Efficacy of stabilisation splint treatment on facial pain – 1‐year follow‐up

The aim of this randomised controlled trial was to assess the efficacy of stabilisation splint treatment on TMD‐related facial pain during a 1‐year follow‐up. Eighty patients were randomly assigned to two groups: splint group (n = 39) and control group (n = 41). The patients in the splint group were treated with a stabilisation splint and received counselling and instructions for masticatory muscle exercises. The controls received only counselling and instructions for masticatory muscles exercises. The outcome variables were the change in the intensity of facial pain (as measured with visual analogue scale, VAS) as well as the patients' subjective estimate of treatment outcome. The differences in VAS changes between the groups were analysed using variance analysis and linear regression models. The VAS decreased in both groups, the difference between the groups being not statistically significant. The group status did not significantly associate with the decrease in VAS after adjustment for baseline VAS, gender, age, length of treatment and general health status. The only statistically significant predicting factor was the baseline VAS, which was also confirmed by the mixed‐effect linear model. After 1‐year follow‐up, 27·6% of the patients in the splint group and 37·5% of the patients in the control group reported ‘very good' treatment effects. The findings of this study did not show stabilisation splint treatment to be more effective in decreasing facial pain than masticatory muscle exercises and counselling alone in the treatment of TMD‐related facial pain over a 1‐year follow‐up.     

Efficacy of stabilisation splint treatment on temporomandibular disorders

Summary The evidence supporting the use of stabilisation splints in the treatment of temporomandibular disorders (TMD) is scarce and a need for well‐controlled studies exists. The aim of this randomised, controlled trial study was to assess the efficacy of stabilisation splint treatment on TMD. The sample consisted of 80 consecutive referred patients who were randomly assigned to the splint group (n = 39) and the control group (n = 41). Subjects in the splint group were treated with a stabilisation splint, whereas subjects in the control group did not receive any treatment except counselling and instructions for masticatory muscle exercises which were given also to the subjects in the splint group. Outcomes were visual analogue scale (VAS) on facial pain intensity and clinical findings for TMD which were measured at baseline and after 1‐month follow‐up. The differences in change between the groups were analysed using regression models. Facial pain decreased and most of the clinical TMD findings resolved in both of the groups. The differences in changes in VAS or clinical TMD findings between the groups were not statistically significant. The findings of this study did not show that stabilisation splint treatment in combination with counselling and masticatory muscle exercises has additional benefit in relieving facial pain and increasing the mobility of the mandible than counselling and masticatory muscle exercises alone in a short time‐interval.     

Headache attributed to masticatory myofascial pain: impact on facial pain and pressure pain threshold

There is no clear evidence on how a headache attributed to temporomandibular disorder (TMD) can hinder the improvement of facial pain and masticatory muscle pain. The aim of this study was to measure the impact of a TMD‐attributed headache on masticatory myofascial (MMF) pain management. The sample was comprised of adults with MMF pain measured according to the revised research diagnostic criteria for temporomandibular disorders (RDC/TMD) and additionally diagnosed with (Group 1, n = 17) or without (Group 2, n = 20) a TMD‐attributed headache. Both groups received instructions on how to implement behavioural changes and use a stabilisation appliance for 5 months. The reported facial pain intensity (visual analogue scale – VAS) and pressure pain threshold (PPT – kgf cm^?2) of the anterior temporalis, masseter and right forearm were measured at three assessment time points. Two‐way anova was applied to the data, considering a 5% significance level. All groups had a reduction in their reported facial pain intensity (P < 0·001). Mean and standard deviation (SD) PPT values, from 1·33 (0·54) to 1·96 (1·06) kgf cm^?2 for the anterior temporalis in Group 1 (P = 0·016), and from 1·27 (0·35) to 1·72 (0·60) kgf cm^?2 for the masseter in Group 2 (P = 0·013), had significant improvement considering baseline versus the 5th‐month assessment. However, no differences between the groups were found (P > 0·100). A TMD‐attributed headache in patients with MMF pain does not negatively impact pain management, but does change the pattern for muscle pain improvement.     

