Temporomandibular disorders: INfORM/IADR key points for good clinical practice based on standard of care.

OBJECTIVE: To present a list of key points for good Temporomandibular Disorders (TMDs) clinical practice on behalf of the International Network for Orofacial Pain and Related Disorders Methodology (INfORM) group of the International Association for Dental, Oral and Craniofacial Research (IADR). METHODS: An open working group discussion was held at the IADR General Session in New Orleans (March 2024), where members of the INfORM group finalized the proposal of a list of 10 key points. RESULTS: The key points covered knowledge on the etiology, diagnosis, and treatment. They represent a summary of the current standard of care for management of TMD patients. They are in line with the current need to assist general dental practitioners advance their understanding and prevent inappropriate treatment. CONCLUSIONS: The key points can be viewed as a guiding template for other national and international associations to prepare guidelines and recommendations on management of TMDs adapted to the different cultural, social, educational, and healthcare requirements.

Jaw-neck motor function 2 years after whiplash trauma.

BACKGROUND: There is limited knowledge about the possible long-term effects on jaw motor function after whiplash trauma. OBJECTIVES: The primary aim was to evaluate integrated jaw and head-neck movement amplitudes during jaw function in individuals 2 years after whiplash trauma, compared to controls. The secondary aim was to evaluate changes between the acute stage and a 2-year follow-up in terms of jaw and head-neck movement amplitudes during jaw function. METHODS: This study included 28 cases exposed to a whiplash trauma 2 years earlier (13 women) and 28 controls (13 women) without previous neck trauma. Head and jaw movement amplitudes were recorded during maximal jaw opening-closing movements using an optoelectronic 3D recording system. For a subpopulation of 12 cases and 15 controls, recordings had also been performed in the acute stage after the whiplash trauma. Jaw and head movement amplitudes were analysed using linear regression with group and sex as independent variables. The subpopulation longitudinal analysis was adjusted for movement amplitudes at baseline. RESULTS: Jaw movement amplitudes were significantly associated with group (coefficient: -0.359: 95% CI: -10.70 to -1.93, p = .006) with smaller amplitudes of jaw movements for whiplash cases. Head movement amplitudes were not associated with group (coefficient: -0.051, 95% CI: -4.81 to 3.20, p = .687). In the longitudinal analysis, both jaw and head movement amplitudes showed significant associations between baseline and the 2-year follow-up. CONCLUSION: The present findings indicate that the effects on jaw function in terms of jaw opening capacity in the acute stage after whiplash trauma do not spontaneously recover.

Whiplash trauma did not predict jaw pain after 2 years: an explorative study.

OBJECTIVES: To explore predictive factors for the development and maintenance of jaw pain over a 2-year period. METHODS: One hundred nineteen cases (73 women) and 104 controls (59 women), mean age 34.9 years (SD 13.9), attended baseline and 2-year follow-up examinations. The whiplash cases visited the emergency department at Umeå University Hospital, Sweden, with neck pain within 72 h following a car accident, and baseline questionnaires were answered within a month after trauma. Controls were recruited via advertising. Inclusion criteria were age 18-70 years, living in Umeå municipality and Swedish speaking. The exclusion criterion was neck fracture for cases and a previous neck trauma for controls. Validated questionnaires recommended in the standardized Research Diagnostic Criteria for temporomandibular disorders were used. Jaw pain was assessed by two validated screening questions answered with "yes" or "no." A logistic regression analysis was used to predict the outcome variable jaw pain (yes/no) after 2 years. RESULTS: Whiplash trauma did not increase the odds of development of jaw pain over a 2-year period (OR 1.97, 95% CI 0.53-7.38). However, non-specific physical symptoms (OR 8.56, 95% CI 1.08-67.67) and female gender (OR 4.89, 95% CI 1.09-22.02) did increase the odds for jaw pain after 2 years. CONCLUSION: The development and maintenance of jaw pain after whiplash trauma are primarily not related to the trauma itself, but more associated with physical symptoms. CLINICAL RELEVANCE: The development of jaw pain in connection with a whiplash trauma needs to be seen in a biopsychosocial perspective, and early assessment is recommended.

