Mechanical fatigue degradation of ceramics versus resin composites for dental restorations

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• 作者：Renan Belli ; ^{rbelli@dent.uni-erlangen.de" class="auth_mail} ; Eva Geinzer ; Anna Muschweck ; Anselm Petschelt ; Ulrich Lohbauer
• 关键词：Resin composite ; Ceramics ; Flexural strength ; Fatigue ; Staircase approach
• 刊名：Dental Materials
• 出版年：April, 2014
• 年：2014
• 卷：30
• 期：4
• 页码：424-432
• 全文大小：1266 K

文摘

Objectives

For posterior partial restorations an overlap of indication exists where either ceramic or resin-based composite materials can be successfully applied. The aim of this study was to compare the fatigue resistance of modern dental ceramic materials versus dental resin composites in order to address such conflicts.

Methods

Bar specimens of five ceramic materials and resin composites were produced according to ISO 4049 and stored for 14 days in distilled water at 37 掳C. The following ceramic materials were selected for testing: a high-strength zirconium dioxide (e.max ZirCAD, Ivoclar), a machinable lithium disilicate (e.max CAD, Ivoclar), a pressable lithium disilicate ceramic (e-max Press, Ivoclar), a fluorapatite-based glass-ceramic (e.max Ceram, Ivoclar), and a machinable color-graded feldspathic porcelain (Trilux Forte, Vita). The composite materials selected were: an indirect machinable composite (Lava Ultimate, 3M ESPE) and four direct composites with varying filler nature (Clearfil Majesty Posterior, Kuraray; GrandioSO, Voco; Tetric EvoCeram, Ivoclar-Vivadent; and CeramX Duo, Dentsply). Fifteen specimens were tested in water for initial strength (蟽_in) in 4-point bending. Using the same test set-up, the residual flexural fatigue strength (蟽_ff) was determined using the staircase approach after 10⁴ cycles at 0.5 Hz (n = 25). Weibull parameters 蟽₀ and m were calculated for the 蟽_in specimens, whereas the 蟽_ff and strength loss in percentage were obtained from the fatigue experiment.

Results

The zirconium oxide ceramic showed the highest 蟽_in and 蟽_ff (768 and 440 MPa, respectively). Although both lithium disilicate ceramics were similar in the static test, the pressable version showed a significantly higher fatigue resistance after cyclic loading. Both the fluorapatite-based and the feldspathic porcelain showed equivalent initial and cyclic fatigue properties. From the composites, the highest filled direct material Clearfil Majesty Posterior showed superior fatigue performance. From all materials, e.max Press and Clearfil Majesty Posterior showed the lowest strength loss (29.6% and 32%, respectively), whereas the other materials lost between 41% and 62% of their flexural strength after cyclic loading.

Conclusions

Dental ceramics and resin composite materials show equivalent fatigue strength degradation at loads around 0.5蟽_in values. Apart from the zirconium oxide and the lithium disilicate ceramics, resin composites generally showed better 蟽_ff after 10,000 cycles than the fluorapatite glass-ceramic and the feldspathic porcelain. Resin composite restorations may be used as an equivalent alternative to glass-rich-ceramic inlays regarding mechanical performance.