title: Evaluation of bond strength of orthodontic brackets without enamel etching.
abstract: BACKGROUND
  To compare the shear bond strength of brackets with and without enamel etching.
  
  
  METHODS
  In this study, 60 sound premolars were randomly divided into four different groups: 1- TXE group: Enamel etching+Transbond XT adhesive+ Transbond XT composite. 2- TXS group: Transbond plus self-etch adhesive+ Transbond XT composite. 3- PQ1E group: Enamel etching+ PQ1 adhesive+ Transbond XT composite. 4- PQ1 group: PQ1 adhesive+ Transbond XT composite. The shear bond strengths of brackets were evaluated using universal testing machine at cross head speed of 0.5 mm/min. The Adhesive Remnant Index (ARI) was also measured. One-way ANOVA, Tukey's post hoc, Kruskal-wallis and Mann-Witney U test were used for data analysis.
  
  
  RESULTS
  There was a significant difference between etched and unetched groups respect to SBS and ARI (p<0.05), however; no significant difference was observed between unetched group and self-etch adhesive group (p>> 0.05). The shear bond strength of PQ1 group was the least but in acceptable range and its ARI was less than other groups.
  
  
  CONCLUSIONS
  PQ1 adhesive can be used for bracket bonding without enamel etching with adequate bond strength and minimal ARI.
  
  
  BACKGROUND
  Bracket, shear bond strength, filled-adhesive, self-etch adhesive.
authors.affiliation: Assistant Professor of Restorative Dentistry, Dental Research Center, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Boruziniat
authors.affiliation: Under-graduate student, Student Research Center, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Yegane
authors.initials: Y
authors.lastname: Khazaei
authors.affiliation: Under-graduate student, Student Research Center, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Shiva
authors.initials: S
authors.lastname: Motaghi
authors.affiliation: Associated Professor of Restorative Dentistry, Dental Research Center, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Mohmmadjavad
authors.initials: M
authors.lastname: Moghaddas