title: Four-Millimeter-Long Posterior-Mandible Implants: 5-Year Outcomes of a Prospective Multicenter Study.
abstract: BACKGROUND
  There is lack of evidence on long-term success of short dental implants in reduced alveolar bone.
  
  
  OBJECTIVE
  In this prospective 5-year study, survival and marginal bone loss of 4-mm implants, which supported fixed dental prostheses (FDPs) in severely resorbed posterior mandibles, were evaluated.
  
  
  METHODS
  In 28 patients, evaluation of 86 osseointegrated 4-mm-long implants, which supported a 3- or a 4-unit FDP by crown splinting without the use of pontics or cantilevers, was performed over a 5-year period.
  
  
  RESULTS
  Three subjects dropped out for non-study reasons: one subject had her three implants removed after 1 year and two subjects died (six implants). Five implants in three subjects were lost between 3 and 5 years. Twenty-four subjects and 71 implants were active at the 5-year follow-up (92.2% survival). After 1 year, significant (p < .001) mean (standard error of the mean [SEM]) 0.44-mm (0.05) marginal bone loss occurred. At 2, 3, and 5 years, mean (SEM) bone loss of 0.57 mm (0.06), 0.55 mm (0.07), and 0.53 mm (0.08) occurred, respectively (no significant change after 1 year). At 5 years, average plaque levels were 13.3%; 69% of the implants were plaque free. On average, mucosal bleeding occurred at 8.1% of the implants. During 5 years, two subjects experienced uncomplicated bridge loosening. No other complications occurred during the study.
  
  
  CONCLUSIONS
  Four-millimeter implants can support FDPs in severely resorbed posterior mandibles for 5 years with healthy peri-implant conditions.
authors.affiliation: Department of Periodontology, The Institute for Postgraduate Dental Education, Jönköping, Sweden.|Department of Biomaterials, Institute for Clinical Sciences, Göteborg University, Göteborg, Sweden.
authors.forename: Christer
authors.initials: C
authors.lastname: Slotte
authors.affiliation: Oral Surgery, Faculty of Dentistry, University of Bergen, Bergen, Norway.
authors.forename: Arne
authors.initials: A
authors.lastname: Grønningsaeter
authors.affiliation: Prosthodontics, Faculty of Dentistry, University of Bergen, Bergen, Norway.
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Halmøy
authors.affiliation: Department of Oral & Maxillofacial Surgery, Borås County Hospital, Borås, Sweden.
authors.forename: Lars-Olof
authors.initials: LO
authors.lastname: Öhrnell
authors.affiliation: Department of Oral & Maxillofacial Surgery, Gävle County Hospital, Gävle, Sweden.
authors.forename: Arne
authors.initials: A
authors.lastname: Mordenfeld
authors.affiliation: Department of Oral & Maxillofacial Surgery, Halmstad County Hospital, Halmstad, Sweden.
authors.forename: Sten
authors.initials: S
authors.lastname: Isaksson
authors.affiliation: Department of Prosthodontics, Halmstad County Hospital, Halmstad, Sweden.
authors.forename: Lars-Åke
authors.initials: LÅ
authors.lastname: Johansson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016301:Alveolar Bone Loss / Q000453:epidemiology / Q000209:etiology; D003758:Dental Implantation, Endosseous / Q000009:adverse effects*; D015921:Dental Implants; D019232:Dental Restoration Failure; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible / Q000601:surgery; D008875:Middle Aged; D011446:Prospective Studies; D016896:Treatment Outcome
chemical_list: D015921:Dental Implants
keywords: bone atrophy; bone loss; bone resorption; clinical trial; crown-implant ratio; short implants