Central sensitization inventory is associated with psychological functioning but not with psychophysical assessment of pain amplification.

BACKGROUND: The central sensitization inventory (CSI) is a questionnaire that has been widely used as a tool for assessing symptoms associated with sensitization. However, its ability to identify individuals with this phenomenon has recently been questioned. The aim of this study was to assess the correlation of CSI with psychosocial and psychophysical factors in patients with painful TMD diagnosed according to diagnostic criteria for temporomandibular disorders (DC/TMD) and asymptomatic controls, as well as to determine the influence of these variables on the CSI scores variations. METHODS: This cross-sectional study with 77 patients diagnosed with painful TMD according to DC/TMD and 101 asymptomatic controls realized correlations between CSI, WUR, PPT, CPM and psychosocial questionnaires (HADS, PSQI, PCS and PSS). In cases where significant correlations existed, the potential influence of these variables on CSI variation was explored through linear regression analysis. RESULTS: It has been found that the CSI correlates with psychosocial variables (anxiety, depression, catastrophizing, sleep and stress) (p < 0.0006) regardless of the presence of TMD, and that 68.9% of the variation in CSI scores can be influenced by all these variables (except stress). On the contrary, the CSI does not correlate with psychophysical parameters indicative of pain amplification (wind-up ratio and conditioned pain modulation) (p > 0.320). CONCLUSION: CSI is more associated with psychosocial factors than with more robust indicators of probable central sensitization (CS), thus limiting its utility in detecting this phenomenon both in TMD patients and healthy individuals. SIGNIFICANCE STATEMENT: The research highlights a noteworthy relationship between the central sensitization inventory and psychological factors, emphasizing their substantial influence on inventory values. This correlation offers crucial insights into mental health markers within the questionnaire. Additionally, the lack of connection with pain amplification implies a necessary re-evaluation of the inventory's diagnostic suitability, especially in cases of painful temporomandibular disorders. Thus, caution is urged in its application for identifying CS in these individuals.

Impact of streptozotocin-induced diabetes on experimental masseter pain in rats.

This study aimed to assess the influence of streptozotocin (STZ)-induced diabetes on the nociceptive behavior evoked by the injection of hypertonic saline (HS) into the masseter muscle of rats. Forty male rats were equally divided into four groups: a) isotonic saline control, which received 0.9% isotonic saline (IS), (Ctrl-IS); b) hypertonic saline control, which received 5% HS (Ctrl-HS); c) STZ-induced diabetic, which received IS, (STZ-IS); d) STZ-induced diabetic, which received HS (STZ-HS). Experimental diabetes was induced by a single intraperitoneal injection of STZ at dose of 60 mg/kg dissolved in 0.1 M citrate buffer, and 100 µL of HS or IS were injected into the left masseter to measure the nociceptive behavior. Later on, muscle RNA was extracted to measure the relative expression of the following cytokines: cyclooxygenase-2 (COX-2), tumor necrosis factor (TNF-α), and interleukins (IL)-1ß, -2, -6, and -10. One-way analysis of variance (ANOVA) was applied to the data (p < 0.050). We observed a main effect of group on the nociceptive response (ANOVA: F = 11.60, p < 0.001), where the Ctrl-HS group presented the highest response (p < 0.001). However, nociceptive response was similar among the Ctrl-IS, STZ-IS, and STZ-HS group (p > 0.050). In addition, the highest relative gene expression of TNF-α and IL-6 was found in the masseter of control rats following experimental muscle pain (p < 0.050). In conclusion, the loss of somatosensory function can be observed in deep orofacial tissues of STZ-induced diabetic rats.

Somatosensory alterations after single-unit dental implant immediate loading: A 1-year follow-up study.

OBJECTIVE: This cohort study aimed to assess the incidence of somatosensory alterations after implant surgery using standardized quantitative and qualitative sensory testing. METHODS: 33 participants with single-tooth loss, undergoing immediate implant loading were included. Quantitative Sensory Testing (QST) and Qualitative Sensory Testing (QualST) were conducted at eight time points over a year (baseline to 1 year). Two-Way Repeated Measures ANOVA and post hoc Tukey test were used on QST values and Cochran Q test on QualST. RESULTS: The study revealed significant increase in thermal thresholds overtime. At the operated side, overall Cold Pain Threshold (extraoral: p = 0.030; intraoral: p < 0.001), and Cold Detection Threshold (intraoral: p < 0.001) increased overtime. In contralateral region, maxilla Cold Detection Threshold (extraoral: p = 0.024; intraoral: p = 0.031), Warm Detection Threshold (extraoral: p = 0.026; intraoral: p = 0.047) and overall Cold Pain Threshold (extraoral and intraoral: p < 0.001) also increased. QualST showed extraoral pinprick (p = 0.032) and intraoral pinprick (p = 0.000), cold (p = 0.000) and touch (p = 0.002) stimuli abnormalities overtime. CONCLUSIONS: Somatosensory alterations after implant surgery were detected in both quantitative and qualitative sensory assessments, but rapidly decreased during the first follow-ups, and then continuously until 1-year. CLINICAL SIGNIFICANCE: This study provides clinical and controlled evidence on the real effect of the somatosensory alterations overtime, leading to a better understanding of neurosensory behaviour after single-tooth dental implant rehabilitation.

