Constructing the brief diagnostic criteria for temporomandibular disorders (bDC/TMD) for field testing.

BACKGROUND: Despite advances in temporomandibular disorders' (TMDs) diagnosis, the diagnostic process continues to be problematic in non-specialist settings. OBJECTIVE: To complete a Delphi process to shorten the Diagnostic Criteria for TMD (DC/TMD) to a brief DC/TMD (bDC/TMD) for expedient clinical diagnosis and initial management. METHODS: An international Delphi panel was created with 23 clinicians representing major specialities, general dentistry and related fields. The process comprised a full day workshop, seven virtual meetings, six rounds of electronic discussion and finally an open consultation at a virtual international symposium. RESULTS: Within the physical axis (Axis 1), the self-report Symptom Questionnaire of the DC/TMD did not require shortening from 14 items for the bDC/TMD. The compulsory use of the TMD pain screener was removed reducing the total number of Axis 1 items by 18%. The DC/TMD Axis 1 10-section examination protocol (25 movements, up to 12 sets of bilateral palpations) was reduced to four sections in the bDC/TMD protocol involving three movements and three sets of palpations. Axis I then resulted in two groups of diagnoses: painful TMD (inclusive of secondary headache), and common joint-related TMD with functional implications. The psychosocial axis (Axis 2) was shortened to an ultra-brief 11 item assessment. CONCLUSION: The bDC/TMD represents a substantially reduced and likely expedited method to establish (grouping) diagnoses in TMDs. This may provide greater utility for settings requiring less granular diagnoses for the implementation of initial treatment, for example non-specialist general dental practice.

Pain sensitivity after low-level clenching is influenced by preloading eccentric exercise.

PURPOSE: To examine the effect of preloading eccentric exercise on pain sensitivity in healthy volunteers. METHODS: In 20 healthy volunteers, pain-related sensations (6 items: pain, unpleasantness, fatigue, stiffness, tension, and soreness during maximum biting), and pain intensities induced by repeated electrical stimuli on the masseter and the hand palm were evaluated using a visual analog scale (VAS) of 0-100 mm. Eccentric exercise (6 min-test) or gum chewing (6 min-control) was used as preloading exercise to evaluate the effect on pain sensitivities before and after low-level clenching (15 min) performed 2 days after the preloading exercise. RESULTS: Eccentric exercise induced only low levels of pain-related sensations 2 days later. However, the time course of temporal summation induced by four repeated electrical stimuli on the masseter was influenced by the type of preloading exercise, i.e., temporal summation increased after the low-level clenching (P = 0.016) when preloading was done by the eccentric exercise, while no significant change was observed when preloading was done by the gum chewing. CONCLUSIONS: Eccentric exercise may facilitate pain sensitivity induced by subsequent low-level clenching via the central nervous system. In addition, it was demonstrated that pain sensitivity after the low-level clenching could be influenced by the type of preloading exercise. These experimental results may suggest that eccentric exercise could act as one of the triggering factors in the mechanism by which tooth clenching leads to a chronic pain condition in susceptible individuals.

Signal acquisition and analysis of ambulatory electromyographic recordings for the assessment of sleep bruxism: A scoping review.

BACKGROUND: Ambulatory electromyographic (EMG) devices are increasingly being used in sleep bruxism studies. EMG signal acquisition, analysis and scoring methods vary between studies. This may impact comparability of studies and the assessment of sleep bruxism in patients. OBJECTIVES: (a) To provide an overview of EMG signal acquisition and analysis methods of recordings from limited-channel ambulatory EMG devices for the assessment of sleep bruxism; and (b) to provide an overview of outcome measures used in sleep bruxism literature utilising such devices. METHOD: A scoping review of the literature was performed. Online databases PubMed and Semantics Scholar were searched for studies published in English until 7 October 2020. Data on five categories were extracted: recording hardware, recording logistics, signal acquisition, signal analysis and sleep bruxism outcomes. RESULTS: Seventy-eight studies were included, published between 1977 and 2020. Recording hardware was generally well described. Reports of participant instructions in device handling and of dealing with failed recordings were often lacking. Basic elements of signal acquisition, for example amplifications factors, impedance and bandpass settings, and signal analysis, for example rectification, signal processing and additional filtering, were underreported. Extensive variability was found for thresholds used to characterise sleep bruxism events. Sleep bruxism outcomes varied, but typically represented frequency, duration and/or intensity of masticatory muscle activity (MMA). CONCLUSION: Adequate and standardised reporting of recording procedures is highly recommended. In future studies utilising ambulatory EMG devices, the focus may need to shift from the concept of scoring sleep bruxism events to that of scoring the whole spectrum of MMA.

