title: An economic evaluation of maxillary implant overdentures based on six vs. four implants.
abstract: BACKGROUND
  The purpose of the present study was to assess the value for money achieved by bar-retained implant overdentures based on six implants compared with four implants as treatment alternatives for the edentulous maxilla.
  
  
  METHODS
  A Markov decision tree model was constructed and populated with parameter estimates for implant and denture failure as well as patient-centred health outcomes as available from recent literature. The decision scenario was modelled within a ten year time horizon and relied on cost reimbursement regulations of the German health care system. The cost-effectiveness threshold was identified above which the six-implant solution is preferable over the four-implant solution. Uncertainties regarding input parameters were incorporated via one-way and probabilistic sensitivity analysis based on Monte-Carlo simulation.
  
  
  RESULTS
  Within a base case scenario of average treatment complexity, the cost-effectiveness threshold was identified to be 17,564 € per year of denture satisfaction gained above of which the alternative with six implants is preferable over treatment including four implants. Sensitivity analysis yielded that, depending on the specification of model input parameters such as patients' denture satisfaction, the respective cost-effectiveness threshold varies substantially.
  
  
  CONCLUSIONS
  The results of the present study suggest that bar-retained maxillary overdentures based on six implants provide better patient satisfaction than bar-retained overdentures based on four implants but are considerably more expensive. Final judgements about value for money require more comprehensive clinical evidence including patient-centred health outcomes.
authors.affiliation: Department of Conservative Dentistry, Heidelberg University, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany. stefan.listl@med.uni-heidelberg.de.
authors.forename: Stefan
authors.initials: S
authors.lastname: Listl
authors.forename: Leonhard
authors.initials: L
authors.lastname: Fischer
authors.forename: Nikolaos Nikitas
authors.initials: NN
authors.lastname: Giannakopoulos
mesh_terms: D003362:Cost-Benefit Analysis; D003663:Decision Trees; D015921:Dental Implants / Q000191:economics* / Q000523:psychology; D019094:Dental Prosthesis, Implant-Supported / Q000191:economics* / Q000523:psychology; D019232:Dental Restoration Failure / Q000191:economics; D003781:Denture Retention / Q000191:economics / Q000295:instrumentation; D003827:Denture, Complete, Upper / Q000191:economics* / Q000523:psychology; D003828:Denture, Overlay / Q000191:economics* / Q000523:psychology; D006801:Humans; D007575:Jaw, Edentulous / Q000601:surgery*; D008390:Markov Chains; D008437:Maxilla / Q000601:surgery*; D018803:Models, Economic; D009010:Monte Carlo Method; D010347:Patient Care Planning / Q000191:economics; D057240:Patient Preference / Q000191:economics; D017060:Patient Satisfaction / Q000191:economics; D011336:Probability; D016896:Treatment Outcome
chemical_list: D015921:Dental Implants