PURPOSE: To evaluate the effects of water vs. oil storage on the mechanical properties of dental adhesives over 3 and 6 months. METHODS: Adhesive resin sheets were prepared by pouring either Single Bond (SB), One-Step (OS) or Clearfil Liner Bond 2V (CL) into a mold measuring 15 x 15 x 0.8 mm. After solvent evaporation, the adhesives were light-cured, removed from the mold and trimmed to either hourglass or I-beam shapes that were used to determine the true stress (TS) and modulus of elasticity (E), respectively. Control adhesive specimens were subjected to tensile testing at 0.6 mm/minute after 24 hours of immersion in distilled water. Experimental specimens were stored at 37 degrees C in either distilled water or mineral oil and tested after 3 and 6 months. The data were analyzed by two-way ANOVA and Tukey's test. RESULTS: Storage in water significantly decreased the TS and E of SB and OS specimens after 3 and 6 months (P < 0.05), but did not cause significant changes in either TS or E of CL specimens in the same periods (P > 0.05). Storage in oil significantly increased the TS of the three adhesives after 3 and 6 months (P > 0.05), and the same trend was observed for E value of CL sample (P > 0.05). CLINICAL SIGNIFICANCE: Exposure of cured adhesive systems to long-term immersion in water caused marked reduction in their mechanical properties. Reduced mechanical properties of the adhesive system may compromise resin/dentin bonds and have a clinical implication on the longevity of adhesive restorations.
PURPOSE: To evaluate the effects of water vs. oil storage on the mechanical properties of dental adhesives over 3 and 6 months. METHODS: Adhesive resin sheets were prepared by pouring either Single Bond (SB), One-Step (OS) or Clearfil Liner Bond 2V (CL) into a mold measuring 15 x 15 x 0.8 mm. After solvent evaporation, the adhesives were light-cured, removed from the mold and trimmed to either hourglass or I-beam shapes that were used to determine the true stress (TS) and modulus of elasticity (E), respectively. Control adhesive specimens were subjected to tensile testing at 0.6 mm/minute after 24 hours of immersion in distilled water. Experimental specimens were stored at 37 degrees C in either distilled water or mineral oil and tested after 3 and 6 months. The data were analyzed by two-way ANOVA and Tukey's test. RESULTS: Storage in water significantly decreased the TS and E of SB and OS specimens after 3 and 6 months (P < 0.05), but did not cause significant changes in either TS or E of CL specimens in the same periods (P > 0.05). Storage in oil significantly increased the TS of the three adhesives after 3 and 6 months (P > 0.05), and the same trend was observed for E value of CL sample (P > 0.05). CLINICAL SIGNIFICANCE: Exposure of cured adhesive systems to long-term immersion in water caused marked reduction in their mechanical properties. Reduced mechanical properties of the adhesive system may compromise resin/dentin bonds and have a clinical implication on the longevity of adhesive restorations.
Authors: M Takahashi; M Nakajima; J Tagami; D L S Scheffel; R M Carvalho; A Mazzoni; M Cadenaro; A Tezvergil-Mutluay; L Breschi; L Tjäderhane; S S Jang; F R Tay; K A Agee; D H Pashley Journal: Acta Biomater Date: 2013-08-06 Impact factor: 8.947