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Changes on storage of polyacid-modified composite resins
1Department of Dental Biomaterials, Dental Institute, King's College School of Medicine and Dentistry, London, UK.
Journal of Oral Rehabilitation
|October 22, 1998
Summary
Water uptake in polyacid-modified composite resins (Dyract and Compoglass) differs from conventional resins (Pekafill). Water influences their properties, but strength is maintained in wet conditions while increasing in dry conditions.
Area of Science:
- Dental Materials Science
- Polymer Chemistry
Background:
- Polyacid-modified composite resins are advanced dental restorative materials.
- Understanding their interaction with aqueous environments is crucial for clinical performance.
Purpose of the Study:
- To investigate water uptake in Dyract and Compoglass compared to Pekafill.
- To assess the effect of storage media and cure time on water absorption.
- To evaluate changes in compressive strength after storage in wet and dry conditions.
Main Methods:
- Water uptake measurements in pure water, 0.9% NaCl, and 1 M NaCl at 37°C.
- Comparison of Dyract, Compoglass, and Pekafill.
- Compressive strength testing after storage for up to 30 days in controlled environments.
Main Results:
- Dyract and Compoglass showed greater water uptake than Pekafill, influenced by cure time and ionic strength.
- Water uptake in Pekafill was largely unaffected by ionic strength.
- Compressive strength remained stable in wet storage but significantly increased in dry storage for Dyract and Compoglass.
Conclusions:
- Water plays a role in the neutralization reaction and hydration of polyacid-modified composites.
- These materials exhibit stable mechanical properties in hydrated conditions.
- Dry storage leads to a significant increase in compressive strength, suggesting a different aging mechanism.