Department of Prosthetic Dentistry, Danube Private University, Dr.-Karl-Dorrek-Str. 23, Campus West, 3500 Krems, Austria.
Clin Oral Investig. 2012 Dec;16(6):1659-67. doi: 10.1007/s00784-011-0653-5. Epub 2011 Dec 17.
The objective of this in vitro study was to investigate the behavior of different composite restorative materials under the load of cast circumferential clasps for removable dental prostheses (RDPs).
In 60 human molars, standardized mesial-occlusal-distal cavities were prepared. The cavities were restored with the following materials: Definite, Tetric Ceram, SureFil, Heliomolar RO, Ariston pHc, and Oralloy, and provided with a rest seat. The rest seats were subjected to 5,000 cycles of thermal cycling and 1,200,000 masticatory cycles in a mastication simulator via cobalt-chromium circumferential clasps cast to standardized frameworks in a laboratory model designed to simulate the biomechanics of a free-end denture base. Fracture analysis of the restorations was performed by light microscopy. Before and after loading, material wear was measured with a 3D-laser scanner, and an analysis of the marginal quality was performed in an SEM at ×200 applying the replica technique.
No significant differences in the fracture behavior among the composite materials were found; the amalgam control group showed a significantly higher fracture resistance. Regarding the wear of the materials, the composites Definite and SureFil exhibited a behavior similar to that of amalgam. The other composites demonstrated higher wear rates. The initial marginal quality was significantly worse for Ariston pHc. The marginal adaptation decreased significantly after thermal and mechanical loading for Definite and Ariston pHc.
In terms of the investigated aspects of mechanical performance, the tested composites seemed to be inferior to amalgam. Further clinical studies are needed to evaluate the ability of composite restorations to provide support for RDP clasps.
The use of composites as direct restoration materials should be avoided in teeth, which serve as abutments for clasp-retained RDPs.
本体外研究旨在探讨不同复合修复材料在可摘局部义齿（RDP）铸造环形卡环负载下的行为。
在 60 个人类磨牙中，制备了标准化的近中-颊-远中腔。用以下材料修复腔：Definite、Tetric Ceram、SureFil、Heliomolar RO、Ariston pHc 和 Oralloy，并提供休息座位。在口腔修复模拟器中，通过钴铬环形卡环对休息座位进行了 5000 次热循环和 120 万次咀嚼循环，这些卡环是根据实验室模型中标准化框架铸造的，该模型旨在模拟自由端义齿基的生物力学。通过光显微镜对修复体进行断裂分析。在加载前后，使用 3D 激光扫描仪测量材料磨损，并通过复制技术在 SEM 中以×200 进行边缘质量分析。
未发现复合材料之间的断裂行为有显著差异；汞合金对照组显示出明显更高的断裂阻力。关于材料的磨损，复合材料 Definite 和 SureFil 表现出与汞合金相似的行为。其他复合材料表现出更高的磨损率。Ariston pHc 的初始边缘质量明显较差。热和机械加载后，Definite 和 Ariston pHc 的边缘适应性显著降低。
就机械性能方面的研究而言，测试的复合材料似乎不如汞合金。需要进一步的临床研究来评估复合修复体为 RDP 卡环提供支持的能力。
在作为卡环固位 RDP 基牙的牙齿中，不应使用复合材料作为直接修复材料。
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