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[Opacity and opacity changes in composites]
T Luckenbach1, G M Lösche, J F Roulet
1Fachbereich Zahn-, Mund- und Kieferheilkunde der FU Berlin.
Deutsche Zahnarztliche Zeitschrift
|September 1, 1991
Summary
The opacity of composite resins, crucial for dental restorations, increased after water storage, especially in microfilled types. Longer polymerization times may mitigate these opacity changes.
Area of Science:
- Dental Materials Science
- Polymer Chemistry
Background:
- Composite resins are widely used in dental restorations.
- Understanding their optical properties, like opacity, is vital for aesthetic outcomes.
- Factors influencing resin opacity require thorough investigation.
Purpose of the Study:
- To evaluate the opacity of self-curing and light-curing composite resins.
- To assess the effect of water and dry storage on resin opacity over 180 days.
- To determine the influence of polymerization time on composite resin opacity.
Main Methods:
- Opacity measurements using a UV-visible spectrophotometer.
- Testing of 5 self-curing and 11 light-curing composite resins.
- Storage conditions included dry and water immersion for 180 days.
Main Results:
- Hybrid composite resin opacity ranged from 47.3-62.4%; microfilled resins ranged from 48-64.4%.
- Water storage significantly increased opacity more than dry storage.
- Spectral opacity decreased with increasing wavelengths, particularly in microfilled resins.
Conclusions:
- Water storage negatively impacts the opacity of most composite resins, affecting aesthetics.
- Increased polymerization time may help reduce opacity changes caused by water storage.
- Microfilled composite resins show a notable decrease in spectral opacity with longer wavelengths.