title: Influence of Palatal Coverage and Implant Distribution on Implant Strain in Maxillary Implant Overdentures.
abstract: OBJECTIVE
  Maxillary implant overdentures are often used in clinical practice. However, there is no agreement or established guidelines regarding prosthetic design or optimal implant placement configuration. The purpose of this study was to examine the influence of palatal coverage and implant number and distribution in relation to impact strain under maxillary implant overdentures.
  
  
  METHODS
  A maxillary edentulous model with implants and experimental overdentures with and without palatal coverage was fabricated. Four strain gauges were attached to each implant, and they were positioned in the anterior, premolar, and molar areas. A vertical occlusal load of 98 N was applied through a mandibular complete denture, and the implant strains were compared using one-way analysis of variance (P = .05).
  
  
  RESULTS
  The palatolabial strain was much higher on anterior implants than on other implants in both denture types. Although there was no significant difference between the strain under dentures with and without palatal coverage, palateless dentures tended to result in higher implant strain than dentures with palatal coverage. Dentures supported by only two implants registered higher strain than those supported by four or six implants.
  
  
  CONCLUSIONS
  Implants under palateless dentures registered higher strain than those under dentures with palatal coverage. Anterior implants exhibited higher palatolabial strain than other implants regardless of palatal coverage and implant configuration; it is therefore recommended that maxillary implant overdentures should be supported by six implants with support extending to the distal end of the arch.
authors.forename: Toshihito
authors.initials: T
authors.lastname: Takahashi
authors.forename: Tomoya
authors.initials: T
authors.lastname: Gonda
authors.forename: Yoko
authors.initials: Y
authors.lastname: Mizuno
authors.forename: Yozo
authors.initials: Y
authors.lastname: Fujinami
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Maeda
mesh_terms: D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D019094:Dental Prosthesis, Implant-Supported; D003799:Dental Stress Analysis; D003779:Denture Design; D003827:Denture, Complete, Upper; D003828:Denture, Overlay; D006801:Humans; D008437:Maxilla / Q000601:surgery*; D008954:Models, Biological; D009066:Mouth, Edentulous / Q000601:surgery*; D010159:Palate; D013314:Stress, Mechanical
chemical_list: D015921:Dental Implants