Effects of obesity-induced adipocytokine system metabolic abnormalities on orthodontic tooth movement during growth.

2023 Fiscal Year Final Research Report

• Project/Area Number: 19K19286
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 57070:Developmental dentistry-related
• Research Institution: Tokyo Medical and Dental University
• Principal Investigator: Kato Chiho 東京医科歯科大学, 東京医科歯科大学病院, 助教 (80706987)
• Project Period (FY): 2019-04-01 – 2024-03-31
• Keywords: 肥満 / 矯正 / 咀嚼運動

Outline of Final Research Achievements

This study investigated rhythmic jaw movement (RJM) patterns and masticatory muscle activities during electrical stimulation in obese male Zucker rats (OZRs), compared to lean male Zucker rats (LZRs). At the age of 10 weeks, electromyographic (EMG) activity of the right anterior digastric muscle (RAD) and masseter muscles, and RJMs were recorded during repetitive intracortical micro-stimulation in the left anterior and posterior parts of the cortical masticatory area (A-area and P-area, respectively).During P-area stimulation, the jaw-opening duration was significantly shorter (p<0.01) in OZRs than LZRs, the jaw-opening speed was significantly faster in OZRs than LZRs, and the RAD EMG duration was significantly shorter (p<0.01) in OZRs than LZR. This study shows that obesity affects the coordinated movement of masticatory components during cortical stimulation. While other factors may be involved, functional change in digastric muscle is partly involved in the mechanism.

Free Research Field

矯正歯科

Academic Significance and Societal Importance of the Research Achievements

1975年以来、世界的な肥満の有病率は急激に増加している。矯正歯科臨床においても、肥満患者が多く見受けられるようになってきた。顎顔面領域に関して、肥満は舌への脂肪浸潤の増加、上部気道径の縮小、上部気道軟組織体積の増大など、口腔構造の変化に関連していることは数多く報告されているが、肥満による顎顔面領域への中枢神経系への影響については未だ明らかでなかった。今回の研究により大脳皮質咀嚼野への影響が報告され、矯正治療だけでなく、咀嚼運動に対する肥満の影響が明らかとなった。