title: [Patterns of occlusal contacts during unilateral mastication in asymptomatic subjects].
abstract: OBJECTIVE
  To analyze occlusal contact areas on the working and nonworking sides during unilateral mastication.
  
  
  METHODS
  Eighteen subjects without any temporomandibular disorder (TMD) symptoms participated in the present study. The subjects were presented with 3 g gum for right masticating. Chewing movement was simulated using virtual craniofacial movement simulation system. Then occlusal contact areas were calculated at four selected moments during the closing phase in the third chewing cycle: the occurrence of occlusal contact, one third time, two thirds time, the intercuspal occlusion.
  
  
  RESULTS
  During the closing phase in the third chewing cycle, the total occlusal contact areas on working side increased from (9.3+/-0.4) mm2 to (39.2+/-1.2) mm2, and that on nonworking side increased from (2.3 +/-0.5) mm2 to (40.3+/-1.2) mm2. At the occurrence of occlusal contacts, occlusal contact areas of the first and second mandibular molars were on average (3.7+/-0.2) mm2 and (3.5+/-0.2) mm2 on working side, and (0.5+/-0.2) mm2 and (1.2+/-0.3) mm2 on nonworking side, respectively. However, when the mandible moved to the intercuspal position, their areas were sharply increased to (14.8+/-0.7) mm2 and (13.9+/-0.4) mm2 on working side, and (13.6+/-0.5) mm2 and (12.1+/-0.5) mm2 on nonworking side, respectively. In addition, nonworking-side contacts were observed for 12 subjects at the occurrence of occlusal contacts, and for all subjects at two thirds time.
  
  
  CONCLUSIONS
  This paper provides a new method useful for analyzing occlusal contacts during functional movements. This study revealed the pattern of occlusal contacts during the closing phase in the chewing cycle. Moreover, it was confirmed that nonworking-side contacts occurred during unilateral mastication.
authors.affiliation: Department of Prosthodontics, Peking University School and Hospital of Stomatology, Beijing 100081, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.forename: Hai-lan
authors.initials: HL
authors.lastname: Feng
authors.forename: Feng-jun
authors.initials: FJ
authors.lastname: Zhang
mesh_terms: D000328:Adult; D002638:Chewing Gum; D003766:Dental Occlusion; D005260:Female; D006801:Humans; D008297:Male; D008334:Mandible / Q000502:physiology*; D008409:Mastication / Q000502:physiology*; D008963:Molar / Q000502:physiology; D055815:Young Adult
chemical_list: D002638:Chewing Gum