Influence of sodium hypochlorite and edta on the microtensile bond strength of a self-etching adhesive system.
Chemical substances used during biomechanical preparation of root canals can alter the composition of dentin surface and affect the interaction with restorative materials.


OBJECTIVE
The purpose of this study was to evaluate the microtensile bond strength (µTBS) of a self-etching adhesive system to dentin irrigated with sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA).


METHODS
Thirty human third molars were sectioned 3 mm below the occlusal surface, polished with 600- to 1200-grit silicon carbide papers, and randomly divided into 3 groups: G1 (control): no irrigating solution; G2: 1% NaOCl; and G3: 1% NaOCl followed by the application of 17% EDTA. The specimens received the self-etching adhesive system (XENO III - Dentsply), restored with microhybrid composite resin (Z250 - 3M ESPE), sectioned and trimmed to create 4 hourglass-shaped slabs of each tooth. The slabs were tested in microtensile strength in a universal testing machine (Emic DL 2000) at a crosshead speed of 0.5 mm/min until fracture. The results were analyzed statistically by ANOVA and Newman-Keuls test.


RESULTS
Mean µTBS values and standard deviations in MPa were: G1 = 11.89 ± 4.22; G2 = 19.41 ± 5.32; G3 = 11.34 ± 4.73. 1% NaOCl increased the adhesive resistance significantly (p<0.001/F=22.5763). The application of 1% NaOCl/17% EDTA resulted in statistically similar µTBS to the control group.


CONCLUSIONS
None of the irrigants affected negatively the µTBS of XENO III to dentin. The use of 1% NaOCl alone resulted in higher bond strength than the other treatments. The combination of 1% NaOCl and 17% EDTA produced similar bond strength to that of untreated dentin.
Cecchin
Doglas
D
Endodontic Division, Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas, Piracicaba, SP, Brazil. dgscecchin@yahoo.com.br
Farina
Ana Paula
AP
Galafassi
Daniel
D
Barbizam
João Vicente Baroni
JV
Corona
Silmara Aparecida Milori
SA
Carlini-Júnior
Bruno
B
D000268:Adhesiveness; D002614:Chelating Agents / Q000737:chemistry*; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding; D003799:Dental Stress Analysis / Q000295:instrumentation; D003804:Dentin / Q000648:ultrastructure; D017220:Dentin-Bonding Agents / Q000737:chemistry*; D004492:Edetic Acid / Q000737:chemistry*; D006801:Humans; D008422:Materials Testing; D012388:Root Canal Irrigants / Q000737:chemistry*; D012973:Sodium Hypochlorite / Q000737:chemistry*; D013314:Stress, Mechanical; D013718:Tensile Strength
D002614:Chelating Agents; D003188:Composite Resins; D017220:Dentin-Bonding Agents; C444701:Filtek Z250; D012388:Root Canal Irrigants; C487957:Xeno III; D004492:Edetic Acid; D012973:Sodium Hypochlorite