title: Effect of Different Surface Treatments on Microtensile Bond Strength of Composite Resin to Normal and Fluorotic Enamel After Microabrasion.
abstract: OBJECTIVE
  This study aimed to determine the effect of surface treatments such as tooth reduction and extending the etching time on microtensile bond strength (μTBS) of composite resin to normal and fluorotic enamel after microabrasion.
  
  
  METHODS
  Fifty non-carious anterior teeth were classified into two groups of normal and fluorotic (n=25) using Thylstrup and Fejerskov index (TFI=4-6). Teeth in each group were treated with five modalities as follows and restored with OptiBond FL and Z350 composite resin: 1-Etching (30 seconds), bonding, filling (B); 2-Tooth reduction (0.3mm), etching, bonding, filling (R-B); 3-Microabrasion (120 seconds), etching, bonding, filling (MB); 4- Microabrasion, tooth reduction, etching, bonding, filling (M-R-B); and 5- Microabrasion, etching (60 seconds), bonding, filling (M-2E-B). Ten experimental groups (n=5) were designed; 150 rectangular samples (10 in each group) with a cross-sectional area of 1×1mm2were prepared for μTBS test. Failure mode was determined under a stereomicroscope and one specimen was selected from each group for scanning electron microscopy (SEM) analysis. Data were analyzed using two-way ANOVA and Tukey's test.
  
  
  RESULTS
  The μTBS to normal enamel was higher than to fluorotic enamel in all groups except for group (R-B). The Maximum and minimum μTBS were noted in the group (normal, reduction, bonding) and (fluorosed, microabrasion, bonding), respectively. Tooth reduction increased μTBS more effectively than extended etching time after microabrasion.
  
  
  CONCLUSIONS
  Fluorosis may reduce μTBS of composite resin to enamel. Microabrasion reduced the bond strength. Tooth reduction and extended etching time increased μTBS of composite resin to both normal and fluorotic enamel.
authors.affiliation: Assistant Professor, Department of Restorative Dentistry, Faculty of Dentistry, Shahed University, Tehran, Iran.
authors.forename: Mahshid Mohammadi
authors.initials: MM
authors.lastname: Bassir
authors.affiliation: Assistant Professor, Department of Restorative Dentistry, Faculty of Dentistry, Shahed University, Tehran, Iran.
authors.forename: Mohammad Bagher
authors.initials: MB
authors.lastname: Rezvani
authors.affiliation: Assistant Professor, Department of Restorative Dentistry, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran.
authors.forename: Elham Tabatabai
authors.initials: ET
authors.lastname: Ghomsheh
authors.affiliation: Assistant Professor, Department of Restorative Dentistry, Faculty of Dentistry, Kermanshah University of Medical Sciences, Kermanshah, Iran.
authors.forename: Zahra Malek
authors.initials: ZM
authors.lastname: Hosseini
keywords: Composite Resins; Dental Bonding; Enamel Microabrasion; Fluorosis, Dental