Shimada Eriya, Kanetaka Hiroyasu, Hihara Hiroki, Kanno Akitake, Kawashima Ryuta, Nakasato Nobukazu, Igarashi Kaoru
Division of Craniofacial Anomalies, Graduate School of Dentistry, Tohoku University, Sendai, Japan.
Liaison Center for Innovative Dentistry, Graduate School of Dentistry, Tohoku University, Sendai, Japan.
Heliyon. 2022 May 19;8(5):e09464. doi: 10.1016/j.heliyon.2022.e09464. eCollection 2022 May.
The periodontal ligaments are very important sensory organ for our daily life such as perception of food size or hardness, determination of jaw position, and adjustment of masticatory strength. The sensory properties of the periodontal ligament, especially those of the maxillary and mandibular molars, have not yet been fully investigated. Somatosensory evoked magnetic fields (SEFs) can be measured and evaluated for latency and intensity to determine the sensory transmission characteristics of each body parts. However, previous reports on SEFs in the oral region have only reported differences in upper and lower gingival and lip sensations. In this study, the aim was to clarify these sensory characteristics by measuring SEFs during mechanical stimulation of the periodontal ligament in the maxillary and mandibular first molars. Somatosensory evoked magnetic fields were measured in the contralateral hemispheres of 33 healthy volunteers. Mechanical stimulation of the maxillary and mandibular right first molars, and the left wrist was performed with a specific handmade tool. The first peak latency for the mandibular first molars was 41.7 ± 5.70 ms (mean ± SD), significantly shorter than that for the maxillary first molars at 47.7 ± 7.36 ms. The peak intensity for the mandibular first molars was 13.9 ± 6.06 nAm, significantly larger than that for the maxillary first molars at 7.63 ± 3.55 nAm. The locations in the contralateral hemispheres showed no significant difference between the maxillary first molars and mandibular first molars. These locations were more anteroinferior and exterior than that of the wrist, as suggested by the brain homunculus. Neural signals from the mandibular periodontal ligaments pass faster and more intensely to the central nervous system than those from the maxillary periodontal ligaments, and may preferentially participate in adjustment of the occlusal force and the occlusal position.
牙周韧带是我们日常生活中非常重要的感觉器官，比如对食物大小或硬度的感知、颌骨位置的确定以及咀嚼力量的调整。牙周韧带的感觉特性，尤其是上颌和下颌磨牙的感觉特性，尚未得到充分研究。体感诱发电场（SEFs）可以被测量并评估其潜伏期和强度，以确定身体各部位的感觉传导特征。然而，先前关于口腔区域SEFs的报告仅报道了上下牙龈和嘴唇感觉的差异。在本研究中，目的是通过测量上颌和下颌第一磨牙牙周韧带机械刺激期间的SEFs来阐明这些感觉特征。在33名健康志愿者的对侧半球测量体感诱发电场。使用特定的手工工具对上颌和下颌右侧第一磨牙以及左手腕进行机械刺激。下颌第一磨牙的第一个峰值潜伏期为41.7±5.70毫秒（平均值±标准差），明显短于上颌第一磨牙的47.7±7.36毫秒。下颌第一磨牙的峰值强度为13.9±6.06纳安米，明显大于上颌第一磨牙的7.63±3.55纳安米。上颌第一磨牙和下颌第一磨牙在对侧半球的位置没有显著差异。如大脑小人图所示，这些位置比手腕的位置更靠前、更靠下且更靠外侧。来自下颌牙周韧带的神经信号比来自上颌牙周韧带的神经信号更快、更强烈地传递到中枢神经系统，并且可能优先参与咬合力和咬合位置的调整。