Bruxism and dental implants: A systematic review and meta-analysis.

BACKGROUND: Overload from bruxism may affect survival of dental implants. OBJECTIVES: To evaluate implant failure and marginal bone loss (MBL) in patients presenting with probable bruxism compared to non-bruxers. The study was registered in PROSPERO (CRD42021238397). METHODS: An electronic search September 2022 in PubMed/Medline, Web of Science and Science Direct was combined with a hand search. Two independent reviewers carried out abstract screening, full-text assessment, quality assessment (National Institutes of Health tool) and data extraction. Only studies that provided information on self-report and clinical examination needed for the diagnosis of at least 'probable' bruxism were included. A pairwise random-effect meta-analysis was carried out. RESULTS: In total 1338 studies were identified, and after screening and full-text assessment 27 studies that presented data on 2105 implants in probable bruxers and 10 264 implants in non-bruxers were included, with 138 and 352 implant failures in respective groups. the meta-analysis showed that implants placed in probable bruxers had a higher risk of failure than in non-bruxers (OR 2.189; 95% CI 1.337, 3.583, p = .002). A meta-regression showed that follow-up time did not affect this OR. Eighteen studies provided general data on MBL but did not report results separated between bruxers and non-bruxers. Therefore, an analysis of MBL was not possible. CONCLUSION: The results of the present systematic review show that implants placed in probable bruxers present a significantly higher risk of failure than implants placed in non-bruxers. This should be considered in treatment planning and management of implant patients.

Standardised Tool for the Assessment of Bruxism.

OBJECTIVE: This paper aims to present and describe the Standardised Tool for the Assessment of Bruxism (STAB), an instrument that was developed to provide a multidimensional evaluation of bruxism status, comorbid conditions, aetiology and consequences. METHODS: The rationale for creating the tool and the road map that led to the selection of items included in the STAB has been discussed in previous publications. RESULTS: The tool consists of two axes, specifically dedicated to the evaluation of bruxism status and consequences (Axis A) and of bruxism risk and etiological factors and comorbid conditions (Axis B). The tool includes 14 domains, accounting for a total of 66 items. Axis A includes the self-reported information on bruxism status and possible consequences (subject-based report) together with the clinical (examiner report) and instrumental (technology report) assessment. The Subject-Based Assessment (SBA) includes domains on Sleep Bruxism (A1), Awake Bruxism (A2) and Patient's Complaints (A3), with information based on patients' self-report. The Clinically Based Assessment (CBA) includes domains on Joints and Muscles (A4), Intra- and Extra-Oral Tissues (A5) and Teeth and Restorations (A6), based on information collected by an examiner. The Instrumentally Based Assessment (IBA) includes domains on Sleep Bruxism (A7), Awake Bruxism (A8) and the use of Additional Instruments (A9), based on the information gathered with the use of technological devices. Axis B includes the self-reported information (subject-based report) on factors and conditions that may have an etiological or comorbid association with bruxism. It includes domains on Psychosocial Assessment (B1), Concurrent Sleep-related Conditions Assessment (B2), Concurrent Non-Sleep Conditions Assessment (B3), Prescribed Medications and Use of Substances Assessment (B4) and Additional Factors Assessment (B5). As a rule, whenever possible, existing instruments, either in full or partial form (i.e. specific subscales), are included. A user's guide for scoring the different items is also provided to ease administration. CONCLUSIONS: The instrument is now ready for on-field testing and further refinement. It can be anticipated that it will help in collecting data on bruxism in such a comprehensive way to have an impact on several clinical and research fields.

Research routes on awake bruxism metrics: Implications of the updated bruxism definition and evaluation strategies.