Influence of psychometric and sleep quality features on painful mechanical sensitivity and pain modulation in patients with temporomandibular disorders.

Investigating the collective impact of psychometric properties and sleep quality on pain sensitivity in temporomandibular disorder (TMD) patients could improve clinical management strategies. OBJECTIVE: Assessing whether combined psychometric properties and sleep quality impact painful mechanical sensitivity and pain modulation in TMD patients. MATERIALS AND METHODS: A cross-sectional study using secondary data analysis of 77 TMD patients and 101 controls. All participants completed questionnaires characterizing their psychometric profile (anxiety, depression, stress and catastrophizing) and sleep quality, alongside psychophysical tests for painful mechanical sensory (mechanical pain threshold (MPT), pressure pain threshold (PPT), and wind-up ratio (WUR)) and conditioned pain modulation (CPM). Participants were grouped into "High distress" or "Low distress" categories based on psychometric properties and sleep quality using hierarchical cluster and k-means analyses. Multiple linear regression evaluated the influence of TMD, age, and the distress cluster on MPT, WUR, PPT, and CPM in masseter and thenar muscles. Differences were statistically significant when p < 0.05. RESULTS: The presence of TMD was the strongest predictor of mechanical painful sensitivity in the trigeminal region (MPT[F(3,174) = 51.902;p < .001;R2 = .463]; TMD presence (ß = -.682) / PPT[F(3,174) = 15.573;p < .001;R2 = .198] TMD presence (ß = -.452), and extra-trigeminal (MPT[F(3,174) = 35.897;p < .001;R2 = .382] TMD (ß = -.647) / CPM [F(3,174) = 4.106;p < .05;R2 = .050] TMD presence (ß = .197). Furthermore, neither the high distress group nor the low distress group were able to significantly influence the variation of the values of any of the psychophysical variables evaluated (p > .05). CONCLUSIONS: There is not a significant influence of impairment clusters based on psychological variables and sleep quality on painful mechanical sensitivity and pain modulation, regardless of the presence of TMD. CLINICAL RELEVANCE: This outcome suggests that psychosocial factors and sleep quality may not play a decisive role in the sensory-discriminative aspect of pain, particularly concerning painful TMD.

Referred pain is associated with greater odontogenic spontaneous pain and a heightened pain sensitivity in patients with symptomatic irreversible pulpitis.

BACKGROUND: Symptomatic irreversible pulpitis often results in heightened reactions to thermal stimuli such as pain evoked by a cold stimulus, and spontaneous odontogenic pain (unprovoked pain). OBJECTIVE: This study primarily compared the clinical manifestations of odontogenic spontaneous pain and pain provoked by cold stimulus specifically focusing on their sensory discriminative characteristics (intensity, duration and quality) between symptomatic irreversible pulpitis patients with and without referred pain. METHODS: Twenty-three patients with symptomatic irreversible pulpitis with referred pain and 12 patients without referred pain were included in this cross-sectional study. The following outcomes were assessed: odontogenic spontaneous pain and its descriptors; pain evoked by cold stimulus and qualitative sensory testing before and after local anaesthesia; referred pain location; use of analgesic medication; complementary anaesthesia efficacy. T-test, chi-squared and McNemar tests were applied to the data (p < .50). RESULTS: Patients with referred pain presented a greater odontogenic pain intensity (p < .05) when considered the average of the last 24 h. These patients also showed higher pain rating and pain descriptors (p < .05). Intensity and duration of the pain evoked by cold stimulus in the non-affected contralateral tooth at baseline were higher for patients with referred pain (p < .05). CONCLUSION: Symptomatic irreversible pulpitis patients with referred pain present greater odontogenic spontaneous pain and a heightened pain sensitivity. Therefore, patients with referred pain seem more complex from a pain severity perspective, supporting the clinical utility of discriminating symptomatic irreversible pulpitis with and without referred pain.

