Samar Saleh Mahmoud*, Mohammed Nasser Mohammed Anwar** , Omaima Hassan Ghallab*** And Mokhtar Nagi Ibrahim***,

ABSTRACT

Objectives: This Study Was Conducted To Evaluate The Effect Of Different Curing System Of Self-etch Adhesives(SEA) On Shear Bond Strength(SBS) And Nano-leakage(NL) Of A Light-cured And Dual-cured Composite Core MaterialMethods: For Shear Bond Strength Testing, 150 Bovine Permanent Anterior Teeth Were Used In This Study. Teeth Were Grinding To Expose Super-facial Dentin Layer And Smear Layer Was Subsequently Formed. The Teeth Were Randomly Divided Into Three Experimental Groups (n= 50 Teeth/group) According To Adhesive System Application (A1=self-cured Tokuyama Universal Adhesive,A2=light-cured Futura Bond M+,A3=dual-cured Futura Bond DC). Then Each Group Was Divided Into 2 Sub-groups According To The Applied Core Material (B1=light-cured Xtra Filbulk Material,B2=Dual-cured Estecore Material) Each Material Was Used According To Manufacturers? Instructions. Specimens Were Stored In 100% Relative Humidity For 24 Hours. SBS Test Was Run At A Crosshead Speed Of 0.5 Mm/min Using A Universal Testing Machine. For Nano-leakage Testing, 18 Adhesive/resin Tooth Specimens Were Assigned With The Same Groups And Subgroups (n = 3) As For SBS Testing. Specimens Were Evaluated Using SEM Operated In The Backscattered Mode To Detect Dye Penetration. The Bond Strength Data And Nano-leakage Statistical Analysis Were Subjected To One And Two-way ANOVA Followed By Tukey Post Hoc Test. Spearman Rank Order Correlation Coefficientwas Used To Study The Correlation Between Them.

Results: The Results Showed That The Light-cured Adhesive Exhibited The Significanthighest SBS Values And The Lowest NL Followed By Self-cured Adhesive Then Dual-cured. Light-cured Xtrafillbulk Material Showed Higher SBS Values And NL Values Than Estecore Dual-cured Core Material. A Medium Positive Correlation Was Found Between SBS And NL Readings.

Conclusions: Light-cured 10-MDP Based SEA Remain To Be The Most Efficientsystem Light Curing Of The Dual Cured Resin Cement Was Crucial To Achieve High SBS Values. Dual-cured Composite Core Material Offers Low Degree Of Nano-leakage. There Was A Positive Direct Correlation Between The Shear Bond Strength And The Degree Of Nano-leakage Of Resin Material.