Islam Moftah, Enas Fathelbab And Mohammed M. Shalaby,

ABSTRACT

Objectives: The Aim Of The Study Was To Investigate The Influence Of Thermocycling On Shear Bond Strength Of Two CAD-CAM Fabricated Materials Luted To Teeth With Different Luting Agents. Methods: Thirty Six Freshly Extracted Sound Human Upper Six Molars Were Collected And Placed Into Color Coded Acrylic Molds. Occlusal Surfaces Of Teeth Were Reduced To Expose Dentin Then Flattened. Thirty Six Discs With 10mm Diameter And 1.5mm Thickness Were Milled Via CAD/CAM; Eighteen Of Vita Enamic And Eighteen Of Bio Hpp. Each Group Was Divided Into Three Subgroups According To The Used Luting Agent (six Samples Each). Subgroups (A1&B1) Luted By Vario-link, (A2&B2); Luted By Panavia And (A3&B3) Luted By Rely-X. All Samples Were Cemented Under Constant Static Load And Thermocycled 5000 Cycles Then Shear Bond Strength Was Tested. Data Were Collected, Tabulated And Statistically Analyzed Using SPSS. Failure Modes Were Evaluated Using SEM. For Parametric Data; One-way (ANOVA) Was Used To Analyze The Data, Followed By Scheffe?s Post-hoc. The Significance Level Was Set At P � 0.05.

Results: Statistical Analysis Revealed That There Is A Statistical Significant Difference Between Both Tested Materials At P Value 0.05. One Way Anova Revealed That There Was Statistical Significant Difference Between Mean Values Of SBS Of The Bio Hpp And Vita Enamic Among The Six Tested Sub Groups At 0.05 Level.Scheffe?spost-hoc Test Showed That Veriolink Luted Samples Of Both Tested Materials (VA& VB) Recorded The Highest Mean Values Of SBS. There Was No Statistical Significant Difference Between Subgroup (PB & RB). However There Was Statistical Significant Difference Between Mean Values Of SBS Of Both Subgroups To Those Of Subgroups (VA, PA& RA). All Tested Vita Enamic Subgroups Showed Mixed Mode Of Failure. Whereas, All Tested Bio Hpp Subgroups Showed Adhesive Failure Mode. Conclusion: Total Etch And Bond Resin Cements Yield The Highest Shear Bond Strength When Bonded To Bio Hpp And Vita Enamic, Self-etch Resin Cements Yield Low Shear Bond Strength When Bonded To Vita Enamic, While Self-adhesive Resin Cements Yield Low Shear Bond Strength When Bonded To Bio Hpp.