title: Single dental implant retained mandibular complete dentures--influence of the loading protocol: study protocol for a randomized controlled trial.
abstract: BACKGROUND
  Over the years, there has been a strong consensus in dentistry that at least two implants are required to retain a complete mandibular denture. It has been shown in several clinical trials that one single median implant can retain a mandibular overdenture sufficiently well for up to 5 years without implant failures, when delayed loading was used. However, other trials have reported conflicting results with in part considerable failure rates when immediate loading was applied. Therefore it is the purpose of the current randomized clinical trial to test the hypothesis that immediate loading of a single mandibular midline implant with an overdenture will result in a comparable clinical outcome as using the standard protocol of delayed loading.
  
  
  METHODS
  This prospective nine-center randomized controlled clinical trial is still ongoing. The final patient will complete the trial in 2016. In total, 180 edentulous patients between 60 and 89 years with sufficient complete dentures will receive one median implant in the edentulous mandible, which will retain the existing complete denture using a ball attachment. Loading of the median implant is either immediately after implant placement (experimental group) or delayed by 3 months of submerged healing at second-stage surgery (control group). Follow-up of patients will be performed for 24 months after implant loading. The primary outcome measure is non-inferiority of implant success rate of the experimental group compared to the control group. The secondary outcome measures encompass clinical, technical and subjective variables. The study was funded by the Deutsche Forschungsgemeinschaft (German research foundation, KE 477/8-1).
  
  
  CONCLUSIONS
  This multi-center clinical trial will give information on the ability of a single median implant to retain a complete mandibular denture when immediately loaded. If viable, this treatment option will strongly improve everyday dental practice.
  
  
  BACKGROUND
  The trial has been registered at Deutsches Register Klinischer Studien (German register of clinical trials) under DRKS-ID: DRKS00003730 since 23 August 2012. (http://www.germanctr.de).
authors.affiliation: Department of Prosthodontics, Propaedeutics and Dental Materials, Christian-Albrechts University of Kiel, Kiel, Germany. npassia@proth.uni-kiel.de.
authors.forename: Nicole
authors.initials: N
authors.lastname: Passia
authors.forename: Miha
authors.initials: M
authors.lastname: Brezavšček
authors.forename: Elfriede
authors.initials: E
authors.lastname: Fritzer
authors.forename: Stefanie
authors.initials: S
authors.lastname: Kappel
authors.forename: Thomas
authors.initials: T
authors.lastname: Kern
authors.forename: Ralph G
authors.initials: RG
authors.lastname: Luthardt
authors.forename: Nadine
authors.initials: N
authors.lastname: Frfr von Maltzahn
authors.forename: Torsten
authors.initials: T
authors.lastname: Mundt
authors.forename: Michael
authors.initials: M
authors.lastname: Rädel
authors.forename: Axel
authors.initials: A
authors.lastname: von Stein-Lausnitz
authors.forename: Matthias
authors.initials: M
authors.lastname: Kern
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002985:Clinical Protocols; D003757:Dental Implantation / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D003799:Dental Stress Analysis; D003828:Denture, Overlay; D005260:Female; D005858:Germany; D006801:Humans; D007575:Jaw, Edentulous / Q000601:surgery*; D008297:Male; D008334:Mandible / Q000601:surgery*; D008875:Middle Aged; D011446:Prospective Studies; D012107:Research Design; D013314:Stress, Mechanical; D013997:Time Factors; D016896:Treatment Outcome