title: Clinical performance of cements as luting agents for telescopic double crown-retained removable partial and complete overdentures.
abstract: OBJECTIVE
  The aim of this study was to investigate the survival rates and technical failures of removable prostheses (RPs) supported by telescopic double crown (TDC)-retained abutment teeth luted with zinc-phosphate or glass-ionomer cement.
  
  
  METHODS
  Clinical records of 577 patients (288 women, 289 men) who received 577 TDC-retained RPs supported by 1,807 abutments at the Department of Prosthodontics of the University Hospital Regensburg, Regensburg, Germany, between 1984 and 2007 were analyzed. The 577 prostheses included 200 attached to telescopic crowns with friction fit (FFs), 62 to conical crowns (CCs), and 315 to parallel-sided telescopic crowns with clearance fit (CFs). Survival probabilities were evaluated for the RPs, loss of cementation of the inner copings, secondary caries, and abutment teeth that required endodontic treatment using the Kaplan-Meier method. A Cox regression analysis determined the impact of covariates such as sex, denture location (maxilla/mandible), Eichner classification, number of abutment teeth, and the type of double crown system used.
  
  
  RESULTS
  The 10-year survival probability was 98.8% +/- 0.09% for FFs, 92.9% +/- 0.41% for CCs, and 86.6% +/- 0.05% for CFs. During the observation period, loss of cementation was frequently observed (FFs: 32%, CCs: 53.2%, CFs: 21.3%). After 15 years, more than 75% of patients had experienced at least one "loss of cementation" event. In this respect, zinc-oxide phosphate and glass-ionomer cements did not show any significant difference.
  
  
  CONCLUSIONS
  The long-term successful outcome of the RP experience was not compromised, although numerous clinical visits were required for maintenance. The predominant maintenance procedure was the need for recementation of the inner copings.
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: Carola
authors.initials: C
authors.lastname: Kolbeck
authors.forename: Reinhold
authors.initials: R
authors.lastname: Lang
authors.forename: Sebastian
authors.initials: S
authors.lastname: Hahnel
authors.forename: Lisa
authors.initials: L
authors.lastname: Dirschl
authors.forename: Gerhard
authors.initials: G
authors.lastname: Handel
mesh_terms: D002484:Cementation / Q000379:methods; D003442:Crowns; D000044:Dental Abutments; D003731:Dental Caries / Q000209:etiology; D003738:Dental Cements / Q000737:chemistry*; D018772:Dental Marginal Adaptation; D017267:Dental Prosthesis Design; D017269:Dental Prosthesis Repair; D003823:Denture Rebasing; D003780:Denture Repair; D003781:Denture Retention; D003824:Denture, Complete; D003828:Denture, Overlay; D003832:Denture, Partial, Removable; D005260:Female; D005500:Follow-Up Studies; D005899:Glass Ionomer Cements / Q000737:chemistry; D006801:Humans; D008297:Male; D011336:Probability; D019279:Resin Cements / Q000737:chemistry; D012189:Retrospective Studies; D012390:Root Canal Therapy; D012737:Sex Factors; D016019:Survival Analysis; D016896:Treatment Outcome; D015035:Zinc Oxide-Eugenol Cement / Q000737:chemistry; D015036:Zinc Phosphate Cement / Q000737:chemistry
chemical_list: D003738:Dental Cements; D005899:Glass Ionomer Cements; D019279:Resin Cements; D015035:Zinc Oxide-Eugenol Cement; D015036:Zinc Phosphate Cement