title: Retrospective evaluation of complete-arch fixed partial dentures connecting teeth and implant abutments in patients with normal and reduced periodontal support.
abstract: BACKGROUND
  The clinical outcome of complete-arch fixed prostheses supported by implants and natural tooth abutments in patients with normal or reduced periodontal support has been reported by few studies, with controversial results.
  
  
  OBJECTIVE
  The purpose of this study was to report on the implant success rate, prosthetic complications, and the occurrence of tooth intrusion, when complete-arch fixed prostheses, supported by a combination of implants and teeth, were fabricated for patients with normal and reduced periodontal support.
  
  
  METHODS
  Nineteen patients with residual teeth that served as abutments were consecutively treated with combined tooth- and implant-supported complete-arch fixed prostheses and were retrospectively evaluated after a period varying from 24 to 94 months. Nine patients showed reduced periodontal support as a result of periodontal disease and treatment (RPS group), and 10 patients had normal periodontal support of the abutment teeth (more than 2/3 of periodontal support [NPS group]). Ninety implants and 72 tooth abutments were used to support 19 fixed partial dentures. Screw- and cement-retained metal-ceramic and metal-resin prostheses were fabricated with rigid and nonrigid connectors. Implant survival and success rates, occurrence of caries and tooth intrusion, and prosthetic complications were recorded. The number of teeth, implants, prosthetic units, fixed partial dentures, and nonrigid connectors were compared with a t test to assess differences between the 2 groups, while data for the occurrence of intrusions and prosthetic complications were compared with the Fisher exact test (alpha=.05).
  
  
  RESULTS
  One of the 90 implants was lost (99% survival rate) over 24 to 94 months, while 3 implants showed more than 2 mm of crestal bone loss (96% success rate) over the same period. No caries were detected, but 5.6% (4/72) of the abutment teeth exhibited intrusion. Intrusion of abutment teeth was noted in 3 patients who had normal periodontal support (13% of teeth in NPS group) of the abutment teeth and was associated with nonrigid connectors. No intrusion of teeth was noted in the patients exhibiting reduced periodontal support regardless of the type of connector or when a rigid connector was used for either group. The number of intruded teeth was significantly greater in patients with intact periodontal support (P=.03).
  
  
  CONCLUSIONS
  Complete-arch fixed prosthesis supported by implant and tooth abutments may be associated with intrusion of teeth with intact periodontal support when nonrigid connectors are used to join the implant- and tooth-supported sections of the prostheses. However, fixed partial dentures supported by implants and teeth with reduced periodontal support were not associated with tooth intrusion, regardless of the type of connectors used.
authors.affiliation: Section of Periodontics and Implant Dentistry, Eastman Dental Hospital, University of Rochester Eastman Dental Center, Rochester, NY, USA. lucacordaro@uysa.net
authors.forename: Luca
authors.initials: L
authors.lastname: Cordaro
authors.forename: Carlo
authors.initials: C
authors.lastname: Ercoli
authors.forename: Carlo
authors.initials: C
authors.lastname: Rossini
authors.forename: Ferruccio
authors.initials: F
authors.lastname: Torsello
authors.forename: Changyong
authors.initials: C
authors.lastname: Feng
mesh_terms: D000328:Adult; D000368:Aged; D016301:Alveolar Bone Loss / Q000209:etiology; D002484:Cementation; D003188:Composite Resins; D000044:Dental Abutments / Q000009:adverse effects; D003731:Dental Caries / Q000209:etiology; D015921:Dental Implants / Q000009:adverse effects; D003776:Dental Porcelain; D019094:Dental Prosthesis, Implant-Supported / Q000009:adverse effects; D003834:Denture Precision Attachment; D003781:Denture Retention; D003828:Denture, Overlay; D003830:Denture, Partial, Fixed / Q000009:adverse effects; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D016876:Metal Ceramic Alloys; D008875:Middle Aged; D010510:Periodontal Diseases / Q000628:therapy*; D012189:Retrospective Studies; D014086:Tooth Mobility / Q000209:etiology; D016896:Treatment Outcome
chemical_list: D003188:Composite Resins; D015921:Dental Implants; D016876:Metal Ceramic Alloys; D003776:Dental Porcelain