title: [Clinical effect of removable lingual arch plus auxiliary spring for dental arch expansion].
abstract: OBJECTIVE
  Observe the clinical effect of removable lingual arch plus auxiliary spring for convenient dental (especially mandibular) arch expansion.
  
  
  METHODS
  Seventeen patients with dental arch constriction complicated by mild dental crowding were enrolled in this study, including 9 requiring maxillary arch expansion and 8 necessitating mandibular expansion. The patients were divided to two groups at random for arch expansion with removable lingual arch plus auxiliary spring and with Quad-helix, respectively, and the effect of arch expansion was compared between the two groups.
  
  
  RESULTS
  After 8 weeks of arch expansion, the average width of U4-U4 and U5-U5 in removable lingual arch group was enlarged by 2.2 mm and 3.0 mm, and that in Quad-helix group by 2.3 mm and 3.5 mm, respectively, showing no significant differences between the two groups (P>0.05). After 12 weeks of treatment, the average width of L4-L4 and L5-L5 in the former group was enlarged by 2.3 mm and 2.5 mm, respectively, significantly greater than that in the latter group (1.0 mm and 1.2 mm, P<0.05).
  
  
  CONCLUSIONS
  Removable lingual arch plus auxiliary spring allows significant expansion of the middle segment of the dental arch (bicuspids), and can be more effective than Quad-helix for mandibular arch expansion.
authors.affiliation: Department of Stomatopathy, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China. E-mail: bailangsfy@163.com
authors.forename: Feng-yang
authors.initials: FY
authors.lastname: Sun
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D002648:Child; D003724:Dental Arch / Q000473:pathology*; D006801:Humans; D008310:Malocclusion / Q000628:therapy*; D009968:Orthodontic Appliances, Removable; D009971:Orthodontics, Corrective / Q000379:methods*; D010155:Palatal Expansion Technique / Q000295:instrumentation*; D055815:Young Adult