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Degradation of microfilled posterior composite
R B Mazer1, K F Leinfelder, C M Russell
1School of Dentistry, University of Alabama at Birmingham.
Summary
Posterior composite restorations show wear and marginal defects. This study found that submicron-filled composites degrade cohesively, likely due to tensile fatigue, with an average wear rate of 8 microns/year.
Area of Science:
- Dental Materials Science
- Biomaterials Engineering
- Clinical Dentistry
Background:
- Advancements in posterior composites have increased their clinical use.
- However, issues like wear, marginal leakage, and recurrent caries persist.
- Failure mechanisms in submicron-filled composites remain under-investigated.
Purpose of the Study:
- To analyze clinical characteristics of a posterior composite.
- To determine mechanisms responsible for marginal degradation.
- To investigate failure modes in submicron-filled materials.
Main Methods:
- Utilized optical standards for wear assessment.
- Analyzed marginal defects in posterior composite restorations.
- Evaluated wear rate and defect nature.
Main Results:
- Established a linear wear rate averaging 8 microns/year.
- Identified marginal defects as cohesive in nature.
- Linked cohesive defects to tensile fatigue failure.
Conclusions:
- Submicron-filled posterior composites exhibit inherent cohesive marginal defects.
- Tensile fatigue failure is the probable cause of these defects.
- Understanding these mechanisms is crucial for improving composite longevity.