title: Masseter muscle thickness, chewing efficiency and bite force in edentulous patients with fixed and removable implant-supported prostheses: a cross-sectional multicenter study.
abstract: OBJECTIVE
  Edentulous patients may be restored with conventional dentures (C/C), implant-supported overdentures (IOD) or implant-supported fixed dental prostheses (IFDP). Null-hypotheses: chewing efficiency, maximum voluntary bite force (MBF) and masseter muscle thickness (MMT) are lower in patients with C/IOD compared with the patients with bimaxillary IFDPs. Both groups perform better than C/C and are inferior to fully dentate controls.
  
  
  METHODS
  Ethical approval was obtained. For this multicenter cross-sectional study, 80 patients were recruited. Four groups of different dental states comprised of either implant-supported prostheses (C/IOD and IFDP/IFDP) or served as control-groups (C/C and fully dentate D/D). Chewing efficiency was assessed with a two-colour mixing ability test. MBF was measured bilaterally with a force gauge. Two dimensional ultrasonography was used to measure MMT bilaterally.
  
  
  RESULTS
  Chewing efficiency in C/IOD and IFDP/IFDP (difference NS) was better than in C/C, but not as good as in D/D. MBF in C/IOD was lower than in IFDP/IFDP. Chewing efficiency and MBF were significantly lower in IFDP/IFDP, who had experienced chipping or fracture of the prosthetic superstructure. Median MMT of patients with implant-supported prostheses was between those with C/C and fully dentate participants. There was no significant difference in MMT between C/IOD and IFDP/IFDP.
  
  
  CONCLUSIONS
  Supporting complete prostheses with oral implants seems to have positive effects on the thickness of the masseter muscle, maximum bite force as well as chewing efficiency. The type of implant-supported prostheses may have an influence on the magnitude of the effect.
authors.affiliation: Division of Gerodontology and Removable Prosthodontics, University of Geneva, Geneva, SwitzerlandDepartment of Rehabilitation and Geriatrics, University Hospitals of Geneva, Thonex, SwitzerlandDepartment of Periodontology, Oral Surgery, Oral Medicine, University Complutense Madrid, Madrid, SpainDepartment of Maxillofacial Surgery, Plastic Surgery and Centre of Oral Implantology, Katharinen Hospital, Stuttgart, GermanyDivision of Fixed Prosthodontics and Occlusion, University of Geneva, Geneva, Switzerland.
authors.forename: Frauke
authors.initials: F
authors.lastname: Müller
authors.affiliation: Division of Gerodontology and Removable Prosthodontics, University of Geneva, Geneva, SwitzerlandDepartment of Rehabilitation and Geriatrics, University Hospitals of Geneva, Thonex, SwitzerlandDepartment of Periodontology, Oral Surgery, Oral Medicine, University Complutense Madrid, Madrid, SpainDepartment of Maxillofacial Surgery, Plastic Surgery and Centre of Oral Implantology, Katharinen Hospital, Stuttgart, GermanyDivision of Fixed Prosthodontics and Occlusion, University of Geneva, Geneva, Switzerland.
authors.forename: Marta
authors.initials: M
authors.lastname: Hernandez
authors.affiliation: Division of Gerodontology and Removable Prosthodontics, University of Geneva, Geneva, SwitzerlandDepartment of Rehabilitation and Geriatrics, University Hospitals of Geneva, Thonex, SwitzerlandDepartment of Periodontology, Oral Surgery, Oral Medicine, University Complutense Madrid, Madrid, SpainDepartment of Maxillofacial Surgery, Plastic Surgery and Centre of Oral Implantology, Katharinen Hospital, Stuttgart, GermanyDivision of Fixed Prosthodontics and Occlusion, University of Geneva, Geneva, Switzerland.
authors.forename: Linda
authors.initials: L
authors.lastname: Grütter
authors.affiliation: Division of Gerodontology and Removable Prosthodontics, University of Geneva, Geneva, SwitzerlandDepartment of Rehabilitation and Geriatrics, University Hospitals of Geneva, Thonex, SwitzerlandDepartment of Periodontology, Oral Surgery, Oral Medicine, University Complutense Madrid, Madrid, SpainDepartment of Maxillofacial Surgery, Plastic Surgery and Centre of Oral Implantology, Katharinen Hospital, Stuttgart, GermanyDivision of Fixed Prosthodontics and Occlusion, University of Geneva, Geneva, Switzerland.
authors.forename: Luis
authors.initials: L
authors.lastname: Aracil-Kessler
authors.affiliation: Division of Gerodontology and Removable Prosthodontics, University of Geneva, Geneva, SwitzerlandDepartment of Rehabilitation and Geriatrics, University Hospitals of Geneva, Thonex, SwitzerlandDepartment of Periodontology, Oral Surgery, Oral Medicine, University Complutense Madrid, Madrid, SpainDepartment of Maxillofacial Surgery, Plastic Surgery and Centre of Oral Implantology, Katharinen Hospital, Stuttgart, GermanyDivision of Fixed Prosthodontics and Occlusion, University of Geneva, Geneva, Switzerland.
authors.forename: Dieter
authors.initials: D
authors.lastname: Weingart
authors.affiliation: Division of Gerodontology and Removable Prosthodontics, University of Geneva, Geneva, SwitzerlandDepartment of Rehabilitation and Geriatrics, University Hospitals of Geneva, Thonex, SwitzerlandDepartment of Periodontology, Oral Surgery, Oral Medicine, University Complutense Madrid, Madrid, SpainDepartment of Maxillofacial Surgery, Plastic Surgery and Centre of Oral Implantology, Katharinen Hospital, Stuttgart, GermanyDivision of Fixed Prosthodontics and Occlusion, University of Geneva, Geneva, Switzerland.
authors.forename: Martin
authors.initials: M
authors.lastname: Schimmel
mesh_terms: D000368:Aged; D001732:Bite Force; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D019094:Dental Prosthesis, Implant-Supported; D003828:Denture, Overlay; D003830:Denture, Partial, Fixed; D005260:Female; D006801:Humans; D008297:Male; D008406:Masseter Muscle / Q000000981:diagnostic imaging / Q000502:physiology*; D008409:Mastication / Q000502:physiology*; D008875:Middle Aged; D009066:Mouth, Edentulous / Q000534:rehabilitation*; D018709:Statistics, Nonparametric; D014463:Ultrasonography