Nutrition and chronic musculoskeletal pain: A narrative review and directions for temporomandibular disorder research and management.

BACKGROUND: Recent evidence suggests neuro-immune mechanisms may link dietary patterns to chronic painful conditions (CPC). In the research field of oro-facial pain (OFP), studies focuses primarily on dietary mechanical limitations due to pain and dysfunction. OBJECTIVE: This narrative review aimed to overview the role of nutrition on CPC, with emphasis on temporomandibular disorder (TMD), enlightening OFP researcher on dietary assessment possibilities and providing directions for studies in the field of OFP and nutrition. METHODS: A PubMed database search was performed using the MeSH and non-MeSH descriptors: "temporomandibular joint disorder"; "orofacial pain"; "musculoskeletal pain"; "chronic pain disorders"; "nutrition"; "diet"; "dietary therapy"; "dietary intake" and "inflammation". No time restrictions were applied. Literature reviews, systematic reviews, meta-analyses and clinical and pre-clinical trials were included. RESULTS: Exogenous oxidants from unhealthy dietary patterns may contribute to peripheral and central pro-inflammatory immune signalling leading to peripheral and central sensitization. Furthermore, diets rich in bioactive compounds are suggested to contribute to pain management of CPC. High dietary intake of ultra-processed foods impacts the quality of the diet and shows adverse health outcomes. In this context, the role of nutrition on TMD remains overlooked. CONCLUSION: Considering diet may influence CPC, allied with the scarcity of studies evaluating the role of nutrition on TMD, well-designed clinical trials based on dietary assessments and measurements capable of evaluating food quality, UPF consumption and nutrient adequacy-added to serum nutrient levels evaluation-are suggested.

Prediction of duloxetine efficacy in addition to self-management in painful temporomandibular disorders: A randomised, placebo-controlled clinical trial.

BACKGROUND: Conditioned pain modulation (CPM) is a potential predictor of treatment response that has not been studied in temporomandibular disorders (TMD). OBJECTIVES: We conducted a randomised, double-blind, placebo-controlled trial (RCT) of duloxetine in addition to self-management (SM) strategies to investigate its efficacy to reduce pain intensity in painful TMD patients. Moreover, we investigated whether baseline CPM would predict the duloxetine efficacy to reduce TMD pain intensity. METHODS: Eighty participants were randomised to duloxetine 60 mg or placebo for 12 weeks. The primary outcomes were the change in the pain intensity from baseline to week-12 and CPM-sequential paradigm at baseline. Safety, physical and emotional functioning outcomes were also evaluated. RESULTS: Of 80 participants randomised, 78 were included in intention-to-treat analysis. Pain intensity decreased for SM-duloxetine and SM-placebo but did not differ between groups (p = .82). A more efficient CPM was associated with a greater pain intensity reduction regardless of the treatment group (p = .035). Physical and emotional functioning did not differ between groups, but adverse events (p = .014), sleep impairment (p = .003) and catastrophizing symptoms (p = .001) were more prevalent in SM-duloxetine group. CONCLUSION: This study failed to provide evidence of a beneficial effect of adding duloxetine to SM strategies for treatment of painful TMD. Nonetheless, this RCT has shown the feasibility of applying pain modulation assessment to predict short-term treatment response in painful TMD patients, which confirms previous finds that CPM evaluation may serve a step forward in individualising pain treatment.

Secondary bruxism: A valid diagnosis or just a coincidental finding of additional masticatory muscle activity? A narrative review of literature.

INTRODUCTION: Bruxism is defined as a repetitive masticatory muscle activity that can manifest it upon awakening (awake bruxism-AB) or during sleep (sleep bruxism-SB). Some forms of both, AB and SB can be associated to many other coexistent factors, considered of risk for the initiation and maintenance of the bruxism. Although controversial, the term 'secondary bruxism' has frequently been used to label these cases. The absence of an adequate definition of bruxism, the non-distinction between the circadian manifestations and the report of many different measurement techniques, however, are important factors to be considered when judging the literature findings. The use (and abuse) of drugs, caffeine, nicotine, alcohol and psychoactive substances, the presence of respiratory disorders during sleep, gastroesophageal reflux disorders and movement, neurological and psychiatric disorders are among these factors. The scarcity of controlled studies and the complexity and interactions among all aforementioned factors, unfortunately, does not allow to establish any causality or temporal association with SB and AB. The supposition that variables are related depends on different parameters, not clearly demonstrated in the available studies. OBJECTIVES: This narrative review aims at providing oral health care professionals with an update on the co-risk factors and disorders possibly associated with bruxism. In addition, the authors discuss the appropriateness of the term 'secondary bruxism' as a valid diagnostic category based on the available evidence. CONCLUSION: The absence of an adequate definition of bruxism, the non-distinction between the circadian manifestations and the report of many different measurement techniques found in many studies preclude any solid and convincing conclusion on the existence of the 'secondary' bruxism.

