Ahmed Salah Abbas, Yasser Fathi Hussein And Mohammed Mustafa Zayed,

ABSTRACT
Aim Of The Study: This Study Was Carried Out To Investigate The Effect Of Thermocycling On Shear Bond Strength Of Conventional Highly Viscous Glass Ionomer (CHVGI), Ceramic Reinforced Glass Ionomer (CRGI) And Glass Ionomer With Hybrid Technology (GIHT) To Nano-hybrid Composite (NHCR) And Nanofilled Resin-based Composite (NRC).

Materials and Methods: A Total Of One Hundred And Twenty Human Maxillary First And Second Premolars Were Invested In Acrylic Resin Blocks. The Proximal Surfaces Were Grinded Parallel To The Long Axis Of The Tooth To Obtain A Flat Surface. Then A Cavity Of 4 Mm Diameter And 2 Mm Depth Was Prepared To Retain The Liner. The Samples Are Divided Into Six Groups (A-F). Groups (A-C), Glass Ionomer Restoration Was Bonded To Nano-hybrid Composite Resin And Groups (D-F), Glass Ionomer Restorations Were Bonded To Nano-filled Composite Resin, Half Pf Samples In Each Group Were Subjected To Thermocycling At 1000 Cycles.

Results: Based On The Effect Of Thermocycling: The Shear Bond Strength Between (CHVGI) And (NHCR) (2.41�0.49 Mpa: Megapascal) Is Higher Than The Shear Bond Strength Between (CHVGI) And (NRC) (2.01�0.60Mpa). The Shear Bond Strength Between (CRGI) With (NHCR) (2.00�0.83Mpa) Is Less Than The Shear Bond Strength Between (CRGI) And (NCR) (5.71�0.61Mpa). The Shear Bond Strength Between (GIHT) And (NHCR) (2.31�1.12Mpa) Is Less Than The Shear Bond Strength Between (GIHT) And (NCR) (3.51�1.24 Mpa). Conclusion: Thermocycling Has A Negative Significant Statistical Effect On Shear Bond Strength Between High Viscous Glass Ionomer And Nanohybrid Composite Resin, High Viscous Glass Ionomer And Nanofilled Composite Resin, Ceramic Reinforced Glass Ionomer And Nanofilled Composite Resin, Glass Ionomer With Hybrid Technology With Nanohybrid Composite Resin. Thermocycling Has No Significant Statistical Effect On Shear Bond Strength Between Ceramic Reinforced Glass Ionomer And Nanohybrid Composite Resin, Glass Ionomer With Hybrid Technology And Nanofilled Composite Resin.