BACKGROUND: With time, due to the poor knowledge on it epidemiology, the need to focus on awake bruxism as a complement of sleep studies emerged. OBJECTIVE: In line with a similar recent proposal for sleep bruxism (SB), defining clinically oriented research routes to implement knowledge on awake bruxism (AB) metrics is important for an enhanced comprehension of the full bruxism spectrum, that is better assessment and more efficient management. METHODS: We summarised current strategies for AB assessment and proposed a research route for improving its metrics. RESULTS: Most of the literature focuses on bruxism in general or SB in particular, whilst knowledge on AB is generally fragmental. Assessment can be based on non-instrumental or instrumental approaches. The former include self-report (questionnaires, oral history) and clinical examination, whilst the latter include electromyography (EMG) of jaw muscles during wakefulness as well as the technology-enhanced ecological momentary assesment (EMA). Phenotyping of different AB activities should be the target of a research task force. In the absence of available data on the frequency and intensity of wake-time bruxism-type masticatory muscle activity, any speculation about the identification of thresholds and criteria to identify bruxers is premature. Research routes in the field must focus on the improvement of data reliability and validity. CONCLUSIONS: Probing deeper into the study of AB metrics is a fundamental step to assist clinicians in preventing and managing the putative consequences at the individual level. The present manuscript proposes some possible research routes to advance current knowledge. At different levels, instrumentally based and subject-based information must be gathered in a universally accepted standardised approach.

Smartphone application to report awake bruxism: Development and testing of the Swedish version and a pilot study to evaluate family history in young adults and their parents.

BACKGROUND: Together with psychosocial and hereditary factors, bruxism is a possible risk factor for orofacial pain. Bruxism is defined as a masticatory muscle activity characterized by repetitive or sustained tooth contact, or by bracing or thrusting of the mandible. A smartphone application to report awake bruxism (AB) has been developed and translated into more than 25 languages. OBJECTIVE(S): To translate the application into Swedish, adapt it to Swedish culture and conduct a study to evaluate the usability of the application for studies on family history and associated risk factors. METHODS: Translation and cultural adaption of the Swedish version of the application (BruxApp) was carried out in a four-step sequential process. Ten young adults (22-30 years) were recruited together with ten parents (42-67 years) and reported their AB with the application over two seven-day periods. Pain, stress and parafunctional behaviours were assessed by questionnaires. RESULTS: The back translation check showed minimal discrepancies between the translation and the English version. Participants did not report any problems with the application. Response rates for both groups were 65%. A difference in frequency of AB was shown between young adults and parents (22.0% vs. 12.5%, p < .001). A positive moderate correlation was found between AB and stress (r = 0.54, p = .017). CONCLUSION: The use of application strategies enables data collection on AB which can be used in both clinical and research settings. The results suggest that the Swedish version is ready for implementation and for studies on the relationships between AB, family history and psychosocial factors.

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.

Patients' experiences of temporomandibular disorders and related treatment.

BACKGROUND: Temporomandibular disorders (TMD) are common and therefore managed by dentists on a daily basis. However, patients with TMD consistently go undetected and therefore untreated in dentistry. The reasons for these shortcomings have not been fully explored, specifically with regard to patients' perspectives. Therefore, this study aimed to explore patients' experiences of TMD and related treatment, with special focus on the experiences of having TMD, factors related to seeking care, and perspectives on received treatment. METHODS: Purposive sampling was used to recruit adult patients at the Public Dental Health services (PDHS) in the Region of Västerbotten, Sweden, during 2019. Individual semi-structured interviews were conducted and analysed using Qualitative Content Analysis. Sixteen patients were interviewed (ten women and six men, 20-65 years). The interviews probed the patients' perspectives of having TMD, seeking care, and receiving treatment. All participants were also examined according to the Diagnostic Criteria for TMD (DC/TMD) and qualified for at least one DC/TMD diagnosis. RESULTS: The data analysis led to the main theme Seeking care when the situation becomes untenable, but dental care fails to meet all needs. The patients expressed worry and social discomfort because of the symptoms but still strived to have an as normal daily life as possible. However, severe symptoms and associated consequences compelled them to seek professional help. Experiences of distrust together with challenges to access the PDHS were identified and related to the patients' unfulfilled expectations. CONCLUSIONS: Patients' reported experiences indicate that receiving timely and appropriate care is more of an unfulfilled expectation than the current state of management of patients with TMD in dentistry.