The effect of culture on pain sensitivity

Cross‐cultural differences in pain sensitivity have been identified in pain‐free subjects as well as in chronic pain patients. The aim was to assess the impact of culture on psychophysical measures using mechanical and electrical stimuli in patients with temporomandibular disorder (TMD) pain and pain‐free matched controls in three cultures. This case–control study compared 122 female cases of chronic TMD pain (39 Saudis, 41 Swedes and 42 Italians) with equal numbers of age‐ and gender‐matched TMD‐free controls. Pressure pain threshold (PPT) and tolerance (PPTo) were measured over one hand and two masticatory muscles. Electrical perception threshold and electrical pain threshold (EPT) and tolerance (EPTo) were recorded between the thumb and index fingers. Italian females reported significantly lower PPT in the masseter muscle than other cultures (P < 0·001) and in the temporalis muscle than Saudis (P = 0·003). Swedes reported significantly higher PPT in the thenar muscle than other cultures (P = 0·017). Italians reported significantly lower PPTo in all muscles than Swedes (P ≤ 0·006) and in the masseter muscle than Saudis (P < 0·001). Italians reported significantly lower EPTo than other cultures (P = 0·01). Temporomandibular disorder cases, compared to TMD‐free controls, reported lower PPT and PPTo in all the three muscles (P < 0·001). This study found cultural differences between groups in the PPT, PPTo and EPTo. Overall, Italian females reported the highest sensitivity to both mechanical and electrical stimulation, while Swedes reported the lowest sensitivity. Mechanical pain thresholds differed more across cultures than did electrical pain thresholds. Cultural factors may influence response to type of pain test.     

Correlation of splint therapy outcome with the electromyography of masticatory muscles in temporomandibular disorder with myofascial pain

Abstract

Objectives. The aim of this study was to assess the effect of occlusal splint therapy on the electromyographic amplitude records (μV) of masticatory muscles in temporomandibular disorder (TMD) with myofascial pain and to detect a possible existence of a relationship between this effect and the treatment outcome. Materials and methods. Forty patients (23 females and 17 males) having TMD with myofascial pain were included in this study. They were randomly divided into two equal groups (20 of each). The first group (A) was treated by occlusal splints for 6 months while the second group (B) acted as a control. A clinical assessment and surface electromyography (EMG) for the masticatory muscles were performed at the beginning of the study, then 6 months later. The collected data were statistically analyzed using paired t-test. The differences were considered significant at p < 0.05. Results. The results showed that 85% of group A either completely recovered (35%) or clinically improved (50%) while only 20% of group B had a spontaneous improvement. In group A, the means of the electromyographic amplitude records (μV) of the monitored muscles have decreased after 6 months. However, the decrease was statistically insignificant (p > 0.05) in the patients (15%) who had no clinical changes. In group B, the means of the muscles' records (μV) in the left side slightly increased while those of the right side slightly decreased. These changes were statistically insignificant (p > 0.05). Conclusions. Occlusal splint could eliminate or improve the signs and symptoms of TMD patients with myofascial pain. It reduces the electromyographic amplitude records (μV) of the masticatory muscles. The splint therapy outcome has a correlation with the electromyographic amplitude changes of the masticatory muscles.     

咬合恢复对偏侧咀嚼大鼠咀嚼肌影响的实验研究

目的：研究咬合恢复对偏侧咀嚼大鼠咀嚼肌的影响.方法：40只Wister大鼠随机分为4组,所有动物间断磨除有上、下颌磨牙牙冠至龈下,实验1组第3周、实验2组第9周停止磨牙,任其自行萌出,恢复咬合关系.对照组不停止牙冠磨除,饲养条件相同.实验1组磨除牙冠后10周末、实验2组磨除牙冠后16周末处死动物,取其双侧颞肌、咬肌进行光镜、电镜切片检查,结果与对照组对照.采用SPSS10.0软件进行统计学分析.结果：实验1组与对照1组双侧咀嚼肌受损情况有显著性差异（χ2=40,P＜0.01）.实验2组与对照2组双侧咀嚼肌受损情况无显著性差异（χ2=3.66,P＞0.05）.结论：早期咬合恢复,可恢复偏侧咀嚼大鼠咀嚼肌的损害.     