Differential diagnosis of toothache to prevent erroneous and unnecessary dental treatment.

Toothache represents the most common example of oro-facial pain. Its origin is mostly odontogenic, but several other conditions may mimic dental pain or present themselves as such. Well-known examples are myofascial pain, trigeminal neuropathies like neuralgia and painful post-traumatic trigeminal neuropathic pain, oro-facial neurovascular pains, cardiac pain and sinus disease. This review first discusses the current knowledge on the underlying pathophysiology of heterotopic tooth pain. Afterwards, several conditions potentially presenting as toothache will be illustrated regarding clinical features, diagnosis and management.

Signs and symptoms, quality of life and psychosocial data in 1331 post-traumatic trigeminal neuropathy patients seen in two tertiary referral centres in two countries.

BACKGROUND: Post-traumatic trigeminal neuropathy (PTN) is a disturbance of function or pathological change of the trigeminal nerve branches following trauma and has an important impact on patient's quality of life (QoL). OBJECTIVES: To provide diagnostic data on PTN and illustrate differences in aetiology, injured nerve, pain distribution, sensory profile and QoL between PTN subgroups. METHODS: 1331 patients with painful or non-painful PTN were retrospectively reviewed in two centres, extracting demographic data, time and cause of trauma, clinical findings including signs and symptoms, basic neurosensory testing, imaging modalities, treatments, and QoL or psychosocial assessment. RESULTS: More females were represented (70%) than males. The inferior alveolar nerve was most frequently damaged (60%) followed by the lingual nerve (28%). Wisdom teeth removal was considered the main cause (48%). Pain was reported in 63% of patients and pain frequency increased with age without clinically significant gender differences. Numbness was reported in 50% of PTN patients. Neurosensory testing showed larger affected dermatome involvement in persistent injuries, with no differences between the non-painful and painful PTN groups. Patient clustering indicated different sensory profile distributions when stratified according to aetiology or affected nerve branch. High interference with lifestyle was reported (78%), and patients suffering from painful PTN had worse QoL and psychosocial outcomes. CONCLUSION: Patients with painful PTN had different clinical profiles and lower QoL scores than those with non-painful PTN. Sensory profiles may provide important prognostic and therapeutic information; however, more research is needed to assess the clustering procedure and link these clusters to therapeutic guidelines.

Evidence-based dentistry or meta-analysis illness? A commentary on current publishing trends in the field of temporomandibular disorders and bruxism.

The field of temporomandibular disorders (TMDs) and bruxism research has recently witnessed a publishing trend leaning towards an overuse of systematic reviews (SRs) that contribute little or nothing to current knowledge. The majority of these seem to be more methodological exercises than manuscripts prepared to provide clinicians and researchers with up-to-date information to advance knowledge. In addition, given the increasing number of researchers who have been reviewing the dental literature on various topics without seemingly having any specific clinical or scientific background in the topic under review, the ultimate value of some SRs is questionable. Some of them end up producing meta-analyses (MAs) to give "numbers" (eg, risk measures and strength of association) that do not have a biological basis, due to the clinical heterogeneity of the articles being reviewed. Based on the above, the present commentary discusses this ongoing publishing trend that is affecting the TMD and bruxism field, which does not align well with the core principles of evidence-based dentistry (EBD). Ideally, EBD should be derived from a combination of literary, clinical and patient-centred information, but relying only on the bibliographic aspects could potentially expose less expert clinicians and other readers who merely browse the literature to incomplete, misdirected or even incorrect conclusions.