Facial representation of paroxysmal hemicrania and associated temporomandibular disorder: a case report / Hemicrania paroxística com representação na face e associação com disfunção temporomandibular: relato de caso

ABSTRACT Paroxysmal Hemicrania is a trigeminal autonomic cephalalgia described as a severe and strictly unilateral pain, which occurs in paroxysms at orbital, supraorbital and/ or temporal region. A 45-year-old woman presented to an orofacial pain specialist reporting severe, burning, throbbing, strictly right-sided headache associated to ipsilateral autonomic symptoms and orofacial pain. The pain was perceived on the maxillary region followed by pain spread to the head. Interdisciplinary evaluation, along with absolute responsiveness to indomethacin and normal Brain Magnetic Resonance imaging, led to the diagnosis of primary Episodic paroxysmal hemicrania with facial representation and myofascial pain of masticatory muscles. Dentists should be aware of paroxysmal hemicrania with facial representation and the possibility of temporomandibular disorder coexistence, in order to avoid misdiagnosis and inadequate management. Paroxysmal hemicrania may be first perceived on the face and may be associated with interparoxysmal pain. In these cases, efficient anamnesis and clinical evaluation followed by interdisciplinary approach is needed.

RESUMO A Hemicrania Paroxística é uma cefalalgia autonômica trigeminal descrita como uma dor severa e estritamente unilateral, que ocorre em paroxismos na região orbital, supraorbital e/ou temporal. Uma mulher de 45 anos de idade apresentou-se a um especialista em dor orofacial, referindo uma cefaleia intensa, ardente, latejante, estritamente do lado direito, associada a sintomas autonómicos ipsilaterais e dor orofacial. A dor era sentida na região maxilar, seguida de dor que se estendia à cabeça. A avaliação interdisciplinar, aliada à resposta absoluta à indometacina e à normalidade em ressonância magnética cerebral, levou ao diagnóstico de hemicrania paroxística episódica primária com representação facial e dor miofascial dos músculos mastigatórios. Os médicos dentistas devem estar atentos à hemicrania paroxística com representação facial e à possibilidade de coexistência de Disfunção Temporomandibular, de modo a evitar diagnósticos incorretos e um tratamento inadequado. A hemicrania paroxística pode ser percebida inicialmente na face e pode estar associada à dor interparoxística. Nesses casos, é necessária uma anamnese e avaliação clínica eficientes, seguidas de abordagem interdisciplinar.

Duloxetine in addition to self-management for painful temporomandibular disorders: a post hoc responder analysis of a randomized, placebo-controlled clinical trial

Abstract Aim To identify the phenotypic characteristics of individuals with temporomandibular disorders (TMD) who may benefit from adding duloxetine to self-management (SM) strategies. Methodology This was a post hoc exploratory analysis of a randomized, placebo-controlled clinical trial with SM-duloxetine (duloxetine 60 mg/day plus SM strategies for 12 weeks) in adult participants with painful TMD. The primary outcome was the proportion of responders to treatment (individuals with ≥ 30% reduction in pain intensity) in SM-duloxetine and SM-placebo group at week 12. For responder analysis, five phenotyping domains recommended by Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials were assessed: pain, psychological, sleep, quantitative sensory testing, and conditioned pain modulation. Relative risk (RR), 95% confidence intervals (CI), and absolute risk reduction were calculated. Results Among participants treated with SM-duloxetine, severe pain intensity (RR 1.33, 95% CI: 0.56, 3.17), pain disability (RR 1.30, 95% CI: 0.63, 2.67), ≥ 1 painful comorbidity (RR 1.48, 95% CI: 0.57, 3.79), and anxiety symptoms (RR 1.80, 95% CI: 0.75, 4.34) were associated with greater likelihood of response to treatment. Among individuals treated with SM-placebo, only temporal summation of pain was associated with greater likelihood of response to treatment. Conclusion Personalized medicine may be implemented in painful TMD management, and phenotype characteristics related to pain and psychological domains may predict which individuals with painful TMD are more likely to respond to the addition of serotonin and norepinephrine reuptake inhibitors to SM strategies to clinically and significantly reduce pain intensity.

