Oper Dent. 2020 Jan/Feb;45(1):52-61. doi: 10.2341/18-098-L. Epub 2019 May 14.
The purpose of this study was to investigate the effect of four direct restorative materials that can be used in the proximal box elevation (PBE) technique.
Seventy-five molar teeth were randomly assigned to one of five groups (n=15): type II glass ionomer (GI), type II resin-modified glass ionomer (RMGI), resin-based composite (RBC), bulk-fill (BF) resin-based composite, and a control with no box elevation procedure. Specimens were prepared for a standard mesio-occlusal-distal, computer-aided design/computer-aided manufactured (CAD-CAM) resin, nanoceramic onlay with mesial cervical margins located 1 mm above the cementoenamel junction (CEJ) and distal cervical margins located 2 mm below the CEJ. PBE was used to elevate the distal margins to 1 mm above the CEJ in all groups except the control group. For the control group the onlay margin was placed directly on the prepared distal tooth structure without PBE. A Lava Ultimate CAD/CAM resin, nanoceramic onlay restorative was manufactured and bonded on all specimens with RelyX Ultimate adhesive resin cement. The quality of the tooth-PBE material and PBE material-onlay interface was evaluated with scanning electron microscopy using epoxy resin replicas before and after cyclic loading (100,000 cycles, 1.2 Hz at 65N and 37°C). In addition to margin quality, the fracture resistance of each group was measured using a universal testing machine. Fracture pattern was recorded by visual examination. The Levene test for homogeneity and the Welch analysis of variance were completed for fracture resistance and margin quality. A χ test was completed for break mode.
For dentin margins, a statistically significant difference was detected between the RMGI and control groups at baseline (=0.0442). All other groups-GI, RBC, and BF-showed no difference from the control at baseline (>0.05). No statistical significance was observed among groups for post-cyclic fatigue (=0.8735). For onlay margins, no statistical significance was observed among groups for pre-cyclic fatigue, post-cyclic fatigue, or change (=0.9713, =0.528, =0.4385, respectively). No significant difference was observed for the fracture resistance among groups or for the type of break by material used (=0.1593, =0.77, respectively).
Within the parameters of this study, after mechanical fatigue, the materials used for PBE: RMGI, RBC, and BF, did not influence results in terms of margin quality and fracture resistance. Therefore, collective findings suggest that these materials might be suitable for PBE procedures. Nevertheless, clinical caution is recommended with any PBE procedure and further testing of GI materials is needed.
本研究旨在探讨可用于近中盒提升（PBE）技术的四种直接修复材料的效果。
75 颗磨牙随机分为五组（每组 15 颗）：Ⅱ型玻璃离子体（GI）、Ⅱ型树脂改性玻璃离子体（RMGI）、树脂基复合材料（RBC）、块状充填（BF）树脂基复合材料和无盒提升术的对照组。标本制备为标准的近中-颊-远颊，计算机辅助设计/计算机辅助制造（CAD-CAM）树脂，纳米陶瓷嵌体，近中颈缘位于牙釉质牙骨质界（CEJ）上方 1mm，远中颈缘位于 CEJ 下方 2mm。除对照组外，所有组均采用 PBE 将远中边缘提升至 CEJ 上方 1mm。对于对照组，嵌体边缘直接放置在预备的远中牙体结构上，不进行 PBE。所有标本均用 RelyX Ultimate 胶粘剂树脂水泥制造和粘结 Lava Ultimate CAD/CAM 树脂纳米陶瓷嵌体修复体。在循环加载（100,000 次循环，1.2Hz，65N 和 37°C）前后，使用环氧树脂复制件通过扫描电子显微镜评估牙齿-PBE 材料和 PBE 材料-嵌体界面的质量。除了边缘质量外，还使用万能试验机测量每组的断裂阻力。通过视觉检查记录断裂模式。使用 Levene 检验进行同质性检验和 Welch 方差分析进行断裂阻力和边缘质量检验。使用 χ 检验进行断裂模式检验。
对于牙本质边缘，RMGI 组与对照组在基线时存在统计学显著差异（=0.0442）。所有其他组-GI、RBC 和 BF-在基线时与对照组无差异（>0.05）。组间循环疲劳后无统计学差异（=0.8735）。对于嵌体边缘，组间预循环疲劳、循环疲劳后或变化无统计学意义（=0.9713，=0.528，=0.4385，分别）。组间断裂阻力或使用材料的断裂类型无统计学差异（=0.1593，=0.77，分别）。
在本研究参数范围内，经过机械疲劳后，用于 PBE 的材料：RMGI、RBC 和 BF 不会影响边缘质量和断裂阻力的结果。因此，综合研究结果表明，这些材料可能适用于 PBE 程序。然而，任何 PBE 程序都需要临床谨慎，并且需要进一步测试 GI 材料。
