title: Validation of the Eichner index in relation to occlusal force and masticatory performance.
abstract: OBJECTIVE
  Eichner Indices (A, B, and C), especially the Eichner subgroups (A1-A3, B1-B4, C1-C3), have not been validated in relation to oral functions. The purpose of this study was to investigate the association of posterior occlusal contact loss with occlusal force and masticatory performance in subjects who had a normal dentition or partially edentulous arches restored with removable prostheses.
  
  
  METHODS
  The study sample consisted of 1,288 independently living patients over the age of 60 years. Subjects were grouped into 10 subgroups by posterior occlusal contacts according to the Eichner Index. Bilateral maximum occlusal force in the intercuspal position was measured using pressure-sensitive sheets. Masticatory performance was determined by the concentration of dissolved glucose obtained from comminuted gummy jellies.
  
  
  RESULTS
  Occlusal force and masticatory performance were significantly associated with posterior occlusal contacts. Occlusal force measured in subgroups A2 to B2 and B3 to C3 did not differ statistically, although overall occlusal force decreased significantly as the loss of occlusal contacts increased. Similarly, masticatory performance was reduced with decreasing occlusal contact, although the decline was more gradual. Masticatory performance among subgroups A1 to B1, A3 to B2, B2 to B3, B4 to C2, and C1 to C3 did not differ significantly.
  
  
  CONCLUSIONS
  The Eichner Index subgroups were significantly associated with reduced oral functions, even if the teeth were restored with removable prostheses. Preservation of occlusal contacts of the bilateral (B2) and unilateral (B3) premolars was critical for occlusal force and masticatory performance, respectively.
authors.affiliation: Department of Prosthodontics and Oral Rehabilitation, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita, Osaka, Japan. ikebe@dent.osaka-u.ac.jp
authors.forename: Kazunoir
authors.initials: K
authors.lastname: Ikebe
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Matsuda
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Murai
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Maeda
authors.forename: Takashi
authors.initials: T
authors.lastname: Nokubi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001641:Bicuspid / Q000502:physiology; D001732:Bite Force; D003430:Cross-Sectional Studies; D003442:Crowns; D003817:Dentition; D003824:Denture, Complete; D003832:Denture, Partial, Removable; D005260:Female; D006801:Humans; D007574:Jaw Relation Record; D007575:Jaw, Edentulous / Q000503:physiopathology / Q000534:rehabilitation; D007576:Jaw, Edentulous, Partially / Q000145:classification* / Q000503:physiopathology / Q000534:rehabilitation; D008297:Male; D008409:Mastication / Q000502:physiology*; D008875:Middle Aged; D008963:Molar / Q000502:physiology