Study of adaptability to oral environmental changes from brain plasticity perspective

2007 Fiscal Year Final Research Report Summary

• Project/Area Number: 18390510
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 補綴理工系歯学
• Research Institution: Tohoku University
• Principal Investigator: WATANABE Makoto Tohoku University, Graduate School of Dentistry, Visiting Professor (80091768)
• Co-Investigator(Kenkyū-buntansha): TSUBOI Akito TOHOKU UNIVERSITY, Tohoku University Hospital, Associate Professor (00241646) ; ITOH Shintaro Tohoku University, Graduate School of Dentistry, Assistant Professor (00361105) ; YAMAGUCHI Satoshi TOHOKU UNIVERSITY, Tohoku University Hospital, Assistant Professor (50400263)
• Project Period (FY): 2006 – 2007
• Keywords: fMRI / motor learning / oral environment / oral function

Research Abstract

Nine subjects (mean age 28.7) underwent fMRI during chewing gum on the left side of jaw, with and without a resin cap on the lingual region of the maxillary left canine. fMRI acquisition protocol used in the present study has been optimised in our pilot study. fMRI was performed before, immediately after and 30min after applying resin cap. Six out of nine subjects were asked to masticate a wax cube on the left side of jaw in each condition to determine masticatory efficiency. fMRI data were analyzed with SPM2 (Statistical Parametric Mapping 2) to determine differences of brain activity (p=0.001 uncorrected, extent threshold=20voxels).
During left side gum chewing, bilateral cerebellar posterior lobe and the proximal part of right supramarginal gyrus were more activated immediately after applying resin cap than before applying it. The activation of cerebellum might show the activity of cerebellum during "motor learning". During left side gum chewing, right cerebellar posterior lobe were less activated 30min after applying resin cap than immediately after applying it. This result might show that the motor learning of left masticatory muscles and the adaptation to left gum chewing with regin cap were achievement.
The brain regions showing negative correlation to masticatory efficiency were bilateral postcentral gyrus, left precentral gyrus, right cingulate gyrus, right superior temporal gyrus, right cerebellar posterior lobe and right cerebellar anterior lobe. These findings suggest that right cerebellar posterior and anterior lobe were activated to achieve motor learning of left masticatory muscles to remedy reduced masticatory efficiency immediately after applying resin cap, and were less activated with the improvement of masticatory efficiency and achievement of motor learning 30min after applying resin cap.