Effect of Saliva Contamination on the Microshear Bond Strength of One-step Self-etching Adhesive Systems to Dentin

Abstract

Saliva contamination significantly affects the bond strength of one-step self-etching adhesive systems to dentin; therefore, saliva contamination must be avoided when using these systems. ©Operative Dentistry, 2006, 31-1, 127-134 SUMMARYThis study evaluated the effect of saliva contamination and decontamination methods on the dentin bond strength of one-step self-etching adhesive systems. Three commercially available "all-in-one" adhesives (One Up Bond F, Xeno III and Adper Prompt) and one resin composite (Filtek Z-250) were used. Third molars stored in distilled water with 0.5% thymol at 4°C were ground with #600 SiC paper under running water to produce a standardized smear layer. The specimens were randomly divided into groups according to contamination methods: no contamination, which was the control (C); contamination of the adhesive surface with fresh saliva before light curing (A) and contamination of the adhesive surface with fresh saliva after light curing (B). Each contamination group was further subdivided into three subgroups according to the decontamination method: A1-Saliva was removed by a gentle air blast and the adhesive was light-cured; A2-Saliva was rinsed for 10 seconds, gently air-dried and the was adhesive lightcured; A3-Saliva was rinsed and dried as in A2, then the adhesive was re-applied to the dentin surface and light-cured; B1-Saliva was removed with a gentle air blast; B2-Saliva was rinsed and dried; B3-Saliva was rinsed, dried and the adhesive was re-applied and light cured. Tygon tubes filled with resin composite were placed on each surface and light cured. All specimens were stored in distilled water at 37°C for 24 hours. Microshear bond strength was measured using a universal testing machine (EZ test), and data were analyzed by one-way ANOVA followed by the Duncan test to make comparisons among the groups (p<0.05). After debonding, five specimens 128Operative Dentistry were selected and examined in a scanning electron microscope to evaluate the modes of fracture.The A2 subgroup resulted in the lowest bond strength. For One Up Bond F and Adper Prompt, there was no significant difference between subgroup A1 and the control, and subgroup A3 and the control (p>0.05). Bond strengths of all B groups were significantly lower compared to the controls (p<0.05). For Xeno III, A1 subgroup showed the greatest decrease in bond strength as compared to the control (p<0.05). On the other hand, it showed more resistance to salivary contamination after adhesive curing. There was no statistically significant difference among the control groups (p>0.05).

Bond Strength of Self-etch Adhesives After Saliva Contamination at Different Application Steps

“…17 Moreover, the salivary pellicle protects dental hard tissues against demineralization caused by acid attacks. 18,19 Similar to previous studies, 1,3,4 drying the contaminated dentin surface alone significantly decreased the bond strength values to dentin of both self-etch adhesives when contamination occurred before application of the primer (group 2).…”

“…10 However, few studies have been published on the influence of saliva contamination during the different application steps of self-etch systems to dentin. 1,2,4,9,11 The purpose of this study was to evaluate the effects of saliva contamination at different bond application steps on the shear bond strength of two different two-step self-etch adhesive systems and to identify a decontamination method that reestablishes bond strengths comparable with the noncontaminated control group.…”

“…3 In addition, most carious cavities are found in sites at or near the gingival margins where saliva contamination is most likely to occur. 1,4 Therefore, the effects of oral fluids on bond strength of bonding systems to enamel/dentin must be considered during the clinical application of these materials.…”

Experimental Initial Partial Polymerization Method for Fuji II Placement Evaluated for Microleakage With/Without Fuji Coat

“…Greater time for placement or difficulty in handling can lead to increased likelihood of contamination, particularly in some pediatric patients. 5 Investigators in the present study found that a brief, 1-second partial light-cure during placement of RMGI material mildly stiffened the consistency and improved its handling characteristics. The material became packable and no longer tended to flow out of some of the restorative preparations.…”

“…4 While these materials allow for more esthetic and conservative restorations, they are also more technique-sensitive. 5,6 Microleakage is the leading cause of replacing bonded restorations and is responsible for roughly 30% or more of direct restorations being replaced. 7,8 This can be caused by shrinkage stress, inadequate wetting or adaptation of the material along the cavity wall, and gaps formed between the material and the tooth caused by thermally and mechanically induced stresses.…”