title: One-year prospective three-center study comparing the outcome of a "soft bone implant" (prototype Mk IV) and the standard Brånemark implant.
abstract: BACKGROUND
  Oral implant treatment ad modum Brånemark has been used for decades in the rehabilitation of edentate and partially dentate patients. Posterior jaw regions frequently exhibit bone of poor texture, and it is often difficult to obtain primary stability. Thus, it may prove beneficial to deviate from the original protocol and to use implants with a modified design, for example, with a slightly tapered geometry.
  
  
  OBJECTIVE
  The purpose of the investigation was to compare the early behavior of a modified (prototype Mk IV, Brånemark System, Nobel Biocare AB, Gothenburg, Sweden; test) implant with that of the standard Brånemark implant (control) in regions of mainly type 4 bone.
  
  
  METHODS
  Three Swedish centers participated, and a total of 44 patients were treated with oral implants for 39 maxillas and 5 mandibles. The study focused on the most distal right and left implant sites (88 implants), which were randomized to receive either a test or a control implant. Various parameters were recorded, such as registered insertion torque (OsseoCare), Nobel Biocare AB), wobbling during insertion, primary and secondary stability (as measured with resonance frequency), and marginal bone loss. The implants were followed up for 1 year.
  
  
  RESULTS
  The test implant more frequently required a higher insertion torque and showed a significantly higher primary stability than the control implant. This difference in stability leveled out over time, and test and control implants exhibited similar secondary stability at abutment operation and at the 1-year visit. Wobbling during insertion was rarely recorded for either of the implant designs. The 1-year cumulative success rate was 93.1% for test implants and 88.4% for control implants.
  
  
  CONCLUSIONS
  The modified implant design resulted in an increased primary stability, which may be important when placing implants in jaw regions of type 4 bone. However, independent of the achieved primary stability, successful implants tended to approach similar secondary stability in the two designs tested.
authors.affiliation: The Brånemark Clinic, Public Dental Health Service and Faculty of Odontology, University of Gothenburg, Gothenburg, Sweden. bertil.frigberg@vgregion.se
authors.forename: Bertil
authors.initials: B
authors.lastname: Friberg
authors.forename: Sven
authors.initials: S
authors.lastname: Jisander
authors.forename: Göran
authors.initials: G
authors.lastname: Widmark
authors.forename: AnnaKarin
authors.initials: A
authors.lastname: Lundgren
authors.forename: Carl-Johan
authors.initials: CJ
authors.lastname: Ivanoff
authors.forename: Lars
authors.initials: L
authors.lastname: Sennerby
authors.forename: Christina
authors.initials: C
authors.lastname: Thorén
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016301:Alveolar Bone Loss / Q000209:etiology; D015519:Bone Density / Q000502:physiology*; D000044:Dental Abutments; D015921:Dental Implants; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D016348:Osseointegration; D011446:Prospective Studies; D013499:Surface Properties; D019415:Torque; D016896:Treatment Outcome
chemical_list: D015921:Dental Implants