Effect of sleep restriction on somatosensory sensitivity in the oro-facial area: An experimental controlled study.

BACKGROUND: No studies have addressed the effect of SR on somatosensory function in the oro-facial area. OBJECTIVES: The aim of this study was to investigate the effect of sleep restriction (SR) on the somatosensory perception of the tip of the tongue. MATERIALS AND METHODS: Using a crossover study design, 13 healthy participants took part in a random order, to a two arms experiments: the SR and control/no SR-arms. For all participants, the Epworth Sleepiness Scale (ESS) was used to assess sleepiness and mechanical sensitivity, and pain detection threshold was estimated at the tongue tip and right thumb (as a body area control site). In the SR-arm of the study, on day one, we estimated sensory baseline perception and repeated tests on day two, after a night of voluntary SR, and on day 3, after a recovery night. In the second arm, same sensory tests were done but no SR was requested. RESULTS: Significantly more sleepiness was observed after SR in comparison with baseline and recovery testing days (P < 0.05). After SR, mechanical pain threshold on the tip of the tongue was significantly lower on day after SR (day 2) and a rebound, higher values, were observed on the third day (P < 0.05); no difference on thumb site. In the control arm, no SR and no significant differences between days were observed for all the variables of interest. CONCLUSIONS: The present results suggest that SR may affect somatosensory perception in the oro-facial area.

An RCT comparing patient-centred outcome variables of guided surgery (bone or mucosa supported) with conventional implant placement.

AIM: To assess in a randomized study the patient-centred outcome of two guided surgery systems (mucosa or bone supported) compared to conventional implant placement, in fully edentulous patients. MATERIAL AND METHODS: Fifty-nine patients (72 jaws) with edentulous maxillas and/ or mandibles, were consecutively recruited and randomly assigned to one of the treatment groups. Outcome measures were the Dutch version of the McGill Pain Questionnaire (MPQ-DLV), the Health-related quality of life instrument (HRQOL), visual analogue scales (VAS), the duration of the procedure, and the analgesic doses taken each day. RESULTS: Three hundred and fourteen implants were placed successfully. No statistical differences could be shown between treatment groups on pain response (MPQ-DLV), treatment perception (VAS) or number or kind of pain killers. For the HRQOLI-instrument, a significant difference was found between the Materialise Mucosa and Materialise Bone group at day 1 (p = 0.02) and day 2 (p = 0.01). For the duration of the surgery, a statistical difference (p = 0.005) was found between the Materialise mucosa and the Mental group, in favour of the first. CONCLUSION: In this study little difference could be found in the patient outcome variables of the different treatment groups. However there was a tendency for patients treated with conventional flapped implant placement to experience the pain for a longer period of time.

Age differences in pain sensitivity and effect of topical lidocaine on the tongue in healthy female subjects.

PURPOSE: To assess the sensitivity and the effect of topical lidocaine on the tongue by quantitative sensory testing, comparing healthy middle-aged female subjects with healthy young female subjects. METHODS: Sixteen healthy female subjects including eight in their fifties and eight in their twenties participated. They participated in two sessions at a 2-week interval in randomized order: lidocaine (experimental session) or placebo gel (placebo session) was applied on the tongue tip for 5min. The following parameters were taken on the tongue tip before and after application of the gel in each session: tactile detection threshold (TDT), filament-prick pain detection threshold (FPT), and numerical rating scale (NRS). RESULTS: An increase of both TDT and FPT and a decrease of NRS were found after lidocaine application in both middle-aged and young female subjects. In the elder females, an increase of TDT, FPT, and NRS was also found after placebo gel application. However, the changes were not statistically significant, except for FPT in middle-aged subjects. CONCLUSION: The reactions found after lidocaine application in middle-aged female subjects could be due to habituation as well as to the post-application effect of placebo gel. Placebo-induced changes appeared more pronounced in the elder females.