Development of integrated jaw-neck motor function in children at 6, 10 and 13 years of age compared to adults: A kinematic longitudinal study.

BACKGROUND: The functional integration of the jaw and neck motor systems, of great importance to everyday oral activities, is established in early childhood. Detailed characterisation of this developmental progress is largely unknown. OBJECTIVE: To establish developmental changes in jaw-neck motor function in children over the ages 6-13 years compared to adults. METHODS: Jaw and head movement kinematics during jaw opening-closing and chewing were longitudinally recorded in 20 Swedish children (8 girls) at 6 (6.3 ± 0.4), 10 (10.3 ± 0.3) and 13 (13.5 ± 0.7) years of age and 20 adults (9 women, 28.2 ± 6.7). Movement amplitudes, jaw movement cycle time (CT), coefficient of variation (CV) and head/jaw ratio for amplitudes were analysed. Linear mixed effect analysis and Welch's t-test were used. RESULTS: Children showed pronounced movement variability and longer CT at 6 and 10 years old during opening and chewing (p < .001). Compared to adults, 6-year-olds showed higher head/jaw ratios (p < .02) and longer CT (p < .001) during opening and chewing, and higher CV-head (p < .001) during chewing. Whereas 10-year-olds showed larger jaw and head amplitudes (p < .02) and longer CT (p < .001) during opening, and longer CT (p < .001) and higher CV-head (p < .001) during chewing. For 13-year-olds, longer CT (p < .001) during chewing was found. CONCLUSION: Children showed pronounced movement variability and longer movement cycle time at 6-10 years and developmental progress in jaw-neck integration from 6 to 13 years, with 13-year-olds displaying adult-like movements. These results add new detailed understanding to the typical development of integrated jaw-neck motor function.

Ecological Momentary Assessment of Awake Bruxism Behaviors: A Scoping Review of Findings from Smartphone-Based Studies in Healthy Young Adults.

BACKGROUND: The recent introduction of ecological momentary assessment (EMA) smartphone-based strategies has allowed achieving some interesting data on the frequency of different awake bruxism (AB) behaviors reported by an individual in the natural environment. OBJECTIVE: The present paper aims to review the literature on the reported frequency of AB based on data gathered via smartphone EMA technology. METHODS: On September 2022, a systematic search in the Pubmed, Scopus and Google Scholar databases was performed to identify all peer-reviewed English-language studies assessing awake bruxism behaviors using a smartphone-based Ecological Momentary Assessment. The selected articles were assessed independently by two authors according to a structured reading of the articles' format (PICO). RESULTS: A literature search, for which the search terms "Awake Bruxism" and "Ecological Momentary Assessment" were used, identified 15 articles. Of them, eight fulfilled the inclusion criteria. The results of seven studies using the same smartphone-based app reported a frequency of AB behaviors in the range between 28.3 and 40% over one week, while another investigation adopted a different smartphone-based EMA approach via WhatsApp using a web-based survey program and reported an AB frequency of 58.6%. Most included studies were based on convenience samples with limited age range, highlighting the need for more studies on other population samples. CONCLUSIONS: Despite the methodological limits, the results of the reviewed studies provide a standpoint for comparison for future studies on the epidemiology of awake bruxism behaviors.

Clinical signs in the jaw and neck region following whiplash trauma-A 2-year follow-up.

