Se. Bishara et al., EFFECT OF APPLYING CHLORHEXIDINE ANTIBACTERIAL AGENT ON THE SHEAR BOND STRENGTH OF ORTHODONTIC BRACKETS, The Angle orthodontist, 66(4), 1996, pp. 313-316
The purpose of this study was to determine whether the application of
chlorhexidine as an antibacterial agent affects the shear bond strengt
h and debonding failure modes of orthodontic brackets. Thirty-six rece
ntly extracted human premolars were cleaned and randomly assigned to o
ne of three groups: prophylaxis with pumice only, prophylaxis using a
13,500 ppm fluoridated pumice, and prophylaxis with pumice followed by
application of 0.12% chlorhexidine paste. All teeth were etched with
a 37% phosphoric acid gel and metal orthodontic brackets were bonded t
o each tooth using the same bonding system. The teeth were mounted in
phenolic rings and stored in deionized water at 37 degrees C for 72 ho
urs. A Zwick Universal Testing Machine was used to determine shear bon
d strengths. The residual adhesive on the enamel surfaces was estimate
d using the Adhesive Remnant Index. The analysis of variance was used
to compare the various groups. Significance was predetermined at P < 0
.05. The results indicated that there were no significant differences
in bond strengths between the chlorhexidine-, fluoride-, and nonfluori
de-treated teeth (P=0.233). The Chi-Square test evaluating the residua
l adhesive on the enamel surfaces also showed no significant differenc
es (P=0.456) between the various groups. In conclusion, the use of chl
orhexidine and/or fluoride prophylactic pastes does not significantly
affect shear bond strength nor bond failure location of orthodontic br
ackets.