Methodological quality of a systematic review on physical therapy for temporomandibular disorders: influence of hand search and quality scales.

The validity of a systematic review depends on completeness of identifying randomised clinical trials (RCTs) and the quality of the included RCTs. The aim of this study was to analyse the effects of hand search on the number of identified RCTs and of four quality lists on the outcome of quality assessment of RCTs evaluating the effect of physical therapy on temporomandibular disorders. In addition, we investigated the association between publication year and the methodological quality of these RCTs. Cochrane, Medline and Embase databases were searched electronically. The references of the included studies were checked for additional trials. Studies not electronically identified were labelled as "obtained by means of hand search". The included RCTs (69) concerning physical therapy for temporomandibular disorders were assessed using four different quality lists: the Delphi list, the Jadad list, the Megens & Harris list and the Risk of Bias list. The association between the quality scores and the year of publication were calculated. After electronic database search, hand search resulted in an additional 17 RCTs (25%). The mean quality score of the RCTs, expressed as a percentage of the maximum score, was low to moderate and varied from 35.1% for the Delphi list to 54.3% for the Risk of Bias list. The agreement among the four quality assessment lists, calculated by the Interclass Correlation Coefficient, was 0.603 (95% CI, 0.389; 0.749). The Delphi list scored significantly lower than the other lists. The Risk of Bias list scored significantly higher than the Jadad list. A moderate association was found between year of publication and scores on the Delphi list (r = 0.50), the Jadad list (r = 0.33) and the Megens & Harris list (r = 0.43).

Prognostic factors, symptom evolution, and quality of life of posttraumatic trigeminal neuropathy.

ABSTRACT: Neurosensory disturbances (NSDs) caused by injury to the trigeminal nerve can affect many aspects of daily life. However, factors affecting the persistence of NSDs in patients with posttraumatic trigeminal neuropathies (PTTNs) remain largely unknown. The identification of such risk factors will allow for the phenotyping of patients with PTTNs, which is crucial for improving treatment strategies. We therefore aimed to identify the prognostic factors of NSD persistence, pain intensity, and quality of life (QoL) in patients with PTTNs and to use these factors to create a prognostic prediction model. We first performed a bivariate analysis using retrospective longitudinal data from 384 patients with NSDs related to posttraumatic injury of the trigeminal nerve (mean follow-up time: 322 ± 302 weeks). Bivariate and multivariate analyses were performed. The multivariable prediction model to predict persistent NSDs was able to identify 76.9% of patients with persistent NSDs, with an excellent level of discrimination (area under the receiver operating characteristic curve: 0.84; sensitivity: 81.8%; specificity: 70.0%). Furthermore, neurosensory recovery was significantly associated with sex; injury caused by local anesthesia, extraction, third molar surgery, or endodontic treatment; and the presence of thermal hyperesthesia. Pain intensity and QoL analysis revealed several factors associated with higher pain levels and poorer QoL. Together, our findings may aid in predicting patient prognosis after dental, oral, and maxillofacial surgery and might lead to personalized treatment options and improved patient outcomes.

Correlation of MRI and arthroscopic findings with clinical outcome in temporomandibular joint disorders: a retrospective cohort study.

BACKGROUND: Arthroscopy is a minimally invasive diagnostic tool and treatment strategy in patients suffering from temporomandibular disorders (TMD) when conservative treatment fails. This study aimed to find specific variables on pre-operative MRI or during arthroscopy that could predict success of arthroscopic lysis and lavage. METHODS: This retrospective analysis compared pre-operative maximum interincisal opening (MIO), pain and main complaint (pain, limited MIO or joint sounds) with results at short-term and medium-term follow-up (ST and MT respectively). Different variables scored on MRI or arthroscopy were used to make a stepwise regression model, subsequently a combined analysis was conducted using variables from both MRI and arthroscopy. RESULTS: A total of 47 patients (50 joints) met the inclusion criteria. The main complaint improved by 62 and 53% at ST and MT respectively. The absolute or probable absence of a crumpled disc scored on MRI predicted success at ST and MT (p = 0.0112 and p = 0.0054), and remained significant at MT in the combined analysis (p = 0.0078). Arthroscopic findings of degenerative joint disease predicted success at ST (p = 0.0178), absolute or probable absence of discal reduction scored during arthroscopy significantly predicted success in the combined analysis at ST (p = 0.0474). CONCLUSION: To improve selection criteria for patients undergoing an arthroscopic lysis and lavage of the TMJ, future research might focus on variables visualized on MRI. Although more research is needed, disc shape and in particular the absolute or probable absence of a crumpled disc might be used as predictive variable for success.

