title: Improvement of oral health-related quality-of-life by use of different kinds of double-crown-retained removable partial dentures.
abstract: OBJECTIVE
  To verify the hypotheses that treatment with double-crown-retained removable partial dentures (RPDs) improves oral health-related quality-of life (OHRQoL) over a 36-month period and that the performance of RPDs retained by use of electroplated double crowns (EP-RPDs) was different to that of RPDs retained by use of cast double crowns (C-RPDs).
  
  
  METHODS
  Fifty-four patients (mean age = 64 years, 63% men) were recruited and randomly assigned to C-RPD or EP-RPD. OHRQoL was assessed pre-treatment, post-treatment and 6, 12, 24 and 36 months after insertion, by use of the oral health impact profile (OHIP). An unweighted total score was calculated (OHIP-SUM). A two-level hierarchical model was used for statistical analysis. First-level units were the measurements on the six occasions; second-level units were the patients.
  
  
  RESULTS
  Improvement of OHRQoL was observed in both groups after treatment (t = 7.27, p < 0.001). Whereas a treatment-material interaction indicated that treatment with EP-RPDs resulted in greater immediate improvement of OHRQoL, a time-material interaction indicated that long-term improvement was greater for C-RPDs.
  
  
  CONCLUSIONS
  Treatment with EP-RPDs and C-RPDs improved OHRQoL initially. Over a period of 36 months the effect was significant. The treatment is, therefore, a promising therapeutic option. The cast conical design seems to have advantages with regard to long-term OHRQoL.
authors.affiliation: a 1 Department of Prosthodontics, University Hospital Heidelberg , Heidelberg, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Stober
authors.affiliation: b 2 Gesis-Leibniz-Institute for the Social Sciences , Mannheim, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Danner
authors.affiliation: a 1 Department of Prosthodontics, University Hospital Heidelberg , Heidelberg, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Bömicke
authors.affiliation: a 1 Department of Prosthodontics, University Hospital Heidelberg , Heidelberg, Germany.
authors.forename: Alexander J
authors.initials: AJ
authors.lastname: Hassel
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D002858:Chromium Alloys / Q000737:chemistry; D003442:Crowns; D000044:Dental Abutments; D003722:Dental Alloys / Q000737:chemistry; D003735:Dental Casting Technique; D017267:Dental Prosthesis Design; D003781:Denture Retention; D003828:Denture, Overlay; D003832:Denture, Partial, Removable; D004595:Electroplating; D005500:Follow-Up Studies; D009909:Oral Health; D011446:Prospective Studies; D011788:Quality of Life; D011897:Random Allocation
chemical_list: D002858:Chromium Alloys; D003722:Dental Alloys
keywords: electroplating; quality-of-life; removable partial dentures; telescopic crowns