The Effect of Various Surface Treatment Adhesives and Composite Materials on Repair Strength of Composite Resin

Aims of the study: The aim of this study is to evaluate the effect of a flowable composite and total etch adhesive on shear bond strength of repaired composite with a different types of tooth colored restorations (microhybrid, nanohybrid, and ormocer). Materials and Methods Ninety Teflon mold (4 mm ×2mm), of Tetric® Ceram prepared then divided into two main groups 1st control ( without etching ), 2 ed etched with 37 phosphoric acid. Both groups were divided into three subgroups according to a type of adhesive applied, 1st control, 2 ed the Excite® and in 3ed the tgflow applied The second split of Teflon mold (4mm×1mm) placed onto the prepared specimen Each subgroup (1st control, 2 ed the Excite® and in 3rd the tgflow) were farther divided into three subgroups which entrain filled as fallow: 1st split filled with a Tetric® Ceram, in 2 ed split filled with Tetric N Ceram, and in 3 rd. split filled with Admira. Shear bond strength was measured by using Universal Testing Machine, and mode of failure examined by a stereomicroscope. Results: No significant difference in the surface treatment groups. For the adhesive, Tgflow showed superior shear value (32 48 MPa) comparing to other adhesives while for the composite materials, The Tetric N Ceram composite showed superior value of shear strength (28 21MPa) comparing to other materials Conclusions: Phosphoric acid has no effect on shear value of repaired composite while Tgflow and Tetric N Ceram give an improvement in its shear value All composites exhibited cohesive and adhesive type of failure.