09:21
Inês Jacyntho Inojosa
REVERSAL OF COMPROMISED BONDING IN BLEACHED ENAMELRESEARCH REPORTS
Biomaterials & Bioengineering
Biomaterials & Bioengineering
S.C.N. Lai1, F.R. Tay1*, G.S.P. Cheung1, Y.F. Mak1, R.M. Carvalho2, S.H.Y. Wei1, M. Toledano3, R. Osorio3, and D.H. Pashley4.Reversal of Compromised Bonding in Bleached Enamel J Dent Res 81(7):477-481, 2002
1Conservative Dentistry, Faculty of Dentistry, University of Hong Kong, Prince Philip Dental Hospital, 34 Hospital Road, Hong Kong, SAR, China; 2Bauru School of Dentistry, University of São Paulo, Brazil; 3Department of Dental Materials, University of Granada, Spain;and4Department of Oral Biology and Maxillofacial Pathology,
School of Dentistry, Medical College of Georgia, Augusta, GA, USA; *corresponding author, kfctay@hknet.com
ABSTRACT
Oxygen inhibits polymerization of resin-based materials. We hypothesized that compromised bonding to bleached enamel can be reversed with sodium ascorbate, an anti-oxidant. Sandblasted human enamel specimens were treated with distilled water (control) and 10% carbamide peroxide gel with or without further treatment with 10% sodium ascorbate. They were bonded with Single Bond (3M-ESPE) or Prime&Bond NT (Dentsply DeTrey) and restored with a composite. Specimens were prepared for microtensile bond testing and transmission electron microscopy after immersion in ammoniacal silver nitrate for nanoleakage evaluation.
1Conservative Dentistry, Faculty of Dentistry, University of Hong Kong, Prince Philip Dental Hospital, 34 Hospital Road, Hong Kong, SAR, China; 2Bauru School of Dentistry, University of São Paulo, Brazil; 3Department of Dental Materials, University of Granada, Spain;and4Department of Oral Biology and Maxillofacial Pathology,
School of Dentistry, Medical College of Georgia, Augusta, GA, USA; *corresponding author, kfctay@hknet.com
ABSTRACT
Oxygen inhibits polymerization of resin-based materials. We hypothesized that compromised bonding to bleached enamel can be reversed with sodium ascorbate, an anti-oxidant. Sandblasted human enamel specimens were treated with distilled water (control) and 10% carbamide peroxide gel with or without further treatment with 10% sodium ascorbate. They were bonded with Single Bond (3M-ESPE) or Prime&Bond NT (Dentsply DeTrey) and restored with a composite. Specimens were prepared for microtensile bond testing and transmission electron microscopy after immersion in ammoniacal silver nitrate for nanoleakage evaluation.
Bond strengths of both adhesives were reduced after bleaching but were reversed following sodium ascorbate treatment . Resin-enamel interfaces in bleached enamel exhibited more extensive nanoleakage in the form of isolated silver grains and bubble-like silver deposits. Reduction of resin-enamel bond strength in bleached etched enamel is likely to be caused by a delayed release of oxygen that affects the polymerization of resin components.KEY WORDS: carbamide peroxide, sodium
ascorbate, microtensile bond strength, ultrastructure.
ascorbate, microtensile bond strength, ultrastructure.
Posted in: trabalhos científicos endodontia
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