title: Clinical performance of cast clasp-retained removable partial dentures: a retrospective study.
abstract: OBJECTIVE
  This retrospective study investigated the survival rate of 174 clasp-retained removable partial dentures (CR-RPDs) made at the Department of Prosthodontics of the Regensburg University Medical Center over a 25-year period (1984 to 2009).
  
  
  METHODS
  The study analyzed the frequency of and time to the fracture of clasps, connectors, or denture bases; the occurrence of caries or periodontal lesions; the loss of abutment teeth; and the necessity of maintenance procedures such as relining or treatment of pressure areas.
  
  
  RESULTS
  The median follow-up time of 3 years was calculated using the inverse Kaplan-Meier method. The 5-year survival rate (time to renewal) of all CR-RPDs was 96.4%; the 10-year survival rate was 89.8%. Fractures most frequently occurred in clasps (n = 28, 16.1%) followed by major connectors (n = 9, 5.1%) and minor connectors (n = 6, 3.4%). The 5-year event-free rate for clasp fracture was 80.4%; the 10-year event-free rate was 76.9%. Caries lesions on abutment teeth were seen in 31.6% of patients, and 35.6% showed inflammation of the periodontal tissue surrounding the abutment teeth. The 5-year event-free rate for caries was 58.4%; the 10-year rate was 39.6%. A frequent complication was loss of abutment teeth (n = 15), but this complication was not age-dependent. After insertion of their prostheses, one-third of patients (n = 53, 30.5%) showed pressure areas of the mucosa. Significantly more (P < .001) pressure areas were caused by prostheses of the mandible (39.6%) than by those of the maxilla (12.5%).
  
  
  CONCLUSIONS
  CR-RPDs showed a survival rate of approximately 90% after 10 years of oral service. The predominant complications during oral service were caries lesions, loss of abutment teeth, and fracture of clasps.
authors.affiliation: Department of Prosthodontics, Regensburg University Medical Center, Regensburg, Germany. michael.behr@klinik.uni-regensburg.de
authors.forename: Michael
authors.initials: M
authors.lastname: Behr
authors.forename: Florian
authors.initials: F
authors.lastname: Zeman
authors.forename: Torsten
authors.initials: T
authors.lastname: Passauer
authors.forename: Michael
authors.initials: M
authors.lastname: Koller
authors.forename: Sebastian
authors.initials: S
authors.lastname: Hahnel
authors.forename: Ralf
authors.initials: R
authors.lastname: Buergers
authors.forename: Reinhold
authors.initials: R
authors.lastname: Lang
authors.forename: Gerhard
authors.initials: G
authors.lastname: Handel
authors.forename: Carola
authors.initials: C
authors.lastname: Kolbeck
mesh_terms: D000044:Dental Abutments; D003731:Dental Caries / Q000145:classification; D016734:Dental Clasps; D019232:Dental Restoration Failure; D003819:Denture Bases; D003823:Denture Rebasing; D003832:Denture, Partial, Removable; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007576:Jaw, Edentulous, Partially / Q000145:classification / Q000534:rehabilitation; D008297:Male; D008334:Mandible; D008437:Maxilla; D008875:Middle Aged; D010518:Periodontitis / Q000145:classification; D012189:Retrospective Studies; D016019:Survival Analysis; D016388:Tooth Loss / Q000145:classification