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Heat Generated by Different Light-Emitting Diode (LED) Curing Units and Their Effect on Pulp: An In Vitro Study
Santhosh Kumar1, Jithesh Kumar2, Panjami Marish2
1Department of Orthodontics, Adhiparasakthi Dental College and Hospital, Chennai, IND.
Cureus
|August 25, 2025
Summary
Higher intensity LED curing lights, like Woodpecker, can increase pulp chamber heat during orthodontic bonding, potentially causing mild inflammation. These thermal effects appear mostly reversible, but sustained rises may irritate dental pulp.
Area of Science:
- Dentistry
- Biomaterials Science
- Orthodontics
Background:
- Light-emitting diode (LED) curing units in orthodontics can cause thermal changes in the pulp chamber.
- Excessive heat may lead to pulpal inflammation or damage, varying by curing light type and power.
- Understanding these thermal effects is crucial for preventing iatrogenic pulpal injury.
Purpose of the Study:
- To quantify heat generation by different LED curing lights during orthodontic bonding.
- To evaluate the resulting histopathological changes in pulpal tissue.
- To correlate light intensity with thermal effects and pulpal response.
Main Methods:
- 42 human premolars were used, divided into histological and thermal assessment groups.
- Temperature changes in the pulp chamber were measured using thermocouples before and after curing.
- Histopathological evaluation assessed pulpal inflammation; statistical analyses included chi-square and ANOVA.
Main Results:
- The Woodpecker LED unit (Group B) showed mild to moderate pulpal inflammation (p=0.047).
- Group E (Woodpecker thermal) had the highest temperature rise (2.586°C), though not statistically significant between groups (p=0.064).
- Significant variations in pre- and post-curing temperatures were noted across devices (p<0.011), with 3M Unitek showing higher values.
Conclusions:
- Higher intensity LED curing lights, specifically the Woodpecker unit, generated more heat, potentially causing early pulpal inflammation.
- Observed pulpal changes were largely reversible.
- A sustained temperature increase exceeding 5.5°C could be a threshold for pulpal irritation.
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