title: Effects of different pre-treatment methods on the shear bond strength of orthodontic brackets to demineralized enamel.
abstract: OBJECTIVE
  To compare the effects of different treatment methods used for the enamel damage, on the shear bond strength (SBS) and fracture mode of orthodontic brackets.
  
  
  METHODS
  Freshly-extracted 140 premolars were randomly allocated to seven groups: Group I was considered as the control of other groups. The remaining groups were exposed to demineralization. In group II, brackets were directly bonded to the demineralized enamel surface. CPP-ACP paste (GC Tooth Mousse), fluoride varnish (Bifluorid 12), microabrasion with a mixture prepared with 18% hydrochloric acid and fine pumice powder, microabrasion with an agent (Opalustre) and resin infiltrant (Icon®) were applied in Groups III, IV, V, VI and VII, respectively. The specimens were tested for SBS and bond failures were scored according to the Adhesive Remnant Index (ARI). Analysis of variance and Tukey tests were used to compare the SBS of the groups. ARI scores were compared with G-test. The statistical significance was set at p < 0.05 level.
  
  
  RESULTS
  Statistically significant differences were found among seven groups (F = 191.697; p < 0.001). The SBSs of groups I (mean = 18.8 ± 2.0 MPa) and VII (mean = 19.1 ± 1.4 MPa) were significantly higher than the other groups. No statistically significant difference was found between groups IV (mean = 11.5 ± 1.2 MPa) and V (mean = 12.6 ± 1.5 MPa). The differences in ARI scores of the groups were statistically significant (p < 0.01).
  
  
  CONCLUSIONS
  All demineralization treatment methods improve bonding to demineralized enamel. Resin infiltrant application after demineralization showed similar bond strength values as intact enamel.
authors.affiliation: a 1 Department of Orthodontics, Faculty of Dentistry, Izmir Katip Celebi University , Izmir, Turkey.
authors.forename: Ilknur
authors.initials: I
authors.lastname: Velİ
authors.affiliation: b 2 Department of Orthodontics, Faculty of Dentistry, Selcuk University , Konya, Turkey.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Akin
authors.affiliation: b 2 Department of Orthodontics, Faculty of Dentistry, Selcuk University , Konya, Turkey.
authors.forename: Zelİha Müge
authors.initials: ZM
authors.lastname: Baka
authors.affiliation: a 1 Department of Orthodontics, Faculty of Dentistry, Izmir Katip Celebi University , Izmir, Turkey.
authors.forename: Tancan
authors.initials: T
authors.lastname: Uysal
mesh_terms: D000134:Acid Etching, Dental / Q000379:methods; D000268:Adhesiveness; D002124:Calcium Fluoride / Q000737:chemistry; D002327:Cariostatic Agents / Q000737:chemistry; D002364:Caseins / Q000737:chemistry; D045424:Complex Mixtures / Q000737:chemistry; D003188:Composite Resins / Q000737:chemistry; D001840:Dental Bonding / Q000379:methods; D003743:Dental Enamel / Q000648:ultrastructure*; D003799:Dental Stress Analysis / Q000295:instrumentation; D019243:Enamel Microabrasion / Q000379:methods; D005460:Fluorides, Topical / Q000737:chemistry; D006801:Humans; D006851:Hydrochloric Acid / Q000737:chemistry; D008422:Materials Testing; D016910:Orthodontic Brackets; D011897:Random Allocation; D019279:Resin Cements / Q000737:chemistry; D012117:Resins, Synthetic / Q000737:chemistry; D033081:Shear Strength; D017640:Silicates / Q000737:chemistry; D012969:Sodium Fluoride / Q000737:chemistry; D013314:Stress, Mechanical; D013696:Temperature; D013997:Time Factors; D017001:Tooth Demineralization / Q000473:pathology*
chemical_list: C094502:Bifluorid 12; D002327:Cariostatic Agents; D002364:Caseins; D045424:Complex Mixtures; D003188:Composite Resins; D005460:Fluorides, Topical; D019279:Resin Cements; D012117:Resins, Synthetic; D017640:Silicates; C516047:Transbond XT Light Cure Adhesive Primer; C447032:casein phosphopeptide-amorphous calcium phosphate nanocomplex; C578177:icon infiltrant; C539075:opalustre; D012969:Sodium Fluoride; C005144:pumice; D002124:Calcium Fluoride; D006851:Hydrochloric Acid
keywords: CPP-ACP; enamel microabrasion; fluorides; shear strength