J Oral Facial Pain Headache. 2017;31(1):72-79. doi: 10.11607/ofph.1765.
To use a randomized, blinded, crossover design to evaluate the possible heterotopic effects of experimental periodontal ligament pain on adjacent gingival somatosensory sensitivity.
A total of 12 healthy volunteers (8 female, 4 male; mean age ± standard error in means (SEM): 28 ± 1 years) participated in two randomized experimental quantitative sensory testing (QST) sessions, one in which capsaicin (experimental) was injected into the periodontal ligament and one in which isotonic saline (control) was injected. A total of 13 standardized QST measures were obtained on the buccal attached gingiva of a maxillary central incisor before, immediately after, and 30 minutes after injection of 30 μL of 5% capsaicin or isotonic saline into the periodontal ligament of the same incisor. The injection-evoked pain was evaluated on a 0-10 numeric rating scale (NRS). QST data were analyzed with two-way repeated measurement analysis of variance.
Capsaicin injected into the periodontal ligament evoked moderate levels of pain (mean peak NRS ± SEM: capsaicin: 5.5 ± .7; control: 0.6 ± 0.5 [P < .001]). Capsaicin injected into the periodontal ligament significantly modulated gingival somatosensory sensitivity: increased sensitivity to warmth and painful heat stimuli occurred immediately and 30 minutes after the injection (P < .025), whereas decreased sensitivity to both tactile and painful mechanical stimuli (P < .011) occurred immediately after the injection and to painful mechanical stimuli only after 30 minutes (P = .016). No somatosensory changes were detected following the injection of isotonic saline (P > .050).
Capsaicin injected into the periodontal ligament caused gain of heterotopic somatosensory sensitivity toward warmth and painful heat stimuli as well as reduction in mechanical sensitivity of the gingiva adjacent to the injected tooth. These findings may have implications for interpretation of somatosensory functions in patients with chronic intraoral pain, where gingival somatosensory profiles similar to those detected after capsaicin injection in the present study may be interpreted as signs of nerve damage.
采用随机、双盲、交叉设计，评估实验性牙周韧带疼痛对相邻牙龈体感觉敏感性的可能异位效应。
共 12 名健康志愿者（8 名女性，4 名男性；平均年龄±平均值标准误差（SEM）：28±1 岁）参加了两个随机实验定量感觉测试（QST）疗程，一个疗程中向牙周韧带内注射辣椒素（实验组），另一个疗程中注射等渗盐水（对照组）。在向同一侧切牙的牙周韧带内注射 30 μL 5%辣椒素或等渗盐水后，立即测量上颌侧切牙颊侧附着牙龈上的 13 项标准化 QST 测量值。使用 0-10 数字评分量表（NRS）评估注射诱发的疼痛。使用双向重复测量方差分析对 QST 数据进行分析。
向牙周韧带内注射辣椒素引起中度疼痛（平均峰值 NRS±SEM：辣椒素：5.5±0.7；对照组：0.6±0.5[P<0.001]）。向牙周韧带内注射辣椒素显著调节了牙龈体感觉敏感性：注射后即刻和 30 分钟，对温暖和疼痛热刺激的敏感性增加（P<0.025），而即刻对触觉和疼痛机械刺激的敏感性降低（P<0.011），仅在 30 分钟后对疼痛机械刺激的敏感性降低（P=0.016）。向牙周韧带内注射等渗盐水后未检测到体感觉变化（P>0.050）。
向牙周韧带内注射辣椒素引起对温暖和疼痛热刺激的异位体感觉敏感性增加，以及注射牙相邻牙龈的机械敏感性降低。这些发现可能对解释慢性口腔内疼痛患者的体感觉功能具有重要意义，在这些患者中，类似于本研究中向牙周韧带内注射辣椒素后检测到的体感觉谱可能被解释为神经损伤的迹象。
