title: Comparison of multiple rebond shear strengths of debonded brackets after preparation with sandblasting and CO2 laser.
abstract: Background. Failure of orthodontic bracket bonds is a common occurrence during orthodontic treatment. Different techniques have been suggested in the literature to remove resin residues from the bracket bases and enamel surfaces to prepare the surfaces again after debonding. This study attempted to compare multiple rebond shear strengths (SBS) of debonded brackets following preparation with sandblasting and CO2 laser. Methods. The brackets were bonded on 30 human and bovine maxillary central incisors using self-curing composite resin. SBS was measured using Hounsfield testing machine. The brackets were rebonded for two other times after composite resin residues on their surfaces were removed, either with air abrasion or CO2 laser. The debonded brackets and enamel surfaces were also evaluated after each debonding procedure under a stereomicroscope in order to determine adhesive remnant index (ARI). SBS of debonded brackets after each step were compared between sandblast and CO2 laser groups. Results. We observed significant differences in SBS values between pre-recycling and first (P = 0.04), second (P = 0.007) and third recycling (P = 0.007) with laser. Recycling with sandblasting resulted in a decrease in SBS after the first and second recycling procedure; however, the SBS increased after the third recycling procedure, with no significant differences. Conclusion. SBS of brackets after recycling with sandblasting and laser beams was not significantly different, and both were at a favorable level. However, repeating the recycling procedure with sandblasting resulted in more favorable SBS compared to laser.
authors.affiliation: Associate Professor, Department of Orthodontics, Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Mojgan
authors.initials: M
authors.lastname: Kachoei
authors.affiliation: Assistant Professor, Department of Orthodontics, Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Amir
authors.initials: A
authors.lastname: Mohammadi
authors.affiliation: Assistant Professor, Department of Orthodontics, Faculty of Dentistry, Urmia University of Medical Sciences, Urmia, Iran.
authors.forename: Maziar
authors.initials: M
authors.lastname: Esmaili Moghaddam
authors.affiliation: Assistant Professor, Department of Restorative Dentistry, Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Sahand
authors.initials: S
authors.lastname: Rikhtegaran
authors.affiliation: Assistant Professor, Department of Orthodontics, Faculty of Dentistry, Qom University of Medical Sciences, Qom, Iran.
authors.forename: Mahmoud
authors.initials: M
authors.lastname: Pourghaznein
authors.affiliation: Research Fellow and Lecturer, Dental and Periodontal Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Biotechnology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Sajjad
authors.initials: S
authors.lastname: Shirazi
keywords: Bond strength; CO2 laser; rebonding; sandblasting