Improving the effect of NaOCl pretreatment on bonding to caries-affected dentin using self-etch adhesives.
OBJECTIVE
To evaluate the effect of sodium hypochlorite pretreatment on adhesion to normal and caries-affected dentin using self-etch adhesives.


METHODS
Forty extracted human molars with coronal carious lesions were used in this experiment. The occlusal dentin surfaces including the caries-affected dentin in each group were treated as follows: group 1, rinsed with water; group 2, treated with 6% NaOCl for 15s; group 3, treated with 6% NaOCl for 30 s; group 4, application with Accel for 30 s after NaOCl-30 s pretreatment. After rinsing with water and air-drying, the treated dentin surfaces were applied with self-etch systems (Bond Force and Clearfil Protect Bond) according to the manufacturers' instructions, and built-up with resin composite. After 37 degrees C water storage for 24 h, the bonded normal or caries-affected dentin areas were isolated to create an hourglass configuration with a cross-sectional area of approximately 1 mm(2). The specimens were subjected to tensile stress at a cross-head speed of 1.0 mm/min.


RESULTS
NaOCl-15 s pretreatment significantly improved the muTBS of both self-etch adhesives to caries-affected dentin, while the 30 s pretreatment did not affect them. For normal dentin, NaOCl-30 s pretreatment significantly reduced the muTBS of both self-etch adhesives although the 15s pretreatment did not alter them. Furthermore, the application of Accel with a reducing effect increased the muTBS to normal and caries-affected dentin treated with NaOCl for 30 s.


CONCLUSIONS
The effects of NaOCl pretreatment on bonding of both self-etch adhesives were dependent upon type of dentin (normal and caries-affected dentin) and the treatment time.
Taniguchi
Gen
G
Cariology and Operative Dentistry, Department of Restorative Science, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan. genkainada31990326@yahoo.co.jp
Nakajima
Masatoshi
M
Hosaka
Keiichi
K
Iwamoto
Nanako
N
Ikeda
Masaomi
M
Foxton
Richard M
RM
Tagami
Junji
J
D003188:Composite Resins; D001840:Dental Bonding; D003731:Dental Caries / Q000628:therapy*; D045662:Dental Etching / Q000379:methods; D003793:Dental Restoration, Permanent; D003799:Dental Stress Analysis; D003804:Dentin / Q000187:drug effects*; D003806:Dentin Permeability / Q000187:drug effects; D017220:Dentin-Bonding Agents; D006801:Humans; D008963:Molar; D016877:Oxidants / Q000008:administration & dosage*; D019163:Reducing Agents / Q000008:administration & dosage; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000008:administration & dosage*; D013718:Tensile Strength; D013997:Time Factors
D003188:Composite Resins; D017220:Dentin-Bonding Agents; D016877:Oxidants; D019163:Reducing Agents; D012973:Sodium Hypochlorite