Orthodontic Force Facilitates Cortical Responses to Periodontal Stimulation
Orthodontic Force Facilitates Cortical Responses to Periodontal Stimulation
复制标题
DOI：
10.1177/0022034515586543
复制
发表时间：
2015-08-01
影响因子：
7.6
通讯作者：
Kobayashi, M.
中科院分区：
文献类型：
--
作者：
Horinuki, E.;Shinoda, M.;Kobayashi, M.
牙周韧带提供的感觉信息在识别咬合力的大小和方向方面起着关键作用。移动牙齿所需的正畸力通常会引起不舒服的感觉，包括牙齿周围的伤害感受，并干扰体感信息处理。然而，正畸治疗是否能调节高级脑功能，尤其是大脑皮层的活动，目前还不清楚。为了解决这个问题，我们首先阐明了皮层区域参与牙周韧带的感觉处理，然后研究实验性牙齿移动（ETM）如何改变这些皮层区域的神经活动。我们进行了在体光学成像，以确定在大鼠的上颌和下颌切牙和第一磨牙牙周韧带的电刺激引起的皮质反应。在幼稚的大鼠，下颌牙周韧带的电刺激最初引起的初级体感皮层（S1），第二体感皮层（S2）的腹侧部分，和岛状口腔区域（IOR）的rostroventral部分的神经兴奋，而上颌牙周韧带引起的兴奋，只有在S2/IOR rostrovorsally相邻的下颌牙周韧带响应区域。相反，在S1和S2/IOR中观察到对下颌和上颌牙周刺激的最大反应，并且2个反应几乎重叠。一天后ETM（上颌磨牙移动Waldo的方法），刺激上颌磨牙牙周膜的最大反应引起更大和更广泛的兴奋S2/IOR，虽然最初的反应没有受到影响。结合ETM模型牙周膜中IL-1 β表达和巨噬细胞浸润的组织学发现，ETM诱导的炎症可能在促进S2/IOR活性中起作用。从临床角度来看，皮层兴奋的幅度越大，对非伤害性刺激的疼痛反应的敏感性越高，反应区的扩大可能反映了放射痛。
Somatosensory information derived from the periodontal ligaments plays a critical role in identifying the strength and direction of occlusal force. The orthodontic force needed to move a tooth often causes uncomfortable sensations, including nociception around the tooth, and disturbs somatosensory information processing. However, it has mostly remained unknown whether orthodontic treatment modulates higher brain functions, especially cerebrocortical activity. To address this issue, we first elucidated the cortical region involved in sensory processing from the periodontal ligaments and then examined how experimental tooth movement (ETM) changes neural activity in these cortical regions. We performed in vivo optical imaging to identify the cortical responses evoked by electrical stimulation of the maxillary and mandibular incisor and the first molar periodontal ligaments in the rat. In naive rats, electrical stimulation of the mandibular periodontal ligaments initially evoked neural excitation in the rostroventral part of the primary somatosensory cortex (S1), the ventrocaudal part of the secondary somatosensory cortex (S2), and the insular oral region (IOR), whereas maxillary periodontal ligaments elicited excitation only in S2/IOR rostrodorsally adjacent to the mandibular periodontal ligament-responding region. In contrast, maximum responses to mandibular and maxillary periodontal stimulation were observed in S1 and S2/IOR, and the 2 responses nearly overlapped. One day after ETM (maxillary molar movement by Waldo's method), the maximum response to stimulation of the maxillary molar periodontal ligament induced larger and broader excitation in S2/IOR, although the initial responses were not affected. Taken together with the histologic findings of IL-1 beta expression and macrophage infiltration in the periodontal ligament of the ETM models, inflammation induced by ETM may play a role in the facilitation of S2/IOR activity. From the clinical viewpoints, the larger amplitude of cortical excitation may induce higher sensitivity to pain responding to nonnoxious stimuli, and enlargement of the responding area may reflect radiating pain.