Statement of problem

Information about the accuracy of maxillary and mandibular denture bases made with different fabrication techniques under uniform test conditions is lacking.

Purpose

The purpose of this in vitro study was to evaluate the denture base adaptation of computer-aided design and computer-aided manufactured (CAD-CAM) milled, 3D printed, and conventional heat-polymerized resin fabrication techniques.

Material and methods

Maxillary and mandibular edentulous models fabricated from cobalt-chromium alloy were scanned, and 2-mm-thick denture bases were designed and fabricated by using 4 fabrication techniques and materials: CAD-CAM milled (CCM), 3D printed (3DP), injection molded (IM), and compression molded (CM). Denture base adaptation was assessed by measuring the thickness of silicone between the denture base and model under a 49-N load at 8 sites. A digital superimposition method was used to compare different groups, and adaptation was assessed by superimposing the scanning data from denture bases and models. The pairwise Wilcoxon signed rank test and Kruskal-Wallis analysis of variance were used for statistical analyses (α=.05).

Results

According to the silicone thickness method, the lowest values (0.127-0.567 mm) were present at the bilateral maxillary tuberosities, and the highest values (0.529-2.211 mm) occurred at the postpalatal seal area in all groups. The CCM group had the lowest silicone thickness (P<.05). The 3DP group recorded greater thickness than the IM and CM groups (P<.05). In the mandible, the 3DP group recorded the lowest silicone thickness, followed by the CCM group. The overall results for digital superimposition revealed no significant difference (P>.05) in the trueness of the intaglio surfaces among CCM, IM, and CM. The 3DP group recorded the lowest trueness significantly among all the groups.

Conclusions

CCM, IM, and CM exhibited superior denture adaptation, especially CCM, to both maxillary and mandibular arches compared with 3DP.

中文翻译：

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制造技术对义齿基托适应性的影响：一项体外研究。

问题陈述

缺乏有关在统一的测试条件下用不同的制造技术制成的上颌和下颌义齿基托准确性的信息。

目的

这项体外研究的目的是评估计算机辅助设计和计算机辅助制造（CAD-CAM）研磨，3D打印和常规热聚合树脂制造技术的义齿基托适应性。

材料与方法

扫描由钴铬合金制成的上颌和下颌无牙模型，并使用4种制造技术和材料设计和制造2毫米厚的义齿基托：CAD-CAM铣削（CCM），3D打印（3DP），注塑（IM）和压缩成型（CM）。通过在8个位置的49 N负载下测量义齿基托与模型之间的硅树脂厚度来评估义齿基托的适应性。使用数字叠加方法比较不同组，并通过叠加来自义齿基托和模型的扫描数据评估适应性。使用成对的威尔科克森符号秩检验和方差的Kruskal-Wallis分析进行统计分析（α= .05）。

结果

根据硅树脂厚度法，在所有上颌骨双侧结节中，最小值（0.127-0.567 mm）存在，而最高值（0.529-2.211 mm）出现在pal骨后密封区域。CCM组的硅树脂厚度最低（P <.05）。3DP组记录的厚度大于IM组和CM组（P <.05）。在下颌骨中，3DP组的硅树脂厚度最低，其次是CCM组。数字叠加的总体结果显示，在CCM，IM和CM之间，凹版表面的真实性没有显着差异（P > .05）。3DP组在所有组中的真实性最低。

结论

与3DP相比，CCM，IM和CM对上颌和下颌牙弓均表现出优异的义齿适应性，尤其是CCM。