Impact of streptozotocin-induced diabetes on experimental masseter pain in rats

Abstract This study aimed to assess the influence of streptozotocin (STZ)-induced diabetes on the nociceptive behavior evoked by the injection of hypertonic saline (HS) into the masseter muscle of rats. Forty male rats were equally divided into four groups: a) isotonic saline control, which received 0.9% isotonic saline (IS), (Ctrl-IS); b) hypertonic saline control, which received 5% HS (Ctrl-HS); c) STZ-induced diabetic, which received IS, (STZ-IS); d) STZ-induced diabetic, which received HS (STZ-HS). Experimental diabetes was induced by a single intraperitoneal injection of STZ at dose of 60 mg/kg dissolved in 0.1 M citrate buffer, and 100 μL of HS or IS were injected into the left masseter to measure the nociceptive behavior. Later on, muscle RNA was extracted to measure the relative expression of the following cytokines: cyclooxygenase-2 (COX-2), tumor necrosis factor (TNF-α), and interleukins (IL)-1β, -2, -6, and -10. One-way analysis of variance (ANOVA) was applied to the data (p < 0.050). We observed a main effect of group on the nociceptive response (ANOVA: F = 11.60, p < 0.001), where the Ctrl-HS group presented the highest response (p < 0.001). However, nociceptive response was similar among the Ctrl-IS, STZ-IS, and STZ-HS group (p > 0.050). In addition, the highest relative gene expression of TNF-α and IL-6 was found in the masseter of control rats following experimental muscle pain (p < 0.050). In conclusion, the loss of somatosensory function can be observed in deep orofacial tissues of STZ-induced diabetic rats.

Level of knowledge of pediatric dentists on awake and sleep bruxism in children / Nível de conhecimento de odontopediatras sobre bruxismo em vigília e do sono em crianças

Objetivo: Avaliar o conhecimento dos odontopediatras sobre o bruxismo em crianças e discutir o tema de acordo com as evidências científicas atuais. Material e Métodos: 425 odontopediatras preencheram um formulário online composto por 17 afirmações sobre bruxismo em crianças durante a vigília e o sono. Os dados foram interpretados de duas formas distintas: conhecimento do participante e conhecimento das afirmações. O conhecimento do participante foi considerado aceitável quando pelo menos 10 das 17 afirmações foram respondidas corretamente. O conhecimento das afirmações foi considerado satisfatório quando foi respondido corretamente por, pelo menos, 70% dos participantes. Resultados: O número médio de respostas corretas foi de 9,73 (±3,41). Cinquenta e dois por cento dos participantes demonstraram conhecimentos aceitáveis e apenas 4 afirmações obtiveram uma percentagem de respostas consideradas satisfatórias. Conclusão: O conhecimento dos odontopediatras sobre o bruxismo em crianças em vigília e durante o sono é deficiente, sugerindo-se a educação continuada sobre o tema, a fim de evitar diagnósticos equivocados e condutas inadequadas (AU)

Objective: To evaluate the knowledge of pediatric dentists concerning bruxism in children and explore the subject according to the latest scientific evidence. Material and Methods: Four hundred and twenty-five pediatric dentists filled out an online form comprising 17 statements regarding awake and sleep bruxism in children. Data was analyzed in two distinct ways: participant's knowledge and statements knowledge. Participant ́s knowledge was considered acceptable when at least 10 out of 17 statements were correctly answered. Statements knowledge was considered satisfactory when correctly answered by, at least, 70% of the participants. Results: The average of correct answers was 9.73 (±3.41). Fifty-two percent of the participants showed acceptable knowledge and only 4 statements obtained a percentage of answers considered satisfactory. Conclusion: The knowledge of pediatric dentists regarding awake and sleep bruxism in children is deficient, and continuous education concerning this topic is suggested to avoid misdiagnosis and inadequate management (AU)

Divergence between confidence and knowledge of endodontists regarding non-odontogenic pain.

INTRODUCTION: This study aimed to assess the self-reported levels of confidence and knowledge related to non-odontogenic pain among a group of Brazilian endodontists. METHODOLOGY: A total of one hundred and forty-six endodontists affiliated with the Brazilian Society of Endodontics participated in the survey. The questionnaire, distributed via email or WhatsApp, contained inquiries designed to gauge self-perceived confidence and knowledge concerning non-odontogenic pain. The practitioners were categorized into four groups based on their self-reported familiarity with various orofacial pain types, classified as either sufficient or insufficient, and on their engagement in ongoing educational programs related to orofacial pain. Data were analyzed by Chi-Square Test and Fischer's exact test (p<0.05). RESULTS: Overall, self-reported confidence about non-odontogenic pain was high, especially for endodontists who considered their knowledge about orofacial pain sufficient, regardless of whether they had (71.1% - 97.8%) or not (35.7% - 96.4%) been continuously involved in education courses on orofacial pain. In general, self-reported knowledge about non-odontogenic pain was insufficient (0% - 42%), except in the question about how they would act in cases of pain that persists beyond the normal healing time after an endodontic procedure (70.6% - 81.9%). In general, endodontists are confident in their diagnosis and treatment of non-odontogenic pain. Nonetheless, this confidence did not correlate with a commensurate knowledge depth of. Thus, specialization courses in endodontics should highly consider training and qualifying these professionals in the diagnosis of non-odontogenic pain.

