歯の触覚機能における歯肉の役割を皮質レベルで調査する

Investigating the role of gingiva in the tactile function of teeth at the cortical level.

抄録

歯の触覚における歯肉の役割は不明であり、歯の触覚機能の生理的基盤を皮質反応レベルで検討する必要がある。今回の研究では、5頭の猫から局所麻酔下で左上犬歯の歯肉を摘出した。Intrinsic Signal Optical Imagingを用いて、歯肉を除去した左犬歯と無傷の右犬歯に別々に穿刺的な機械的刺激を加えたときの猫の口腔関連皮質の集団反応特性を測定した。その後、両者の応答特性を比較した。その結果、麻酔をかけたイヌとかけていないイヌでは、大脳皮質の反応強度に有意な差はなかった。歯肉を剥離した歯の信号強度は，低刺激強度では無処置の歯の信号強度よりも有意に弱かった．しかし，歯肉を除去した歯と無傷の歯の間には，飽和後も有意な差は見られなかった。誘発された皮質反応から，歯肉は歯の低強度の触覚に関与しており，慢性歯肉炎で天然歯の知覚異常が生じる理由を説明できる可能性がある．

The role of the gingiva in the tactile perception of teeth is unclear, and the physiological basis of tooth tactile function needs to be examined at the cortical response level. In the presented study, gingiva from the upper left canine was removed under local anesthesia from five cats. Intrinsic signal optical imaging was used to measure population response characteristics of the cat oral-related cortex when punctate mechanical stimuli were separately applied to the left gingiva-stripped canine and right intact canine. Then, their response characteristics were compared. There were no significant differences in the cortical response strength between the anesthetized and unanesthetized canines. Signal strength of the gingiva-stripped tooth was significantly weaker than that of the intact tooth at low stimulus strength. However, no significant differences between the gingiva-stripped tooth and intact tooth were found after saturation. Based on the evoked cortical responses, the gingiva is involved in low-intensity tactile perception of teeth, which could explain the reason why chronic gingivitis results in the paresthesia of natural teeth.