Microtensile and microshear bond strength of an antibacterial self-etching system to primary tooth dentin.

Objectives: The aim of this study was to test the hypothesis that the bonding ability of antibacterial bonding system to primary dentin was not different from the parental material which did not contain any antibacterial component.
Methods: Extracted human non-carious primary molars were ground to expose the coronal dentin, and then randomly divided into two experimental groups: treatment with Clearfil Protect Bond or with Clearfil SE Bond (Kuraray Medical Inc.). Composite-dentin sticks with a cross-sectional area of approximately 0.90 mm(2) were prepared and subsequently subjected to microtensile bond strength (muTBS) and microshear bond strength (muSBS) tests. For the muTBS tests, specimens were attached to an Instron testing machine with a cyanoacrylate adhesive. For muSBS testing, the sticks were mechanically fixed to the muSBS testing apparatus. The bonds were stressed in shear or tension at a crosshead speed of 1mm/min until failure occurred. Resin-dentin interfaces produced by each system were examined using SEM. The data were analyzed with Mann-Whitney's U test.
Results: The muTBS and muSBS of Clearfil Protect Bond were 30.69+/-9.71 and 9.94+/-3.78 MPa, respectively. Clearfil SE Bond showed significantly greater values of 37.31+/-9.57 and 12.83+/-3.15 MPa, respectively. SEM analysis demonstrated similar micro-morphological features including the thickness of the hybrid layer for both materials.
Conclusions: It was showed that antibacterial self-etching system Clearfil Protect Bond showed lower bond strength values compared to primary dentin than that of to Clearfil SE Bond on primary dentin. (Eur J Dent 2008;2:11-17).