title: Clinical and radiographic comparison of the effects of two types of fixed retainers on periodontium - a randomized clinical trial.
abstract: BACKGROUND
  Most orthodontists believe that fixed retainers are necessary to maintain ideal dental relationships. However, untoward side effects might result from their long-term placement. The aim of this study was to evaluate the clinical and radiographic effect of two commonly used fixed retainers on the health of the periodontium.
  
  
  METHODS
  Thirty patients were randomly divided into two groups to receive either a fiber-reinforced composite retainer or a spiral wire retainer extended on the lingual surfaces of both maxillary and mandibular arches from canine to canine. Periapical radiographs were obtained from the patients at the time of placement of the retainers and after the 6-month period to assess the radiographic conditions of the periodontium. Clinical examination was carried out at the same two time intervals.
  
  
  RESULTS
  Even though there were no significant differences between the two groups of study at the beginning of the trial, there were statistically significant differences after the 6-month follow-up regarding the main outcomes of the study. Nearly all indices showed to deteriorate after 6 months in the fiber-reinforced group, while in the spiral wire group, this was not the case. As for the secondary outcomes, radiographic examination did not reveal any statistically significant differences after 6 months or between the two groups.
  
  
  CONCLUSIONS
  It can be concluded that spiral wire retainers elicit less detrimental periodontal response in the short-term follow-up compared to fiber-reinforced composite retainers as revealed by the primary outcomes of the study.
  
  
  BACKGROUND
  ClinicalTrials.gov: NCT01314729.
authors.affiliation: Orthodontics Department, Shiraz University of Medical Sciences, Shiraz Orthodontic Research Center, Shiraz, 71345, Iran. sepideh.torkan@yahoo.com.
authors.forename: Sepideh
authors.initials: S
authors.lastname: Torkan
authors.forename: Morteza
authors.initials: M
authors.lastname: Oshagh
authors.forename: Leila
authors.initials: L
authors.lastname: Khojastepour
authors.forename: Shoaleh
authors.initials: S
authors.lastname: Shahidi
authors.forename: Somayeh
authors.initials: S
authors.lastname: Heidari
mesh_terms: D000293:Adolescent; D003188:Composite Resins / Q000737:chemistry; D003724:Dental Arch / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D003728:Dental Calculus / Q000145:classification; D003764:Dental Materials / Q000737:chemistry; D003774:Dental Plaque Index; D005500:Follow-Up Studies; D005891:Gingivitis / Q000145:classification; D006801:Humans; D009911:Oral Hygiene Index; D016382:Orthodontic Appliance Design; D018704:Orthodontic Retainers; D009969:Orthodontic Wires; D010512:Periodontal Index; D010519:Periodontium / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D016300:Radiography, Bitewing / Q000379:methods; D019252:Radiography, Dental, Digital / Q000379:methods; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D003188:Composite Resins; D003764:Dental Materials