Effects of storage time and temperature on the properties of two self-etching systems

Sadr, Alireza; Ghasemi, Amir; Shimada, Yasushi; Tagami, Junji

doi:10.1016/j.jdent.2006.08.004

« Previous Next »Journal of Dentistry
Volume 35, Issue 3 , Pages 218-225, March 2007

Effects of storage time and temperature on the properties of two self-etching systems

Alireza Sadr
- Cariology and Operative Dentistry, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
- Corresponding author. Tel.: +81 3 5803 5483; fax: +81 3 5803 0195.
Amir Ghasemi
- Department of Operative Dentistry, Dental School, Shahid Beheshti University of Medical Sciences, Daneshjou Blvd., Evin, Tehran 19834, Iran
Yasushi Shimada
- Cariology and Operative Dentistry, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan
Junji Tagami
- Cariology and Operative Dentistry, Graduate School, 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 22 June 2006; received in revised form 9 August 2006; accepted 16 August 2006.

Abstract

Objectives

To evaluate the micro-shear bond strength to enamel and dentin, pH and hardness of two self-etching adhesives over a period of 60 weeks storage at different temperatures.

Materials and methods

Two self-etching systems, an all-in-one adhesive, Clearfil Tri-S Bond (TS) and a two-step adhesive, Clearfil SE Bond (SE) were used in this study (both by Kuraray Medical, Osaka, Japan). Their micro-shear bond strengths to enamel and dentin were measured. The materials were then stored at 4, 23 or 37°C. Their bond strengths were measured again after 1, 4, 16 and 60 weeks and compared to the base line. The nano-indentation hardness of the polymerized bonding, pH of SE primer and TS were also measured at the baseline and after 60 weeks of storage at three different temperatures. Bond-strength and hardness data were analyzed using ANOVA and post hoc tests at the significance level of 0.05.

Results

Two-way ANOVA analysis showed that both storage conditions and material type had significant effects on bond strength to enamel or dentin but the interactions of these factors were not significant for any of the substrates. One-way ANOVA post hoc tests revealed that the bond strength of adhesives stored at 37°C significantly decreased during the storage period; with the earliest significant decreases observed at 4 weeks for TS and at 16 weeks for SE. After 60 weeks of storage, the hardness obtained for SE bonding resin was not significantly different with that at the baseline for 4, 23 and 37°C groups, but there was a significant decrease observed in hardness for TS stored at 37°C, compared to that at the baseline. The pH of both self-etching materials decreased when they were stored at 37°C.

Conclusion

Storage time and temperature significantly affected the bond strength of both materials through the time dependent hydrolysis and other changes that are likely to occur in the water-containing self-etching agents at high temperatures.

Keywords: Self-etching primer, Acidic monomer MDP, Micro-shear bond strength, Hydrolytic stability, Shelf-life, Storage temperature, pH, Nano-indentation, Hardness