Kocak Elif Figen, Ekren Orhun, Ucar Yurdanur
Department of Prosthodontics, Faculty of Dentistry, Çukurova University, Adana, Turkey.
Abdi Sutcu Vocational School of Health Services, Çukurova University, Adana, Turkey.
J Prosthodont. 2022 Dec;31(9):766-770. doi: 10.1111/jopr.13501. Epub 2022 Mar 22.
The purpose of the study was to assess the effect of internal design modifications on the mechanical properties of multi-unit Cobalt-Chromium (Co-Cr) metal-ceramic frameworks manufactured by direct metal laser sintering.
Four-unit fixed partial denture metal-ceramic frameworks were digitally designed on a metal die model using 3D software. A total of 30 specimens were prepared using Co-Cr alloy powder with direct metal laser sintering (n = 10). The control group specimens were solid where the inside of the specimens was completely full. For the test groups, the internal design of the framework was modified. Leaving the outer shell thickness of the framework at 0.5 mm, two different internal designs with hollow geometries were created (1.5 mm and 2 mm inner bar distances) and a cross section area of the connector was calculated. The weights of the specimens were measured and subjected to a 3-point-bending test at 1 mm/min crosshead speed. Data were statistically analyzed using One-way ANOVA followed by Tukey (α = 0.05).
There was a statistically significant difference among the groups in terms of weight of the specimens (p ≤ 0.05). However, no significant difference was observed among groups in term of both flexural strength and flexural modulus (p ≤ 0.05).
Within the limitations of the study, it was concluded that changing the internal design of the metal frameworks decreases the weight of the framework, but does not affect the flexural strength and flexural modulus. Therefore, clinical applications of internally modified frameworks seem promising for metal-ceramic restorations.
本研究旨在评估内部设计修改对通过直接金属激光烧结制造的多单位钴铬（Co-Cr）金属陶瓷框架机械性能的影响。
使用3D软件在金属模具模型上对四单位固定局部义齿金属陶瓷框架进行数字化设计。使用钴铬合金粉末通过直接金属激光烧结制备了总共30个样本（n = 10）。对照组样本为实心，样本内部完全填满。对于测试组，框架的内部设计进行了修改。将框架的外壳厚度保持在0.5毫米，创建了两种具有中空几何形状的不同内部设计（内杆距离为1.5毫米和2毫米），并计算了连接器的横截面积。测量样本的重量，并以1毫米/分钟的十字头速度进行三点弯曲试验。使用单因素方差分析（One-way ANOVA）和Tukey检验（α = 0.05）对数据进行统计分析。
各组样本重量之间存在统计学显著差异（p≤0.05）。然而，在弯曲强度和弯曲模量方面，各组之间未观察到显著差异（p≤0.05）。
在本研究的局限性内，得出的结论是，改变金属框架的内部设计会降低框架的重量，但不会影响弯曲强度和弯曲模量。因此，内部修改框架在金属陶瓷修复体的临床应用中似乎很有前景。
