Dentin wettability enhancement for three irrigating solutions and their effect on push out bond strength of gutta percha / AH Plus

BACKGROUND The aim of this study was to investigate the effect of wettability enhancement for 17% EDTA, 2.5% sodium hypochlorite and 7% maleic acid solutions on push out bond strength of gutta percha /AH Plus to root dentin. MATERIAL AND METHODS One hundred and eight extracted single rooted human lower premolars were instrumented up to Protaper Universal F5 then irrigated with 3ml of 2.5% NaOCl after each file. Irrigants were prepared and a pilot study for determination of Tween 80 concentration yielding the lowest surface tension value in every solution was conducted. Samples were randomly divided into a control group and two experimental groups (17% EDTA and 7% Maleate), further split into eight subgroups (n=12), according to Tween 80 implementation sequence. Roots were obturated using gutta percha and AH plus by lateral condensation. Bond strength was measured by push out test. Mode of failure was then evaluated quantitatively by stereomicroscopy. Data were statistically analyzed using one way ANOVA followed by Tukey-Kramer for multiple comparisons. RESULTS Control group showed the lowest values. Maleic acid subgroups showed significantly higher overall values than EDTA subgroups (P<0.05). Protocols implementing surfactant containing NaOCl showed significantly lower values than plain counterparts. Failure pattern was predominantly cohesive for plain regimens and the ones implementing Tween 80 in maleic acid solutions with plain NaOCl. CONCLUSIONS Tween 80 addition to demineralizing irrigants increased the bond strength values. Surfactant containing NaOCl solutions yielded lower bond strength than plain ones. Key words:Wettability enhancement for three irrigants vs. corresponding gutta percha/AH Plus bonding.