Fatigue Property of a New Indirect Composite Laminated with FRC

Objectives: To evaluate fatigue property of a new indirect composite system using a cyclic loading tester. Methods: Indirect composites tested included a new indirect composite system (an indirect composite (MP) laminated with a fiber-reinforced composite (FRC, Sun Medical)), MP, Gradia (GR, GC), and Estenia C&B (ES, Kuraray Medical). The FRC was lining composite for the MP, and it was consisted of a new monomer creating ductile polymer, 25% of silanized glass fiber (11µm diameter, 150µm long), 5% of colloidal silica, and a photoinitiator¹⁾. Cylindrical specimens (8mm diameter, 7mm height) with a conical opening at the bottom (5.5mm top diameter, 6mm bottom diameter, 6mm height) were fabricated with MP laminated using 0.3 mm thick FRC (MP/FRC, control), MP, GR, ES, and FRC. All specimens were subjected to the cyclic loading test after storing in 37˚C water for 24 hours. A 184g load was cyclically applied to the specimen top using a steel stylus (8mm tip diameter) with a 10 mm traveling distance at 1 Hz. Seven specimens were evaluated for each condition, and the data were statistically analyzed with one-way ANOVA. Results:The results (table) showed that the number of loading cycles to the breakage of the specimens using an new indirect composite system, the MP/FRC, was significantly higher than those of the other indirect composites excluding the FRC (p≤0.05). Conclusion: With the limitation of these results, it was concluded that the fatigue property of the MP was drastically improved by laminating with the FRC.

Table. The number of loading cycles to the breakage of specimens

Products	Indirect composites				Lining composite
	MP/FRC (control)	MP	GR	ES	FRC
Mean (s.d.)	1062 (509)a	120 (61)b	397 (243)b	166 (125)b	more than 5,000c

Values with the same letters were not significantly different (p>0.05).

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