Evaluation of Bond Strength Between New and Old Composite Resin Restorations Using Two Universal Bonding Agents
Document Type : Original Articles
Authors
1 Assistant professor, Department of Operative Dentistry, School of Dentistry, Shahrekord University of Medical Sciences, Shahrekord, Iran
2 Department of Endodontic Dentistry, School of Dentistry, Shahrekord University of Medical Sciences, Shahrekord, Iran
3 Postgraduate student of oral and maxillofacial radiology, School of Dentistry, Isfahan University of Medical Science, Isfahan, Iran
4 Dentist, private practice, Shahrekord, Iran
Abstract
Materials and Methods: This study was conducted in 2023 at Shahrekord University of Medical Sciences. Forty G-ænial composite discs (2×8 mm) were prepared and subjected to 10000 thermal cycles to simulate one year of aging. After etching and rinsing, each bonding agent was applied to 20 samples. A second layer of composite (2×6 mm) was placed in molds and cured. From each group, 10 samples were stored in water for two weeks, and the other 10 samples underwent further thermal cycling. Shear bond strength was measured using a universal testing machine, and data were analyzed using Independent and Paired T-Tests (P < 0.05 significant).
Results: The mean shear bond strength of both bonding agents showed no significant difference after two weeks and one year (p > 0.05).
Conclusion: Both G2 Bond and Clearfil SE Bond provided adequate bond strength between old and new composite restorations (9.02 to 11.08 MPa), meeting ISO 10477 standards. No significant difference was observed between immediate and aged results. These bonding agents, combined with proper surface preparation, are reliable options for composite restorations.
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