title: Influence of restoration adjustments on prefrontal blood flow: A simplified NIRS preliminary study.
abstract: OBJECTIVE
  The aim of this study was to examine, after setting several restorations, the influence of adjusted occlusal interference during gum chewing on blood flow in the prefrontal area as determined using near-infrared spectroscopy.
  
  
  METHODS
  The physiological rate was assessed using a visual analog scale (VAS) questionnaire. We selected 16 patients who desired prosthetic restorative treatment on the lateral dentition, and eight healthy volunteers. Subjects were divided into three eight-person groups. One group received restorations on the premolar area (PA), another group received restorations on the molar area (MA), and the control group (CT) received no prosthetic restorations. The spectroscope was fastened to the frontal region of the head after placement of the final restoration, but before adjustment.
  
  
  RESULTS
  Pre-adjustment (first gum chewing for CT) blood flow in the prefrontal cortex was measured during gum chewing. Blood flow was again measured during gum chewing after the restoration (second gum chewing for CT) had been adjusted in accordance with the subjective assessment of the patient while wearing the device. The VAS provided quantification of comfort during gum chewing before and after restoration adjustment. For the PA and MA groups, adjusting restorations decreased discomfort significantly during gum chewing. Moreover, in the MA group, prefrontal blood flow was significantly reduced, and blood flow correlated with discomfort.
  
  
  CONCLUSIONS
  Activation of the prefrontal area may provide an objective criterion for judging the functionality of occlusion after prosthetic occlusal reconstruction and/or orthodontics.
authors.affiliation: Division of Orthodontics, Department of Oral Science, Kanagawa Dental University Graduate School, 82 Inaoka-cho, 238-8580 Yokosuka, Kanagawa Japan.
authors.forename: Kenichi
authors.initials: K
authors.lastname: Sasaguri
authors.affiliation: Division of Orthodontics, Department of Oral Science, Kanagawa Dental University Graduate School, 82 Inaoka-cho, 238-8580 Yokosuka, Kanagawa Japan.
authors.forename: Takero
authors.initials: T
authors.lastname: Otsuka
authors.affiliation: Division of Brain functions and Neuroscience, Department of Oral Science, Kanagawa Dental University Graduate School, Yokosuka, Kanagawa Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tsunashima
authors.affiliation: Division of Orthodontics, Department of Oral Science, Kanagawa Dental University Graduate School, 82 Inaoka-cho, 238-8580 Yokosuka, Kanagawa Japan.
authors.forename: Tateshi
authors.initials: T
authors.lastname: Shimazaki
authors.affiliation: Seijoh University Graduate School of Health Care Studies, Tokai, Aichi Japan.
authors.forename: Kin-Ya
authors.initials: KY
authors.lastname: Kubo
authors.affiliation: Department of Medical Science, Nippon Sport Science University, Kumashida-cho, Aoba-ku, Yokohama, Kanagawa Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Onozuka
keywords: Chewing; Occlusal adjustment; Prefrontal cortex; Restorations; Stress