title: Open or submerged healing of implants with platform switching: a randomized, controlled clinical trial.
abstract: OBJECTIVE
  The temporal pattern of bone-level alterations in conventionally restored implants is dependent upon healing mode (open or submerged). This study examined the influence of healing on marginal bone levels at implants with a medium-rough surface including the implant collar and a clearance-fit implant-abutment connection restored according to a platform-switching concept.
  
  
  METHODS
  Two implants were placed in the posterior mandible of 21 test subjects, randomly assigned to open (OH) or submerged (SH) healing. Standardized radiographs were obtained after implant surgery, before re-entry, after crown mounting, 1 and 2 years after implant surgery, and evaluated for implant-bone-level alterations (ΔIBL). Bacterial samples of the implants' inner cavities were analysed by cultivation.
  
  
  METHODS
  Brunner-Langer Model, equivalence testings by Wilcoxon's (equivalence range ±0.4mm).
  
  
  RESULTS
  After 2 years, ΔIBL were -0.47±0.46mm (OH) and -0.54±0.38mm (SH). At the 1-year follow-up, all implants were contaminated with bacteria. ΔIBL (p<0.001) and the amount of bacterial contamination (p<0.001) significantly depended on time, but not on healing mode. ΔIBL of OH and SH were equivalent at all time points (all p0.044).
  
  
  CONCLUSIONS
  Platform-switched implants showed very limited peri-implant bone-level alterations. The healing-mode neither affected the total amount nor the temporal patterns of ΔIBL. Thus, the results for the tested implants with a non-rigid implant-abutment connection were similar to results reported previously for implants with a rigid implant-abutment connection.
authors.affiliation: Department of Prosthodontics, University of Berne, Berne, Switzerland Department of Oral Surgery, University of Witten/Herdecke, Witten/Herdecke, Germany.
authors.forename: Norbert
authors.initials: N
authors.lastname: Enkling
authors.forename: Peter
authors.initials: P
authors.lastname: Jöhren
authors.forename: Torben
authors.initials: T
authors.lastname: Klimberg
authors.forename: Regina
authors.initials: R
authors.lastname: Mericske-Stern
authors.forename: Pia-Merete
authors.initials: PM
authors.lastname: Jervøe-Storm
authors.forename: Stefan
authors.initials: S
authors.lastname: Bayer
authors.forename: Norbert
authors.initials: N
authors.lastname: Gülden
authors.forename: Søren
authors.initials: S
authors.lastname: Jepsen
mesh_terms: D000539:Alveolar Process / Q000000981:diagnostic imaging; D058491:Bacterial Load; D003442:Crowns; D000044:Dental Abutments; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants / Q000382:microbiology; D003774:Dental Plaque Index; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported / Q000382:microbiology; D004866:Equipment Contamination; D005260:Female; D005500:Follow-Up Studies; D005884:Gingival Hemorrhage / Q000382:microbiology; D006801:Humans; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000601:surgery; D008875:Middle Aged; D016348:Osseointegration / Q000502:physiology; D010512:Periodontal Index; D010514:Periodontal Pocket / Q000382:microbiology; D011446:Prospective Studies; D019252:Radiography, Dental, Digital; D011862:Radiography, Panoramic; D016037:Single-Blind Method; D013499:Surface Properties; D014945:Wound Healing / Q000502:physiology
chemical_list: D015921:Dental Implants