title: The platform switching concept revisited. An experimental study in dogs.
abstract: OBJECTIVE
  To evaluate the influence of the configuration of the marginal aspect of implants placed immediately into extraction sockets on peri-implant hard tissue adaptation.
  
  
  METHODS
  In 6 Labrador dogs, endodontic treatments of the mesial roots of 1 M1 were performed and the distal roots were removed. 2 P2 was extracted as well. Implants were immediately placed in the center of the distal alveoli. Cylindrical straight implants were installed in the right side of the mandible (Control), while, in the left side, implants with a reduced diameter in the coronal portion, yielding an indentation in the surface continuity (Test), were installed. Cover screws were affixed, and the flaps were sutured to allow non-submerged healing. After 4 months of healing, histological slides were obtained for assessments.
  
  
  RESULTS
  A buccal resorption of 1.58 ± 1.28 and 1.90 ± 1.93 mm at the control and of 0.26 ± 0.90 and 0.14 ± 0.66 mm at the test sites was observed at the premolar and molar regions, respectively. The buccal coronal level of osseointegration was located apically to the margin of the smooth/rough surface border by 2.40 ± 0.90 and 3.70 ± 0.87 mm at the control sites and 1.19 ± 0.45 and 2.16 ± 0.96 mm at the test sites at the premolar and molar sites, respectively. All differences yielded statistical significance.
  
  
  CONCLUSIONS
  The use of implants with a reduced diameter in their coronal aspect may contribute to preservation of the buccal bony crest in a more coronal level compared with conventional implants. Thus, the study confirmed the efficacy of the "platform switching" concept.
authors.affiliation: Faculty of Dentistry, University of Medical Science, La Habana, Cuba; School of Dentistry, University of Padua, Padova, Italy.
authors.forename: Eriberto
authors.initials: E
authors.lastname: Bressan
authors.forename: Niklaus P
authors.initials: NP
authors.lastname: Lang
authors.forename: Boris
authors.initials: B
authors.lastname: Corazza
authors.forename: Sara
authors.initials: S
authors.lastname: Ricci
authors.forename: Zoraya
authors.initials: Z
authors.lastname: Almagro Urrutia
authors.forename: Daniele
authors.initials: D
authors.lastname: Botticelli
mesh_terms: D000818:Animals; D015921:Dental Implants; D017267:Dental Prosthesis Design; D004285:Dogs; D057893:Immediate Dental Implant Loading / Q000379:methods*; D020007:Implants, Experimental; D016348:Osseointegration; D012390:Root Canal Therapy; D013524:Surgical Flaps; D020390:Tooth Socket / Q000601:surgery; D014945:Wound Healing
chemical_list: D015921:Dental Implants
keywords: animal study; extraction socket; hard tissue; immediate implants; implant configuration; implant dentistry; peri-implant mucosa; placed immediately into extraction sockets; soft tissues