title: Surface pH and bond strength of a self-etching primer/adhesive system to intracoronal dentin after application of hydrogen peroxide bleach with sodium perborate.
abstract: This study compared the dentin bond strength of a self-etching primer/adhesive system with dentin surface pH with or without bleaching and observed the morphological changes in bleached dentin treated with a self-etching primer. Dentin disks were prepared from the coronal-labial region of 32 human anterior teeth. The pulpal surfaces of the dentin disks were polished with 600-grit SiC paper under running water. The dentin surfaces on all specimens were bleached with a mixture of 30% hydrogen peroxide and sodium perborate in 100% humidity at 37 degrees C for one week. The bleaching agent was then rinsed off with water for 5, 15 or 30 seconds. All specimens were stored in water at 37 degrees C. Half of the five-second rinsing specimens were stored in water for an additional week. Dentin surface pH with or without bleaching was examined using a pH-imaging microscope (SCHEM-100). A self-etching primer/adhesive system (Clearfil SE Bond) was applied to bleached or unbleached dentin according to the manufacturer's instructions. After 24-hour water storage, the bonded specimens were prepared for microtensile testing. Microtensile bond strength (microTBS) to dentin was measured using a universal-testing machine (EZ test, Shimadzu, Japan) at a crosshead speed of 1.0 mm/minute. Data were analyzed by one-way ANOVA and Scheffe's test (alpha=0.05). The pH values of the dentin surfaces of the 5 and 15 second rinsing groups were significantly higher than the control group (p<0.05), while the 30-second rinsing and one-week water storage groups had similar surface pH values to the control group (p<0.05). The microTBS of 5, 15 and 30 second rinsing specimens after bleaching were significantly lower than the control specimens (p<0.05). However, after one-week of water storage, the microTBS returned to the control group. The application of a bleaching agent increased the pH value of the dentin surface and decreased the bond strength of the self-etching primer/adhesive system. One-week water storage after bleaching recovered the surface pH and the microTBS to dentin.
authors.affiliation: Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Hanadi
authors.initials: H
authors.lastname: Elkhatib
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Nakajima
authors.forename: Noriko
authors.initials: N
authors.lastname: Hiraishi
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kitasako
authors.forename: Junji
authors.initials: J
authors.lastname: Tagami
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nomura
mesh_terms: D000704:Analysis of Variance; D001881:Borates / Q000494:pharmacology; D001840:Dental Bonding; D003799:Dental Stress Analysis; D003804:Dentin / Q000737:chemistry / Q000187:drug effects* / Q000648:ultrastructure; D017220:Dentin-Bonding Agents; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007180:Incisor; D008855:Microscopy, Electron, Scanning; D019279:Resin Cements; D013499:Surface Properties / Q000187:drug effects; D013718:Tensile Strength; D014073:Tooth Bleaching; D019228:Tooth Crown; D014867:Water
chemical_list: D001881:Borates; C438313:Clearfil SE Bond; D017220:Dentin-Bonding Agents; D019279:Resin Cements; D014867:Water; D006861:Hydrogen Peroxide; C027707:sodium perborate