title: Ongoing Crestal Bone Loss around Implants Subjected to Computer-Guided Flapless Surgery and Immediate Loading Using the All-on-4® Concept.
abstract: BACKGROUND
  The All-on-4(®) concept is widely applied for full-arch rehabilitations, using two tilted and two axially loaded implants in order to overcome anatomical constraints.
  
  
  OBJECTIVE
  The aim of this study was to assess the survival and individual success of implants immediately loaded with an All-on-4 full-arch screw-retained prosthetic bridge in fully edentulous mandibles or maxillae over up to 3 years.
  
  
  METHODS
  In total, 20 patients with atrophic jaws (9 maxillae, 11 mandibles) were treated with computer-guided flapless surgery and immediately provided with a provisional bridge. The final prosthesis was delivered after 6 months. In total, 80 TiUnite(™) Brånemark implants were placed. Radiographs were taken after surgery and 1 and 3 years later.
  
  
  RESULTS
  A 3-year survival rate of 100% was seen for all implants, both in lower and in upper jaw. None of the temporary or definite prostheses were lost over the follow-up period of 3 years. After 1 year, the mean bone loss was 1.13 mm (SD 0.94; range -0.1 to 3.8), and after 3 years, it was 1.61 mm (SD 1.40; range 0 to 5). The mean bone loss between the 1-year and 3-year follow-ups was 0.48 mm (SD 0.66; range -1.2 to 3.6). This difference was statistically significant (p < .001), indicative of ongoing bone loss. Twenty-six percent of the implants had bone loss above 1.5 mm after 1 year, but after 3 years, 30% of the implants had already lost more than 1.9 mm.
  
  
  CONCLUSIONS
  The implant and prosthetic survival was 100%, and patients benefited from the All-on-4 treatment. However, unacceptable ongoing bone loss was seen in 49.2% of the patients; this may be a warning sign for future problems and needs clinical attention. Overloading and surgery-related aspects need to be investigated as potential explanations.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Dental School, Faculty of Medicine and Health Sciences, University of Ghent, University Hospital Ghent, Ghent, Belgium.
authors.forename: Hilde
authors.initials: H
authors.lastname: Browaeys
authors.affiliation: Department of Periodontology and Oral Implantology, Dental School, Faculty of Medicine and Health Sciences, University of Ghent, University Hospital Ghent, Ghent, Belgium.
authors.forename: Melissa
authors.initials: M
authors.lastname: Dierens
authors.affiliation: Department of Periodontology and Oral Implantology, Dental School, Faculty of Medicine and Health Sciences, University of Ghent, University Hospital Ghent, Ghent, Belgium.
authors.forename: Christian
authors.initials: C
authors.lastname: Ruyffelaert
authors.affiliation: Department of Periodontology and Oral Implantology, Dental School, Faculty of Medicine and Health Sciences, University of Ghent, University Hospital Ghent, Ghent, Belgium.
authors.forename: Carine
authors.initials: C
authors.lastname: Matthijs
authors.affiliation: Department of Periodontology and Oral Implantology, Dental School, Faculty of Medicine and Health Sciences, University of Ghent, University Hospital Ghent, Ghent, Belgium.|Department of Prosthodontics, School of Dentistry, Malmö University, Malmö, Sweden.
authors.forename: Hugo
authors.initials: H
authors.lastname: De Bruyn
authors.affiliation: Department of Periodontology and Oral Implantology, Dental School, Faculty of Medicine and Health Sciences, University of Ghent, University Hospital Ghent, Ghent, Belgium.
authors.forename: Stefan
authors.initials: S
authors.lastname: Vandeweghe
mesh_terms: D000328:Adult; D000368:Aged; D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging / Q000453:epidemiology*; D015921:Dental Implants; D005260:Female; D006801:Humans; D057893:Immediate Dental Implant Loading / Q000706:statistics & numerical data; D007575:Jaw, Edentulous / Q000601:surgery*; D008297:Male; D008334:Mandible / Q000601:surgery*; D008437:Maxilla / Q000601:surgery*; D008875:Middle Aged; D011446:Prospective Studies
chemical_list: D015921:Dental Implants
keywords: All-on-4; bone level; bone remodeling; immediate loading; one-stage surgery; prosthetic complications; success