title: Microleakage under orthodontic bands cemented with nano-hydroxyapatite-modified glass ionomer.
abstract: OBJECTIVE
  To estimate the in vivo effect of nano-hydroxyapatite (HA) modification of banding glass-ionomer cement on microleakage under orthodontic bands.
  
  
  METHODS
  Eighty noncarious premolars scheduled for extraction in 20 orthodontic patients were randomly divided into four groups. Grouping was based on the ratio of nano-HA (0%, 5%, 10%, 15% by weight) added to the luting glass-ionomer cement (GIC) Ketac-Cem, which was used for cementation of prefabricated micro-etched orthodontic bands. Dye penetration method was used for microleakage evaluation at the cement-band and cement-enamel interfaces. Statistical evaluation was performed with a Kruskal-Wallis test and a Mann-Whitney U-test, and a Bonferroni-adjusted significance level was calculated.
  
  
  RESULTS
  Bands cemented with conventional GIC showed the highest microleakage scores in comparison to those cemented with nano-HA-modified GIC. No significant difference was found between teeth banded with 10% and 15% modified GIC.
  
  
  CONCLUSIONS
  Modification of the banding GIC with 15% nano-HA revealed a positive effect on reducing microleakage around orthodontic bands.
authors.affiliation: a  Assistant Professor of Dental Biomaterials, Faculty of Dentistry, Mansuora University, Mansoura, Egypt.
authors.forename: Enas T
authors.initials: ET
authors.lastname: Enan
authors.forename: Shaza M
authors.initials: SM
authors.lastname: Hammad
mesh_terms: D000293:Adolescent; D001641:Bicuspid; D003763:Dental Leakage; D017886:Durapatite / Q000737:chemistry*; D005260:Female; D005899:Glass Ionomer Cements / Q000737:chemistry*; D006801:Humans; D008297:Male; D008422:Materials Testing; D049329:Nanostructures / Q000737:chemistry*; D016910:Orthodontic Brackets; D018709:Statistics, Nonparametric; D014081:Tooth Extraction; D055815:Young Adult
chemical_list: D005899:Glass Ionomer Cements; D017886:Durapatite