Department of Prosthetic Dentistry, Justus-Liebig-University, D-35392 Giessen, Germany.
Dent Mater. 2011 Apr;27(4):339-47. doi: 10.1016/j.dental.2010.11.012. Epub 2010 Dec 21.
This study aimed at investigating the influence of fabrication method, storage condition and material on the fracture strength of temporary 3-unit fixed partial dentures (FPDs).
A CrCo-alloy master model with a 3-unit FPD (abutment teeth 25 and 27) was manufactured. The master model was scanned and the data set transferred to a CAD/CAM unit (Cercon Brain Expert, Degudent, Hanau, Germany). Temporary 3-unit bridges were produced either by milling from pre-fabricated blanks (Trim, Luxatemp AM Plus, Cercon Base PMMA) or by direct fabrication (Trim, Luxatemp AM Plus). 10 FPDs per experimental group were subjected either to water storage at 37 °C for 24h and 3 months, respectively, or thermocycled (TC, 5000×, 5-55 °C, 1 week). Maximum force at fracture (Fmax) was determined in a 3-point bending test at 200 mm/min. Data was analyzed using parametric statistics (α = 5%).
Fmax values ranged from 138.5 to 1115.5N. FPDs, which were CAD/CAM fabricated, showed a significant higher Fmax compared to the directly fabricated bridges (p < 0.05). TC significantly affected Fmax for Luxatemp (p < 0.05) but not for the PMMA based materials (p > 0.05). CAD/CAM milled FPDs made of Luxatemp showed significantly higher Fmax values compared to Trim and Cercon Base PMMA (p < 0.05).
CAD/CAM fabricated FPDs exhibit a higher mechanical strength compared to directly fabricated FPDs, when manufactured of the same material. Composite based materials seem to offer clear advantages versus PMMA based materials and should, therefore, be considered for CAD/CAM fabricated temporary restorations.
本研究旨在探讨制作方法、储存条件和材料对临时三单位固定局部义齿（FPD）断裂强度的影响。
制作带有三单位 FPD（基牙 25 和 27）的 CrCo 合金母模。扫描母模并将数据集传输到 CAD/CAM 单元（德国 Degudent 的 Cercon Brain Expert）。临时三单位桥通过从预制毛坯（Trim、Luxatemp AM Plus、Cercon Base PMMA）铣削或直接制作（Trim、Luxatemp AM Plus）来制作。每个实验组有 10 个 FPD，分别在 37°C 下储存 24 小时和 3 个月，或进行热循环（TC，5000×，5-55°C，1 周）。在 200mm/min 的三点弯曲试验中测定断裂时的最大力（Fmax）。使用参数统计（α=5%）分析数据。
Fmax 值范围为 138.5 至 1115.5N。与直接制作的桥相比，CAD/CAM 制作的 FPD 显示出显著更高的 Fmax（p<0.05）。TC 显著影响 Luxatemp 的 Fmax（p<0.05），但不影响基于 PMMA 的材料（p>0.05）。与 Trim 和 Cercon Base PMMA 相比，CAD/CAM 铣削的 Luxatemp 基 FPD 显示出显著更高的 Fmax 值（p<0.05）。
当使用相同的材料制造时，CAD/CAM 制作的 FPD 比直接制作的 FPD 具有更高的机械强度。基于复合材料的材料似乎比基于 PMMA 的材料具有明显优势，因此应考虑用于 CAD/CAM 制作的临时修复体。
