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Dent Mater. 2018 Jul;34(7):967-977. doi: 10.1016/j.dental.2018.03.010. Epub 2018 Apr 13.

Optimization of the etch-and-rinse technique: New perspectives to improve resin-dentin bonding and hybrid layer integrity by reducing residual water using dimethyl sulfoxide pretreatments.

Author information

1
Department of Restorative Dentistry and Cariology, Adhesive Dentistry Research Group, Institute of Dentistry, University of Turku, Turku, Finland; Turku University Hospital, TYKS, University of Turku, Turku, Finland. Electronic address: thscst@utu.fi.
2
Department of Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland; Helsinki University Hospital, Helsinki, Finland; Research Unit of Oral Health Sciences, and Medical Research Center Oulu (MRC Oulu), Oulu University Hospital and University of Oulu, Oulu, Finland. Electronic address: leo.tjaderhane@oulu.fi.
3
Piracicaba Dental School, University of Campinas, Department of Restorative Dentistry, Dental Materials Area, Piracicaba, SP, Brazil. Electronic address: abuna@outlook.com.
4
Piracicaba Dental School, University of Campinas, Department of Restorative Dentistry, Dental Materials Area, Piracicaba, SP, Brazil. Electronic address: sinhoreti@fop.unicamp.br.
5
Piracicaba Dental School, University of Campinas, Department of Restorative Dentistry, Piracicaba, SP, Brazil. Electronic address: martins@fop.unicamp.br.
6
Department of Restorative Dentistry and Cariology, Adhesive Dentistry Research Group, Institute of Dentistry, University of Turku, Turku, Finland; Turku University Hospital, TYKS, University of Turku, Turku, Finland. Electronic address: arztez@utu.fi.

Abstract

OBJECTIVE:

To determine whether bonding effectiveness and hybrid layer integrity on acid-etched dehydrated dentin would be comparable to the conventional wet-bonding technique through new dentin biomodification approaches using dimethyl sulfoxide (DMSO).

METHODS:

Etched dentin surfaces from extracted sound molars were randomly bonded in wet or dry conditions (30s air drying) with DMSO/ethanol or DMSO/H2O as pretreatments using a simplified (Scotchbond Universal Adhesive, 3M ESPE: SU) and a multi-step (Adper Scotchbond Multi-Purpose, 3M ESPE: SBMP) etch-and-rinse adhesives. Untreated dentin surfaces served as control. Bonded teeth (n=8) were stored in distilled water for 24h and sectioned into resin-dentin beams (0.8mm2) for microtensile bond strength test and quantitative interfacial nanoleakage analysis (n=8) under SEM. Additional teeth (n=2) were prepared for micropermeability assessment by CFLSM under simulated pulpar pressure (20cm H2O) using 5mM fluorescein as a tracer. Microtensile data was analyzed by 3-way ANOVA followed by Tukey Test and nanoleakage by Kruskal-Wallis and Dunn-Bonferroni multiple comparison test (α=0.05).

RESULTS:

While dry-bonding of SBMP produced significantly lower bond strengths than wet-bonding (p<0.05), DMSO/H2O and DMSO/ethanol produced significantly higher bond strengths for SBMP irrespective of dentin condition (p<0.05). SU presented significantly higher nanoleakage levels (p<0.05) and micropermeability than SBMP. Improvement in hybrid layer integrity occurred for SBMP and SU for both pretreatments, albeit most pronouncedly for DMSO/ethanol regardless of dentin moisture.

CONCLUSION:

DMSO pretreatments may be used as a new suitable strategy to improve bonding of water-based adhesives to demineralized air-dried dentin beyond conventional wet-bonding. Less porous resin-dentin interfaces with higher bond strengths on air-dried etched dentin were achieved; nonetheless, overall efficiency varied according to DMSO's co-solvent and adhesive type.

CLINICAL SIGNIFICANCE:

DMSO pretreatments permit etched dentin to be air-dried before hybridization facilitating residual water removal and thus improving bonding effectiveness. This challenges the current paradigm of wet-bonding requirement for the etch-and-rinse approach creating new possibilities to enhance the clinical longevity of resin-dentin interfaces.

KEYWORDS:

Adhesives; Bond strength; DMSO; Dentin; Dry-bonding; Ethanol; Micropermeability; Nanoleakage; Wet-bonding

PMID:
29661578
DOI:
10.1016/j.dental.2018.03.010
[Indexed for MEDLINE]

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