title: Comparison between complete denture and implant-retained overdenture: effect of different mucosa thickness and resiliency on stress distribution.
abstract: BACKGROUND
  The effect of different mucosa characteristics on stress distribution of complete dentures and overdentures remains unknown.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the effect of different mucosa thickness and resiliency on the stress distribution of complete dentures and implant-retained overdentures using a two-dimensional finite element analysis.
  
  
  METHODS
  Representative models of the edentulous mandible were constructed on AutoCAD software according to the groups' characteristics. In group CD, a model of the edentulous mandible supporting a complete denture was obtained while in group IO, a model of edentulous mandible supporting an overdenture over two unsplinted implants with an o' ring system was constructed. In each group, mucosa assumed three characteristics of thickness (1, 3 and 5 mm) corresponding to the resiliencies hard, resilient and soft respectively. Evaluation was performed on Ansys software with 100N vertical load applied on central incisor teeth. The principal stress was used as analysis criteria.
  
  
  RESULTS
  Group IO showed higher stress values than group CD regardless of mucosal thickness and resiliency. Stress decreased at the supporting tissues in both groups as the thickness and resiliency of mucosa increased. In relation to the supporting tissues, cortical bone showed the highest stress values.
  
  
  CONCLUSIONS
  It was concluded that the use of an attachment system increases stress values and the thickness and resiliency of mucosa influence more on these values.
authors.affiliation: UNESP-São Paulo State University, Araçatuba Dental School, Department of Dental materials and Prosthodontics, São Paulo, Brazil. wirley@foa.unesp.br
authors.forename: Wirley Gonçalves
authors.initials: WG
authors.lastname: Assunção
authors.forename: Valentim Adelino Ricardo
authors.initials: VA
authors.lastname: Barão
authors.forename: Lucas Fernando
authors.initials: LF
authors.lastname: Tabata
authors.forename: Edson Antonio Capello
authors.initials: EA
authors.lastname: de Sousa
authors.forename: Erica Alves
authors.initials: EA
authors.lastname: Gomes
authors.forename: Juliana Aparecida
authors.initials: JA
authors.lastname: Delben
mesh_terms: D000539:Alveolar Process / Q000502:physiology; D003198:Computer Simulation; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D003799:Dental Stress Analysis / Q000379:methods; D003781:Denture Retention; D003824:Denture, Complete; D003828:Denture, Overlay; D055119:Elastic Modulus; D020342:Finite Element Analysis; D006801:Humans; D008334:Mandible; D003765:Models, Dental; D009061:Mouth Mucosa / Q000033:anatomy & histology*