Reinforcement of dentin in self-etch adhesive technology: A new concept

Waidyasekera, Kanchana; Nikaido, Toru; Weerasinghe, Dinesh S.; Ichinose, Shizuko; Tagami, Junji

doi:10.1016/j.jdent.2009.03.021

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Volume 37, Issue 8 , Pages 604-609, August 2009

Reinforcement of dentin in self-etch adhesive technology: A new concept

Kanchana Waidyasekera
- Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan
- Global Center of Excellence Program, International Research Center for Molecular Science in Tooth and Bone Diseases, Tokyo Medical and Dental University, Tokyo, Japan
- Corresponding author at: Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan. Tel.: +81 3 5803 5483; fax: +81 3 5803 0195.
Toru Nikaido
- Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan
Dinesh S. Weerasinghe
- Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan
Shizuko Ichinose
- Instrumental Analysis Research Centre, Tokyo Medical and Dental University, Tokyo, Japan
Junji Tagami
- Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan
- Global Center of Excellence Program, International Research Center for Molecular Science in Tooth and Bone Diseases, Tokyo Medical and Dental University, Tokyo, Japan

Received 22 October 2008; received in revised form 27 March 2009; accepted 31 March 2009. published online 09 April 2009.

Abstract

Objective

Characterize the ultramorphology and secondary caries inhibition potential of different dentin adhesive systems in order to find a satisfactory explanation resist to recurrent caries.

Methods

Human premolar dentin was treated with one of the two self-etching adhesive systems, Clearfil SE Bond, Clearfil Protect Bond or an acid-etching adhesive system, Single Bond. The bonded interface was exposed to an artificial demineralizing solution (pH 4.5) for 90min and then 5% sodium hypochlorite for 20min. Transmission electron microscopic observation was performed at the adhesive–dentin interface. The width of the reinforced zone was measured and data were analyzed with univariate analysis of variance under general linear model. In order to identify type of crystallites in the reinforced zone selected area electron diffraction was performed.

Results

An acid–base resistant zone (ABRZ) was found adjacent to the hybrid layer in the outer lesion front with only Clearfil SE Bond and Clearfil Protect Bond, while Single Bond was devoid of this protective zone. Crystallite arrangement and the ultramorphology were almost similar in the corresponding regions of Clearfil SE Bond and Clearfil Protect Bond. However, thickness of the ABRZ at the mid portion was 1159(±41.91)nm in Clearfil protect Bond, which was significantly thicker than that of Clearfil SE Bond (F=514.84, p<0.001). Selected area electron diffraction confirmed the crystallites in the zone as apatite.

Conclusions

The self-etching adhesive systems created a new reinforced acid resistant dentin under the hybrid layer. Difference in the thickness of the zone expressed a different potential for demineralization inhibition.

Keywords: Dentin adhesives, Self-etch system, Adhesion mechanism, Interface, Acid–base resistant zone, Ultrastructure, TEM