O objetivo deste trabalho foi analisar a influência da ansiedade e do estresse no limiar de dor à pressão (LDP) de músculos mastigatórios, numa amostra de estudantes universitários em diferentes períodos do ano letivo. Para este propósito, foram selecionados 45 indivíduos, sendo 29 estudantes, que apresentavam DTM de origem miogênica seguindo critérios de inclusão propostos pelo Research Diagnostic Criteria (RDC) e 16 que não apresentavam características de DTM, do gênero feminino, equilibrados em relação à idade. Utilizando um algômetro (KRATOS®) foram realizadas tomadas bilaterais dos limiares de dor à pressão (LDP) dos indivíduos da amostra nos músculos masseter, temporal anterior, médio e posterior. Além disso, os participantes foram solicitados a responder questionários multidimensionais, através do Inventário de Ansiedade de Beck (BAI) e o Inventário de Sintomas de Stress de Lipp (ISSL), para mensurar reações emocionais ou afetivas em situações que causem estresse e/ou ansiedade. Também, o nível de dor foi registrado pela Escala de Análise Visual (EAV). Todos os exames foram realizados em quatro momentos distintos (T1, T2, T3 e T4) tendo como parâmetro o período de avaliações acadêmicas da Faculdade de Odontologia de Bauru. Os dados obtidos foram submetidos à análise estatística (ANOVA, Teste de Tukey, Teste de Friedman e Mann-Whitney), em um nível de significância de 5%. A comparação entre os diferentes tempos do estudo nos 2 grupos mostrou diferença estatisticamente significativa (p<0,05), sendo que o período das avaliações mostrou maiores níveis de estresse e ansiedade e menores valores de LDP. Sob o ponto de vista do músculo nos diferentes grupos e nos diferentes tempos, foram encontradas diferenças estatisticamente significativas (p<0,05). Os resultados da Escala de Análise Visual mostraram diferenças estatisticamente significantes entre o grupo sintomático e o grupo assintomático em T1, T2, T3 e T4. Com relação ao estresse e ansiedade, não houve diferenças estatisticamente significante entre os grupos. Houve, no entanto, uma associação entre o aumento do estresse e da ansiedade e diminuição dos valores de LDP em cada tempo. Concluiu-se que existe relação entre estresse e ansiedade e LDP tanto para indivíduos assintomáticos quanto para sintomáticos com DTM de origem miogênica. / The aim of this research was to evaluate the influence of stress and anxiety on the Pressure Pain Threshold (PPT) of the masticatory muscles and on the subjective pain report of dental students of the Bauru School of Dentistry (University of São Paulo, Brazil) at different situations. Forty-five females, matched for age, were divided into two groups: 29 presenting with myofascial pain, according to the RDC/TMD criteria, and 16 with no TMD signs or symptoms. PPT measurements were taken bilaterally at the masseter, anterior, middle and posterior temporalis muscles in four different occasions throughout the academic year. The Achilles tendon was used as control. In order to quantify emotional or affective reactions under stress/anxiety situations, the sample were requested to fill out multidimensional questionnaires, such as the Beck Anxiety Inventory (BAI) and the Lipp Inventory for Stress Symptoms (LISS). In addition, pain levels were registered with a Visual Analog Scale (VAS). Data obtained were submitted to statistical analysis (ANOVA, Tukey, Friedman, and Mann-Whitney tests), at a 5% significance level. The VAS and PPT had a negative correlation, regardless the period, and group studied (p<.05). Higher levels of stress and anxiety were detected at the time of school examinations for both groups, with a strong association with decreased PPT figures (p<.05). Stress and anxiety, however, were not statistically different between groups. It can be concluded that external stressors as academic examinations have a potential impact on the masticatory muscle tenderness, regardless the presence of a previous condition, such as the masticatory myofascial pain.

