Objectives

To evaluate and compare the fatigue behavior (fatigue limit and fatigue life) and damage modes of high-performance poly-ether-ketone-ketone (PEKK), zirconia and alloy bilayered crowns.

Materials and methods

A total of 110 crowns (n = 50 for fatigue limit and n = 60 for fatigue life) were fabricated and used in this study. Pekkton® ivory discs, yttrium stabilized zirconia blanks and NiCr casting alloy were used to produce the respective PEKK, zirconia and alloy copings for crown fabrication. The prepared crowns were veneered with composite resin and subjected to fatigue tests. The fatigue limit was evaluated using the staircase method and the fatigue life of the samples was evaluated by subjecting the crowns to a load lower than the fatigue limit of that particular group, and also with an intermediate load of 522 N. A graphical plot was generated from the shape parameter (β) and life parameter (α) values obtained through the Weibull analysis method. Kruskal-Wallis and Mann-Whitney tests were applied to determine the significance differences in the recorded fracture mode between the study groups. The damage modes of the samples were assessed using Burke's classification.

Results

The recorded fatigue limits of the groups were 442.8 ± 42.1 N, 608.7 ± 7.6 N, and 790.4 ± 29.2 N for zirconia, NiCr and PEKK, respectively. A significant difference in the fatigue limit of the groups was observed (p < 0.05). PEKK samples demonstrated the highest survival cycles of 1,170,000 and the lowest survival cycles was observed with zirconia samples at 100,000 under 522 N loading. The fracture modes in PEKK samples were largely distributed between code 1 and 2 whereas the fracture modes in NiCr group was distributed between code 1 and 4 and YZ crowns exhibited more of code 5 fractures. The difference in fracture modes among the groups was statistically significant (p < 0.05).

Conclusion

The PEKK group demonstrated better results compared to zirconia and NiCr based crowns. The PEKK group demonstrated high fatigue limit and survived the highest fatigue life cycles among the tested groups.

中文翻译：

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高性能聚醚酮-酮PEKK双层冠的疲劳行为和损伤模式。

目标

评估和比较高性能聚醚-酮-酮（PEKK），氧化锆和合金双层冠的疲劳行为（疲劳极限和疲劳寿命）和损伤模式。

材料和方法

总共制造了110冠（疲劳极限为n = 50，疲劳寿命为n = 60）。用Pekkton®象牙盘，钇稳定的氧化锆毛坯和NiCr铸造合金分别生产了用于冠加工的PEKK，氧化锆和合金顶盖。制备的牙冠用复合树脂贴面，并进行疲劳测试。使用阶梯法评估疲劳极限，并通过使胎冠承受的载荷低于该特定组的疲劳极限的载荷，以及中间载荷为522 N的载荷，来评估样品的疲劳寿命。通过Weibull分析方法获得的形状参数（β）和寿命参数（α）值。使用Kruskal-Wallis和Mann-Whitney检验确定研究组之间记录的骨折模式的显着性差异。使用伯克分类法评估样品的损坏模式。

结果

对于氧化锆，NiCr和PEKK，记录的疲劳极限分别为442.8±42.1 N，608.7±7.6 N和790.4±29.2N。观察到两组的疲劳极限存在显着差异（p  <0.05）。PEKK样品显示出最高的生存周期为1,170,000，而在522 N负载下，氧化锆样品在100,000时观察到了最低的生存周期。PEKK样品中的断裂模式主要分布在代码1和2之间，而NiCr组的断裂模式分布在代码1和4之间，而YZ牙冠显示出代码5中更多的断裂。各组之间骨折模式的差异具有统计学意义（p  <0.05）。

结论

与氧化锆和NiCr基牙冠相比，PEKK组表现出更好的结果。PEKK组表现出较高的疲劳极限，并在测试组中保持了最高的疲劳寿命。