title: Failure Rates of Orthodontic Fixed Lingual Retainers bonded with Two Flowable Light-cured Adhesives: A Comparative Prospective Clinical Trial.
abstract: BACKGROUND
  This comparative prospective randomized clinical trial examined the in vivo failure rates of fixed mandibular and maxillary lingual retainers bonded with two light-cured flowable composites over 6 months.
  
  
  METHODS
  Consecutive patients were divided into two groups on a 1:1 basis. Two hundred fixed lingual retainers were included, and their failures were followed for 6 months. One group (n = 50) received retainers bonded with a nano-hybrid composite based on nano-optimized technology (Tetric-N-Flow, Ivoclar Vivadent). Another group (n = 50) received retainers bonded with a low viscosity (LV) composite (Transbond Supreme LV, 3M Unitek).
  
  
  RESULTS
  There was no significant difference between the overall failure rates of mandibular retainers bonded with Transbond (8%) and those bonded with Tetric-N-Flow (18%). However, the odds ratio for failure using Tetric-N-flow was 2.52-fold greater than that of Transbond. The failure rate of maxillary retainers bonded with Transbond was higher (14%), but not significantly different, than that of maxillary retainers bonded with Tetric-N-flow (10%). There was no significant difference in the estimated mean survival times of the maxillary and mandibular retainers bonded with the two composites.
  
  
  CONCLUSIONS
  Both types of composites tested in the current study can be used to bond fixed maxillary and mandibular lingual retainers, with low failure rates.
authors.affiliation: Associate Professor and Consultant, Department of Pediatric Dentistry and Orthodontics, College of Dentistry, King Saud University, Riyadh, Kingdom of Saudi Arabia, e-mail: nftalic@yahoo.com.
authors.forename: Nabeel F
authors.initials: NF
authors.lastname: Talic
mesh_terms: D017438:Bisphenol A-Glycidyl Methacrylate; D003188:Composite Resins; D001840:Dental Bonding; D004868:Equipment Failure; D005260:Female; D006801:Humans; D055115:Light-Curing of Dental Adhesives; D008297:Male; D018704:Orthodontic Retainers; D011446:Prospective Studies; D019279:Resin Cements; D055815:Young Adult
chemical_list: D003188:Composite Resins; D019279:Resin Cements; C090969:Tetric; C065742:Transbond; D017438:Bisphenol A-Glycidyl Methacrylate
keywords: Failure rates; Flowable composite; Orthodontic fixed retainers.