title: Predictors of long-term stability of maxillary dental arch dimensions in patients treated with a transpalatal arch followed by fixed appliances.
abstract: BACKGROUND
  The aim of this retrospective study was to identify which dental and/or cephalometric variables were predictors of long-term maxillary dental arch stability in patients treated with a transpalatal arch (TPA) during the mixed dentition phase followed by full fixed appliances in the permanent dentition.
  
  
  METHODS
  Thirty-six patients, treated with TPA followed up by full fixed appliances, were divided into stable and relapse groups based on the long-term presence or not of relapse. Intercuspid, interpremolar and intermolar widths, arch length and perimeter, crowding, and upper incisor proclination were evaluated before treatment (T 0), post-TPA treatment (T 1), post-fixed appliance treatment (T 2), and a minimum of 3 years after full fixed appliances' removal (T 3). A binary logistic regression was performed thereafter to evaluate the impact of the dental arch and cephalometric measurements at T 1 and the changes between T 0 and T 1 as predictive variables for relapse at T 3.
  
  
  RESULTS
  The proposed model explained 42.7 % of the variance in treatment stability and correctly classified 72.2 % of the sample. Of the seven predictive variables, only upper anterior crowding (p = 0.029) was statistically significant. For every millimeter of decreased crowding at T 1 (after TPA treatment/before starting the fixed orthodontic treatment), there was an increase of 3.57 times in the odds of having stability.
  
  
  CONCLUSIONS
  The best predictor of relapse was maxillary crowding before treatment. The odds of relapse increase by 3.6 times for every millimeter of crowding at baseline.
authors.affiliation: Multidisciplinary Department of Medical-Surgical and Dental Specialties, Post-Graduate Orthodontics Program and Operative Unit, Second University of Naples, Via Luigi De Crecchio 6, 80138, Naples, Italy, tania.raucci@libero.it.
authors.forename: Gaetana
authors.initials: G
authors.lastname: Raucci
authors.forename: Maryam
authors.initials: M
authors.lastname: Elyasi
authors.forename: Camila
authors.initials: C
authors.lastname: Pachêco-Pereira
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Grassia
authors.forename: Fabrizia
authors.initials: F
authors.lastname: d'Apuzzo
authors.forename: Carlos
authors.initials: C
authors.lastname: Flores-Mir
authors.forename: Letizia
authors.initials: L
authors.lastname: Perillo
mesh_terms: D001641:Bicuspid / Q000473:pathology; D002508:Cephalometry / Q000379:methods; D002648:Child; D003481:Cuspid / Q000473:pathology; D003724:Dental Arch / Q000473:pathology*; D003818:Dentition, Mixed; D005260:Female; D005500:Follow-Up Studies; D005544:Forecasting; D006801:Humans; D007180:Incisor / Q000473:pathology; D008297:Male; D008310:Malocclusion / Q000473:pathology / Q000628:therapy; D008311:Malocclusion, Angle Class I / Q000628:therapy; D008312:Malocclusion, Angle Class II / Q000628:therapy; D008437:Maxilla / Q000473:pathology*; D008963:Molar / Q000473:pathology; D016910:Orthodontic Brackets; D010155:Palatal Expansion Technique / Q000295:instrumentation*; D012008:Recurrence; D012189:Retrospective Studies; D016896:Treatment Outcome