title: Effect of blood contamination on shear bond strength of orthodontic brackets and disinclusion buttons.
abstract: Our aim was to assess the effect of blood contamination on the shear bonding strength and sites of failure of orthodontic brackets and bondable buttons. We randomly divided 160 bovine permanent mandibular incisors into 8 groups of 20 specimens each. Both orthodontic brackets (Step brackets, Leone, Sesto Fiorentino, Italy) and bondable buttons (Flat orthodontic buttons, Leone, Sesto Fiorentino, Italy) were tested on four different enamel surfaces: dry; contamination with blood before priming; after priming; and before and after priming. Brackets and buttons were bonded to the teeth and subsequently tested using a Instron universal testing machine. Shear bonding strength and the rate of adhesive failures were recorded. Data were analysed using the analysis of variance (ANOVA), Scheffè tests, and the chi-square test. Uncontaminated enamel surfaces showed the highest bonding strengths for both brackets and buttons. When they were contaminated with blood, orthodontic brackets had significantly lower shear strengths than bondable buttons (P=0.0001). There were significant differences in sites of failure among the groups for the various enamel surfaces (P=0.001). Contamination of enamel by blood during bonding lowers the strength of the bond, more so with orthodontic brackets than with bondable buttons.
authors.affiliation: Department of Orthodontics, University of Pavia, Pavia, Italy.
authors.forename: Maria Francesca
authors.initials: MF
authors.lastname: Sfondrini
authors.forename: Sara
authors.initials: S
authors.lastname: Gatti
authors.forename: Andrea
authors.initials: A
authors.lastname: Scribante
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000818:Animals; D001769:Blood; D002417:Cattle; D003722:Dental Alloys / Q000737:chemistry; D003743:Dental Enamel / Q000648:ultrastructure; D003799:Dental Stress Analysis / Q000295:instrumentation; D003890:Desiccation; D004866:Equipment Contamination; D004868:Equipment Failure; D055115:Light-Curing of Dental Adhesives; D016382:Orthodontic Appliance Design; D009967:Orthodontic Appliances; D016910:Orthodontic Brackets; D010756:Phosphoric Acids / Q000737:chemistry; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry; D033081:Shear Strength; D013193:Stainless Steel / Q000737:chemistry; D013314:Stress, Mechanical; D013696:Temperature; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D003722:Dental Alloys; D010756:Phosphoric Acids; D019279:Resin Cements; C477790:Transbond XT; D014867:Water; D013193:Stainless Steel; C030242:phosphoric acid