J Oral Facial Pain Headache. 2018;32(4):418-427. doi: 10.11607/ofph.2042.
To investigate whether glutamate-evoked pain in the masseter region differs between three different depths of injection, targeting subcutaneous, muscle, and bone tissues.
A total of 16 healthy volunteers participated and, in a randomized order, received injections of glutamate (1.0 M, 0.2 mL) and isotonic saline (0.9%, 0.2 mL) in the masseter region that targeted subcutaneous, intramuscular, and bone surface tissues. Following injection, pain intensity was measured using electronic visual analog scale (eVAS) and numeric rating scale (NRS) scores of unpleasantness, tiredness, tension, soreness, and stiffness. Pressure pain sensitivity (PPS), pain drawing areas, and McGill Pain Questionnaire (MPQ) scores were also assessed. Repeated-measures analysis of variance, McNemar test, and Tukey post hoc tests were used for statistical analyses. P < .05 was considered statistically significant.
Overall, subcutaneous injections induced significantly more unpleasantness and pain than intramuscular injections, and PPS scores evoked after glutamate injection at the surface of the bone were significantly higher than after intramuscular glutamate injection. Subcutaneous glutamate injections were more often described as "sharp" and "pinching."
The subcutaneous injection was more painful and unpleasant than the intramuscular injection. The glutamate injection at the surface of the bone sensitized the deep pain tissues to pressure stimulation. Clinically, it may be difficult to differentiate between the source or site of pain originating from the masseter region, but the specific quality and word descriptors could assist in differential diagnosis.
研究在三种不同注射深度（靶向皮下、肌肉和骨组织）时，咬肌区域谷氨酸诱发的疼痛是否存在差异。
共 16 名健康志愿者参与研究，按照随机顺序，在咬肌区域接受谷氨酸（1.0 M，0.2 mL）和等渗盐水（0.9%，0.2 mL）注射，分别靶向皮下、肌肉和骨表面组织。注射后，使用电子视觉模拟量表（eVAS）和不愉快、疲倦、紧张、酸痛和僵硬的数字评分量表（NRS）评分来测量疼痛强度。还评估了压力疼痛敏度（PPS）、疼痛绘图区域和 McGill 疼痛问卷（MPQ）评分。采用重复测量方差分析、McNemar 检验和 Tukey 事后检验进行统计学分析。P<.05 被认为具有统计学意义。
总体而言，皮下注射比肌肉内注射引起更明显的不愉快和疼痛，且骨表面的谷氨酸注射后诱发的 PPS 评分明显高于肌肉内的谷氨酸注射。皮下注射谷氨酸的描述更多是“尖锐”和“刺痛”。
与肌肉内注射相比，皮下注射更疼痛和不愉快。骨表面的谷氨酸注射使深部疼痛组织对压力刺激敏感。临床上，可能难以区分源自咬肌区域的疼痛来源或部位，但特定的质量和词语描述可能有助于鉴别诊断。
