title: Disinclusion of unerupted teeth by mean of self-ligating brackets: effect of blood contamination on shear bond strength.
abstract: OBJECTIVE
  The aim of this study was to assess the effect of blood contamination on the shear bond strength and failure site of three different orthodontic self-ligating brackets.
  
  
  METHODS
  240 bovine permanent mandibular incisors were randomly divided into 12 groups of 20 specimens each. Orthodontic self-ligating brackets were tested under four different enamel surface conditions: a) dry, b) blood contamination before priming, c) blood contamination after priming, d) blood contamination before and after priming. Brackets were bonded to the teeth and subsequently tested using a Instron universal testing machine. Shear bond strength values and adhesive failure rate were recorded. Statistical analysis was performed using ANOVA and Tukey tests (strength values), and Chi squared test (ARI Scores).
  
  
  RESULTS
  Non-contaminated enamel surfaces showed highest bond strengths for all self ligating brackets. Under blood-contamination shear bond strengths lowered for all brackets tested. Groups contaminated before and after primer application showed the lowest shear bond strength. Significant differences in debond locations were found among the groups under the various enamel surface conditions.
  
  
  CONCLUSIONS
  Blood contamination of enamel during the bonding procedure lowers bond strength values of self ligating brackets, expecially when contamination occur in different times of the bonding procedure.
authors.affiliation: Department of Orthodontics and Department of Surgical Sciences (Head: Prof. Paolo Dionigi), University of Pavia, Pavia, Italy. andrea.scribante@unipv.it
authors.forename: Andrea
authors.initials: A
authors.lastname: Scribante
authors.forename: Maria-Francesca
authors.initials: MF
authors.lastname: Sfondrini
authors.forename: Sara
authors.initials: S
authors.lastname: Gatti
authors.forename: Paola
authors.initials: P
authors.lastname: Gandini
mesh_terms: D000818:Animals; D001769:Blood; D002417:Cattle; D001840:Dental Bonding; D003799:Dental Stress Analysis; D016910:Orthodontic Brackets; D033081:Shear Strength; D014097:Tooth, Unerupted / Q000628:therapy*