Department of Cariology, Endodontology & Pediatric Dentistry, School of Dentistry, University of Geneva, Geneva, Switzerland.
Department of Cariology, Endodontology & Pediatric Dentistry, School of Dentistry, University of Geneva, Geneva, Switzerland.
J Dent. 2021 Dec;115:103828. doi: 10.1016/j.jdent.2021.103828. Epub 2021 Oct 20.
to test if cavity dimensions and restorative protocol have potential to influence in-vitro adaptation of class II restoration after simulated thermo-occlusal stressing.
A total of 32 prepared teeth were randomly assigned to one of the 4 experimental groups depending on cavity size, composite system and filling technique; group 1: small cavity and multi-layered conventional restorative composite (Tetric Evo-ceram: TEC), group 2: small cavity and flowable bulk-filled composite (SDRFlow: SDR) + one single occlusal layer of conventional restorative composite (TEC), group 3: large cavity and multilayered conventional restorative composite (TEC) and group 4: large cavity and bulk-filled flowable composite (SDR) + one single occlusal layer conventional restorative composite (TEC). All specimens were submitted to 500'000 cycles of thermomechanical loading (50 N, 5 to 55 °C). The proximal tooth-restoration interface was analyzed quantitatively by SEM, prior and after thermomechanical loading.
Before loading, continuous enamel adaptation varied from 61.49% (Gr 1) to 68.39% (Gr 4) proximally and from 50.93% (Gr2) to 68.65% (Gr1) cervically, with no statistical difference among groups for both segments. After thermomechanical loading, continuous enamel adaptation varied from 36.6% (Gr2) to 46.6% (Gr1) proximally, without significant difference, and from 20.2% (Gr4) to 51.3% (Gr1) cervically; statistical differences in cervical enamel adaptation were found in-between groups 1 and 2 (p = 0.0479), 1 and 4 (P = 0.0116), 2 and 3 (p = 0.0028) and 3 and 4 (p = 0.001). Before loading, dentin continuous adaptation varied from 55.32% (Gr3) to 81.82% (Gr4) with statistical difference in-between those groups (p = 0.045); after loading, dentin continuous adaptation varied from 31.56% (gr2) to 51% (Gr4) with a statistical difference between those 2 groups (p = 0.019). The drop in adaptations values after loading was significant in all groups and segments.
The impact of the restorative technique and cavity size on marginal adaptation appeared essentially after simulated fatigue for enamel adaptation. Cervical enamel and dentin continuous adaption of small and large bulk-filled restorations dropped significantly while the change was lower in layered restorations made of conventional restorative composite.
Restorations made with bulk-filled flowable composite behaved differently from layered ones using conventional resin composite, according to cavity size and loading.
测试窝洞尺寸和修复方案是否会影响模拟热咬合应力后 II 类修复体的体外适应性。
总共 32 颗制备好的牙齿被随机分配到 4 个实验组中的一个，根据窝洞大小、复合系统和填充技术；第 1 组：小窝洞和多层常规修复复合（Tetric Evo-ceram：TEC），第 2 组：小窝洞和流动块状填充复合（SDRFlow：SDR）+单层常规修复复合（TEC），第 3 组：大窝洞和多层常规修复复合（TEC），第 4 组：大窝洞和块状填充流动复合（SDR）+单层常规修复复合（TEC）。所有标本均接受 500'000 次热机械加载循环（50 N，5 至 55°C）。在热机械加载之前和之后，通过 SEM 对近端牙-修复体界面进行定量分析。
在加载之前，连续的牙釉质适应性从 61.49%（Gr 1）到 68.39%（Gr 4）近端，从 50.93%（Gr2）到 68.65%（Gr1）颈部，各组之间没有统计学差异。在热机械加载后，连续的牙釉质适应性从 36.6%（Gr2）到 46.6%（Gr1）近端，没有显著差异，从 20.2%（Gr4）到 51.3%（Gr1）颈部；在 1 组和 2 组（p=0.0479）、1 组和 4 组（P=0.0116）、2 组和 3 组（p=0.0028）以及 3 组和 4 组（p=0.001）之间观察到颈部牙釉质适应性的统计学差异。在加载之前，连续的牙本质适应性从 55.32%（Gr3）到 81.82%（Gr4）变化，各组之间有统计学差异（p=0.045）；在加载后，连续的牙本质适应性从 31.56%（Gr2）到 51%（Gr4）变化，两组之间有统计学差异（p=0.019）。所有组和段的适应性值在加载后均显著下降。
在模拟疲劳后，修复技术和窝洞大小对边缘适应性的影响主要出现在牙釉质适应性上。小和大的块状填充修复体的颈部牙釉质和牙本质连续适应性明显下降，而由常规修复复合材料制成的分层修复体的变化较低。
根据窝洞大小和负荷，使用块状填充流动复合材料制成的修复体与使用常规树脂复合材料制成的分层修复体表现不同。
