title: Use of short implants (6 mm) in a single-tooth replacement: a 5-year follow-up prospective randomized controlled multicenter clinical study.
abstract: OBJECTIVE
  To evaluate prospectively clinical and radiographic outcomes of 6- or 10 mm-long implants with moderately rough surface (SLA(®) ) loaded within 7 weeks from installation and supporting single crowns in the posterior regions in the course of 5 years of loading.
  
  
  METHODS
  Sixty implants with a moderately rough surface, 30 tests (6 mm long, 4.1 mm in diameter) and 30 controls (10 mm long, 4.1 mm in diameter), were placed in posterior regions in 45 patients. After 6 weeks, impressions were taken and the implants were restored with a single fixed prosthesis made with gold-palladium alloy and porcelain. Survival rate and marginal bone loss were evaluated yearly. The clinical crown/implant ratio was calculated.
  
  
  RESULTS
  During the follow-up period, five implants, four tests and one control, were lost. Of the four test implants, one was lost before loading, two between the 2nd and the 3rd years, and one during the 4th year of the follow-up period. The control implant was lost during the first year of function. Consequently, after 5 years of follow-up, a survival rate of 86.7% and 96.7% was observed at the test and control sites, respectively.
  
  
  CONCLUSIONS
  The results of this study showed that 6-mm-long implants supporting single crowns loaded within 7 weeks from installation lose a small amount of marginal bone during 5 years of functional loading, similar to that of 10-mm-long implants. However, a higher degree of implant loss was recorded at the short implants, probably due to the fracturing of the surrounding bone.
authors.affiliation: Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Rossi
authors.affiliation: ARDEC, Ariminum Odontologica, Rimini, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Botticelli
authors.affiliation: Faculty of Dentistry, University of Medical Science, La Habana, Cuba.
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Cesaretti
authors.affiliation: ARDEC, Ariminum Odontologica, Rimini, Italy.
authors.forename: Enzo
authors.initials: E
authors.lastname: De Santis
authors.affiliation: Unit of Implantology and Prosthodontics, Department of Health Sciences, Dental Clinic, San Paolo Hospital, University of Milan, Milan, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Storelli
authors.affiliation: Center for Dental Medicine, University of Zurich, Zurich, Switzerland.|University of Bern, Bern, Switzerland.
authors.forename: Niklaus P
authors.initials: NP
authors.lastname: Lang
mesh_terms: D003758:Dental Implantation, Endosseous; D019250:Dental Implants, Single-Tooth; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D005500:Follow-Up Studies; D006801:Humans; D011446:Prospective Studies; D016896:Treatment Outcome
keywords: SLA surface; dental implants; early loading; implant length; prospective randomized; short implants