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This study tested the reproducibility of visual analog scale (VAS) pain scores to measure changes in masseter muscle pain evoked by maximally tolerable mechanical stimulation over a short time period in healthy subjects. This study also evaluated gender differences in reproducibility of VAS scores to mechanical stimulation. Ten healthy female and eight healthy male individuals participated in this study. The recordings of VAS pain scores to an identical mechanical pressure on the masseter muscle were performed at three different sessions (T1, T2, and T3). The subjects rated their pain on a VAS to a maximally tolerable stimulus that was recorded on an algometer at the first session. The algometer pressure reading was recorded for each subject and then used to duplicate the same identical mechanical stimulus at each of the three sessions. This identical pressure was repeated in the same marked spot at six minutes and after 30 minutes. The subjects rated the pain on a VAS to this identical stimulus at each session. There was no significant difference in VAS pain scores of all subjects at T1, T2, and T3. There was no significant difference in reproducibility of VAS pain scores in females compared to males. Intraclass correlation coefficients were 0.811 on the right masseter and 0.844 on the left masseter. VAS pain scores to mechanical stimulation were reproducible over a short time period. Gender did not affect the reproducibility. This previously unreported method of measuring pain to repeated identical mechanical stimulation appears to have potential for both clinical and research application.

Background: Several studies have shown that both acupuncture and dry needling are effective in the treatment of musculoskeletal pains. Therefore, the aim of this network meta‐analysis (NMA) was to investigate the treatment outcome of acupuncture and dry‐needling for masticatory muscle pain (TMD‐M) and to compare with active and inactive placebo. Material and Method: An electronic search was performed to identify randomised controlled trials (RCTs) published until September 2019, comparing dry‐needling, acupuncture, and inactive as well as active placebo in patients with TMD‐M. Outcome variables were post‐treatment pain intensity, pressure pain threshold (PPT), and maximum mouth opening (MMO). The quality of evidence was rated according to Cochrane's tool for assessing the risk of bias. Mean difference was used to analyse via frequentist NMA using STATA‐software. Results: Both NMA and direct pairwise meta‐analysis have shown that there was no difference between active treatment with either acupuncture or dry‐needling when compared to active and inactive placebo in patients with TMD‐M with respect to pain intensity, and PPT (p >.05). However, there was a significant increase in MMO following dry‐needling when compared to the placebo (very low‐quality evidence). Conclusion: Despite the short‐term positive effect of MMO by dry‐needling, this NMA could not show any pain‐reducing effect in patients with TMD‐M by acupuncture or dry‐needling when compared to an active or inactive placebo. Taken together, this NMA indicates that it is the placebo effect that accounts for the majority of the treatment effect of TMD‐M, rather than a real therapeutic effect of acupuncture/dry‐needling. [ABSTRACT FROM AUTHOR]

Aims: To evaluate the effectiveness of acupuncture in treating symptoms associated with myofascial pain of the jaw muscles. Methods: Twenty-eight subjects over the age of 18 and diagnosed with chronic myofascial pain of the jaw muscles were randomized to receive real (n = 16) or sham (n = 12) acupuncture. Prior to treatment, each subject clenched his or her teeth for 2 minutes. Acupuncture or sham acupuncture was then administered at the Hegu large intestine 4 (LI4) acupoint for 15 minutes. Real acupuncture was given by penetrating the needle through a sticky foam pad at the acupoint. Sham acupuncture was conducted by pricking the skin, without penetration, with a shortened, blunted acupuncture needle through a foam pad placed away from the acupoint. General head and neck pain ratings were obtained before and after treatment on a numerical rating scale. A mechanical pain stimulus on the masseter muscle was given before and after treatment and rated on a visual analog scale to measure pain tolerance level. Paired t tests were performed to detect significant changes in pain levels. Results: Subjects receiving real acupuncture experienced a significant reduction in jaw pain (P = .04), jaw/face tightness (P = .04), and neck pain (P = .04), and a significant increase in pain tolerance of the masseter muscle (P = .001). Subjects were not able to determine whether they received real or sham acupuncture (P = .69). No significant pain reductions were observed in the sham acupuncture group. Conclusion: A single acupuncture session using one acupoint at Hegu large intestine 4 significantly reduced most myofascial pain endpoints when compared to sham acupuncture. [ABSTRACT FROM AUTHOR]

