Effects of Saliva Contamination on Bond Strength of Luting Cements

Objectives: To examine the effect of saliva contamination and decontamination methods on the microtensile bond strength (µTBS) of resin luting cements to human dentin.

Methods: Dentin surfaces from fifty extracted human third molars were abraded with 600-grit SiC paper. For RelyX ARC (ARC: 3M ESPE), the dentin surfaces were treated with 32% phosphoric acid (Uni-Etch, Bisco) and the subgroups were: ARC-control (uncontaminated), ARC-I (saliva contamination, blot dried), ARC-II (saliva contamination, rinse, blot dried) and ARC-III (saliva contamination, rinse, re-etch, rinse, blot dried). For Panavia F (PF: Kuraray), the subgroups were: PF-control (uncontaminated), PF-I (saliva contamination, dried), PF-II (saliva contamination, rinse, dried), PF-III (primer, saliva contamination, dried), PF-IV (primer, saliva contamination, dried, primer re-applied) and PF-V (primer, saliva contamination, rinse, dried, primer re-applied). Cylindrical composite blocks were luted onto dentin using the two cements. The bonded specimens were stored at 37°C for 24h and sectioned into 0.9x0.9mm beams for µTBS testing. The data were analysed using one-way ANOVA and Student-Newman-Keuls test (p<0.05).

Results: Microtensile bond strength (MPa, Mean ± SD, N=40).

Groups ARC-I and ARC-III showed statistically significant lower µTBS than ARC-control and ARC-II (p<0.005). All PF subgroups had significantly lower µTBS than the control (p<0.005).

Conclusion: Saliva contamination during luting deteriorated the bond quality of resin cements. Decontamination by rinsing with water was effective for restoring the bond strength of ARC, while re-etching decreased the bond strength. For PF, decontamination by rinsing with water and re-application of primer after rinsing improved the bond strength.

Supported by HKU Grant no. 10207402.07840.08004.323.01