Influence of pH cycling on the microtensile bond strength of self-etching adhesives containing MDPB and fluoride to dentin and microhardness of enamel and dentin adjacent to restorations.
OBJECTIVE
To evaluate the influence of pH cycling on microtensile bond strength (µTBS) and fracture pattern of MDPB- and fluoride-containing self-etching adhesive systems to dentin, and on the cross-sectional Knoop microhardness (CSMH) of enamel and dentin adjacent to restorations.


METHODS
The two-step self-etching adhesive Clearfil SE Bond (SE; Kuraray), the two-step MDPBand fluoride-containing adhesive Clearfil Protect Bond (PB; Kuraray), and the one-step fluoride-containing adhesive One-Up Bond F Plus (OU; Tokuyama) were used to bond resin composite to midcoronal dentin surfaces (for µTBS testing) or to Class V cavities (for CSMH testing). µTBS and CSMH tests were performed after a 15-day period of pH cycling or storage in artificial saliva.


RESULTS
µTBS to dentin was not affected by pH cycling or storage in artificial saliva; however, µTBS values found for PB were higher than those observed for OU. No difference existed among the µTBS values shown by PB, OU, and SE. The fracture pattern was affected by both pH cycling and adhesive system. In enamel, there was no difference in CSMH values provided by the different adhesive systems and storage media, regardless of the distance and depth from restoration. In dentin, PB and SE showed the highest CSMH values, which differed from those obtained for OU. Significantly higher CSMH values were found 100 µm from the restoration margin for all adhesive systems tested.


CONCLUSIONS
The bond strength and microhardness in the vicinity of restorations were adhesive dependent, with MDPB and fluoride exerting no effect on the performance of the adhesive systems.
Departamento de Odontologia Restauradora-Dentistica, Swift Campinas, Brazil.
Vivianne Oliveira
VO
Pedrosa
Flávia Martão
FM
Flório
Cecília Pedroso
CP
Turssi
Flávia Lucisano
FL
Amaral
Roberta Tarkany
RT
Basting
Fabiana Mantovani
FM
França
D000134:Acid Etching, Dental; D001840:Dental Bonding; D003743:Dental Enamel / Q000187:drug effects / Q000502:physiology; D019232:Dental Restoration Failure; D003793:Dental Restoration, Permanent; D003799:Dental Stress Analysis; D003804:Dentin / Q000187:drug effects / Q000502:physiology; D017220:Dentin-Bonding Agents / Q000737:chemistry; D005459:Fluorides; D006244:Hardness / Q000187:drug effects; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008689:Methacrylates / Q000737:chemistry; D011726:Pyridinium Compounds; D019279:Resin Cements / Q000737:chemistry* / Q000494:pharmacology; D013718:Tensile Strength
C503075:Clearfil Protect Bond; C438313:Clearfil SE Bond; D017220:Dentin-Bonding Agents; D008689:Methacrylates; C446260:One-Up-Bond F; D011726:Pyridinium Compounds; D019279:Resin Cements; C089392:methacryloyloxydodecylpyridinium bromide; D005459:Fluorides