The impact of stress and anxiety on the pressure pain threshold of myofascial pain patients

Summary  The purpose of this study was to evaluate the influence of stress and anxiety on the pressure pain threshold (PPT) of masticatory muscles and on the subjective pain report. Forty-five women, students, with mean age of 19·75 years, were divided into two groups: group 1:29 presenting with masticatory myofascial pain (MFP), according to the Research Diagnostic Criteria for Temporomandibular Disorders and group 2: 16 asymptomatic controls. An electronic algometer registered the pain thresholds on four different occasions throughout the academic year. To measure levels of stress, anxiety and pain, the Beck Anxiety Inventory, Lipp Stress Symptoms Inventory and Visual Analog Scale (VAS) were used. Three-way anova and Tukey's tests were used to verify differences in PPT between groups, times and sites. Levels of anxiety and VAS were compared using Mann–Whitney test, while Friedman's test was used for the within-groups comparison at different times (T1 to T4). The chi-squared and Cochran tests were performed to compare groups for the proportion of subjects with stress (α = 0·05). Differences in PPT recordings between time ( P  = 0·001) and sites ( P  < 0·001) were detected. Higher levels of anxiety and lower PPT figures were detected at T2 (academic examination) ( P  = 0·001). There was no difference between groups for anxiety and stress at any time ( P  > 0·05). The MFP group also has shown significant increase of VAS at the time of academic examination ( P  < 0·001). External stressors such as academic examinations have a potential impact on masticatory muscle tenderness, regardless of the presence of a previous condition such as masticatory myofascial pain.     

Effect of high‐frequency bio‐oxidative ozone therapy for masticatory muscle pain: a double‐blind randomised clinical trial

To evaluate the effect of bio‐oxidative ozone application at the points of greatest pain in patients with chronic masticatory muscle pain. A total number of 40 (40 women, with a mean age of 31·7) were selected after the diagnosis of myofacial pain dysfunction syndrome according to the Research Diagnostic Criteria for temporomandibular disorder (RDC/TMD). The patients were randomly divided into two groups: patients received the ozone therapy at the point of greatest pain, ozone group (OG; n = 20); patients received the sham ozone therapy at the point of greatest pain, placebo group (PG; n = 20). Ozone and placebo were applied three times per week, for a total of six sessions. Mandibular movements were examined, masticator muscles tenderness were assessed and pressure pain threshold (PPT) values were obtained. Subjective pain levels were evaluated using visual analogue sale (VAS). These assessments were performed at baseline, 1 month and 3 months. Ozono therapy decreased pain intensity and increased PPT values significantly from baseline to 1 month and 3 months in OG compared with PG. PPTs of the temporal (OG = 24·85 ± 6·65, PG = 20·65 ± 5·43, P = 0.035) and masseter (OG = 19·03 ± 6·42, PG = 14·23 ± 2·95, P = 0.007) muscles at 3 months of control (T2) were significantly higher in the OG group. PPT value of the lateral pole was also significantly higher at T2 in the OG group (OG = 21·25 ± 8·43, PG = 15·35 ± 4·18, P = 0.012). Mandibular movements did not show significant differences between treatment groups except right lateral excursion values at T2 (OG = 8·90 ± 1·77, PG = 6·85 ± 2·41, P = 0.003); however, OG demonstrated significantly better results over time. Overall improvements in VAS scores from baseline to 3 months were OG 67·7%; PG 48·4%. Although ozone therapy can be accepted as an alternative treatment modality in the management of masticatory muscle pain, sham ozone therapy (placebo) showed significant improvements in the tested parameters.     

Can an NTI‐tss device be effective as a first‐line therapy in patients with TMD myofascial pain?

