Dentin deproteinization effect on the push out shear bond strength of self-adhesive resin cements

Objective

Self-adhesive resin cements are easy to use and do not need further preparation but their bonding ability to dentin is somehow questionable.Ddentin preparation with acidic solutions and therefore removing smear layer can increase bond strength of self-adhesive resin cements to dentin. As a matter of fact it is assumed that deproteinization of dentin can increase contact between cement and dentin. In the present study the effect of deproteinization of dentin with different concentrations and times of sodium hypochlorite on the push out bond strength of resin cement to dentin is assessed.

Materials and methods

60 third molar teeth were selected and divided to 4 groups consisting of 5% and 20% concentrations and 2 and 10 minutes of using. Samples were randomly divided into six groups of ten. All samples used size 2 Whitepost FGM fiber posts (FGM, Joinville, SC, Brazil), with a diameter of 1.2 mm. Samples were cemented using dual-cure self-adhesive TheraCem (Bisco, USA), cured for 40 seconds with an LED Plus device from Woodpecker made in China

All the specimens were then mounted in plastic cylinders. After 24 hours they were cut with 0.2 mm thickness diamond disc to two coronal and apical parts. Push out strength test was done with Instron 1122R (Universal Testing Machine).

Results

Increasing the concentration and using time of sodium hypochlorite increased push out bond strength.

Discussion

Deproteinization not only can increase push out bond strength but also increase time and concentration can elevate bond strength measures.