Comparison Load-Fatigue Performance of Self-Adhesive Resin Cements Bonded To Dentin

Objectives: This study investigated the load-fatigue performance of full gold crowns cemented with four different self-adhesive resin cements.

Methods: Extracted human molars were prepared for standard complete gold crown (10^o, h=4 mm), and then randomly divided into 5 groups, based on the type of cement to be used; RelyX Unicem (RXU, 3M ESPE), Biscem (BIS, Bisco), Maxcem (MAX, Kerr), Multilink Automix (MTL, Ivoclar Vivadent), and a control, resin modified glass ionomer, RelyX Plus (RXP, 3M ESPE). Complete gold crowns were cast with Type 3 gold alloy and cemented to the prepared teeth (n=8/gp). A 1.2 Hz fatigue load of 200 N was applied at an angle of 135 degrees to the long axis of each tooth. Cement failure was indicated by a micro-measurement strain gauge that was placed over the crown margin and the failure was defined as the propagation of a crack in or around the crown luting cement layer. The number of cycles that were required for inducing the failure of the crown luting cement and the cement failure location were determined.

Results: Statistical analysis (ANOVA, Tukey's tests) revealed that there was a significant difference among the different self-adhesive resin cements (P <.05). RXU and BIS had a significantly higher number of cycles to failure than other cements.

Cement Group	Number of Cycles to Failure (×103)	Cement Failure Location (%)
		Crown-cement interface	Tooth-cement interface	Mixed
RXU	29.821±11.558a	62.5	12.5	25
BIS	21.906±8.992a	12.5	62.5	25
MAX	12.122±5.116c	-	75	25
MTL	19.190±5.686b	-	50	50
RXP	13.698±5.845c	37.5	37.5	25

Note that the data with same superscript demonstrate no statistically significant difference.

Conclusions: All but one self-adhesive resin cements demonstrated superior load fatigue performance compared with resin modified glass ionomer.