This study was conducted to evaluate whether integrating a nociceptive trigeminal inhibition–tension suppression system (NTI‐tss) device with first‐line therapy of myofascial pain, which includes guidance, assurance, counselling and behavioural changes, would be more effective in alleviating symptoms. This randomised controlled clinical trial included 40 patients who were clinically diagnosed with myofascial pain according to Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). Patients were randomly divided into two groups: the first group comprised patients who received guidance, assurance, counselling and behavioural changes; an NTI‐tss device was integrated to this protocol in the second group. Both groups exhibited reduction in pain levels and improvement of jaw function compared with baseline values, but the difference was not significant. Both groups demonstrated improvements in 6 weeks; however, the integration of NTI‐tss device into the therapy protocol did not provide any additional benefit in relieving symptoms of myofascial pain.     

The efficacy of occlusal appliance therapy in patients with temporomandibular disorders of mainly myogenous pain. A randomized controlled trial in a short-term perspective

The aim of the present study was to compare the efficacy of physiotherapy and counselling for the treatment of myofascial pain of the jaw muscles. Sixty-three consecutive myogenous TMD patients, diagnosed according to the RDC-TMD criteria, were assigned to two treatment groups with a balanced-block randomization. The first group received only counselling with general information about self-care of jaw musculature. The second group received the same general information supplemented by self-massage, application of moist heating pads and stretching exercises of the masticatory muscles.
Treatment success was decided on treatment contrast (TC), based on relative changes of sufficiently large anamnestic and clinical scores ( van der Glas and van Grootel, 2000 ). Additional measurements included pressure pain threshold (PPT) of the masseter, anterior temporalis and Achilles' tendon, pain during gum chewing and spontaneous muscle pain scores rated on visual analogue scales (VAS). Data were collected at baseline and 3 months after start of treatment. Mann–Whitney's test and Fisher's exact test were used for statistical analysis. Sixteen patients dropped out from the study: eight from the counselling and eight from the physiotherapy group. The success rate was 13 of 23 (57%) patients for counselling and 18 of 24 (75%) for the physiotherapy group ( P  > 0·05). There was no significant difference between groups in all the other variables.
Over a short-term period, physiotherapy, as used in this protocol, does not appear superior to counselling for the treatment of TMD myofascial pain .     

Efficacy of Appliance Therapy on Temporomandibular Disorder Related Facial Pain and Mandibular Mobility: A Randomized Controlled Study

There is limited evidence supporting the role of occlusal splints in Temporomandibular disorder (TMD) therapy. The aim of this randomized controlled clinical trial was to assess the efficacy of stabilization splint therapy on TMD related facial pain and mandibular mobility. The sample of study consisted of eighty consecutive patients diagnosed with TMD. Patients were randomly assigned into two groups: a splint group (n = 40) comprising of patients treated with stabilization splint, councelling and masticatory muscle exercises, and a control group (n = 40), comprising of patients treated with councelling and masticatory muscle exercises alone. Data from both the groups were collected at the beginning of the study and after a 6-month follow up. The outcome variables were visual analogue scale on facial pain intensity and clinical findings for TMD (anterior maximal opening, mandibular right laterotrusion, mandibular left laterotrusion, mandibular protrusion, and number of painful muscle sites). Changes within the splint and control groups (before treatment and 6 months after treatment) were analyzed using paired samples t test. Differences in change between the splint and control groups were analyzed using independent samples t-test. The level of significance was set at p < 0.05. Facial pain and number of painful muscle sites decreased, and the mandibular mobility increased significantly in both groups after treatment; however the differences in changes in VAS or clinical TMD findings between the two groups were not statistically significant. The findings of this study show that stabilization splint treatment in combination with counselling and masticatory muscle exercises has no additional benefit in relieving facial pain and increasing the mobility of the mandible than counselling and masticatory muscle exercises alone over a 6-months’ time interval.     