BACKGROUND: Pain in the orofacial region is often reported after whiplash trauma. However, prospective studies evaluating clinical signs related to orofacial pain and disability in whiplash populations are rare. The aim of the present study was to evaluate clinical signs related to pain and dysfunction in orofacial and neck regions after whiplash trauma, in a short- and long-term perspective. METHODS: In total, 84 cases (48 women) diagnosed with neck distortion after a car accident and 116 controls (68 women) were examined within 1 month, and 49 cases (27 women) and 71 controls (41 women) were re-examined 2 years later. Outcome measures were pain on palpation of jaw and neck muscles and maximal jaw opening. Analysis was performed using mixed-models. RESULTS: Cases and women were at higher risk for pain on palpation of jaw muscles (OR:7.7; p < 0.001 and OR:3.2; p = 0.010 respectively) and neck muscles (OR:12.7; p < 0.001 and OR:2.9; p = 0.020 respectively) but with no significant effect of time. Cases and women also had lower maximal jaw opening (-3.1; p = 0.001 and -3.3; p = 0.001 respectively). There was no significant time effect, but a significant interaction between cases and time (2.2; p = 0.004). CONCLUSION: Individuals with a whiplash trauma present a higher risk for pain on palpation in jaw and neck muscles both in a short- and long-term perspective, but show normal jaw movements. No time effect suggests that cases do not spontaneously improve nor get worse. Investigating pain on palpation in the jaw and neck muscles after whiplash trauma can identify individuals at risk for developing long-term orofacial pain and dysfunction. SIGNIFICANCE: Orofacial pain is often reported after whiplash trauma but most previous studies concerning orofacial pain in whiplash populations have been questionnaire studies. Cases with a previous whiplash trauma and women, in general, had higher risk for pain on palpation in the jaw and neck region. Investigating pain on palpation after a whiplash trauma can help to identify individuals at risk of developing long-lasting pain in the orofacial region.

Marginal bone loss around dental implants: comparison between matched groups of bruxer and non-bruxer patients: A retrospective case-control study.

PURPOSE: To compare marginal bone loss (MBL) around dental implants in a group of bruxers in relation to a matched group of non-bruxers. METHODS: The present record-based retrospective study included patients selected from individuals treated with dental implants at one specialist clinic in Malmö. Only implants not lost and with baseline radiographs taken within 12 months after implant placement and with a minimum of 36 months of radiological follow-up were considered for inclusion. Univariate linear regression models and a linear mixed-effects model were performed. RESULTS: Two hundred and four patients (104 bruxers, 100 non-bruxers), with a total of 811 implants (416 in bruxers, 395 in non-bruxers) were included in the study. The results of the linear mixed-effects model suggested that bruxism, smoking, age, region of the jaws, implant diameter, and prosthesis type had a statistically significant influence on MBL over time. Individuals who are both bruxers and smokers showed greater MBL when compared to individuals who are either a bruxer or smoker, or neither (p < 0.001). CONCLUSIONS: Bruxism is suggested to increase the risk of MBL over time, as well as higher age, smoking, and the combination of bruxism and smoking. Other factors that showed a correlation with increased MBL were implant diameter, region of the jaws, and prosthesis type, but it is not possible to draw robust conclusions for these factors, as the categories of these variables were very unbalanced.

A New Instrument for Assessing Work-Related Body Mechanics and Strain in the General Population.

