Sheta NN, Elfallal AA, El-negooly SA, Hammad EAand Abdallah RM,

ABSTRACT


Purpose: This Study Aimed To Evaluate Microtensile Bond Strength, Antibacterial Activity And Degree Of Conversion Of An Experimental Dental Adhesive Modified With Ascorbic Acid Cross Linker, Silver Nanoparticles And Natural Antibacterial Extract. Materials And Methods : The Experimental Unfilled Adhesive Was Prepared By Stirring 70 Wt% Bis-GMA, 28.7 Wt% HEMA, 0.25 Wt% Camphroquinone And 1 Wt% Ethyl 4-dimethyl-aminebenzoate On A Stirrer For 3 Hours At 24�C. The Resulted Adhesive Was Divided Into Two Equal Parts And Two Ratios Of Ascorbic Acid Were Dissolved In Tetrahydrofurane (THF) Solvent And Each Ratio Was Stirred With One Part Of The Experimental Adhesive. Microtensile Bond Strength Of The Resultant Adhesive Was Measured Using The Universal Testing Machine. The Adhesive With The Resultant Highest Microtensile Bond Strength Was Modified With Two Ratios From The Used Antibacterial Agents (nanosilver And Rumex Dentatus Extract). Then, The Microtensile Bond Strength Was Measured Again. Antibacterial Activity Against Streptococcus Mutans, Staphylococcus Aureus And Esherichia Coli Was Assessed Using Agar Diffusion Method. Degree Of Conversion Was Measured Using Fourier Transform Infrared Spectroscopy (FTIR). The Results Were Then Statistically Analyzed And Compared Using ANOVA And LSD Test At Level Of Significance 0.05.

Results: The Use Of 1wt% Ascorbic Acid Filled Adhesive Showed Highest Microtensile Bond Strength. The Modification Of Adhesive With 1wt% Nanosilver Particles Resulted In The Highest Microtensile Bond Strength While Modification With Rumex Dentatus Caused Lowering In Microtensile Bond Strength And Degree Of Conversion. Nanosilver Modification Resulted In Higher Antibacterial Activity Against Streptococcus Mutans And Staphylococcus Aureaus While Rumex Dentatus Showed Higher Activity Against Esheiricia Coli.

Conclusions: The Use Of Lower Concentration Of Ascorbic Acid As Collagen Cross Linking Agent In Dentine Adhesive May Be Beneficial In Improving Microtensile Bond Strength. Also, Its Modification With Silver Nanoparticles As Antibacterial Agent Is Better Results Than With Natural Extract Of Rumex Dentatus.