The effects of manual therapy and exercise directed at the cervical spine on pain and pressure pain sensitivity in patients with myofascial temporomandibular disorders

Summary No studies have investigated the effects of the treatments directed at the cervical spine in patients with temporomandibular disorders (TMD). Our aim was to investigate the effects of joint mobilization and exercise directed at the cervical spine on pain intensity and pressure pain sensitivity in the muscles of mastication in patients with TMD. Nineteen patients (14 females), aged 19–57 years, with myofascial TMD were included. All patients received a total of 10 treatment session over a 5‐week period (twice per week). Treatment included manual therapy techniques and exercise directed at the cervical spine. Outcome measures included bilateral pressure pain threshold (PPT) levels over the masseter and temporalis muscles, active pain‐free mouth opening (mm) and pain (Visual Analogue Scale) and were all assessed pre‐intervention, 48 h after the last treatment (post‐intervention) and at 12‐week follow‐up period. Mixed‐model anovas were used to examine the effects of the intervention on each outcome measure. Within‐group effect sizes were calculated in order to assess clinical effect. The 2 × 3 mixed model anova revealed significant effect for time (F = 77·8; P < 0·001) but not for side (F = 0·2; P = 0·7) for changes in PPT over the masseter muscle and over the temporalis muscle (time: F = 66·8; P < 0·001; side: F = 0·07; P = 0·8). Post hoc revealed significant differences between pre‐intervention and both post‐intervention and follow‐up periods (P < 0·001) but not between post‐intervention and follow‐up period (P = 0·9) for both muscles. Within‐group effect sizes were large (d > 1·0) for both follow‐up periods in both muscles. The anova found a significant effect for time (F = 78·6; P < 0·001) for changes in pain intensity and active pain‐free mouth opening (F = 17·1; P < 0·001). Significant differences were found between pre‐intervention and both post‐intervention and follow‐up periods (P < 0·001) but not between the post‐intervention and follow‐up period (P > 0·7). Within‐group effect sizes were large (d > 0·8) for both post‐intervention and follow‐up periods. The application of treatment directed at the cervical spine may be beneficial in decreasing pain intensity, increasing PPTs over the masticatory muscles and an increasing pain‐free mouth opening in patients with myofascial TMD.     

Histological study of rat masseter muscle following experimental occlusal alteration

It has been suggested that occlusal interference results in masticatory muscle dysfunction. In our previous study, occlusal interference reduced the rat masseter energy level during masticatory movements. The purpose of this study was to investigate the histological alterations of rat masseter muscles following experimental occlusal alteration with unilateral bite-raising. A total of eight male adult Wistar rats were equally divided into control and experimental groups. The experimental rats wore bite-raising splints on the unilateral upper molar. However, 4 weeks after the operation, the anterior deep masseter muscles were removed and then stained for succinic acid dehydrogenase (SDH), haematoxylin eosin (HE) and myofibrillar ATPase. Most of the muscle fibres in experimental rats remained intact, although partial histological changes were observed, such as extended connective tissue, appearance of inflammatory cells in the muscle fibres and existence of muscle fibres with central nuclei and central cores. Moreover, the fibre area-fibre frequency histograms of experimental muscle indicated a broad pattern than that of controls. These results indicated that occlusal interference caused histological changes in masseter muscles and that this may be related to the fact that the masseter energy level was reduced during masticatory movements in unilateral bite-raised rats.     

髁状突纵形骨折及he夹板治疗时对翼外肌影响的光镜和电镜观察

目的：观察翼外肌下头和嚼肌在髁状突纵形骨折后及舱夹板治疗时的改变。方法：幼年小型猪18头，平均分3组，纵形骨折木治疗组，纵形骨折he夹板治疗组和正常对照组。建立髁状突纵形骨折和he夹板治疗模型。分别在实验后3周、6周和12周取材，进行光镜、电镜观察。结果：骨折后3周，骨折侧的翼外肌下头肌纤维间水肿较重，个别部位出现肌核增多和内移。he夹板治疗组翼外肌肌纤维间的水肿较轻。对侧翼外肌下头以及骨折后6周，12周以及双侧嚼肌肌纤维末见异常。电镜下纵形骨折后3周，可见骨折侧翼外肌下头肌纤维间隙增大，线粒体变圆、增大，数量增多，对侧翼外肌下头以及骨折后6周，12周双侧翼外肌下头以及双侧嚼肌肌纤维未见异常。纵形骨折he夹板治疗组3周可见翼外肌下头肌纤维线粒体轻度变圆、数量稍有增多。结论：幼年小型猪髁状突纵形骨折后，骨折侧的翼外肌下头肌纤维在形态有变化，但翼外肌具有较强的适应能力，he夹板治疗能减轻咀嚼肌的改变。     

