title: Effects of chewing efforts on the sensory and pain thresholds in human facial skin: a pilot study.
abstract: The aim of this study was to examine the effect of chewing efforts on sensory and pain thresholds of the orofacial skin of symptom-free subjects. Fourteen healthy volunteers were recruited. Using a stair-case method, the tactile detection threshold (TDT) and the filament-prick pain detection threshold (FPT) on the cheek skin (CS) and the skin overlying the palm side of the thenar skin (TS) were measured before and after chewing gum for 5 min (Time 1: T1) and keeping the jaw relaxed for 5 min (Time 2: T2) as a control. Both for the test and control situation, the TDT was higher in all measurement sites after 5 min. As for the FPT, the reactions between T1 and T2 were quite opposite: the FPT increased and/or remained stable in T1, while, it decreased at all sites in T2. There were significant session effects (T1-T2) on the FPT at the left CS (P<0.01), right CS (P<0.05) and TS (P<0.05). The increase of TDT after chewing/no chewing could be due to habituation, while the decrease of FPT observed in the control situation might be due to sensitization, respectively. This potential sensitization, however, was not observed after chewing efforts. Further studies are needed to clarify the modulating effect of masticatory function on the trigeminal sensory system.
authors.affiliation: Department of Clinical Physiology, Graduate School of Biomedical Sciences, Nagasaki University, 1-7-1 Sakamoto, Nagasaki, Japan. okayasu@nagasaki-u.ac.jp
authors.forename: Ichiro
authors.initials: I
authors.lastname: Okayasu
authors.forename: Osamu
authors.initials: O
authors.lastname: Komiyama
authors.forename: Noriaki
authors.initials: N
authors.lastname: Yoshida
authors.forename: Kumiko
authors.initials: K
authors.lastname: Oi
authors.forename: Antoon
authors.initials: A
authors.lastname: De Laat
mesh_terms: D000328:Adult; D002610:Cheek / Q000502:physiology; D002638:Chewing Gum; D005145:Face; D005260:Female; D006225:Hand / Q000502:physiology; D006801:Humans; D008297:Male; D008406:Masseter Muscle / Q000502:physiology; D008409:Mastication / Q000502:physiology*; D017288:Pain Threshold / Q000502:physiology*; D010865:Pilot Projects; D012684:Sensory Thresholds / Q000502:physiology*; D012879:Skin Physiological Phenomena; D013933:Thumb / Q000502:physiology; D013997:Time Factors; D014110:Touch / Q000502:physiology*; D014276:Trigeminal Nerve / Q000502:physiology
chemical_list: D002638:Chewing Gum