Bond strength to primary tooth dentin following disinfection with a chlorhexidine solution: an in vitro study.
OBJECTIVE
The aim of this study was to determine the effect on shear bond strength of chlorhexidine used as a cavity disinfectant on primary tooth dentin.


METHODS
Thirty specimens were randomly divided into 3 groups (N = 10) and treated as follows: (1) in Group I, the dentin was acid etched with a 37% phosphoric acid for 15 seconds, washed and dried; (2) in Group II, a 2% commercial chlorhexidine solution (Cav Clean) was applied for 40 seconds, washed and dried following acid etching for 15 seconds; and (3) in Group III, dentin was treated with a 37% phosphoric acid gel containing 2% digluconate of chlorhexidine (Cond AC) for 15 seconds. In all specimens, the adhesive Single Bond (3M) was applied, and composite cylinders (Filtek Z 250) were built. The specimens were sheared with a universal testing machine (Instron) running at a crosshead speed of 0.5 mm/min, and the results calculated in MPa. The specimens were also observed to record the failure mode.


RESULTS
ANOVA analysis revealed that the shear bond strength of Group II (17.99+1.15 MPa) was significantly lower than Group I (19.88+1.02 MPa) and Group III (19.57+1.02 MPa). After debonding, 63% of the specimens presented cohesive failure of the material, 24% adhesive failure and 10% cohesive failure of dentin.


CONCLUSIONS
The commercial cavity disinfectant containing 2% chlorhexidine had an adverse effect on Single Bond and produced significantly lower shear bond strength than the etch gel with chlorhexidine and the acid etch alone.
Vieira
Ricardo de Sousa
Rde S
Pediatric Dentistry Division, Santa Catarina Federal University, Florianópolis, Brazil. rvieira@ccs.ufsc.br
da Silva
Ivo Alves
IA
D000134:Acid Etching, Dental; D000268:Adhesiveness; D000704:Analysis of Variance; D000891:Anti-Infective Agents, Local / Q000627:therapeutic use*; D017438:Bisphenol A-Glycidyl Methacrylate / Q000737:chemistry; D002710:Chlorhexidine / Q000031:analogs & derivatives* / Q000627:therapeutic use*; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003737:Dental Cavity Preparation; D003793:Dental Restoration, Permanent; D003804:Dentin / Q000648:ultrastructure*; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D004203:Disinfection; D006801:Humans; D010756:Phosphoric Acids / Q000737:chemistry; D013314:Stress, Mechanical; D013499:Surface Properties; D014094:Tooth, Deciduous / Q000648:ultrastructure*
D000891:Anti-Infective Agents, Local; D003188:Composite Resins; D017220:Dentin-Bonding Agents; C444701:Filtek Z250; D010756:Phosphoric Acids; C115612:single bond; D017438:Bisphenol A-Glycidyl Methacrylate; C010882:chlorhexidine gluconate; D002710:Chlorhexidine