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Radiant-exposure attenuation through Class-2 proximal slots.
David D Kojic1, Omar El-Mowafy2, Olesya Falenchuk3
1Department of Restorative Dentistry, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada, dave.kojic@utoronto.ca.
American Journal of Dentistry
|May 3, 2021
Summary
Radiant exposure (RE) significantly decreases in Class-2 cavities, impacting resin composite polymerization. Smaller cavity apertures result in greater RE reduction, potentially leading to restoration failure and secondary caries.
Area of Science:
- Dental Materials Science
- Biomedical Engineering
- Restorative Dentistry
Background:
- Effective polymerization of resin composites in Class-2 cavities is crucial for restoration longevity.
- Light-polymerization units (LPUs) deliver radiant exposure (RE) to initiate polymerization.
- Challenges exist in achieving adequate RE at the base of Class-2 preparations due to geometry and light attenuation.
Purpose of the Study:
- To quantify the radiant exposure (RE) attenuation of three LED light-polymerization units (LPUs) within Class-2 preparations.
- To analyze the beam profile of LPUs and its effect on RE delivery at the base of the cavity.
- To assess the impact of varying Class-2 slot sizes on RE transmission.
Main Methods:
- Three LED-LPUs (Bluephase-Style, Demi-Plus, Deep-Cure-S) delivered 10-second RE to a light meter (MARC-PS).
- Class-2 proximal box preparations of two sizes (3x2x4 mm and 4x4x4 mm) were created in artificial teeth.
- RE attenuation was measured at the bottom of the preparations using the MARC-PS sensor, with data analyzed via correlation and ANOVA.
Main Results:
- Significant RE attenuation was observed, with ratios ranging from 32.8% to 80.25% depending on the LPU and cavity size.
- A strong correlation (r=0.86) was found between reduced aperture size and decreased RE.
- All tested LED-LPUs showed reduced RE at the bottom of the proximal box, with over 80% reduction in the smallest cavity simulated.
Conclusions:
- The small aperture, depth, and difficult access of Class-2 cavities significantly impede adequate polymerization.
- Inadequate polymerization at the base of Class-2 restorations is a contributing factor to secondary caries.
- Restoration failure is a potential outcome of insufficient light penetration and polymerization in deep Class-2 preparations.
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