Objectives: Understanding the fatigue behavior of dental materials is essential for prognosis of restorations. We have reported that the fatigue crack growth exponents (FCGE) of dental ceramics (J Dent Res 80: 559, 2001, abst.# 257). In this study, the FCGE of bovine dentin was determined in an effort to evaluate the effect of cyclic loading and to compare FCGEs of dental ceramics. Methods: Sixty discs (12.0 mm/ diameter and 1.2 mm/ thickness) of bovine labial dentin of lower first incisors were prepared using a low-speed saw and an air-turbine. The cyclic fatigue test with the piston-on-three-ball method according to ISO: 6872: 1995 was performed using a servo-hydraulic test machine (8871, Instron) with a sinusoidal cyclic unipolar load of 5 Hz frequency in distilled water. The cyclic fatigue strength (CFS) at 10, 10 3, and 10 5 cyclic loading was determined by the staircase method employing 20 specimens. The FCGE was calculated as an inverted gradient between logarithmic fatigue strengths and logarithmic cyclic numbers. The regression line gradients of the dentin and the ceramics previously reported were compared by covariance analysis. Results: CFSs (sd) and FCGE are summarized as follows (* previously reported values). The gradient of the dentin was steeper but not significantly different from those of the ceramics (p<0.05). Conclusion: These results suggest that the effect of cyclic loading on bovine dentin might be slightly greater than that of the dental ceramics, however, statistically insignificant.
9:00 AM-11:00 AM, Saturday, 9 March 2002 San Diego Convention Center Room 8 (Upper Level)
Back to the Dental Materials: VIII - Others-Non-metallic Program
Back to the IADR/AADR/CADR 80th General Session (March 6-9, 2002)