This article presents a comprehensive review of the topic of placebos, with a special focus on placebo analgesia. It includes a discussion of how placebos work (the placebo effect) and how patients react to them (the placebo response). A literature search was performed to identify relevant literature and publications related to the topic, and a qualitative assessment of papers was undertaken based on accepted rules for scientific evidence. The major finding from this review was that concepts about placebo effects and responses have changed dramatically over the years, especially in more recent years. This has occurred primarily as a result of more sophisticated experimental protocols using placebos in clinical studies of patients in pain, as well as various studies involving normal subjects. Our understanding of the biological and psychological mechanisms underlying placebo effects has expanded significantly due to recent developments in the technology of brain imaging. Based on findings from brain-imaging analyses, we now know that placebo analgesia is definitely a real (ie, biologically measurable) phenomenon. It can be pharmacologically blocked and behaviorally enhanced, and these responses have been demonstrated to be similar to those elicited by administration of "real" analgesic substances. Psychological mechanisms involved in placebo analgesia include expectancy, meaning response, and classical conditioning. This article concludes with an emphasis on understanding therapeutic responses to various treatments for temporomandibular disorders (TMD). Acupuncture and splint therapy can be good examples of powerful placebos in the field of TMD, and both of these are discussed in detail. Present knowledge suggests that every treatment for pain contains a placebo component, which sometimes is as powerful as the so-called "active" counterpart. While the deceptive use of placebos must be considered unethical, every health provider who is treating pain patients must be aware of this important phenomenon in order to harness its huge potential. [ABSTRACT FROM AUTHOR]

Aims: To compare the effectiveness of dry needling in classically recognized acupuncture points ("acupuncture") with dry needling in skin areas not recognized as acupuncture points ("sham acupuncture") in reducing masseter muscle pain in a group of patients with myofascial pain of the jaw muscles. Methods: Eighteen patients were randomly assigned to 1 of 2 experimental groups: Ten patients received acupuncture and 8 received sham acupuncture. A visual analog scale (VAS) was used to measure changes in masseter muscle pain evoked by mechanical stimulation of the masseter muscle before and after the experiment. Results: Both groups showed a statistically significant reduction in VAS pain scores (P = .001). Seven out of 10 acupuncture subjects had a 10 mm or greater VAS reduction in pain, while 4 out of 8 of the sham acupuncture subjects had that great a pain reduction. There was no significant difference between the 2 groups. Conclusion: Both acupuncture and sham acupuncture reduced pain evoked by mechanical stimulation of the masseter muscles in myofascial pain patients. However, this reduction in pain was not dependent on whether the needling was performed in standard acupuncture points or in other areas of the skin. These results suggest that pain reduction resulting from a noxious stimulus (ie, needling) may not be specific to the location of the stimulus as predicted by the classical acupuncture literature. [ABSTRACT FROM AUTHOR]

Background: Subjective symptoms of temporomandibular disorders (TMDs) have rarely been studied by age group. We aimed to compare self-reported pain intensity, sleeping difficulty, and treatment outcomes of patients with myofascial TMDs among three age groups. Methods: The study population included 179 consecutive patients (151 women and 28 men) who underwent comprehensive clinical examinations at a university-based orofacial pain center. They were classified into myofascial pain subgroups based on the Research Diagnostic Criteria for Temporomandibular Disorders. They were stratified by age group: M1, under 20 years; M2, 20-39 years; and M3, 40 years and older. The patients scored their pretreatment symptoms (first visit) and post-treatment symptoms (last visit) on a form composed of three items that assessed pain intensity and one item that assessed sleeping difficulty. Their treatment options (i.e., pharmacotherapy, physical therapy, and orthopedic appliances) and duration were recorded. All variables were compared between sexes in each group and between the age groups by using the Kruskal-Wallis test, the Mann-Whitney U test, the chisquare test, and analysis of variance (p < 0.05). Results: No significant sex differences were found in any age group. Only sleeping difficulty was significantly different before treatment (p = 0.009). No significant differences were observed in the treatment options or treatment duration. After treatment, the intensity of jaw/face pain and headache and sleeping difficulty was significantly reduced in groups M2 and M3, but only the intensity of jaw/face pain was significantly decreased in group M1. The changes in the scores of pain intensity and sleeping difficulty were not different between the groups. Conclusions: Pain intensity does not differ by age group, but older patients with myofascial TMDs had greater sleeping difficulties. However, there were no differences between the age groups in the treatment outcomes. Clinicians should carefully consider the age-related characteristics of patients with myofascial TMDs when developing appropriate management strategies. [ABSTRACT FROM AUTHOR]

The authors assessed the subjective symptoms of temporomandibular disorders (TMDs) in 167 young patients using self-reported forms, with five ratings for pain intensity and six ratings for difficulty in activities of daily living (ADL), to compare TMD symptoms according to gender and three age groups: group 1: 6- to 12-year-olds (juvenile); group 2: 13- to 15-year-olds (early adolescent); group 3: 16- to 18-year-olds (late adolescent). No significant gender differences were found in the symptoms among the groups, except for headache and neck pain in group 3. Pain intensity and tightness in the jaw/face, headache, and neck pain, as well as the ADL-related difficulty in prolonged jaw opening, eating soft/hard foods, and sleeping significantly differed among the groups (p<0.01, Kruskal-Wallis test). Therefore, late adolescent patients with TMDs have higher pain intensity in the orofacial region and greater difficulty in ADL than do early adolescent and juvenile patients with TMDs. [ABSTRACT FROM AUTHOR]