Influence of awake bruxism behaviors on fatigue of the masticatory muscles in healthy young adults.

The present cross-sectional study aimed to analyze the relationship between awake bruxism and fatigue of masticatory muscles in healthy young adults. For this purpose, 121 graduate students participated in this study. Frequency of awake bruxism was collected for 7 consecutive days by ecological momentary assessment (EMA) using an online survey (mentimeter). Muscle fatigue was tested one day after EMA assessment, which consisted of voluntarily and continuously clenching at 30% (kgf/cm2) of maximum bite force (MBF) until exhaustion. The percentage of change in MBF after the clenching task, as compared to the MBF before the clenching task was measured. The average frequency of awake bruxism was 45.5% during 7 days. Sustained clenching resulted in a significant reduction in MBF values in the total sample (p < 0.05). Nevertheless, no significant correlation was found between frequency of awake bruxism behaviors and percent of change in MBF and endurance time during the fatigue test. Therefore, it can be concluded that young healthy adults present a relatively high frequency of awake bruxism behaviors that do not seem to impact the degree of masticatory muscle fatigue.

Experimental pain thresholds and psychosocial features across menstrual cycle in myofascial orofacial pain compared to healthy individuals: cross-sectional study / Limiares de dor experimental e características psicossociais ao longo do ciclo menstrual na dor miofascial orofacial em comparação com indivíduos saudáveis: estudo transversal

ABSTRACT BACKGROUND AND OBJECTIVES: The hormonal impact on pain perception during the menstrual cycle is a major focus of study, and further elucidation in temporomandibular disorders (TMD) field is necessary. Thus, this cross-sectional study evaluated experimental pain thresholds, psychosocial features, and clinical pain report on TMD women across menstrual cycle versus healthy controls. METHODS: A total of 220 women's clinical files were screened, with 80 selected and divided into control group (healthy individuals, n=40) and TMD group (myofascial pain, n=40). Regarding the menstrual cycle phases, the files were divided into Pre-Luteal and Luteal. The Perceived Stress Scale (PSS), Pain Catastrophizing Scale (PCS), Mechanical Pain Threshold (MPT), Wind-up (WUR), Pressure Pain Threshold (PPT), Conditioned Pain Modulation (CPM) and Visual Analogue Scale (VAS) were analyzed at a 5% significance level, by Two-Way ANOVA test and post hoc Tukey test. RESULTS: PSS and PCS were significantly different between TMD and control group (p<0.001), regardless of menstrual cycle. Healthy individuals in the Luteal phase presented higher MPT values compared to the other phases (p<0.001). PPT showed significant difference across menstrual phases (p=0.022), but no differences in multiple comparisons. VAS values showed no difference between menstrual cycle phases (p=0.376). CONCLUSION: Finally, healthy individuals in the Luteal phase have higher MPT and PPT values on the orofacial region. Pain report in patients with TMD showed no difference throughout the menstrual cycle, showing that small alterations on experimental pain thresholds may not be clinically relevant. The presence of chronic pain seems to be more related to psychosocial features than hormonal fluctuations.