Clinical pain is often linked to poor body mechanics, with individuals sometimes presenting multiple painful disorders. Such disorders may be influenced by behaviors that affect the general resiliency and health of the musculoskeletal system. We aimed to develop a self-reported scale using the Malmö Diet and Cancer Study questions on work-related body mechanical exposures. An expert panel identified 41 variables having content validity for musculoskeletal problems. Exploratory factor analysis was conducted on a random selection of 50% of the cohort (n = 6,789 adults); the remaining was reserved for confirmatory factor analyses (CFA), item response theory (IRT) item calibration, and differential item functioning investigations. Supported by standard measure development methods and fit criteria, the final unidimensional item bank contains 13 items. Overall CFA statistics (root mean square error of approximation = .09; comparative fit index = .96; Tucker-Lewis index = .96; standardized root mean residuals = .05) indicated excellent single-factor model fit and appropriateness of IRT modeling and calibration. Expert review and item information values (score-precision) guided selection of an 8-item short form with acceptable score-level reliabilities (≥.70) for T-scores = 39-80+. This measure provides reliable assessment of body mechanics strain in adults and can be useful when evaluating different contributions to musculoskeletal problems affecting pain-treatment success in future clinical research. PERSPECTIVE: This article presents the development and psychometric properties of a new measure, "Work-related Body Mechanics and Strain Scale (WR-BMSS)." The scale has 13-items or alternatively an 8-item short form. This measure could potentially help clinicians who seek to assess how musculoskeletal problems may contribute to patient pain and disability.

The development of the Standardised Tool for the Assessment of Bruxism (STAB): An international road map.

This paper summarises the background reasoning and work that led to the selection of the items included in the Standardised Tool for the Assessment of Bruxism (STAB), also introducing the list of items. The instrument is currently being tested for face validity and on-field comprehension. The underlying premise is that the different motor activities included in the bruxism spectrum (e.g. clenching vs. grinding, with or without teeth contact) potentially need to be discriminated from each other, based on their purportedly different aetiology, comorbidities and potential consequences. Focus should be on a valid impression of the activities' frequency, intensity and duration. The methods that can be used for the above purposes can be grouped into strategies that collect information from the patient's history (subject-based), from the clinical assessment performed by an examiner (clinically based) or from the use of instruments to measure certain outcomes (instrumentally based). The three strategies can apply to all aspects of bruxism (i.e. status, comorbid conditions, aetiology and consequences). The STAB will help gathering information on many aspects, factors and conditions that are currently poorly investigated in the field of bruxism. To this purpose, it is divided into two axes. Axis A includes the self-reported information on bruxism status and potential consequences (subject-based report) together with the clinical (examiner report) and instrumental assessment (technology report). Axis B includes the self-reported information (subject-based report) on factors and conditions that may have an etiological or comorbid role for bruxism. This comprehensive multidimensional assessment system will allow building predictive model for clinical and research purposes.

Current Knowledge and Future Perspectives on Awake Bruxism Assessment: Expert Consensus Recommendations.

Awake bruxism (AB) is differentiated from sleep bruxism (SB) by the differences in etiology, comorbidities, and consequences related to the different spectrum of muscle activities exerted in relation to the different circadian manifestations. Furthermore, less literature data are available on AB than on SB. The introduction of ecological momentary assessment (EMA) strategies has allowed for collecting valuable data on the frequency of the different activities reported by an individual in his/her natural environment. This strategy has been further improved with the recent use of smartphone technologies. Recent studies have described an average frequency of AB behaviors, within the range of 23-40% for otherwise healthy young adults. An association between AB and some psychological traits has emerged, and the findings have indicated that patients with musculoskeletal symptoms (e.g., temporomandibular joint and/or muscle pain, muscle stiffness, and fatigue) report higher AB frequencies. Preliminary data suggest that muscle bracing and teeth contact are the most commonly reported behaviors, while teeth clenching is much less frequently reported than commonly believed previously. Report of teeth grinding during wakefulness is almost absent. This paper has critically reviewed the currently available approaches for the assessment of AB. In addition, some future perspectives and suggestions for further research have been provided.

The association between myofascial orofacial pain with and without referral and widespread pain.

