Experimental tooth movement changes somatotopic organization of the somatosensory and insular cortices

2018 Fiscal Year Final Research Report

• Project/Area Number: 17H07144
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Single-year Grants
• Research Field: Orthodontics/Pediatric dentistry
• Research Institution: Nihon University
• Principal Investigator: HORINUKI Eri 日本大学, 歯学部, 専修医 (30805990)
• Project Period (FY): 2017-08-25 – 2019-03-31
• Keywords: 歯根膜 / 疼痛 / 大脳皮質 / カルシウム・イメージング / 二光子励起レーザー顕微鏡

Outline of Final Research Achievements

In the animals 1d after experimental tooth movement (1d ETM), the number of neurons and their amplitude of Ca2+ signals responding to maxillary molar pulp stimulation were increased both in excitatory and inhibitory neurons.
In contrast to very small population of excitatory and inhibitory neurons responding to the mandibular molar stimulation in control rats, 1d ETM showed significant increases in excitatory and inhibitory neurons responding to mandibular molar stimulation. Interestingly, most of mandibular molar-responding neurons also responded to maxillary molar stimulation. The population of excitatory and inhibitory neurons that responded only to maxillary molar PDL stimulation was almost comparable between control and 1d ETM. The facilitative responses in 1d ETM were almost recovered 7d after ETM.

Free Research Field

歯科矯正学

Academic Significance and Societal Importance of the Research Achievements

本実験で得られた結果は、持続的な末梢刺激である矯正力が大脳皮質に与える影響をより正確に理解する一助となる。
矯正力負荷1日後に、一時的に大脳皮質における興奮性および抑制性ニューロンの神経活動が変化し、7日後にそれらの活動変化が対照群と同程度にまで回復したという本実験の結果は、「矯正力は大脳皮質の興奮性を持続的には変化させない」という仮説に対する明確なエビデンスとなる。このエビデンスは，矯正治療における中枢神経系の影響は限定的であることを示すものであり，臨床治療での安全性を担保することに寄与する。