title: Alterations in intraoral manipulation and splitting of food by subjects with tooth- or implant-supported fixed prostheses.
abstract: OBJECTIVE
  Sensory information provided by the periodontal mechanoreceptors (PMRs) is used by the nervous system to optimize the positioning of food, force levels, and force vectors involved in biting. The aim of this study was to describe motor performance during a novel manipulation-and-split task and to assess the extent to which control of this performance involves information from the PMRs.
  
  
  METHODS
  A total of 10 subjects with natural teeth, 10 with bimaxillary tooth-supported fixed prostheses (TSP) and 10 with bimaxillary implant-supported fixed prostheses (ISP) (61-83 [mean 69] years of age) were asked to perform an intraoral manipulation-and-split task that involved positioning a spherical chocolate dragée between the front teeth and then splitting it into two parts of equal size. The vertical jaw movement, sound of food cracking and masseter muscle activity were monitored during this task and the accuracy of the split was evaluated.
  
  
  RESULTS
  The group with natural teeth was significantly better than the other groups at splitting the candy with high precision. The jaw movements were similar between groups, but the contact phase prior to the split was significantly longer for those with natural dentition.
  
  
  CONCLUSIONS
  The present findings support the conclusion that the nervous system collects rich information about contact between the teeth and food from the PMRs prior to powerful jaw action. Impairment (TSP) or absence (ISP) of this information alters motor behavior and impairs performance during the natural biting task employed here.
authors.affiliation: Department of Dental Medicine, Karolinska Institutet, Huddinge, Sweden. krister.svensson@ki.se
authors.forename: Krister G
authors.initials: KG
authors.lastname: Svensson
authors.forename: Joannis
authors.initials: J
authors.lastname: Grigoriadis
authors.forename: Mats
authors.initials: M
authors.lastname: Trulsson
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019094:Dental Prosthesis, Implant-Supported; D005260:Female; D006801:Humans; D008297:Male; D008406:Masseter Muscle / Q000502:physiology; D008409:Mastication / Q000502:physiology*; D008465:Mechanoreceptors / Q000502:physiology*; D008875:Middle Aged