Najjar YM, Burhan AS, Hajeer MY, Nawaya FR. Effects of the conventional, soft start, and pulse delay modes produced by light-emitting diode device on microleakage beneath metal brackets: An in vitro comparative study.
Int Orthod 2023;
21:100718. [PMID:
36516656 DOI:
10.1016/j.ortho.2022.100718]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/25/2022] [Accepted: 11/27/2022] [Indexed: 12/14/2022]
Abstract
BACKGROUND
This study aimed to evaluate microleakage beneath metal brackets cured by different light curing modes.
MATERIALS AND METHODS
Sixty extracted human premolars were randomly divided into three groups according to the light curing mode. Metal brackets were bonded in all groups according to the manufacturer's recommendations with a light-emitting diode device. Light curing was applied as follows: group 1: conventional mode (10 s mesial+10 s distal); group 2: soft start mode (15 s mesial+15 s distal); group 3: pulse delay mode (3 s mesial+3 s distal, followed by 3min of no photoactivation, then 9 s mesial+9 s distal). Radiant exposure was the same in all study groups. After curing, the teeth were incubated at 37 degrees for 24hours, then thermocycled 500 times. Next, they were sealed with nail varnish, immersed in methylene blue 1% for 24hours, sectioned, and examined under a stereomicroscope. Microleakage was measured at both enamel-adhesive and bracket-adhesive interfaces, and the total microleakage for each tooth was computed. Statistical analyses were performed using Kruskal-Wallis and Welch test for comparing microleakage among groups. Wilcoxon signed ranks test was used for comparing microleakage between the bracket-adhesive and enamel-adhesive interfaces.
RESULTS
There was no significant difference in microleakage at the bracket-adhesive interface among study groups. At the enamel-adhesive interface and total microleakage, the pulse delay group exhibited significantly lower microleakage than the conventional group. Whereas there was no significant difference between the soft start group and other study groups. In all study groups, microleakage at the enamel-adhesive interface was greater than that at the bracket-adhesive interface.
CONCLUSION
The pulse delay mode caused lesser microleakage than the conventional mode. This supports the use of this mode in orthodontic bonding.
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