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Thermal changes and cure depths associated with a high intensity light activation unit
D A Stewardson1, A C C Shortall, E Harrington
1The School of Dentistry, The University of Birmingham, St Chad's Queensway, Birmingham B4 6NN, UK. d.a.stewardson@bham.ac.uk <d.a.stewardson@bham.ac.uk>
Journal of Dentistry
|October 13, 2004
Summary
This study assessed the thermal emission and curing of a halogen light with two composites. Results showed varying temperature rises and depths of cure, with one composite showing better light transmission.
Area of Science:
- Dental Materials Science
- Polymer Chemistry
- Biomedical Engineering
Background:
- Light-curing is essential for dental composite restorations.
- Understanding the thermal effects and curing efficiency of light-activation units is crucial for pulp protection.
- Halogen light-curing units are commonly used, but their thermal output and efficacy with different composites require evaluation.
Purpose of the Study:
- To evaluate the thermal emission and curing characteristics of the Astralis 10 halogen light.
- To compare the performance of the light unit when curing a conventional and a fast-curing micro-hybrid composite.
- To assess the impact of different light output modes on temperature rise and depth of cure.
Main Methods:
- A thermistor measured temperature rises in a model cavity under various conditions (empty, with composites).
- Four output modes of the halogen light were tested.
- Depth of cure, light transmission, and microhardness were assessed using digital penetrometry, a radiometer, and a hardness tester, respectively.
Main Results:
- Peak temperature rises during polymerization ranged from 6.9°C to 11.0°C.
- The InTen-S composite showed a significantly greater depth of cure.
- This improved cure correlated with higher light transmission for InTen-S.
Conclusions:
- The high thermal emission previously reported for this light unit was not confirmed in this study.
- Careful selection of light-activation units and curing programs is advised for deep cavities to prevent potential thermal trauma to the dental pulp.