title: Comparision of shear bond strength of stainless steel and ceramic brackets at 24 hours after etching enamel with different proportions of acidulated phosphate fluoride.
abstract: OBJECTIVE
  To evaluate and compare the shear bond strength of stainless steel brackets and ceramic brackets at 24h after etching the enamel with acidulated phosphate fluoride gel (1.23% APF) at different proportions (40%,30%,20%) incorporated in conventional etchant (37% phosphoric acid).
  
  
  METHODS
  Eighty premolars (maxillary and mandibular first and second premolars) extracted for orthodontic purpose has been selected for the study and samples were divided into 4 groups containing 10 teeth each. Comprised of teeth etched Group 1 with 40% of APF gel etchant is Group 2 teeth etched with 30% of APF gel in Group 3 teeth etched with 20% of APF gel etchant and Group 4 teeth were etched with conventional etchant (37% phosphoric acid).
  
  
  RESULTS
  The experimental group of Acidulated Phosphate Fluoride (APF) at different proportion (40%, 30%, 20%) incorporated with etchant application for 40s on the enamel surface at 24h indicated that group 4 showed the higher bond strength of all other remaining groups and the groups 1, 2 and 3 showed satisfactory bond strength. The statistical evaluation also revealed that the bond strength of control group (37% phosphoric acid) was greater than those of experimental groups.
  
  
  CONCLUSIONS
  The present study results shows that the ceramic brackets have higher bond strength than stainless steel brackets (material wise).
authors.affiliation: Dean and HOD, Department of Orthodontics, Thaimoogambigai Dental College and Hospital , Chennai, India .
authors.forename: Ramachandhra
authors.initials: R
authors.lastname: Prabhakar
authors.affiliation: Post Graduate, Department of Orthodontics, Thaimoogambigai Dental College and Hospital , Chennai, India .
authors.lastname: Abinaya
authors.affiliation: Professor, Department of Orthodontics, Thaimoogambigai Dental College and Hospital , Chennai, India .
authors.lastname: Karthikeyan
authors.affiliation: Professor, Department of Orthodontics, Thaimoogambigai Dental College and Hospital , Chennai, India .
authors.lastname: Sarvanan
authors.affiliation: Reader, Department of Orthodontics, Thaimoogambigai Dental College and Hospital , Chennai, India .
authors.forename: Raj
authors.initials: R
authors.lastname: Vikram
keywords: APF; Bond strength; Ceramic brackets; Phosphoric acid; Stainless steel brackets