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Flexural Performance of Direct Resin Composite Restorative Materials Past Expiration Date
Hiroko Nagaoka1, Susan Bishop1, Howard Roberts1,2
1Division of Restorative Dentistry, University of Kentucky College of Dentistry, Lexington, Kentucky, United States.
European Journal of Dentistry
|May 13, 2020
Summary
Dental resin composites maintained flexural strength and modulus up to 15 months past expiration. However, degradation is complex, so clinicians should adhere to expiration dates for direct restorative materials.
Area of Science:
- Dental Materials Science
- Polymer Chemistry
- Biomaterials Engineering
Background:
- Direct restorative resin composites are widely used in dentistry.
- Understanding the long-term stability of these materials post-expiration is crucial for clinical practice.
- Limited data exists on the degradation of resin composites beyond their stated shelf life.
Purpose of the Study:
- To evaluate the flexural properties of five direct restorative resin composites.
- To assess material stability up to 30 months past the expiration date.
Main Methods:
- Flexural strength and Young's modulus were measured according to ISO 4049.
- Specimens were stored in phosphate-buffered saline.
- Testing was conducted at various time points up to 30 months post-expiration.
- Statistical analysis included Kruskal-Wallis and Dunn's posthoc tests.
Main Results:
- Materials retained baseline flexural strength and modulus for up to 15 months past expiration.
- Two composites showed similar properties at 30 months.
- Degradation mechanisms are complex and not always clinically apparent.
Conclusions:
- While some composites maintain properties beyond expiration, adherence to dates is advised.
- Complex degradation may affect vital constituents not easily detected.
- Standardized dental shelf-life standards are lacking; manufacturer protocols are needed.
