title: A comparison of shear bond strength of orthodontic brackets bonded with four different orthodontic adhesives.
abstract: OBJECTIVE
  The objective of this study is to compare the shear bond strength (SBS) of stainless steel (SS) orthodontic brackets bonded with four different orthodontic adhesives.
  
  
  METHODS
  Eighty newly extracted premolars were bonded to 0.022 SS brackets (Ormco, Scafati, Italy) and equally divided into four groups based on adhesive used: (1) Rely-a-Bond (self-cure adhesive, Reliance Orthodontic Product, Inc., Illinois, USA), (2) Transbond XT (light-cure adhesive, 3M Unitek, CA, USA), (3) Transbond Plus (sixth generation self-etch primer, 3M Unitek, CA, USA) with Transbond XT (4) Xeno V (seventh generation self-etch primer, Dentsply, Konstanz, Germany) with Xeno Ortho (light-cure adhesive, Dentsply, Konstanz, Germany) adhesive. Brackets were debonded with a universal testing machine (Model No. 3382 Instron Corp., Canton, Mass, USA). The adhesive remnant index (ARI) was recordedIn addition, the conditioned enamel surfaces were observed under a scanning electron microscope (SEM).
  
  
  RESULTS
  Transbond XT (15.49 MPa) attained the highest bond strength. Self-etching adhesives (Xeno V, 13.51 MPa; Transbond Plus, 11.57 MPa) showed clinically acceptable SBS values and almost clean enamel surface after debonding. The analysis of variance (F = 11.85, P < 0.0001) and Chi-square (χ(2) = 18.16, P < 0.05) tests revealed significant differences among groups. The ARI score of 3 (i.e., All adhesives left on the tooth) to be the most prevalent in Transbond XT (40%), followed by Rely-a-Bond (30%), Transbond Plus with Transbond XT (15%), and Xeno V with Xeno Ortho (10%). Under SEM, enamel surfaces after debonding of the brackets appeared porous when an acid-etching process was performed on the surfaces of Rely-a-Bond and Transbond XT, whereas with self-etching primers enamel presented smooth and almost clean surfaces (Transbond Plus and Xeno V group).
  
  
  CONCLUSIONS
  All adhesives yielded SBS values higher than the recommended bond strength (5.9-7-8 MPa), Seventh generation self-etching primer Xeno V with Xeno Ortho showed clinically acceptable SBS and the least amount of residual adhesive left on the enamel surface after debonding.
authors.affiliation: Department of Orthodontics and Dentofacial Orthopaedics, Faculty of Dental Sciences, CSM Medical University, Lucknow, Uttar Pradesh, India.
authors.forename: Sudhir
authors.initials: S
authors.lastname: Sharma
authors.affiliation: Department of Orthodontics and Dentofacial Orthopaedics, Faculty of Dental Sciences, CSM Medical University, Lucknow, Uttar Pradesh, India.
authors.forename: Pradeep
authors.initials: P
authors.lastname: Tandon
authors.affiliation: Department of Orthodontics and Dentofacial Orthopaedics, Faculty of Dental Sciences, CSM Medical University, Lucknow, Uttar Pradesh, India.
authors.forename: Amit
authors.initials: A
authors.lastname: Nagar
authors.affiliation: Department of Orthodontics and Dentofacial Orthopaedics, CSM University, Lucknow, Uttar Pradesh, India.
authors.forename: Gyan P
authors.initials: GP
authors.lastname: Singh
authors.affiliation: Department of Orthodontics and Dentofacial Orthopaedics, Faculty of Dental Sciences, CSM Medical University, Lucknow, Uttar Pradesh, India.
authors.forename: Alka
authors.initials: A
authors.lastname: Singh
authors.affiliation: Department of Orthodontics and Dentofacial Orthopaedics, Faculty of Dental Sciences, CSM Medical University, Lucknow, Uttar Pradesh, India.
authors.forename: Vinay K
authors.initials: VK
authors.lastname: Chugh
keywords: Adhesive remnant index; orthodontic adhesives; self-etching primer; shear bond strength