title: Shear Bond Strength of Ceramic Brackets with Different Base Designs: Comparative In-vitro Study.
abstract: BACKGROUND
  Knowledge about the Shear Bond Strength (SBS) of ceramic brackets with different base design is essential as it affects bond strength to enamel.
  
  
  OBJECTIVE
  The aim of the present study was to evaluate and compare the effect of base designs of different ceramic brackets on SBS, and to determine the fracture site after debonding.
  
  
  METHODS
  Four groups of ceramic brackets and one group of metal brackets with different base designs were used. Adhesive precoated base of Clarity Advanced (APC Flash-free) (Unitek/3M, Monrovia, California), microcrystalline base of Clarity Advanced (Unitek/3M, Monrovia, California), polymer mesh base of InVu (TP Orthodontics, Inc., La Porte, IN, United States), patented bead ball base of Inspire Ice (Ormco, Glendora, California), and a mechanical mesh base of Gemini Metal bracket (Unitek/3M, Monrovia, California). Ten brackets of each type were bonded to 50 maxillary premolars with Transbond XT (Unitek/3M). Samples were stored in distilled water at room temperature for 24 hours and subsequently tested in shear mode on a universal testing machine (Model 3382; Instron Corp., Canton, Massachusetts, USA) at a cross head speed of 1mm/minute with the help of a chisel. The debonded interface was recorded and analyzed to determine the predominant bond failure site under an optical microscope (Stereomicroscope) at 10X magnification. One way analysis of variance (ANOVA) was used to compare SBS. Tukey's significant differences tests were used for post-hoc comparisons. The Adhesive Remnant Index (ARI) scores were compared by chi-square test.
  
  
  RESULTS
  Mean SBS of microcrystalline base (27.26±1.73), was the highest followed by bead ball base (23.45±5.09), adhesive precoated base (20.13±5.20), polymer mesh base (17.54±1.91), and mechanical mesh base (17.50±2.41) the least. Comparing the frequency (%) of ARI Score among the groups, chi-square test showed significantly different ARI scores among the groups (χ2= 34.07, p<0.001).
  
  
  CONCLUSIONS
  Different base designs of metal and ceramic brackets influence SBS to enamel and all were clinically acceptable.
authors.affiliation: Postgraduate Student, Department of Orthodontics and Dentofacial Orthopedics, Institute of Dental Sciences , Bareilly, Uttar Pradesh, India .
authors.forename: Mohd Younus
authors.initials: MY
authors.lastname: Ansari
authors.affiliation: Professor and HOD, Department of Orthodontics and Dentofacial Orthopedics, Institute of Dental Sciences , Bareilly, Uttar Pradesh, India .
authors.forename: Deepak K
authors.initials: DK
authors.lastname: Agarwal
authors.affiliation: Reader, Department of Orthodontics and Dentofacial Orthopedics, Institute of Dental Sciences , Bareilly, Uttar Pradesh, India .
authors.forename: Ankur
authors.initials: A
authors.lastname: Gupta
authors.affiliation: Professor, Department of Orthodontics and Dentofacial Orthopedics, Institute of Dental Sciences , Bareilly, Uttar Pradesh, India .
authors.forename: Preeti
authors.initials: P
authors.lastname: Bhattacharya
authors.affiliation: Senior Lecturer, Department of Orthodontics and Dentofacial Orthopedics, Institute of Dental Sciences , Bareilly, Uttar Pradesh, India .
authors.forename: Juhi
authors.initials: J
authors.lastname: Ansar
authors.affiliation: Senior Lecturer, Department of Orthodontics and Dentofacial Orthopedics, Institute of Dental Sciences , Bareilly, Uttar Pradesh, India .
authors.forename: Ravi
authors.initials: R
authors.lastname: Bhandari
keywords: Adhesive precoated base; Fracture sites; Microcrystalline mechanical base; Patented bead ball base; Polymer mesh base