title: Multicenter randomized clinical trial: early loading of implants in maxillary bone.
abstract: OBJECTIVE
  The aim of this study was to show prognostic equivalence between implant loading in the maxilla after 12 weeks versus 4 weeks.
  
  
  METHODS
  One hundred four patients, from four centers in this open-labeled randomized multicenter prospective controlled clinical trial, were assigned to either 12 weeks or 4 weeks of unloaded healing. Two hundred sixty-nine implants (sand blasted large-grid, acid etched [SLA] surface, ≥ 4.1 mm diameter; ≥ 10 mm length) were inserted and evaluated during an individual 5-year follow-up. Primary outcome was implant success after 12 months; prognostic equivalence was characterized by a maximum difference of ± 5% in implant failure rates.
  
  
  RESULTS
  Implant-wise 1-year failure rates were estimated 3.1% (5/163 implants) in the 4 weeks group versus 3.6% (4/112 implants) in the 12 weeks group (95% confidence interval [CI] for the difference -3.2 -+4.2%); implant-wise evaluation demonstrated statistically significant prognostic equivalence of 4 and 12 weeks loading. Patient-wise 1-year failure rates were estimated 6.7% (n = 4 patients) in the 4 weeks group versus 5.1% (n = 2 patients) in the 12 weeks group (95% CI for the difference -9.6 -+6.5%). All implant failures occurred within the first 3 months of the individual observation period. Prior bone augmentation, underdimensioned drilling, bone quality, implant type, implant length, implant diameter, residual teeth, and fixing of the restoration did not reveal associations with the implant outcome: trial site, posterior jaw region, and splinting were associated with a higher failure rate. Resonance frequency analysis did not serve as a predictor of implant failures at the time of implant insertion.
  
  
  CONCLUSIONS
  Loading of standard SLA implants in the maxilla 4 weeks versus 12 weeks after insertion resulted in statistically equivalent failure patterns within a 1-year follow-up period; nevertheless, the observed patient-wise failure patterns of the interim analysis requires further understanding of patient-individual aspects of the early loading concept.
authors.affiliation: Medical director, Department of Oral and Maxillofacial Surgery, Plastic Operations, University Medical Center of the J. Gutenberg University, Mainz, Germany; head of department, Department of Medical Biometry and Epidemiology, Faculty for Health, Witten/Herdecke University, Witten, Germany; private practice, Münster, Germany; medical director, Department of Cranio-Maxillofacial Surgery, University Hospital Muenster, Muenster, Germany; head of department, Department of Maxillofacial Surgery, University of Erlangen, Erlangen, Germany; private practice, Stuttgart, Germany; medical director, Department of Maxillofacial Surgery, University of Erlangen, Erlangen, Germany; head of department, Department for Oral and Maxillofacial Surgery, Katharinenhospital, Stuttgart, Germany; head of department, Department of Oral and Maxillofacial Surgery, Plastic Operations, University Medical Center of the J. Gutenberg University, Mainz, Germany.
authors.forename: Bilal
authors.initials: B
authors.lastname: Al-Nawas
authors.forename: Frank
authors.initials: F
authors.lastname: Krummenauer
authors.forename: André
authors.initials: A
authors.lastname: Büchter
authors.forename: Johannes
authors.initials: J
authors.lastname: Kleinheinz
authors.forename: Friedrich
authors.initials: F
authors.lastname: Neukam
authors.forename: Guido
authors.initials: G
authors.lastname: Petrin
authors.forename: Karl Andreas
authors.initials: KA
authors.lastname: Schlegel
authors.forename: Dieter
authors.initials: D
authors.lastname: Weingart
authors.forename: Wilfried
authors.initials: W
authors.lastname: Wagner
mesh_terms: D015921:Dental Implants; D019544:Equipment Failure Analysis; D006801:Humans; D008437:Maxilla; D016896:Treatment Outcome
chemical_list: D015921:Dental Implants