title: Cone beam computed tomographic evaluation of implants with platform-switched Morse taper connection with the implant-abutment interface at different levels in relation to the alveolar crest.
abstract: OBJECTIVE
  The aim of this study was to evaluate marginal bone levels, with cone beam computed tomography, on the buccal and lingual aspects of implants placed with the implant-abutment interface (IAI) at different positions in relation to the alveolar crest.
  
  
  METHODS
  Thirty patients in need of single-tooth rehabilitation were randomly assigned to three groups based on the position of the IAI in relation to the buccal aspect of the alveolar crest at the time of implant placement. Patients in groups 0, 1, and 2 had their implants placed level with the buccal crest or 1 or 2 mm apical to the buccal aspect of the alveolar crest, respectively. The implants were restored with screw-retained single crowns after 4 months. Marginal bone levels on the buccal and lingual aspects of the implants were evaluated at 12 months after implant placement.
  
  
  RESULTS
  All groups of implants demonstrated significantly different crestal positions. Group 2 implants maintained the greatest subcrestal position (1.33 ± 0.86 mm) compared to the implants of group 0 (-0.04 ± 0.18 mm) and group 1 (0.34 ± 0.44 mm). There were no differences between groups in the level of the first bone-to-implant contact relative to the implant platform. Implants of group 0 exhibited less buccal bone remodeling (-0.08 ± 0.25 mm) compared to group 1 (-0.65 ± 0.45 mm) and group 2 (-0.85 ± 0.75 mm) implants. For groups 1 and 2 implants, there was a significant negative correlation between buccal wall thickness following the osteotomy and the amount of buccal bone remodeling.
  
  
  CONCLUSIONS
  In this study, different responses were seen in the buccal and lingual peri-implant bone for implants with platform-switched Morse taper connections placed with the IAI at different locations in relation to the alveolar crest.
authors.forename: Theofilos
authors.initials: T
authors.lastname: Koutouzis
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Neiva
authors.forename: Madhu
authors.initials: M
authors.lastname: Nair
authors.forename: Jörg
authors.initials: J
authors.lastname: Nonhoff
authors.forename: Tord
authors.initials: T
authors.lastname: Lundgren
mesh_terms: D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging; D000539:Alveolar Process / Q000000981:diagnostic imaging* / Q000601:surgery; D016723:Bone Remodeling / Q000502:physiology; D054893:Cone-Beam Computed Tomography / Q000379:methods*; D003442:Crowns; D059605:Dental Implant-Abutment Design; D003758:Dental Implantation, Endosseous / Q000379:methods*; D019250:Dental Implants, Single-Tooth; D019094:Dental Prosthesis, Implant-Supported; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000601:surgery; D008437:Maxilla / Q000000981:diagnostic imaging / Q000601:surgery; D008875:Middle Aged; D016348:Osseointegration / Q000502:physiology