Tolerance of universal adhesives to saliva and gingival crevicular fluid contamination of dentin.

OBJECTIVES

To evaluate the dentin-bonding durability of universal adhesives under saliva and gingival crevicular fluid (GCF) contamination conditions.

METHODS

Forty patients underwent paper-strip assessment of residual GCF wetting at subgingival margins under four GCF-management conditions. In vitro, dentin from 318 extracted sound human third molars was tested with three universal adhesives (SB/SP/AB) under no contamination, mild saliva, mild GCF, or severe GCF contamination. Artificial saliva or human serum (GCF surrogate; 20 μL) was applied; mild groups were blot-dried, whereas severe GCF contamination was left unblotted. Contact angles and degree of conversion (DC; adhesive-contaminant mixtures) were assessed immediately; microtensile bond strength (μTBS), failure mode, nanoleakage, and in situ zymography were assessed after 24 h water storage or aging (6 months water storage plus 15,000 thermocycles). ANOVA or linear mixed-effects models were used (α = 0.05).

RESULTS

Periodontal status and GCF-management condition affected paper-strip wetted area (both P < 0.001; interaction P < 0.05). Contamination impaired adhesive spreading and reduced DC (P < 0.05). Contamination condition, aging, and adhesive type affected μTBS (all P < 0.05). Aging increased nanoleakage and interfacial gelatinolytic activity (both P < 0.001), particularly under severe GCF contamination. SP showed comparatively greater stability than SB under contamination, whereas differences between SP and AB were condition-dependent.

SIGNIFICANCE: Universal-adhesive tolerance was contaminant- and load-dependent. Mild residual contamination had limited effects for some formulations, whereas severe GCF contamination compromised polymerization, interfacial sealing, and long-term bond durability. Residual wetting may persist despite routine moisture control and GCF management; moisture-tolerant adhesives should complement, not replace, strict moisture control and periodontal inflammation management.