title: A One-year Follow-up Study of a Tapered Hydrophilic Implant Design Using Various Placement Protocols in the Maxilla.
abstract: OBJECTIVE
  To study the clinical/radiographic outcomes and stability of a tapered implant design with a hydrophilic surface when placed in the maxilla using various protocols and followed for one year.
  
  
  METHODS
  Ninety-seven consecutive patients treated as part of daily routine in two clinics with 163 tapered implants in healed sites, in extraction sockets and together with bone augmentation procedures in the maxilla were evaluated after one year in function. Individual healing periods varying from 0 to 6 months had been used. Insertion torque (IT) and resonance frequency analysis (RFA) measurements were made at baseline. Follow-up RFA registrations were made after 6 and 12 months of loading. The marginal bone levels were measured in intraoral radiographs from baseline and after 12 months. A reference group consisting of 163 consecutive straight maxillary implants was used for the comparison of baseline IT and RFA measurements.
  
  
  RESULTS
  Five implants failed before loading, giving an implant survival rate of 96.9% and a prosthesis survival rate of 99.4% after one year. The mean marginal bone loss after one year was 0.5 mm (SD 0.4). The mean IT was statistically significantly higher for tapered than for straight reference implants (41.3 ± 12.0 Ncmvs33.6 ± 12.5 Ncm,p< 0.001). The tapered implants showed a statistically insignificantly higher mean ISQ value than the straight references implants (73.7 ± 6.4 ISQvs72.2 ± 8.0 ISQ,p=0.119). There was no correlation between IT and marginal bone loss. There was a correlation between IT and RFA measurements (p< 0.001).
  
  
  CONCLUSIONS
  The tapered implant showed a high survival rate and minimal marginal bone loss after one year in function when using various protocols for placement. The tapered implant showed significantly higher insertion torque values than straight reference implants.
authors.affiliation: Private Practice, Via S. Rocco 377, 24033 Calusco d'Adda, Italy.
authors.forename: Jakob
authors.initials: J
authors.lastname: Zwaan
authors.affiliation: Private Practice, Via Dante Alighieri 32, 20049 Concorezzo, Italy.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Vanden Bogaerde
authors.affiliation: Clinical Trials, Neoss Ltd, Mölnlycke Fabriker 3, 43535 Mölnlycke, Sweden.
authors.forename: Herman
authors.initials: H
authors.lastname: Sahlin
authors.affiliation: Department of Oral & Maxillofacial Surgery, Institute of Odontology, Sahlgrenska Academy, University of Gothenburg, Medicinaregatan 12C, Box 450, 405 30 Gothenburg, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Sennerby
keywords: Clinical follow-up study; Marginal bone loss; Radiography; Resonance frequency analysis; Tapered implant