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Effect of High-Power LED Barriers on Shear Bond Strength and Curing Time in Orthodontic Brackets With
Yasaman Bozorgnia1, Mahla Tak2, Maryam Jamali3
1Department of Orthodontics, School of Dentistry, North Khorasan University of Medical Sciences, Bojnurd, Iran.
Clinical and Experimental Dental Research
|June 11, 2025
Summary
Using a cellophane barrier on dental light-curing units significantly reduces bracket shear bond strength. Longer curing times (9 seconds) are recommended with cellophane to achieve clinically acceptable bond strengths.
Area of Science:
- Dental Materials Science
- Orthodontic Technology
Background:
- Dental light-curing units are essential for bracket bonding.
- Barriers are used for light-curing units due to sterilization limitations.
- The impact of these barriers on bond strength is not fully understood.
Purpose of the Study:
- To evaluate the effect of a cellophane barrier on the shear bond strength (SBS) of orthodontic brackets.
- To assess the influence of the cellophane layer on the adhesive remnant index (ARI).
Main Methods:
- Fifty human premolars were divided into five groups.
- Groups were exposed to LED light curing with or without a cellophane layer for varying durations (3, 6, 9 seconds).
- Shear bond strength was measured using a universal testing machine; data analyzed with ANOVA and Tukey's test.
Main Results:
- The highest SBS was observed in teeth cured for 6 seconds without a cellophane layer.
- The lowest SBS was recorded for teeth cured for 3 seconds with a cellophane layer.
- No significant differences were found in the adhesive remnant index among the groups.
Conclusions:
- The use of a cellophane barrier significantly reduces bracket shear bond strength.
- To achieve clinically acceptable bond strengths when using cellophane, a minimum of 9 seconds of light exposure is required.
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