Mona Riad , Rofida Ragab And Mohamed Mostafa ,

ABSTRACT
The Aim Of This Study Was To Evaluate The Effect Of Mechanical Loading On The Micro Tensile Bond Strength Of Bioactive Restorative Material To Compare It With Nano Filled Resin Composite Restorative Material In Different Dentin Depths.

Materials and Methods: A Total Of 80 Teeth Were Used In The Study. The Teeth Were Randomly Divided Into 2 Groups Of 40 Specimens Each (n=40) According To Restorative Material Used,activa Bioactive Restorative Material And Filtek Z250. Each Group Represented The Two Dentin Depth Levels (D), The (D1) Represented Superficial Dentin Level And (D2) Represented Deep Dentin Level. Each Group Was Divided Into 2 Subgroups Of 10 Specimens Each (n=10) According To The Number Of Received Cycles That Represent 24 Hours And 3 Months (T). Composite Resin Application Were Done According To Manufacturer?s Instructions. Mechanical Aging Was Performed Using Programmable Logic Controlled Equipment (ROBOTA Chewing Simulator). Restored Teeth Were Serially Sectioned To Obtain Beam-shaped Specimens, With A Cross Section Area 1.0mm2. Data Were Analyzed By Kolmogorov?Smirnov Test For Test Of Normality. Three-way ANOVA Was Used To Showthe Effect Of Different Adhesive, Cycling And Dentin Depth On Microtensile Bond Strength Followed By Pairwise Comparison With Bonferroni Correction (?=0.05).

Results: Composite And Dentin Levels Showed A Significant Effect On The Microtensile Bond Strength At P 0.017* And <0.001* Prespectively. In Contrary The Tested Cyclic Loading Had A Non-significant Difference On The Microtensile Bond Strength Results At P=0.546.

Conclusions: Mechanical Loading (chewing Simulator) Had Negative Effect On Bio Active Material Used After 3months. While It Had No Effect On Nanofilled Composites.