Laboratory and FEA evaluation of dentin-to-composite bonding as a function adhesive layer thickness

Coelho, P.G.; Calamia, C.; Harsono, M.; Thompson, V.P.; Silva, N.R.F.A.

doi:10.1016/j.dental.2008.02.007

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Volume 24, Issue 10 , Pages 1297-1303, October 2008

Laboratory and FEA evaluation of dentin-to-composite bonding as a function adhesive layer thickness

P.G. Coelho
- Department of Prosthodontics, New York University College of Dentistry, NY, USA
- Corresponding author at: Department of Biomaterials and Biomimetics, New York University, 345 East, 24th Street (Room 816), New York, NY 10010, USA. Tel.: +1 212 9989365; fax: +1 212 9954244.
C. Calamia
- Department of Biomaterials and Biomimetics, New York University College of Dentistry, NY, USA
M. Harsono
- Department of Biomaterials and Biomimetics, New York University College of Dentistry, NY, USA
V.P. Thompson
- Department of Prosthodontics, New York University College of Dentistry, NY, USA
N.R.F.A. Silva
- Department of Prosthodontics, New York University College of Dentistry, NY, USA
- Department of Biomaterials and Biomimetics, New York University College of Dentistry, NY, USA

Received 11 December 2007; received in revised form 11 February 2008; accepted 11 February 2008.

Abstract

Objective

The aim of this study was to test the hypothesis that microtensile bond strength values are inversely proportional to dentin-to-composite adhesive layer thickness through laboratory mechanical testing and finite element analysis.

Method

Eighteen noncarious third molars were obtained, and occlusal enamel removed perpendicular to the tooth long axis. Two different adhesive systems were utilized as follows (n=3): (1) application of a single layer of Single Bond (3M ESPE Co.) and Clearfil SE Bond (Kuraray Co.) following the manufacturer's directions; (2) application of one layer of both adhesive systems followed by one additional layer; (3) application of one layer of both adhesive systems followed by two additional layers. A 4mm build up was fabricated in increments on each tooth sample (Z 100 composite, 3M ESPE). Section measurements were performed and specimens were separated into three adhesive thickness groups per material (40, 40–80 and 80–120μm) for microtensile testing. The bond strength data (MPa) were analyzed by one-way ANOVA and Tukey test. Maximum principal stresses (MPS) were determined through FEA for three different adhesive layer thicknesses (20, 50 and 100μm).

Results

The bond strength data obtained for Single Bond at 0–40μm presented significantly higher values compared to higher adhesive layer thickness groups. There were no statistical differences among bond strength values for all Clearfil SE Bond adhesive layer thicknesses. FEA modeling indicated that MPS increased as adhesive layer increased. The hypothesis was accepted for the Single Bond only.

Significance

Correspondence (not tested statistically) between microtensile laboratory testing and FEA model was only observed for Single Bond as increased adhesive layer thickness did not reduce Clearfil SE Bond strength.

Keywords: Finite element analysis, Adhesive system, Microtensile bond strength