Orofacial quantitative sensory testing: Current evidence and future perspectives.

BACKGROUND AND OBJECTIVE: Orofacial quantitative sensory testing (QST) is an increasingly valuable psychophysical tool for evaluating neurosensory disorders of the orofacial region. Here, we aimed to evaluate the current evidence regarding this testing method and to discuss its future clinical potential. DATA TREATMENT: We conducted a literature search in Medline, Embase and Scopus for English-language articles published between 1990 and 2019. The utilized search terms included QST, quantitative, sensory testing and neurosensory, which were combined using the AND operator with the terms facial, orofacial, trigeminal, intraoral and oral. RESULTS: Our findings highlighted many methods for conducting QST-including method of levels, method of limits and mapping. Potential stimuli also vary, and can include mechanical or thermal stimulation, vibration or pinprick stimuli. Orofacial QST may be helpful in revealing disease pathways and can be used for patient stratification to validate the use of neurosensory profile-specific treatment options. QST is reportedly reliable in longitudinal studies and is thus a candidate for measuring changes over time. One disadvantage of QST is the substantial time required; however, further methodological refinements and the combination of partial aspects of the full QST battery with other tests and imaging methods should result in improvement. CONCLUSIONS: Overall, orofacial QST is a reliable testing method for diagnosing pathological neurosensory conditions and assessing normal neurosensory function. Despite the remaining challenges that hinder the use of QST for everyday clinical decisions and clinical trials, we expect that future improvements will allow its implementation in routine practice.

Diagnostic accuracy of temporomandibular disorder pain tests: a multicenter study.

AIMS: To estimate the diagnostic accuracy of the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) clinical examination and of the dynamic/static tests for the recognition of TMD pain. Since the diagnosis of TMD pain is especially complicated in persistent orofacial pain patients, the test outcomes in persistent TMD pain patients were contrasted to those in two control groups: a group of persistent dental pain patients and a group of pain-free subjects. METHODS: In 125 persistent TMD pain patients, 88 persistent dental pain patients, and 121 pain-free subjects, a blind and standardized clinical examination was performed. RESULTS: For the RDC/TMD, sensitivity (88%) was high and specificity was low (pain-free group: 71%; dental pain group: 45%). For the dynamic/static tests, sensitivity was 65% and specificities were 91% and 84%, respectively. Comparing the outcomes of the two examinations showed higher positive likelihood ratios for dynamic/static tests (P < .001), and lower negative likelihood ratios for the RDC/TMD examination (P < .01). CONCLUSION: For the confirmation of a suspicion of TMD pain, it is better to rely on positive dynamic/static tests. To confirm the absence of TMD pain, it is better to rely on a negative RDC/TMD examination.

The Biomechanical Effect of the Sagittal Split Ramus Osteotomy on the Temporomandibular Joint: Current Perspectives on the Remodeling Spectrum.