OBJECTIVES: Pain referral on palpation has been suggested to be a clinical sign of central sensitization potentially associated with widespread pain conditions. Our aim was to evaluate if myofascial pain with referral is a better predictor for widespread pain when compared to no pain or local myofascial pain. MATERIALS AND METHODS: Individuals at the Public Dental services in Västerbotten, Sweden, were randomly invited based on their answers to three screening questions for temporomandibular disorders (TMD). In total, 300 individuals (202 women, 20-69 yrs) were recruited, and examined according to the Diagnostic Criteria for TMD (DC/TMD) after completion of a body pain drawing. Widespread pain was considered present when seven or more pain sites were reported on the widespread pain index. A binary logistic regression model, adjusted for the effect of age and gender were used to evaluate the association between myofascial orofacial pain and widespread pain. RESULTS: Widespread pain was reported by 31.3% of the study sample. There was a 57.3% overlap with myofascial pain. Widespread pain was associated to myofascial orofacial pain with and myofascial orofacial pain (OR 4.83 95% CI 2.62-9.05 and OR 11.62 95% CI 5.18-27.88, respectively). CONCLUSION: These findings reinforce the existing knowledge on the overlap between painful TMD and other chronic pain conditions.

Pain's Adverse Impact on Training-Induced Performance and Neuroplasticity: A Systematic Review.

Motor training is a widely used therapy in many pain conditions. The brain's capacity to undergo functional and structural changes i.e., neuroplasticity is fundamental to training-induced motor improvement and can be assessed by transcranial magnetic stimulation (TMS). The aim was to investigate the impact of pain on training-induced motor performance and neuroplasticity assessed by TMS. The review was carried out in accordance with the PRISMA-guidelines and a Prospero protocol (CRD42020168487). An electronic search in PubMed, Web of Science and Cochrane until December 13, 2019, identified studies focused on training-induced neuroplasticity in the presence of experimentally-induced pain, 'acute pain' or in a chronic pain condition, 'chronic pain'. Included studies were assessed by two authors for methodological quality using the TMS Quality checklist, and for risk of bias using the Newcastle-Ottawa Scale. The literature search identified 231 studies. After removal of 71 duplicates, 160 abstracts were screened, and 24 articles were reviewed in full text. Of these, 17 studies on acute pain (n = 7) or chronic pain (n = 10), including a total of 258 patients with different pain conditions and 248 healthy participants met the inclusion criteria. The most common types of motor training were different finger tasks (n = 6). Motor training was associated with motor cortex functional neuroplasticity and six of seven acute pain studies and five of ten chronic pain studies showed that, compared to controls, pain can impede such trainings-induced neuroplasticity. These findings may have implications for motor learning and performance and with putative impact on rehabilitative procedures such as physiotherapy.

Fear of Movement and Catastrophizing in Participants with Temporomandibular Disorders.

AIMS: To assess differences in catastrophizing and kinesiophobia in relation to areas of pain and somatic symptoms among participants with temporomandibular disorders (TMDs) and controls. METHODS: In total, 401 participants (333 women, 68 men, mean age: 45.8 years) in the TMJ Impact Project were examined in accordance with the Diagnostic Criteria for TMD, including clinical examination (Axis I) and psychosocial assessment (Axis II) augmented with imaging of the temporomandibular joint (TMJ). Of these, 218 participants had a painful TMD pain diagnosis, 63 had a nonpainful TMD diagnosis, and 111 had no TMD. Nine participants had missing data. Participants completed the Pain Catastrophizing Scale, Tampa Scale for Kinesiophobia, Areas of Pain figure, and the Patient Health Questionnaire-15 for assessing somatic symptoms. RESULTS: Compared to controls, participants with TMD pain showed higher levels of catastrophizing (P = .017), kinesiophobia (P < .001), areas of pain (P < .001), and somatic symptoms (P < .001). Participants with nonpainful TMD showed a higher level of kinesiophobia (P < .001) than controls. There was a positive correlation between catastrophizing and kinesiophobia for participants with TMD pain (r = 0.33, P < .001) and nonpainful TMD (r = 0.42, P < .001). DISCUSSION: The results suggest more fear of movement, as well as an association between catastrophizing and fear of movement, in participants with TMD pain and in participants with nonpainful TMD compared to controls. Assessment and management of fear of movement as well as catastrophizing may be useful as part of individualized treatment strategies for patients with TMD.