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The effect of washing water on bonding to etched enamel
Author(s) -
Schneider D. J.,
Combe E. C.,
Martens L. V.
Publication year - 2004
Publication title -
journal of oral rehabilitation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.991
H-Index - 93
eISSN - 1365-2842
pISSN - 0305-182X
DOI - 10.1046/j.0305-182x.2003.01205.x
Subject(s) - distilled water , enamel paint , chemistry , universal testing machine , iodine , nuclear chemistry , bond strength , dental bonding , materials science , composite material , dentistry , analytical chemistry (journal) , ultimate tensile strength , adhesive , chromatography , organic chemistry , medicine , layer (electronics)
summary There is current concern about bacterial contamination of dental unit waterlines. This research hypothesized that the presence of increasing concentrations of bacteria in water used to wash etched enamel would result in a corresponding decrease in both shear bond strength (SBS) and critical surface tension (γ C ) of enamel. A further hypothesis was made that there is a correlation between SBS and γ C . The effect of 3ḃ5 ppm iodine in the water as a bacteriostatic agent was also assessed. Five groups of 10 samples of bovine enamel were etched, washed, and a resin composite bonded to them. The control group was washed with distilled water. Another group was washed with the dilute iodine solution. The remaining three groups used a different concentration of Escherichia coli DH5 α as follows (in cfu mL −1 ): group 1: 10 2 ; group 2: 10 4 ; group 3: 10 6 . Shear bond strength data were measured on an Instron testing machine at a crosshead speed of 1 mm min −1 . Adhesion data were (MPa): control: 24ḃ6 ± 6ḃ0; with iodine: 20ḃ8 ± 2ḃ7; group 1: 19ḃ8 ± 2ḃ7; group 2: 13ḃ5 ± 3ḃ0; group 3: 13ḃ9 ± 3ḃ6. The F ‐test yielded a highly significant difference between control group, iodine group and group 1, compared with groups 2 and 3 ( P < 0ḃ0001). Tukey's Studentized Range Test was used for pairwise comparison testing between groups. Using a Cahn dynamic contact angle analyzer and linear regression analysis, the plots of surface tension versus cos θ were extrapolated to cos θ = 1 to give γ C data for the control group and groups 1–3. In all cases reasonable linearity was observed ( r 2 ≥ 0ḃ87). Data (mN m −1 ) were: control group: 50ḃ8; group 1: 45ḃ; group 2: 43ḃ2; group 3: 39ḃ5. The SBS and γ C were then plotted against each other and linear regression analysis performed. It was concluded that increasing concentrations of bacteria in wash water decreased both SBS and γ C and that a linear correlation ( R 2 = 0ḃ84) was found between the values of these two parameters.