Effect of prolonged photo-irradiation time of three self-etch systems on the bonding to root canal dentine

Aksornmuang, Juthatip; Nakajima, Masatoshi; Foxton, Richard M.; Tagami, Junji

doi:10.1016/j.jdent.2005.09.001

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Volume 34, Issue 6 , Pages 389-397, July 2006

Effect of prolonged photo-irradiation time of three self-etch systems on the bonding to root canal dentine

Juthatip Aksornmuang
- Department of Prosthetic Dentistry, Faculty of Dentistry, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand
- Corresponding author. Tel.: +66 74 429874; fax: +66 74 429874.
Masatoshi Nakajima
- Cariology and Operative Dentistry, Department of Restorative Science, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
Richard M. Foxton
- Department of Conservative Dentistry, Floor 25, Guy's, King's and St Thomas' Dental Institute, King's College London, London Bridge, London SE1-9RT, UK
Junji Tagami
- Cariology and Operative Dentistry, Department of Restorative Science, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
- Center of Excellence Program for Frontier Research on Molecular Destruction and Reconstruction of Tooth and Bone, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan

Received 7 June 2005; received in revised form 2 September 2005; accepted 8 September 2005.

Summary

Objectives

To evaluate the effect of photo-irradiation time to the adhesive on the regional bond strength of a dual-cure resin core material to root canal dentine using photo and dual-cure adhesives with self-etching primer.

Materials and methods

Post spaces were prepared in extracted premolars and then the root canal dentine was treated with one of the following bonding procedures: (1) Clearfil SE Bond Primer/Bond (SE), (2) Nano-Bond Primer/Photo-cure adhesive (PNB), (3) Nano-Bond Primer/Dual-cure adhesive (DNB). Photo-irradiation was performed for 10 or 20s from a coronal direction. The post spaces were then filled with a dual-cure composite resin (Build-It FR) and light-cured for 60s. After 24h storage, each specimen was serially sliced into 8, 0.6×0.6mm-thick beams for the μTBS test. The bond strength data were divided into coronal and apical regions and analysed using three-way ANOVA and Games–Howell multiple comparison (α=0.05).

Results

The μTBS of the photo-cure adhesive resin, SE and PNB, significantly decreased (p<0.05) at the apical region when the photo-irradiation time was 10s. However, the bond strength of the SE group was significantly improved at both regions when photo-irradiation time was extended to 20s (p<0.05). There were no differences in μTBS of the photo-cure adhesive resin (PNB) cured for 20s and dual-cure adhesive resin (DNB) (p>0.05).

Conclusion

Photo-cure adhesive was effective for application on root canal dentine when the photo-irradiation time was sufficient. Extension of photo-irradiation time to the adhesive improved the bond strength depending on the type of adhesive resin.

Keywords: Microtensile bond strength, Root canal dentine, Dual-cure resin core material, Photo-irradiation time