title: Association between occlusal curvature and masticatory movements with different test foods in human young adults with permanent dentitions.
abstract: OBJECTIVE
  Occlusal curvatures such as the curve of Spee, curve of Wilson and Monsons's sphere exist in the human adult mandibular arch. A previous study showed that human young adults with flatter occlusal curvatures had higher ability of food comminution and mixing. The aim of this study was to clarify functional significance of occlusal curvatures in terms of masticatory movements. This study investigated the association between occlusal curvature and mandibular movements while chewing a variety of food items.
  
  
  METHODS
  Forty-six young adults with complete dentitions (mean age, 25.0 years) participated in the study. Sphere radius of occlusal curvature was determined by a three-dimensional analysis of the mandibular arch based on the Broadrick flag method. Mandibular movements during unilateral chewing of six test food items (chewing gum, cheese, kamaboko, boiled beef, gummy jelly and raw carrot) until the subjects felt ready to swallow were recorded using a six-degrees-of-freedom mandibular movement recording system, and 11 parameters for masticatory movements of a lower incisal point of the mandible were analysed.
  
  
  RESULTS
  Linear regression analyses identified the sphere radius as a significant predictor for closing velocity in all test food items, occluding/cycle duration in 3 items, opening velocity, closing duration and chewing time in 2 items, and opening duration in 1 item (P<0.01). The results suggest that subjects with larger sphere radius (flatter occlusal curvature) in the mandibular arch could prepare food bolus effectively for swallowing.
  
  
  CONCLUSIONS
  Occlusal curvature seems to be associated with masticatory movements in young adults with permanent dentition.
authors.affiliation: Department of Masticatory Function Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8549, Japan. kunfu.rpro@tmd.ac.jp
authors.forename: Kenji
authors.initials: K
authors.lastname: Fueki
authors.forename: Eiko
authors.initials: E
authors.lastname: Yoshida
authors.forename: Kota
authors.initials: K
authors.lastname: Okano
authors.forename: Yoshimasa
authors.initials: Y
authors.lastname: Igarashi
mesh_terms: D000328:Adult; D000818:Animals; D001641:Bicuspid / Q000033:anatomy & histology; D001732:Bite Force; D002417:Cattle; D002611:Cheese; D002638:Chewing Gum; D003481:Cuspid / Q000033:anatomy & histology; D018552:Daucus carota; D003679:Deglutition / Q000502:physiology; D003724:Dental Arch / Q000033:anatomy & histology*; D003766:Dental Occlusion; D005260:Female; D005396:Fish Products; D029941:Fish Proteins; D005502:Food; D005782:Gels; D006244:Hardness; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D007180:Incisor / Q000033:anatomy & histology; D008297:Male; D008334:Mandible / Q000033:anatomy & histology* / Q000502:physiology; D008409:Mastication / Q000502:physiology*; D008460:Meat; D008963:Molar / Q000033:anatomy & histology; D009068:Movement; D013997:Time Factors; D055815:Young Adult
chemical_list: D002638:Chewing Gum; D029941:Fish Proteins; D005782:Gels