Treatment outcome of appliance therapy in temporomandibular disorder patients with myofascial pain after 6 and 12 months

Aim: To compare the long‐term effect of treatment with a stabilization appliance (group T) and treatment with a control appliance (group C) in temporomandibular disorder (TMD) patients with myofascial pain. Methods: In this controlled trial, 60 patients (mean age 29 years) with myofascial pain were evaluated after 10 weeks of treatment with either a stabilization appliance or a control appliance. All 60 patients were then assigned to 1 of 3 groups according to demand for treatment. Seventeen patients from group C requested another appliance and were given a stabilization appliance, thus creating a mixed group (group M). Results: A significant difference in improvement of overall subjective symptoms in an intent‐to‐treat analysis between groups T and C was found at the follow‐ups. In a survival analysis of treatment compliance, a significant difference was found between groups T and C. At the 6‐ and 12‐month follow‐ups, a significant reduction in myofascial pain, as measured on a visual analog scale, was found in all three groups. A significant decrease in frequency and intensity of myofascial pain was found in group T at the follow‐ups. A significant decrease in number of tender sites on the masticatory muscles was found in group T at the follow‐ups. Conclusion: The results support the conclusion that the positive treatment outcome obtained by use of a stabilization appliance to alleviate the signs and symptoms in patients with myofascial pain persisted after 6 and 12 months. Most patients in groups T and M reported positive changes in overall subjective symptoms in this trial. We therefore recommend use of the stabilization appliance in the treatment of TMD patients with myofascial pain.     

急、慢性咬合干扰致雌性大鼠咀嚼肌痛觉敏感的研究

目的:探讨咬合干扰对咀嚼肌机械压痛敏感性的影响。方法:对大鼠施以急、慢性咬合干扰,设空白对照和去咬合干扰对照,测量实验前及实验后15d颞肌和咬肌对von Frey尼龙毛刺激反应阈值,以累加logit模型作组间比较。结果:急、慢性咬合干扰均可增高咀嚼肌痛敏分值(P<0.05),急性咬合干扰组更明显,敏感程度由大到小为:干扰侧颞肌、干扰侧咬肌、干扰对侧颞肌(P<0.05),对干扰对侧咬肌的影响不明显。结论:咬合干扰可致咀嚼肌痛觉敏感。     

Management of painful temporomandibular joint clicking with different intraoral devices and counseling: a controlled study

Objective

The benefit of the use of some intraoral devices in arthrogenous temporomandibular disorders (TMD) patients is still unknown. This study assessed the effectiveness of the partial use of intraoral devices and counseling in the management of patients with disc displacement with reduction (DDWR) and arthralgia.

Materials and Methods

A total of 60 DDWR and arthralgia patients were randomly divided into three groups: group I (n=20) wore anterior repositioning occlusal splints (ARS); group II (n=20) wore the Nociceptive Trigeminal Inhibition Clenching Suppression System devices (NTI-tss); and group III (n=20) only received counseling for behavioral changes and self-care (the control group). The first two groups also received counseling. Follow-ups were performed after 2 weeks, 6 weeks and 3 months. In these sessions, patients were evaluated by means of a visual analogue scale, pressure pain threshold (PPT) of the temporomandibular joint (TMJ), maximum range of motion and TMJ sounds. Possible adverse effects were also recorded, such as discomfort while using the device and occlusal changes. The results were analyzed with ANOVA, Tukey’s and Fisher Exact Test, with a significance level of 5%.

Results

Groups I and II showed improvement in pain intensity at the first follow-up. This progress was recorded only after 3 months in Group III. Group II showed an increased in joint sounds frequency. The PPT values, mandibular range of motion and the number of occlusal contacts did not change significantly.

Conclusion

The simultaneous use of intraoral devices (partial time) plus behavioral modifications seems to produce a more rapid pain improvement in patients with painful DDWR. The use of NTI-tss could increase TMJ sounds. Although intraoral devices with additional counseling should be considered for the management of painful DDWR, dentists should be aware of the possible side effects of the intraoral device’s design.     

