击下的预粘固抗折能力。
采用模拟骨和牙周膜的离体牙模型（磨牙和前磨牙）制作中尺寸的近中-颊舌嵌体预备体（磨牙）。对预备好的牙齿进行即刻牙本质密封。使用 Cerec 机分别用复合树脂（Paradigm MZ100）或陶瓷块（e.max CAD 和 Mark II）制作相应的嵌体（n=14）。设计高边缘嵴以产生超咬合。采用闭环伺服液压系统以 2 Hz 的频率模拟预粘固咬合敲击，起始负载为 40 N，然后分别为 80、120、160、200、240 和 280 N（每个负载 10 次）。所有样本均加载至断裂或达到最大 70 次循环。使用寿命表生存分析（p=0.016，Bonferroni 法）对各组进行比较。
生存概率为 e.max CAD>MZ100>Mark II。除了两个 e.max CAD 嵌体外，没有一个样本能在 70 次循环中存活（生存：14%）。
材料选择对 Cerec 嵌体在预粘固功能咬合敲击过程中发生骨折的风险有显著影响。