O objetivo deste trabalho foi analisar a influência do ciclo menstrual nas alterações de limiar de dor à pressão (LDP) na musculatura mastigatória de mulheres com sinais e sintomas de Disfunção Temporomandibular (DTM). Inicialmente 47 voluntárias entre 18 e 40 anos participaram do estudo, das quais 36 foram incluídas no experimento: 15 com sinais e sintomas de DTM (7 sob terapia com contraceptivos orais (CO) e 8 sem CO) e 21 saudáveis, sem sinais e/ou sintomas de DTM (8 com CO e 13 sem CO). Os LDPs dos músculos masseter e temporais (anterior, médio e posterior), e do tendão de Aquiles foram medidos bilateralmente, por meio de um algômetro, durante 2 ciclos menstruais consecutivos, nas 4 diferentes fases: menstrual (dias 1-3), folicular (dias 5-9), periovulatória (dias 12-16) e lútea (dias 19-23). Em cada fase do ciclo, as voluntárias relataram sua dor em uma Escala de Análise Visual (EVA). Os resultados foram submetidos à análise de variância a 3 critérios para mensurações repetidas, a um nível de significância de 5%.Foram encontrados LDPs significativamente menores nos músculos temporal e masseter e no tendão de Aquiles das mulheres com DTM quando comparado às mulheres assintomáticas, independentemente da fase do ciclo e do uso de contraceptivos (p < 0,05). De uma maneira geral, os LDPs foram maiores em mulheres em terapia com contraceptivos orais, quando comparado às mulheres sem terapia. Parece não existir influência das diferentes fases do ciclo menstrual no LDP, independentemente da presença ou não de DTM. / The aim of this study was to investigate the influence of the menstrual cycle on the Pain Pressure Threshold (PPT) figures of the masticatory muscles in women with signs and symptoms of Temporomandibular Disorders (TMD). Forty-seven volunteers (ages between 18-40 years-old) were initially recruited for this purpose. According to the criteria adopted, 36 were included. The experimental group was composed of 15 women with myofascial pain (RDC/TMD) (7 under oral contraceptive medication), while 21 women with no TMD signs or symptoms (8 under oral contraceptive medication) composed the control group. The PPT values of masseter and temporalis (anterior, middle, and posterior regions) muscles, as well as the Achilles? tendon were bilaterally screened during two consecutive menstrual cycles, in the following phases: menstrual (day 1-3), follicular (day 5-9), periovulatory (day 12-16) and luteal (day 19-23). A visual analog scale (VAS) was used to address subjective pain in each menstrual phase. Data were submitted to 3-way ANOVA for repeated measurements, with a 5% significant level. The PPT values were significantly lower in the temporalis, masseter, and the Achilles? tendon of TMD patients when compared with the asymptomatic controls, regardless of the menstrual cycle phase or the use of oral contraceptives (p<.05). Overall, the PPT values were higher for patients under oral contraceptive therapy, while VAS was, in general higher at the menstrual phase (p<.05). It appears that the different phases of menstrual cycle have no influence on the PPT values, regardless of the presence of a previous condition, as myofascial pain.