The sagittal split ramus osteotomy is a key approach for treating dentofacial deformities. Although it delivers excellent results, the sagittal split ramus osteotomy is believed to induce stress to the temporomandibular joint. Potential stress inducers could be classified as intra- and postoperative factors resulting in an inflammatory response and molecular cascades, which initiate physiological remodeling. Occasionally, this process exceeds its capacity and causes pathological remodeling, through either degenerative joint disease or condylar resorption. Hard evidence on how orthognathic surgery causes inflammation and how this inflammation is linked to the spectrum of remodeling remains scarce. Current concepts on this matter are mainly based on clinical observations and molecular mechanisms are extrapolated from fundamental research in other body parts or joints. This perspective study provides an overview of current knowledge on molecular pathways and biomechanical effects in temporomandibular joint remodeling. It provides research directions that could lead to acquiring fundamental evidence of the relation of orthognathic surgery and inflammation and its role in remodeling. Performing osteotomies in animal models and identifying inflammatory mediators as well as their effect on the joint seem promising. Patients affected by pathological remodeling can also provide samples for histological as well as molecular analysis. Individual susceptibility analysis by linking certain suspect phenotypes to genetic variation could identify the cause and molecular pathway responsible for degenerative joint disease and condylar resorption, ultimately leading to clinically applicable treatment and prevention strategies.

Effect of sleep restriction on somatosensory sensitivity including occlusal sensation in the orofacial area.

PURPOSE: To investigate the effect of sleep restriction on somatosensory sensitivity related to occlusion. METHODS: Twelve healthy participants participated in an experimental voluntary total sleep restriction (SR) study. In a study design, they were invited to sleep as usual, normal sleep (NS) or to restrict their sleep for four nights. Following the SR night, participants were followed for 3 consecutive days including the 2 sleep nights. In NS experiment, all participants were instructed to maintain NS both nights. During all nights, actigraphy data were collected and total sleep time was estimated. On days before and after sleep conditions, all participants underwent measurements of tactile detection threshold (TDT), interocclusal detection threshold (IDT), perception of unpleasantness (POU), and the Epworth sleepiness scale (ESS). RESULTS: As expected, total sleep time on the first night in SR experiment was significantly shorter than on the second night in SR experiment and on the first night in NS experiment (P<0.05). ESS values on Day-2 following SR experiment were significantly higher than on Day-1 and Day-3 in SR experiment and Day-2 in NS experiment (P<0.05). There were no significant differences in TDT and IDT between each day at each measurement point in both experiments. POU was significantly lower on Day-2 in SR experiment than on Day-1 and Day-3 in SR experiment and on Day-2 in NS experiment (P<0.05). CONCLUSIONS: The present results suggest that SR affects to occlusal sensation related to POU.

Jaw Exercises in the Treatment of Temporomandibular Disorders-An International Modified Delphi Study.

AIMS: To investigate whether an international consensus exists among TMD experts regarding indications, performance, follow-up, and effectiveness of jaw exercises. METHODS: A questionnaire with 31 statements regarding jaw exercises was constructed. Fourteen international experts with some geographic dispersion were asked to participate in this Delphi study, and all accepted. The experts were asked to respond to the statements according to a 5-item verbal Likert scale that ranged from "strongly agree" to "strongly disagree." The experts could also leave free-text comments, which was encouraged. After the first round, the experts received a compilation of the other experts' earlier responses. Some statements were then rephrased and divided to clarify the essence of the statement. Subsequently, the experts were then asked to answer the questionnaire (32 statements) again for the second round. Consensus was set to 80% agreement or disagreement. RESULTS: There is consensus among TMD experts that jaw exercises are effective and can be recommended to patients with myalgia in the jaw muscles, restricted mouth opening capacity due to hyperactivity in the jaw closing muscles, and disc displacement without reduction. The patients should always be instructed in an individualized jaw exercise program and also receive both verbal advice and written information about the treatment modality. CONCLUSION: This Delphi study showed that there is an international consensus among TMD experts that jaw exercises are an effective treatment and can be recommended to patients with TMD pain and disturbed jaw function.

The influence of psychological state on the masseteric exteroceptive suppression reflex and somatosensory function.

