title: An in vitro investigation on friction generated by ceramic brackets.
abstract: OBJECTIVE
  To compare friction (F) of conventional and ceramic brackets (0.022-inch slot) using a model that tests the sliding of the archwire through 10 aligned brackets.
  
  
  METHODS
  Polycrystalline alumina brackets (PCAs), PCA brackets with a stainless steel slot (PCA-M), and monocrystalline sapphire brackets (MCS) were tested under elastic ligatures using various archwires in dry and wet (saliva) states. Conventional stainless steel brackets were used as controls.
  
  
  RESULTS
  In both dry and wet states, PCA and MCS brackets expressed a statistically significant higher F value with respect to stainless steel and PCA-M brackets when combined with the rectangular archwires (P<.01). PCA brackets showed significantly higher friction than MCS brackets (P<.01) when coupled with 0.014 x 0.025-inch nickel-titanium (Ni-Ti) archwire. SEM analysis showed differences in the surfaces among stainless steel, MCS, PCA-M, and PCA brackets. In the wet state, the mean F values were generally higher than in the dry state.
  
  
  CONCLUSIONS
  PCA brackets showed significantly higher F than MCS brackets only when combined with 0.014 x 0.025-inch Ni-Ti archwires. Thus, in this study, a 10 aligned-brackets study model showed similar results when compared to a single bracket system except for friction level with 0.014 × 0.025-inch Ni-Ti archwires.
authors.affiliation: Department of Oral Science, Nano, and Biotechnology, University G.D'Annunzio, Chieti, Pescara, Italy. simtecc@unich.it
authors.forename: Simona
authors.initials: S
authors.lastname: Tecco
authors.forename: Stefano
authors.initials: S
authors.lastname: Teté
authors.forename: Mario
authors.initials: M
authors.lastname: Festa
authors.forename: Felice
authors.initials: F
authors.lastname: Festa
mesh_terms: D000497:Alloys / Q000737:chemistry; D000537:Aluminum Oxide / Q000737:chemistry; D002516:Ceramics / Q000737:chemistry*; D003461:Crystallography; D003722:Dental Alloys / Q000737:chemistry; D003764:Dental Materials / Q000737:chemistry*; D003799:Dental Stress Analysis / Q000295:instrumentation; D003890:Desiccation; D020724:Elastomers / Q000737:chemistry; D017276:Friction; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D009532:Nickel / Q000737:chemistry; D016382:Orthodontic Appliance Design; D016910:Orthodontic Brackets; D009969:Orthodontic Wires; D012463:Saliva / Q000737:chemistry; D013193:Stainless Steel / Q000737:chemistry; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry
chemical_list: D000497:Alloys; D003722:Dental Alloys; D003764:Dental Materials; D020724:Elastomers; C023988:beta titanium; C525450:titanium molybdenum alloy; C040654:titanium nickelide; D013193:Stainless Steel; D009532:Nickel; D014025:Titanium; D000537:Aluminum Oxide