title: Influence of time after extraction on the development of gingival invagination: study protocol for a multicenter pilot randomized controlled clinical trial.
abstract: BACKGROUND
  Gingival invaginations are a common side effect of orthodontic therapy involving tooth extraction and subsequent space closure. Consequences of gingival invaginations are a jeopardized stability of the space closure and hampered oral hygiene. In a retrospective study, the factor time until initiation of orthodontic space closure after tooth extraction has been identified as a potential risk factor for the development of gingival invaginations. The aim of this pilot study is to proof this hypothesis and to enable a caseload calculation for further clinical trials. The referring question is: is it possible to reduce the number of developing gingival invaginations by initiation of orthodontic space closure after tooth extraction at an early point of time?
  
  
  METHODS
  The intended pilot study is designed as a multicenter randomized controlled clinical trial, comparing the impact of two different time intervals from tooth extraction to initiation of orthodontic space closure on the development of gingival invaginations.Forty participants, men and women in the age range of 11 to 30 years with orthodontically related indication for tooth extraction in the lower jaw, will be randomized 1:1 in one of two treatment groups. In group A the orthodontic tooth movement into the extraction area will be initiated in a time interval 2 to 4 weeks after tooth extraction. In group B the tooth movement will be initiated in a time interval >12 weeks after extraction. A possible effect of these treatment modalities on the development of gingival invaginations will be documented at the moment of space closure or 10 months +/- 14 days after initiation of space closure respectively, by clinical documentation of the primary (reduced number of gingival invagination) and the secondary endpoint (reduction of the severity of gingival invaginations).
  
  
  BACKGROUND
  Universal Trial Number U1111-1132-6655; German Clinical Trials Register DRKS00004248.
authors.affiliation: Department of Orthodontics, University Hospital Bonn, Welschnonnenstraße 17, 53111 Bonn, Germany. c_reichert@web.de
authors.forename: Christoph
authors.initials: C
authors.lastname: Reichert
authors.forename: Eric
authors.initials: E
authors.lastname: Kutschera
authors.forename: Manuel
authors.initials: M
authors.lastname: Nienkemper
authors.forename: Sven
authors.initials: S
authors.lastname: Scharf
authors.forename: Martin
authors.initials: M
authors.lastname: Mengel
authors.forename: Rolf
authors.initials: R
authors.lastname: Fimmers
authors.forename: Christine
authors.initials: C
authors.lastname: Fuhrmann
authors.forename: Christina
authors.initials: C
authors.lastname: Plötz
authors.forename: Lina
authors.initials: L
authors.lastname: Gölz
authors.forename: Dieter
authors.initials: D
authors.lastname: Drescher
authors.forename: Bert
authors.initials: B
authors.lastname: Braumann
authors.forename: Andreas
authors.initials: A
authors.lastname: Jäger
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002985:Clinical Protocols; D005260:Female; D005858:Germany; D005882:Gingival Diseases / Q000209:etiology / Q000517:prevention & control*; D006801:Humans; D008297:Male; D019516:Orthodontic Space Closure / Q000009:adverse effects* / Q000379:methods; D010865:Pilot Projects; D012107:Research Design; D013997:Time Factors; D014081:Tooth Extraction / Q000009:adverse effects*; D016896:Treatment Outcome; D055815:Young Adult