Effect of dentin pretreatment with mild acidic HOCl solution on microtensile bond strength and surface pH.
OBJECTIVE
To evaluate the pretreatment effect of mild acidic HOCl solution on the microtensile bond strength (muTBS) of a two-step self-etch adhesive to dentin and the alteration of dentin surface pH.


METHODS
Thirty-nine flat ground coronal dentin specimens were divided into one control group and 12 experimental groups, which were treated with 6% NaOCl or 50, 100 and 200ppm HOCl (Comfosy) solutions for 5, 15 and 30s. After rinsing with running water for 30s, all the dentin surfaces were bonded with Clearfil SE Bond according to the manufacturer's instructions. After 24h water storage, the bonded specimens were sectioned and trimmed to an hourglass shape with a cross-sectional area of approximately 1.0mm(2) and then subjected to the muTBS test. Thirty-six mid-coronal dentin discs were used for surface pH measurement. Dentin surface pH with or without pretreatment was examined using a pH-imaging microscope (SCHEM-100). The muTBS data were analyzed by one-way ANOVA (Dunnett's T3) and the surface pH data were analyzed by non-parametric statistics (Mann-Whitney U-test).


RESULTS
Pretreatment with Comfosy at concentrations of 50, 100 and 200 ppm did not significantly affect muTBS regardless of the application time compared with the control group, however the 100 and 200ppm Comfosy groups showed significantly lower surface pH values. For the NaOCl pretreatment groups, a longer application time significantly decreased the muTBS and increased the surface pH values compared to the control group.


CONCLUSIONS
The 50ppm Comfosy pretreatments for 5, 15 and 30s did not affect the muTBS of the two-step self-etch adhesive to dentin and dentin surface pH.
Kunawarote
Sitthikorn
S
Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan. korn_ope@hotmail.com
Nakajima
Masatoshi
M
Shida
Kanako
K
Kitasako
Yuichi
Y
Foxton
Richard M
RM
Tagami
Junji
J
D000704:Analysis of Variance; D003188:Composite Resins; D003799:Dental Stress Analysis; D003804:Dentin / Q000187:drug effects*; D017220:Dentin-Bonding Agents; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006997:Hypochlorous Acid / Q000737:chemistry / Q000494:pharmacology; D055115:Light-Curing of Dental Adhesives; D008689:Methacrylates; D019279:Resin Cements; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000737:chemistry / Q000494:pharmacology; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013718:Tensile Strength
C112828:Clearfil AP-X; C438313:Clearfil SE Bond; D003188:Composite Resins; D017220:Dentin-Bonding Agents; D008689:Methacrylates; D019279:Resin Cements; D006997:Hypochlorous Acid; D012973:Sodium Hypochlorite