One-year stability of resin–dentin bonds created with a hydrophobic ethanol-wet bonding technique

Sadek, Fernanda T.; Castellan, Carina S.; Braga, Roberto R.; Mai, Sui; Tjäderhane, Leo; Pashley, David H.; Tay, Franklin R.

doi:10.1016/j.dental.2009.12.009

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Volume 26, Issue 4 , Pages 380-386, April 2010

One-year stability of resin–dentin bonds created with a hydrophobic ethanol-wet bonding technique

Fernanda T. Sadek
- Department of Dental Materials, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil
- Corresponding author. Tel.: +55 11 30917840; fax: +55 11 30917842.
Carina S. Castellan
- Department of Dental Materials, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil
Roberto R. Braga
- Department of Dental Materials, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil
Sui Mai
- Guanghua School of Stomatology & Institute of Stomatological Research, Sun Yat-sen University, Guangzhou, China
Leo Tjäderhane
- Institute of Dentistry, University of Oulu, Oulu University Hospital, Oulu, Finland
David H. Pashley
- Department of Oral Biology, School of Dentistry, Medical College of Georgia, Augusta, GA, USA
Franklin R. Tay
- Department of Oral Biology, School of Dentistry, Medical College of Georgia, Augusta, GA, USA
- Department of Endodontics, School of Dentistry, Medical College of Georgia, Augusta, GA, USA

Received 7 May 2009; received in revised form 8 September 2009; accepted 9 December 2009.

Abstract

Dentin bonding performed with hydrophobic resins using ethanol-wet bonding should be less susceptible to degradation but this hypothesis has never been validated.

Objectives

This in vitro study evaluated stability of resin–dentin bonds created with an experimental three-step BisGMA/TEGDMA hydrophobic adhesive or a three-step hydrophilic adhesive after one year of accelerated aging in artificial saliva.

Methods

Flat surfaces in mid-coronal dentin were obtained from 45 sound human molars and randomly divided into three groups (n=15): an experimental three-step BisGMA/TEGDMA hydrophobic adhesive applied to ethanol (ethanol-wet bonding—GI) or water-saturated dentin (water-wet bonding—GII) and Adper Scotchbond Multi-Purpose [MP—GIII] applied, according to manufacturer instructions, to water-saturated dentin. Resin composite crowns were incrementally formed and light-cured to approximately 5mm in height. Bonded specimens were stored in artificial saliva at 37°C for 24h and sectioned into sticks. They were subjected to microtensile bond test and TEM analysis immediately and after one year. Data were analyzed with two-way ANOVA and Tukey tests.

Results

MP exhibited significant reduction in microtensile bond strength after aging (24h: 40.6±2.5^a; one year: 27.5±3.3^b; in MPa). Hybrid layer degradation was evident in all specimens examined by TEM. The hydrophobic adhesive with ethanol-wet bonding preserved bond strength (24h: 43.7±7.4^a; one year: 39.8±2.7^a) and hybrid layer integrity, with the latter demonstrating intact collagen fibrils and wide interfibrillar spaces.

Significance

Coaxing hydrophobic resins into acid-etched dentin using ethanol-wet bonding preserves resin–dentin bond integrity without the adjunctive use of MMPs inhibitors and warrants further biocompatibility and patient safety's studies and clinical testing.

Keywords: Hydrophobic resin, Ethanol-wet bonding, Hybrid layer, Degradation