Statement of problem

Interim restorations represent an essential clinical treatment step; however, limited information is available concerning the performance of computer-aided design and computer-aided manufacturing (CAD-CAM) interim materials.

Purpose

The purpose of this in vitro study was to evaluate the performance and fracture load of resin anterior implant-supported interim fixed partial dentures (IFPDs).

Material and methods

Identical anterior resin IFPDs (maxillary central incisor to canine; n=16 per material) were milled from polymethylmethacrylate (PMMA) or di-methacrylate (DMA) systems with different filler content. The IFPD groups were split to simulate a chairside (cemented implant-supported prosthesis) or laboratory procedure (screw-retained implant-supported prosthesis). A cartridge DMA material served as a control. After interim cementation, combined thermocycling and mechanical loading (TCML) was performed on all restorations to approximate a maximum of 2.5 years of clinical function. Behavior during TCML and fracture force was determined, and failures were analyzed. The data were statistically investigated (Kolmogorov-Smirnov test, 1-way-ANOVA; post hoc Bonferroni, Kaplan-Meier survival, α=.05).

Results

Drop out during TCML varied between no failures and complete failure during loading. For most systems, failure occurred between 120 000 and 600 000 mechanical loading cycles. For IFPDs without a screw channel fracture, values varied between 644 ±263 N and 987 ±101 N. Those with a screw channel fracture failed between 493 ±89 N and 951 ±248 N. Individual IFPDs had significantly higher mean fracture loads (P<.002), but the mean fracture values between IFPDs with and without a screw channel were not significantly different (P>.137). Failures were characterized by fracture of the connector (n=53) followed by mixed failures (n=22) or fractures at the abutment (n=21).

Conclusions

These interim materials are sufficiently fracture resistant for the fabrication of implant-supported anterior IFPDs and are expected to survive between 6 months and 2 years before failure. The stability of IFPDs depended on the type of material but not on the restoration design (with or without a screw channel).

中文翻译：

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临时传统或 CAD-CAM 种植体支持的螺钉或水泥固位前牙固定局部义齿的体外性能和抗断裂性

问题陈述

临时修复是一个重要的临床治疗步骤；然而，关于计算机辅助设计和计算机辅助制造 (CAD-CAM) 临时材料的性能的可用信息有限。

目的

这项体外研究的目的是评估树脂前牙种植体支持的临时固定局部义齿 (IFPD) 的性能和断裂负荷。

材料与方法

相同的前树脂 IFPD（上颌中切牙到犬齿；每种材料 n=16）由具有不同填料含量的聚甲基丙烯酸甲酯 (PMMA) 或二甲基丙烯酸酯 (DMA) 系统研磨而成。IFPD 组被分成模拟椅旁（骨水泥种植体支撑假体）或实验室手术（螺钉固位种植体支撑假体）。盒式 DMA 材料用作对照。临时粘接后，对所有修复体进行联合热循环和机械载荷 (TCML)，以达到最长 2.5 年的临床功能。确定了 TCML 和断裂力期间的行为，并分析了故障。对数据进行统计调查（Kolmogorov-Smirnov 检验，单向方差分析；post hoc Bonferroni，Kaplan-Meier 生存率，α=.05）。

结果

TCML 期间的退出在加载期间没有失败和完全失败之间变化。对于大多数系统，故障发生在 120 000 到 600 000 次机械加载循环之间。对于没有螺钉通道断裂的 IFPD，值在 644 ±263 N 和 987 ±101 N 之间变化。那些螺钉通道断裂的失败在 493 ±89 N 和 951 ±248 N 之间。单个 IFPD 的平均断裂载荷显着更高（P < .002），但有和没有螺钉通道的 IFPD 之间的平均骨折值没有显着差异（P > .137）。故障的特征是连接器断裂 (n=53)，然后是混合故障 (n=22) 或基台处的断裂 (n=21)。

结论

这些临时材料具有足够的抗断裂性，可用于制造植入物支撑的前牙 IFPD，预计可在 6 个月至 2 年之间存活，直至失效。IFPD 的稳定性取决于材料类型，而不取决于修复体设计（带或不带螺钉通道）。