The hemodynamic effects of occlusal splint therapy on the masseter muscle of patients with myofascial pain accompanied by bruxism

ABSTRACT

Objective: The aim of this study was to investigate the hemodynamic effects of occlusal splint therapy on masseter muscles of patients with myofascial pain accompanied by bruxism with near-infrared spectroscopy (NIRS).

Methods: Twenty-four patients were randomly divided into two groups, where the study group (n = 12) received occlusal splint therapy and the control group (n = 12) underwent no therapy. Measurements were categorized into four subgroups: painful or painless control and painful or painless splint. Percent changes in deoxyhemoglobin (Hb), oxyhemoglobin (HbO₂), and OXY (HbO₂-Hb) values were calculated during a 1-month period.

Results: Statistically significant inter-session differences between painful-splint and painful-control groups were detected for NIRS oxygenation parameters, whereas inter-session differences between painless groups were statistically insignificant.

Conclusion: The results suggest that occlusal splint usage causes a decrease in hyperemic response, which is indicative of a decrease in masseter muscle contraction strength.     

慢性咀嚼肌疼痛患者面部和手指电刺激痛阈的初步观察

目的 通过测定和对比慢性咀嚼肌痛(masticatory muscle pain,MMP)患者及健康对照组双侧咬肌区、双侧颞肌区及左手中指的电刺激感觉阈和痛阈,初步探讨慢性MMP患者的三叉神经感觉功能是否出现变化.方法 收集慢性MMP患者12例(慢性MMP患者组),以及年龄、性别与慢性MMP患者组相似的健康对照者12名(健康对照组),分别行咬肌区、颞肌区疼痛的视觉模拟量表(visual analogy scale,VAS)评分;对两组双侧咬肌区、双侧颞肌区和左手中指的电刺激感觉阈和痛阈进行榆查.对两组5个部位的电刺激感觉阈和痛阈进行分析对比.结果 与健康对照组相比,慢性MMP患者组左侧咬肌、右侧咬肌、左侧颞肌、右侧颞肌和左手中指的电刺激痛阈均明显降低[分别为(5.9±1.1)、(5.7±1.0)、(5.3±1.4)、(5.5±1.7)和(5.2±1.0)mA],差异均有统计学意义(F=24.433,P＜0.001);而两组电刺激感觉阈的差异无统计学意义(F=0.341,P=0.959).慢性MMP患者组VAS得分与咀嚼肌电刺激感觉阈和痛阈之间未发现相关关系.结论 相比健康对照组,慢性MMP患者的咬肌、颞肌及手指的电刺激痛阈均显著降低,提示患者三叉神经感觉功能出现变化,其机制可能涉及高级神经中枢.     

Electromyographic power spectrum of jaw muscles during clenching in unilateral temporomandibular joint osteoarthritis patients

The relationship between temporomandibular joints (TMJ) osteoarthritis and masticatory muscle disorders is poorly understood. The data are sparse, the results are conflicting, and electromyographic (EMG) power spectrum analysis has not been used. The aims of this study were to compare the differences in EMG power spectrum during, and pressure pain thresholds (PPTs) before and after, sustained clenching in patients with unilateral TMJ osteoarthritis and healthy control subjects. Nineteen patients with unilateral TMJ osteoarthritis without masticatory muscle pain and 20 control subjects were evaluated. We measured EMG amplitudes at maximum voluntary contraction, median frequency from the EMG power spectrum during sustained clenching at 70% and PPTs before and after the clenching in both temporalis and masseter muscles. There were no significant differences in PPT decrease between muscles or between groups during sustained clenching. There were no significant differences in maximum voluntary contraction EMG activity ratios of affected to unaffected sides between groups, or of masseter to temporalis muscles between affected and unaffected side of patients with TMJ osteoarthritis. Median frequencies decreased from the beginning to the end of the sustained clench, and the interaction between group and clench was significant: the median frequency decrease was larger in the osteoarthritis group. Our results suggested that masticatory muscles of patients with unilateral TMJ osteoarthritis are more easily fatigued during sustained clenching than normal subjects.