Sara A. Botros, Zainab M. Soliman, Dalia I. El-Korashy And Farid S. El-Askary,

ABSTRACT


Aim: To Evaluate The Effect Of Pre-heating Temperatures Of A Dual-cured Adhesive And A Dual-cured Resin Composite As Well As Tubule Orientation On Micro-shear Bond Strength (?SBS) To Dentin. The Degree Of Conversion (DC%) Of The Adhesive And The Composite Was Also Evaluated At The Different Temperatures.

Materials and Methods: For ?SBS, 90 Human Molars Were Randomly Divided Into 18 Groups (n=5) According To The Three Experimental Factors. Factor 1: Adhesive Temperature, Factor 2: Resin Composite Temperature; And Factor 3: Tubule Orientation (occlusal Or Axial). Adhesive And Composite Temperatures Were Set At 25?C, 32?C And 40?C. The Adhesive Was Applied To Dentin According To Manufacturer Instructions. Each Occlusal Dentin Was Stored With Four Composite Micro-cylinders, While Each Axial Dentin Was Stored With Two Micro-cylinders. The ?SBS Testing Was Run At A Crosshead Speed Of 1mm/min. The DC% Of Adhesive And Composite Was Evaluated At Each Temperature Using FTIR. Data Were Analyzed By ANOVA/Tukey?s HSD Post-hoc Test (P=0.05).

Results: Three-Way ANOVA Revealed That Only ?tubule Orientation? And ?adhesive Temperature X Composite Temperature? Had A Significant Effect On ?SBS (P=0.001 And P=0.002, Respectively). For Occlusal Surfaces, ?adhesive Temperature?, ?composite Temperature? And ?adhesive Temperature X Composite Temperature? Had No Significant Effect On ?SBS (P>0.05). For Axial Surfaces, ?adhesive Temperature?, ?composite Temperature? Showed No Significant Effect On ?SBS (P>0.05), While ?adhesive Temperature X Composite Temperature? Had A Significant Effect On ?SBS (P=0.002). The Predominant Failure Mode Was The Mixed Type (57.43%). The Three Temperatures Tested Showed No Significant Effect On The DC% Of The Adhesive. On The Contrary, Pre-heating The Resin Composite To 40?C Revealed A Significant Higher DC% Compared To 25?C. Conclusion: Tubular Orientation Seemed To Be An Influencing Factor On ?SBS. Raising The Temperature To 40?C Improved The DC% Of Dual-cured Resin Composite, But Had No Effect On The Dual-cured Adhesive.