Yang Guangju, Jin Jianqiu, Wang Kelun, Baad-Hansen Lene, Liu Hongwei, Cao Ye, Xie Qiu-Fei, Svensson Peter
Department of Prosthodontics and Center for Oral Functional Diagnosis, Treatment and Research, Peking University School and Hospital of Stomatology, National Engineering Laboratory for Digital and Material Technology of Stomatology, Key Laboratory of Digital Stomatology, Beijing, China.
Department of Oral Medicine, Peking University School and Hospital of Stomatology, Beijing, China.
J Oral Rehabil. 2025 Apr;52(4):443-452. doi: 10.1111/joor.13876. Epub 2024 Nov 4.
To evaluate conditioned pain modulation (CPM) in burning mouth syndrome (BMS) patients with different pain mechanisms.
Twenty BMS patients (52.0 ± 6.8 years, 17 women and 3 men) and age- and gender-matched 22 healthy controls were enrolled in this randomised controlled trial. The patients received an active lingual nerve block (lidocaine) and a placebo injection (saline) randomly with an interval of 1 week in a double-blinded manner. Patients evaluated their pain intensity on a 0- to 10-cm visual analogue scale (VAS) before and after each injection, with or without CPM. Based on the anaesthesia effect, BMS patients were divided into two groups with presumed different pain mechanisms; a 'central subgroup (n = 11)' with pain relief less than 1 cm and 'peripheral subgroup (n = 9)' with pain relief more than 1 cm on the VAS. Mechanical pain threshold (MPT) and wind-up ratio (WUR) were investigated at two oral mucosa regions: the region with most intense symptoms and a control region for the patient group; tongue and buccal region for the control group. CPM was induced by immersing the left hand into cold water. A moderate level of pain (around five on the VAS) was obtained by adjusting the water temperature. MPT and WUR were measured twice for all the participants with and without CPM, which was analysed and presented as relative change in MPT and WUR. Differences between groups were analysed using two-way ANOVA. Differences within group between tests were assessed by paired t-test.
At baseline, there were no significant group differences for MPT or WUR between BMS patients and healthy controls (p ≥ 0.156). The mean bath temperature to evoke moderate pain for the BMS group was significantly lower than that for the healthy control group (8.9°C vs. 11.9°C, p = 0.003). The CPM evoked an inhibitory modulation in 18.2%-44.4% of BMS patients, while for the healthy group, the ratio was 68.2%-81.8%. Central BMS patients had smaller CPM effects than healthy participants at the painful site and control site, which indicated a decreased CPM function (p ≤ 0.034). Peripheral BMS patients had lower CPM effects than healthy participants only at the painful site (p = 0.037).
The present findings documented impairment of central nociceptive inhibition processing in BMS patients which was more extensive in central BMS than peripheral BMS. These findings add to the suggestion that BMS may a heterogeneous pain condition with at least two different phenotypes.
评估不同疼痛机制的灼口综合征（BMS）患者的条件性疼痛调制（CPM）。
本随机对照试验纳入了20例BMS患者（年龄52.0±6.8岁，17例女性，3例男性）以及22例年龄和性别匹配的健康对照者。患者以双盲方式随机接受一次有效的舌神经阻滞（利多卡因）和一次安慰剂注射（生理盐水），间隔1周。患者在每次注射前后，无论有无CPM，均使用0至10厘米的视觉模拟量表（VAS）评估疼痛强度。根据麻醉效果，将BMS患者分为两组，推测其疼痛机制不同；VAS上疼痛缓解小于1厘米的“中枢亚组（n = 11）”和疼痛缓解大于1厘米的“外周亚组（n = 9）”。在两个口腔黏膜区域研究机械性疼痛阈值（MPT）和累加比率（WUR）：患者组症状最严重的区域和一个对照区域；对照组的舌部和颊部区域。通过将左手浸入冷水中诱导CPM。通过调节水温获得中度疼痛水平（VAS上约为5）。对所有参与者在有和无CPM的情况下分别测量两次MPT和WUR，并将其分析结果表示为MPT和WUR的相对变化。组间差异采用双向方差分析。组内测试间的差异采用配对t检验进行评估。
在基线时，BMS患者和健康对照者之间的MPT或WUR无显著组间差异（p≥0.156）。BMS组诱发中度疼痛的平均水温显著低于健康对照组（8.9°C对11.9°C，p = 0.003）。CPM在18.2%-44.4%的BMS患者中诱发了抑制性调制，而健康组的这一比例为68.2%-81.8%。中枢性BMS患者在疼痛部位和对照部位的CPM效应均小于健康参与者，这表明CPM功能下降（p≤0.034）。外周性BMS患者仅在疼痛部位的CPM效应低于健康参与者（p = 0.037）。
本研究结果证明BMS患者存在中枢伤害性抑制处理受损，中枢性BMS比外周性BMS更为广泛。这些发现进一步提示BMS可能是一种具有至少两种不同表型的异质性疼痛疾病。
