Mohamed A. Elattar, Ahmed H. Khalil And Jihan F. Younis ,

ABSTRACT
Statement Of Problem: Cementation Is A Critical Step That Determines The Success And Longevity Of Indirect Restorations. Cement Dissolution At The Marginal Interface Is One Of The Causes That Leads To Micro Leakage And Diminishes Bond Strength Of The Indirect Restoration Which Leads Eventually To Its Failure. New Bio-active Cement Was Introduced To Overcome That Disadvantage By Re-mineralizing Of The Disintegrated Joint. Due To The Lack Of Data About The Bioactive Cement, It Required Investigation To Assess Its Shear Bond Strength. Aim Of The Study: Is To Evaluate Shear Bond Strength Of Activa Bio-active And Self-adhesive Resin Cement When Bonded To Enamel And Zirconia. Methodology: 20 Extracted Human Mandibular Molars Were Prepared To Produce Flat Enamel Surface. Enamel Samples Were Divided Randomly Into Two Groups, Wet And Dry Where (n=10). Each Subgroup Was Bonded Using Either Self-adhesive Resin Cement As Control Group Or Bioactive Cement (n=5) To Zirconia. Shear Bond Strength Was Examined After Thermo-cycling Using Universal Testing Machine. Mann-Whitney U Test Was Used To Compare Between Wet And Dry Conditions And The Effect Of Different Cement Types. The Significance Level Was Set At P ? 0.05.

Results: Either With Wet Or Dry Enamel There Was No Statistically Significant Difference. Both Cements Showed No Significant Difference When Bonded To Wet Or Dry Enamel. Conclusion: Neither The Different Humid Conditions Nor The Different Cement Types Demonstrated Significant Impact On The Shear Bond Strength Values.