Effects of different chlorhexidine formulations on shear bond strengths of orthodontic brackets.
OBJECTIVE
To test the hypothesis that the application of different chlorhexidine formulations to the etched enamel will not affect shear bond strength (SBS).


METHODS
Forty-four freshly extracted human premolars were collected and stored in distilled water. The teeth were etched with 37% phosphoric and were rinsed and dried. The teeth then were divided into four equal groups. While Group 1 served as a control, Groups 2 to 4 were treated before bonding with a chlorhexidine formulation that included solution (2%), gel (1%), and mouthwash (0.2%). Orthodontic brackets were bonded with Transbond XT (3M Unitek, Monrovia, Calif). Bond strength results were evaluated with the use of one-way analysis of variance (ANOVA) (P < .05) and post hoc tests. Modes of failures were verified by means of scanning electron microscopy.


RESULTS
Although no statistically significant difference was observed between Groups 1 and 4 (P > .05), both were statistically superior to Groups 2 and 3 (P < .05). In this in vitro study, the observed measures for Groups 2 and 3 (14.5-10.6 MPa) were lower than those for Groups 1 and 4 (27.3-24.9 MPa), but these values were much higher than those required for clinical use (6-8 MPa).


CONCLUSIONS
The hypothesis is rejected. The application of chlorhexidine mouth rinse before bonding had no significant effect on the SBS value, and the application of chlorhexidine solution and gel significantly decreased SBS.
Catalbas
Bülent
B
Department of Orthodontics, University of Kirikkale, Kirikkale, Turkey. bulentcatalbas@hotmail.com
Ercan
Ertuğrul
E
Erdemir
Ali
A
Gelgor
Ibrahim Erhan
IE
Zorba
Yahya Orçun
YO
D000134:Acid Etching, Dental; D000891:Anti-Infective Agents, Local / Q000008:administration & dosage*; D002626:Chemistry, Pharmaceutical; D002710:Chlorhexidine / Q000008:administration & dosage*; D055117:Curing Lights, Dental; D001840:Dental Bonding; D003799:Dental Stress Analysis / Q000295:instrumentation; D005782:Gels; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D009067:Mouthwashes; D016910:Orthodontic Brackets; D010756:Phosphoric Acids / Q000737:chemistry; D019279:Resin Cements / Q000737:chemistry; D033081:Shear Strength; D013314:Stress, Mechanical; D013499:Surface Properties
D000891:Anti-Infective Agents, Local; D005782:Gels; D009067:Mouthwashes; D010756:Phosphoric Acids; D019279:Resin Cements; C477790:Transbond XT; C030242:phosphoric acid; D002710:Chlorhexidine