title: Effect of laser-assisted bleaching with Nd:YAG and diode lasers on shear bond strength of orthodontic brackets.
abstract: The aim of the present study was to assess the effect of laser-assisted bleaching with neodymium:yttrium-aluminum-garnet (Nd:YAG) and diode lasers on shear bond strength (SBS) of orthodontic brackets. One hundred and four extracted human premolars were randomly divided into four groups: group 1: No bleaching applied (control group); group 2: Teeth bleached with 40 % hydrogen peroxide; group 3: Teeth treated with 30 % hydrogen peroxide activated with Nd:YAG laser (1064 nm, 2.5 W, 25 Hz, pulse duration of 100 μs, 6 mm distance); and group 4: Teeth treated with 30 % hydrogen peroxide activated with diode laser (810 nm, 1 W, CW, 6 mm distance). Equal numbers of teeth in groups 2, 3, and 4 were bonded at start, 1 h, 24 h, and 1 week after bleaching. A universal testing machine measured the SBS of the samples 24 h after bonding. After bracket debonding, the amount of residual adhesive on the enamel surface was observed under a stereomicroscope to determine the adhesive remnant index (ARI) scores. The SBS in the unbleached group was significantly higher than that in the bleached groups bonded immediately and 1 h after laser-assisted bleaching (P < 0.05). In groups 3 and 4 at start and group 2 at start and 1 h after laser-assisted bleaching, the SBS was found to be significantly lower than that in the control group. Significant differences in the ARI scores existed among groups as well. The SBS of brackets seems to increase quickly within an hour after laser-assisted bleaching and 24 h after conventional bleaching. Thus, this protocol can be recommended if it is necessary to bond the brackets on the same day of bleaching.
authors: Orthodontic Department, School of Dentistry, Tehran University of Medical Sciences, International Campus, Laser Research Center of Dentistry, Tehran, Iran.
authors: Amirhossein
authors: A
authors: Mirhashemi
authors: Orthodontic Department, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
authors: Elham Sadat
authors: ES
authors: Emadian Razavi
authors: School of Dentistry, Tehran University of Medical Sciences, International campus, Tehran, Iran. sarabehboodiii@gmail.com.
authors: Sara
authors: S
authors: Behboodi
authors: Laser Research Center of Dentistry, Dental Research Institute, Tehran University of Medical Sciences, Tehran, Iran.
authors: Nasim
authors: N
authors: Chiniforush
mesh_terms: D001840:Dental Bonding; D003743:Dental Enamel / Q000187:drug effects / Q000528:radiation effects; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D053844:Lasers, Solid-State / Q000009:adverse effects*; D016910:Orthodontic Brackets; D033081:Shear Strength; D014073:Tooth Bleaching / Q000379:methods*
chemical_list: D006861:Hydrogen Peroxide
keywords: Bleaching; Diode; Laser; Nd:YAG; Shear bond strength