RESUMO JUSTIFICATIVA E OBJETIVOS: O impacto do ciclo menstrual na percepção da dor é um foco importante de estudo, sendo necessária uma maior elucidação na disfunção temporomandibular (DTM). Assim, este estudo transversal avaliou limiares de dor experimental, características psicossociais e relatos de dor em mulheres com DTM ao longo do ciclo menstrual, comparadas com controles saudáveis. MÉTODOS: 220 prontuários de mulheres foram analisados, sendo 80 selecionados para os grupos de controle (saudáveis, n=40) e DTM (dor miofascial, n=40). Nas fases do ciclo menstrual, as pacientes foram divididas nas categorias Pré-Luteal e Luteal. Os instrumentos Escala de Estresse Percebido (PSS), Escala de Pensamentos Catastróficos (PCS), Limiar de Dor Mecânica (MPT), Wind-up Ratio (WUR), Limiar de Dor à Pressão (PPT), Modulação Condicionada da Dor (CPM) e Escala analógica visual (EAV) foram analisados com nível de significância de 5%, pelos testes ANOVA de dois fatores e Tukey post hoc. RESULTADOS: As escalas PSS e PCS foram significativamente diferentes entre os grupos DTM e controle (p<0,001), independentemente do ciclo menstrual. Indivíduos saudáveis na fase luteal apresentaram MPT maior em comparação com outras fases (p,0,001). O PPT mostrou diferença significativa entre as fases menstruais (p=0,022), sem diferença nas comparações múltiplas. Os valores da EAV não apresentaram diferença entre as fases menstruais (p=376). CONCLUSÃO: Indivíduos saudáveis na fase luteal têm MPT e PPTl maior na região orofacial. Os relatos de dor em pacientes com DTM não mostraram diferença ao longo do ciclo menstrual, indicando que pequenas alterações nos limiares experimentais podem ser clinicamente relevantes. A presença de dor crônica parece estar mais relacionada com características psicossociais do que com flutuações hormonais.

Influence of genetic polymorphisms on mechanical pain sensitivity and endogenous pain modulation of trigeminal and spinal areas.

BACKGROUND: Previous evidence indicates significant association between genetic polymorphisms and phenotypes related to pain sensitivity in patients with temporomandibular disorders (TMD). Despite the important advances in cataloguing diverse factors such as sleep disorders, anxiety and depression, the interrelated mechanisms of painful TMD aetiopathogenesis still need investigation. OBJECTIVES: This case-control study aimed to evaluate the influence of genetic polymorphisms (rs6296, rs6295, rs1799971, rs4680, rs4633, rs4818) and psychosocial factors on the mechanical pain sensitivity and endogenous pain modulation in women with painful TMD and asymptomatic controls. METHODS: We evaluated six independent variables: anxiety levels, depression, stress, sleep quality, pain catastrophising and genetic polymorphisms, and four dependent variables: mechanical pain threshold (MPT), pressure pain threshold (PPT), wind-up ratio (WUR) and conditioned pain modulation (CPM) collected at masseter (trigeminal) and hand (spinal) areas in a sample of 95 painful TMD patients and 85 controls. A regression model was used to test the possible effect of the independent variables on dependent variables. RESULTS: The regression model was significant for MPT (F11,168  = 9.772; R2  = .390). Painful TMD diagnoses and sleep quality were associated with trigeminal MPT (B coefficient = -.499; and B coefficient = -.211, respectively). WUR was associated with rs6295 and rs6746030, respectively, for the spinal and the trigeminal area. CONCLUSION: Genetic polymorphisms had a slight contribution to endogenous pain modulation as indicated by the significant association with WUR but did not contribute to mechanical pain sensitivity. On the other hand, the presence of painful TMD and the sleep quality contributed significantly to mechanical pain sensitivity.

Influence of awake bruxism behaviors on fatigue of the masticatory muscles in healthy young adults

Abstract The present cross-sectional study aimed to analyze the relationship between awake bruxism and fatigue of masticatory muscles in healthy young adults. For this purpose, 121 graduate students participated in this study. Frequency of awake bruxism was collected for 7 consecutive days by ecological momentary assessment (EMA) using an online survey (mentimeter). Muscle fatigue was tested one day after EMA assessment, which consisted of voluntarily and continuously clenching at 30% (kgf/cm2) of maximum bite force (MBF) until exhaustion. The percentage of change in MBF after the clenching task, as compared to the MBF before the clenching task was measured. The average frequency of awake bruxism was 45.5% during 7 days. Sustained clenching resulted in a significant reduction in MBF values in the total sample (p < 0.05). Nevertheless, no significant correlation was found between frequency of awake bruxism behaviors and percent of change in MBF and endurance time during the fatigue test. Therefore, it can be concluded that young healthy adults present a relatively high frequency of awake bruxism behaviors that do not seem to impact the degree of masticatory muscle fatigue.

Divergence between confidence and knowledge of endodontists regarding non-odontogenic pain

