Influence of casein phosphopeptide-amorphous calcium phosphate application, smear layer removal, and storage time on resin-dentin bonding

The aim of this study is to evaluate the influence of Tooth Mousse (TM) application, smear layer removal, and storage time on resin-dentin microtensile bond strength (mu TBS). Dentin specimens were divided into two groups: (1) smear layer covered; (2) smear layer removed using 15% EDTA for 90 s. In each group, half the specimens were treated once with TM for 60 min. After bonding procedures using a two-step self-etching adhesive (Clearfil SE Bond (CSE); Kuraray Medical, Tokyo, Japan), an all-in-one adhesive (G-Bond (GB); GC Corp, Tokyo, Japan), and a total-etch adhesive (Adper Single Bond 2 (SB); 3M ESPE, St. Paul, MN, USA), the specimens were stored for 3 d or 6 months in deionized water at 37 degrees C, and mu TBS was tested and analyzed. With the exception of SB (no TM application) and GB, the mu TBS was significantly increased for CSE and SB using EDTA pre-conditioning and 3 d of storage (P <= 0.001). Bond strength of GB decreased significantly when using EDTA (3 d storage, P<0.05). TM application only increased the mu TBS of GB (no EDTA) and SB (with EDTA) after 3 d (P <= 0.02). Comparing the adhesives after 3 d of storage, CSE exhibited the greatest mu TBS values followed by GB and SB (P <= 0.02). The factors of adhesive, EDTA, and TM did not show any significant impact on mu TBS when specimens were stored for 6 months (P>0.05). The additional application of TM and EDTA for cavity preparation seems only to have a short-term effect, and no influence on mu TBS of dentin bonds after a period of 6 months.