Effects of dietary oil contamination and absence of prophylaxis on orthodontic bonding.

The effect of contamination by dietary oil on acid etching has not been reported in the literature. If dietary oil adversely affects acid etching, then a decrease in bond strength is expected. This in vitro study investigated the bond strength of brackets bonded to tooth surfaces that had been contaminated with dietary oil and on which prophylaxis was not carried out. The mean shear bond strengths for the control, teeth with oil contamination and teeth with oil contamination but no prophylaxis undertaken were 53.33 +/- 14.31 (SD), 61.76 +/- 19.32 and 64.12 +/- 17.90 N, respectively. An analysis of variance (ANOVA) test showed that there was no significant difference between the three groups. The power of the ANOVA was calculated for the minimum clinical change that would be worth detecting and was found to be approximately 1.0. It can therefore be concluded that the presence of dietary oil on the tooth surface does not adversely affect shear bond strength, even if prophylaxis is not carried out. Bond failures for all three groups occurred mainly at the tooth-adhesive interface.