title: Conometric retention for complete fixed prosthesis supported by four implants: 2-years prospective study.
abstract: OBJECTIVE
  The aim of this study was to verify the reliability of a conometric system for a fixed retention of complete prostheses (CPs) on four implants followed for 2 years.
  
  
  METHODS
  Twenty-five patients received four implants and only one CPs for a total of 100 implants followed. Each prosthesis was supported by four implants. An immediate loading surgical protocol was used. The CPs were provided to be fixed to conometric abutments without prostheses removal by the patients, to test this retention for a fixed instead of a removable rehabilitation. Clinical and radiographical parameters were assessed at the yearly follow-up visit. A follow-up of 2 years was observed for each patient. Moreover, biological and technical complications were recorded. Changes overtime of clinical and radiographic parameters were analyzed as well as the satisfaction degree for each patient.
  
  
  RESULTS
  No patient was classified as "dropout." The following results were observed after 2 years of follow-up: all the implants supporting the 25 CPs completed the follow-up examination. No implant, reconstruction, and abutment failure were recorded; therefore, the prosthetic survival was 100% for all the abutments and restorations. No significant differences in biological indexes were observed when compared with the baseline. No significant change of the mean marginal bone level (MBL) was found between the baseline and the last follow-up. No loss of retention was recorded for the CPs. No technical complications referred to abutments and frameworks were observed: a prosthetic survival rate of 100% can be recorded. Mucositis was recorded for two implants and successfully treated with interceptive supportive therapy. No significant differences (P < 0.05) were found between plaque index and MBi parameters at baseline and after 2 years of function. Similar results were recorded for the mean probing pocket depth Index at baseline (1.2 mm with SD of 0.3 mm) and after 2 years of function (1.2 mm with SD of 0.2 mm).
  
  
  CONCLUSIONS
  The present implant-supported conometric retention system can be used to give a fixed retention to a CPs supported by four implants immediately loaded. Furthermore, costs reduction and simplified treatment procedures were provided by such a clinical approach.
authors: Department of Oral Surgery, Dental Clinic, School of Dentistry, University of Padova, Padova, Italy.
authors: Eriberto
authors: E
authors: Bressan
authors: Diego
authors: D
authors: Lops
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000044:Dental Abutments; D015921:Dental Implants; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007575:Jaw, Edentulous / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000601:surgery; D008875:Middle Aged; D011446:Prospective Studies; D011862:Radiography, Panoramic; D015203:Reproducibility of Results; D016896:Treatment Outcome
chemical_list: D015921:Dental Implants
keywords: conometric retention; dental implants; edentulous mandible; fixed prosthesis