title: Comparison of the frictional characteristics of aesthetic orthodontic brackets measured using a modified in vitro technique.
abstract: OBJECTIVE
  The coefficients of friction (COFs) of aesthetic ceramic and stainless steel brackets used in conjunction with stainless steel archwires were investigated using a modified linear tribometer and special computer software, and the effects of the bracket slot size (0.018 inches [in] or 0.022 in) and materials (ceramic or metal) on the COF were determined.
  
  
  METHODS
  Four types of ceramic (one with a stainless steel slot) and one conventional stainless steel bracket were tested with two types of archwire sizes: a 0.017 × 0.025-in wire in the 0.018-in slots and a 0.019 × 0.025-in wire in the 0.022-in slot brackets. For pairwise comparisons between the 0.018-in and 0.022-in slot sizes in the same bracket, an independent sample t-test was used. One-way and two-way analysis of variance (ANOVA) and Tukey's post-hoc test at the 95% confidence level (α = 0.05) were also used for statistical analyses.
  
  
  RESULTS
  There were significant differences between the 0.022-in and 0.018-in slot sizes for the same brand of bracket. ANOVA also showed that both slot size and bracket slot material had significant effects on COF values (p < 0.001). The ceramic bracket with a 0.022-in stainless steel slot showed the lowest mean COF (µ = 0.18), followed by the conventional stainless steel bracket with a 0.022-in slot (µ = 0.21). The monocrystalline alumina ceramic bracket with a 0.018-in slot had the highest COF (µ = 0.85).
  
  
  CONCLUSIONS
  Brackets with stainless steel slots exhibit lower COFs than ceramic slot brackets. All brackets show lower COFs as the slot size increases.
authors: Department of Orthodontics, Faculty of Dentistry, Ondokuz Mayis University, Samsun, Turkey.
authors: Nursel
authors: N
authors: Arici
authors: Department of Orthodontics, Faculty of Dentistry, Ondokuz Mayis University, Samsun, Turkey.
authors: Berat Serdar
authors: BS
authors: Akdeniz
authors: Department of Orthodontics, Faculty of Dentistry, Ondokuz Mayis University, Samsun, Turkey.
authors: Selim
authors: S
authors: Arici
keywords: Archwires; Brackets; Coefficient of friction; Tribometer