OBJECTIVE: This study examined the somatosensory function in the trigeminal region and quantitative measures of the exteroceptive suppression (ES) period in the masseteric EMG, in relation to a psychological evaluation. METHODS: The ES in the surface EMG was recorded from the left masseter muscle in 12 men and 12 women. The stimulation intensity at which the ES appeared first and the lowest intensity at which the subjects reported it to be painful were defined as the electrical reflex threshold and electrical pain threshold, respectively. Three experimental sessions were scheduled. The state and trait anxiety inventory was used to evaluate the psychological status. RESULTS: The electrical reflex threshold significantly decreased (p<0.01), and the electrical pain threshold significantly increased (p<0.01) over the sessions in line with the effect on the state anxiety inventory (p<0.05). CONCLUSIONS: The present results illustrate that reflex parameters and electrical pain thresholds are associated with state anxiety. Possibly, habituation or decreased fear from the experimental set-up may play a role. SIGNIFICANCE: This is important when electrophysiology or quantitative sensory testing is used to assess trigeminal nociception, e.g., in orofacial pain conditions.

Tactile and pain thresholds in patients with myofascial pain of the jaw muscles: a case-control study.

AIMS: To compare the tactile detection threshold, the filament-prick pain detection threshold, the pressure pain threshold, and the pressure pain tolerance detection threshold at multiple measuring points in the orofacial region and at the thenar muscle of symptom-free subjects and patients with myofascial pain of the masticatory muscles. METHODS: Twenty patients (age range: 25 to 55 years) and 20 healthy subjects (age range: 25 to 55 years) were recruited. The tactile detection threshold and the filament prick-pain detection threshold were measured at the cheek skin overlying the central part of the left and right masseter muscles, at the right thenar muscle and at the tip of the tongue, using Semmes-Weinstein monofilaments. The pressure pain threshold and the pressure pain tolerance threshold were measured at the central part of the masseter muscle and on the thenar muscle, using a pressure algometer. The intensity of pain perceived during the assessment of filament prick-pain detection threshold, pressure pain threshold, and the pressure pain tolerance threshold was scored on visual analog scales. RESULTS: The tongue tip had the lowest filament prick-pain detection thresholds as compared to the other sites. Filament prick-pain detection thresholds of the tongue and thumb sites were significantly lower in myofascial pain patients than in controls. Pressure pain thresholds of the masseter and thenar muscles were significantly lower in patients with myofascial pain than in control subjects whereas pressure pain tolerance thresholds did not differ significantly between patients and controls. CONCLUSIONS: The findings of the present study show topographic variations in the pain responses to different stimulus modalities. Different pain responses were also found between patients with myofascial pain and control subjects and were interpreted to support theories of centrally mediated pain for temporomandibular disorders.

Effect of 8% lidocaine spray on the sensory and pain thresholds of the skin of the face and hands evaluated by quantitative sensory testing.

BACKGROUND: Recently, we examined the effects of 2% lidocaine gel on the tactile sensory and pain thresholds of the face, tongue and hands of symptom-free individuals using quantitative sensory testing (QST); its effect was less on the skin of the face and hands than on the tongue. Consequently, instead of 2% lidocaine gel, we examined the effect of 8% lidocaine spray on the tactile sensory and pain thresholds of the skin of the face and hands of healthy volunteers. METHODS: Using Semmes-Weinstein monofilaments, QST of the skin of the cheek and palm (thenar skin) was performed in 20 healthy volunteers. In each participant, two topical sprays were applied. On one side, 0.2 mL of 8% lidocaine pump spray was applied, and on the other side, 0.2 mL of saline pump spray was applied as control. In each participant, QST was performed before and 15 min after each application. Pain intensity was measured using a numeric rating scale (NRS). RESULTS: Both the tactile detection threshold and filament-prick pain detection threshold of the cheek and thenar skin increased significantly after lidocaine application. A significant difference between the effect of lidocaine and saline applications was found on the filament-prick pain detection threshold only. NRS of the cheek skin and thenar skin decreased after application of lidocaine, and not after application of saline. CONCLUSION: The significant effect of applying an 8% lidocaine spray on the sensory and pain thresholds of the skin of the face and hands can be objectively scored using QST.