Micro-shear Bond Strength of Composite-Resin to MTA with Different Treatments

Objectives:

The purpose of this study was to compare the effect of different surface treatments of MTA on micro-shear bond strength of composite resin to MTA.

Methods:

In 60 acrylic blocks 2x5mm cavities were prepared and filled by PRO ROOT MTA(Dentsply).After 72 hours storage in 37șc and 100% humidity samples were divided into 6 groups randomly.For each group different surface treatment was done : Group 1:No surface treatment , only Opti Bond Solo Plus (kerr) adhesive-resin application , Group 2: Phosphoric acid etching and Opti Bond Solo Plus adhesive-resin , Group 3:Clearfil SE Bond (kuraray) self-etching system , Group 4:Sandblasting and Opti Bond Solo Plus adhesive resin , Group 5:Panavia F2.0 (kuraray) cement application,Group 6:Hidrofluoric acid etching , silane application and Opti Bond Solo Plus adhesive-resin.Composite cylinders (0.7x0.5mm) were bonded on the surface of samples.After 24 hours storage in distilled water samples were thermocycled for 1000 cycles between 5șc and 55șc . Samples were tested with universal testing machine (Zwick/Roell Z020) for micro-shear bond strength .The data were analyzed by Kruskal-Wallis and Mann-Whitney tests.SEM images were prepared from one sample of each group after surface treatment and from fractured specimens..

Results:

The mean micro-shear bond strength in groups 1 to 6 were 14.8±7.7 , 21.8±7.0 , 12.4±6.8 , 2.8±2.1 , 26.0±11.0 in mega pascal(Mpa). There was a significant difference between micro-shear bond strength in 6 groups (P<0.05).

Conclusion:

It is observed that all surface treatment methods in this study made the surface rougher and more pourous.Regarding these surface porosities and because of micro-mechanical bonding mechanism high values of micro-shear bond strength in this study can be explained.Maximum bond strength in hidrofluoric acid and silane treatment group can be explained by chemical bonding between silica groups in MTA surface and the silane molecule.