title: The effect of one-time abutment placement on interproximal bone levels and peri-implant soft tissues: a prospective randomized clinical trial.
abstract: OBJECTIVE
  To compare the effect of placing the definitive abutment at the time of implant placement versus at a later stage, on the soft and hard tissue changes around dental implants.
  
  
  METHODS
  Platform-switched implants were placed in the posterior maxilla or mandible of partial edentulous patients and they were randomized to receive the definitive abutment at the moment of implant placement, or 6-12 weeks later. Final prostheses were delivered 2-4 weeks later. Radiographic assessment of vertical bone level changes (primary outcome), clinical status of peri-implant tissues, changes in soft tissues margin, papilla filling, patient-related outcomes and adverse events were assessed 6 and 12 months after loading.
  
  
  RESULTS
  60 implants were placed in 40 patients, replacing single or multiple absent teeth. One implant was lost 1 week after insertion (overall survival rate: 98.3%). A statistically significant greater bone resorption from surgery to 6 months post-loading was observed for those implants subjected to abutment change (control group: -1.24 ± 0.79 mm; test group: -0.61 ± 0.40 mm; P = 0.028). Periodontal clinical parameters and patient-related outcomes, however, did not demonstrate significant differences between groups at any time point. A significant increase in papilla height was observed from loading to 12 months in all implants (control group: 1.17 ± 1.47 mm; test group: 0.98 ± 0.89 mm) and a slight but not significant coronal migration of the gingival margin.
  
  
  CONCLUSIONS
  The connection and disconnection of healing abutments is associated with significantly increased bone loss during the healing period between implant placement and 6 months post-loading, when compared to one-time abutment placement.
authors.affiliation: Section of Graduate Periodontology, University Complutense, Madrid, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Molina
authors.affiliation: Section of Graduate Periodontology, University Complutense, Madrid, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Sanz-Sánchez
authors.affiliation: Section of Graduate Orthodontics, University Complutense, Madrid, Spain.
authors.forename: Conchita
authors.initials: C
authors.lastname: Martín
authors.affiliation: Section of Graduate Periodontology, University of Santiago de Compostela, A Coruña, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Blanco
authors.affiliation: Section of Graduate Periodontology, University Complutense, Madrid, Spain.|ETEP (Etiology and Therapy of Periodontal Diseases) Research Group, University Complutense, Madrid, Spain.
authors.forename: Mariano
authors.initials: M
authors.lastname: Sanz
mesh_terms: D000328:Adult; D000368:Aged; D016301:Alveolar Bone Loss / Q000175:diagnosis* / Q000503:physiopathology; D000044:Dental Abutments; D059605:Dental Implant-Abutment Design; D003758:Dental Implantation, Endosseous; D019250:Dental Implants, Single-Tooth; D005260:Female; D005500:Follow-Up Studies; D005881:Gingiva / Q000503:physiopathology; D006801:Humans; D008297:Male; D008334:Mandible / Q000601:surgery; D008437:Maxilla / Q000601:surgery; D008875:Middle Aged; D016348:Osseointegration / Q000502:physiology*; D011183:Postoperative Complications / Q000175:diagnosis* / Q000503:physiopathology; D011446:Prospective Studies; D012086:Reoperation
keywords: alveolar bone loss; dental implant-abutment design; dental implants; patient outcome assessment; platform switching; randomized controlled trial