Abstract This study aimed to assess the self-reported levels of confidence and knowledge related to non-odontogenic pain among a group of Brazilian endodontists. Methodology A total of one hundred and forty-six endodontists affiliated with the Brazilian Society of Endodontics participated in the survey. The questionnaire, distributed via email or WhatsApp, contained inquiries designed to gauge self-perceived confidence and knowledge concerning non-odontogenic pain. The practitioners were categorized into four groups based on their self-reported familiarity with various orofacial pain types, classified as either sufficient or insufficient, and on their engagement in ongoing educational programs related to orofacial pain. Data were analyzed by Chi-Square Test and Fischer's exact test (p<0.05). Results Overall, self-reported confidence about non-odontogenic pain was high, especially for endodontists who considered their knowledge about orofacial pain sufficient, regardless of whether they had (71.1% - 97.8%) or not (35.7% - 96.4%) been continuously involved in education courses on orofacial pain. In general, self-reported knowledge about non-odontogenic pain was insufficient (0% - 42%), except in the question about how they would act in cases of pain that persists beyond the normal healing time after an endodontic procedure (70.6% - 81.9%). In general, endodontists are confident in their diagnosis and treatment of non-odontogenic pain. Nonetheless, this confidence did not correlate with a commensurate knowledge depth of. Thus, specialization courses in endodontics should highly consider training and qualifying these professionals in the diagnosis of non-odontogenic pain.

Primary headache and myofascial pain: a data based study / Cefaleia primária e dor miofascial: um estudo baseado em dados

Aim: This study aimed to evaluate the relationship be-tween the presence of primary headaches and myofascial pain in orofacial patients. Materials and methods: Six hundred and ninety-nine records of patients seeking treatment in a specialized orofacial pain clinic were assessed. The primary diagnostic categories of heada-che and myofascial pain were recorded. Data analyses were carried out by Pearson Chi-square and Logistic Regression, with a p-value of 0.05. Results: Average age of patients was 34.6 years. Females constituted 82.8% of the sample. A relationship between the presence of tension-type headache and myofascial pain was found (p=0.00); however, this relationship was not found for the presence of migraine and myofascial pain (p>0.05). Discussion: Tension-type headaches may be triggered or perpetuated by trigger points in orofacial structures. Conclusion: It can be concluded that trigger points in myofascial pain patients can play an important role in the genesis of tension-type headache.

Objetivo: Este estudo avaliou a relação entre a presença de cefaleia primária e dor miofascial em pacientes orofaciais. Materiais e métodos: Foram avaliados 699 prontuários de pacientes que buscavam atendimento em clínica especiali-zada em dor orofacial. As categorias diagnósticas primárias de cefaleia e dor miofascial foram registradas. A análise dos dados foi realizada pelo Qui-quadrado de Pearson e Regressão Logística, com valor de p=0,05. Resultados: A idade média dos pacientes foi de 34,6 anos. O sexo feminino constituiu 82,8% da amostra. Foi encontrada relação entre a presença de cefaleia do tipo tensional e dor miofascial (p = 0,00); en-tretanto, essa relação não foi encontrada para a presença de enxaqueca e dor miofascial (p> 0,05). Discussão: As cefaleias primárias do tipo tensionais podem ser desencadeadas ou perpetuadas por pontos-gatilhos nas estruturas orofaciais. Conclusão: Pode-se concluir que os pontos-gatilhos em pacientes com dor miofascial podem desempenhar um papel importante na gênese da cefaleia do tipo tensional.

Who is the individual that will complain about temporomandibular joint clicking?

BACKGROUND: Understanding the profile of the individual complaining of TMJ clicking can help in the clinical approach of these patients. OBJECTIVE: To identify clinical variables associated with individuals who complain about and seek treatment for TMJ clicking. METHODS: Seventy-two individuals, composed the sample: Group 1 - patients with a complaint of TMJ clicking who sought treatment; (n = 36); Group 2 - individuals with TMJ clicking who have no complaints about it (n = 36). Three categories of data were evaluated: clinical (gender; age; side of TMJ clicking; TMJ pain; self-reported level of bother; previous TMJ clicking information); somatosensory (mechanical pain threshold [MPT], wind-up ratio [WUR], pressure pain threshold [PPT]); and, psychosocial (Pain Vigilance and Awareness Questionnaire [PVAQ]; Pain Catastrophising Scale [PCS]; Tampa Scale for Kinesiophobia for Temporomandibular Disorders [TSK/TMD]); The Perceived Stress Scale (PSS); The State-Trait Anxiety Inventory (STAI). RESULTS: Group 1 was composed mostly of female patients, with TMJ pain, without previous orientation about the condition, bothered by the clicking, with lower PPT and higher scores in the PVAQ, PCS, TKS/TMD, PSS and STAI scales than Group 2. The groups did not differ significantly for side of TMJ clicking, age, MPT and WUR. CONCLUSION: Individuals who have a TMJ clicking complaint and seek treatment are mostly female, have TMJ pain, have not received previous orientation about TMJ clicking, are bothered by the clicking, have a lower pain threshold and higher scores of hypervigilance, catastrophising, kinesiophobia, stress and anxiety than people with TMJ clicking who do not report it.