title: Comparison of shear bond strength of orthodontic brackets bonded with halogen and plasma arc light curing.
abstract: BACKGROUND
  Reduced time and appropriate bond strength of brackets is one of the most important aspects of orthodontic treatments. Prolonged halogen light curing for bonding of brackets is undesirable, so the purpose of this study was to compare the shear bond strength of brackets bonded with halogen light and plasma arc system.  MATERIALS AND MEHODS: This was an experimental in vitro study. A total of 60 intact premolar teeth were collected and divided into four groups. Stainless steel orthodontic brackets were bonded to them. In groups 1 and 2, curing was done using halogen light given for 20 seconds from two and four angles. In groups 3 and 4, curing was carried out using the plasma arc system for 6 seconds from two and four angles. The shear bond strength was recorded by Instron. The statistics of ANOVA, Tukey's test, and T-test were used in data analysis.
  
  
  RESULTS
  There was a statistically significant difference in shear bond strength among the four groups (P = 0.043) and between group 1 with group 2 (P = 0.035). Yet, there was no statistically significant difference between brackets bonded with plasma arc and those bonded with halogen light or between the two groups of plasma arc.
  
  
  CONCLUSIONS
  Using the plasma arc system is superior to other methods due to reduced curing time. Also, since in using the halogen light system, an increase in curing periods from different angles resulted in a significant increase in shear bond strength; it is advisable to apply the halogen light from different angles.
authors.affiliation: Department of Orthodontics, School of Dentistry, Shahid Sadughi University of Medical Sciences, Yazd, Iran.
authors.forename: Mohammad Hossein
authors.initials: MH
authors.lastname: Toodehzaeim
authors.forename: Alireza Danesh
authors.initials: AD
authors.lastname: Kazemi
authors.forename: Hossein Agha
authors.initials: HA
authors.lastname: Aghili
authors.forename: Kazem
authors.initials: K
authors.lastname: Barzegar
authors.forename: Taranom
authors.initials: T
authors.lastname: Fallahtafti
keywords: Halogen light; plasma arc; shear bond strength