Amr Hany Hassan, Inas Mohy Eldin And Hadeel Farouk,

ABSTRACT

Objectives: The Aim Is To Investigate The Effect Of Two Desensitizing Agents As Dentin Surface Pretreatments On Microtensile Bond Strength Of A Direct Resin Composite Restoration Using Two Adhesive Systems. In Addition Fracture Mode Of The Specimens At Dentin - Restoration Interface Was Studied. Methods: A Total Of 22 Extracted Molar Teeth Were Selected. A Flat Dentin Occlusal Surface Was Prepared Using A Low Speed Diamond Saw Under Water Coolant. Teeth Were Randomly Divided Into Three Main Groups According To Surface Pretreatment. First Group, No Dentin Pretreatment (A1), Second Group Tricalciam Phosphate (TCP) Pretreatment And Third Group, Sodium Fluoride (NaF) Pretreatment (A3). Each Group Was Further Subdivided Into Two Subgroups According To The Adhesives Used Namely Etch And Rinse Adhesive (B1) And Self-etch Adhesive (B2). A Teflon Mold Was Used To Build Up Resin Composite; Teeth Were Sectioned In A Longitudinal And A Horizontal Direction To Obtain 0.9�0.1 Mm In Thickness Beams. All Samples Were Tested By Universal Testing Machine To Examine Microtensile Bond Strength Followed By Measuring Fracture Mode At Restoration-tooth Interface By Using A Stereomicroscope.

Results: Showed That TCP Group Had No Statistically Significant Difference With No Pretreatment Group, But Showed Higher Significance Difference When Compared With NaF Group. On Other Hand SE Adhesive Showed Higher Statistically Significant Difference When Compared With Etch&Rinse Adhesive Regardless Of The Type Of Dentin Pretreatment. Adhesive Failures Were The Most Prominent Mode Of Failure In All Groups. Conclusion: Tri Calcium Phosphate Desensitizing Agent Can Be Used To Treat Hypersensitive Dentin Without Deranged Effect On MTBS At Resin Composite - Dentin Interface Regardless Of The Adhesive Used.