O objetivo deste trabalho foi analisar a influência do ciclo menstrual nas alterações de limiar de dor à pressão (LDP) na musculatura mastigatória de mulheres com sinais e sintomas de Disfunção Temporomandibular (DTM). Inicialmente 47 voluntárias entre 18 e 40 anos participaram do estudo, das quais 36 foram incluídas no experimento: 15 com sinais e sintomas de DTM (7 sob terapia com contraceptivos orais (CO) e 8 sem CO) e 21 saudáveis, sem sinais e/ou sintomas de DTM (8 com CO e 13 sem CO). Os LDPs dos músculos masseter e temporais (anterior, médio e posterior), e do tendão de Aquiles foram medidos bilateralmente, por meio de um algômetro, durante 2 ciclos menstruais consecutivos, nas 4 diferentes fases: menstrual (dias 1-3), folicular (dias 5-9), periovulatória (dias 12-16) e lútea (dias 19-23). Em cada fase do ciclo, as voluntárias relataram sua dor em uma Escala de Análise Visual (EVA). Os resultados foram submetidos à análise de variância a 3 critérios para mensurações repetidas, a um nível de significância de 5%.Foram encontrados LDPs significativamente menores nos músculos temporal e masseter e no tendão de Aquiles das mulheres com DTM quando comparado às mulheres assintomáticas, independentemente da fase do ciclo e do uso de contraceptivos (p < 0,05). De uma maneira geral, os LDPs foram maiores em mulheres em terapia com contraceptivos orais, quando comparado às mulheres sem terapia. Parece não existir influência das diferentes fases do ciclo menstrual no LDP, independentemente da presença ou não de DTM. / The aim of this study was to investigate the influence of the menstrual cycle on the Pain Pressure Threshold (PPT) figures of the masticatory muscles in women with signs and symptoms of Temporomandibular Disorders (TMD). Forty-seven volunteers (ages between 18-40 years-old) were initially recruited for this purpose. According to the criteria adopted, 36 were included. The experimental group was composed of 15 women with myofascial pain (RDC/TMD) (7 under oral contraceptive medication), while 21 women with no TMD signs or symptoms (8 under oral contraceptive medication) composed the control group. The PPT values of masseter and temporalis (anterior, middle, and posterior regions) muscles, as well as the Achilles? tendon were bilaterally screened during two consecutive menstrual cycles, in the following phases: menstrual (day 1-3), follicular (day 5-9), periovulatory (day 12-16) and luteal (day 19-23). A visual analog scale (VAS) was used to address subjective pain in each menstrual phase. Data were submitted to 3-way ANOVA for repeated measurements, with a 5% significant level. The PPT values were significantly lower in the temporalis, masseter, and the Achilles? tendon of TMD patients when compared with the asymptomatic controls, regardless of the menstrual cycle phase or the use of oral contraceptives (p<.05). Overall, the PPT values were higher for patients under oral contraceptive therapy, while VAS was, in general higher at the menstrual phase (p<.05). It appears that the different phases of menstrual cycle have no influence on the PPT values, regardless of the presence of a previous condition, as myofascial pain.

Thèse présentée en vue de l’obtention du grade de Philosophiae Doctor (Ph.D.) en Psychologie, option Neuropsychologie clinique / La douleur est un enjeu central dans le domaine médical. La gestion efficace de la douleur aiguë est cruciale pour prévenir la douleur chronique. Parmi les diverses conditions cliniques, la douleur est prédominante chez les patients ayant subi un trauma orthopédique, persistant plusieurs jours après la blessure, avec un risque élevé de complications. Cependant, les traitements pharmacologiques, comme les opiacés et les anti-inflammatoires non stéroïdiens, bien que couramment utilisés, peuvent avoir des effets négatifs sur la consolidation osseuse et la santé générale. Dans ce contexte, il apparaît pertinent d’explorer des méthodes d’intervention alternatives, telles que la stimulation magnétique transcrânienne répétitive (SMTr). Bien que cette technique soit prometteuse pour le traitement de la douleur chronique, son efficacité dans les douleurs aiguës reste incertaine. De plus, l’effet placebo, qui joue un rôle dans les traitements de la douleur, a souvent été sous-estimé dans les études antérieures sur la SMTr. Par ailleurs, le taux de réponse à la SMTr varie beaucoup chez les individus. Ainsi, mieux comprendre les effets spécifiques de la SMTr et de l’effet placebo associé pourrait améliorer son efficacité. Cette thèse visait donc à combler ces lacunes en poursuivant deux objectifs principaux. Le premier était d’explorer l’effet placebo associé à l’utilisation d’un protocole multisessions de SMTr en phase aiguë chez des patients ayant subi une fracture du membre supérieur. Dans cette étude, un groupe a reçu une intervention de SMTr sham, tandis que l’autre a uniquement bénéficié des soins orthopédiques usuels. Les résultats ont révélé un effet significatif du placebo dans le groupe ayant reçu la SMTr sham, suggérant des bénéfices de l’intervention sur la guérison en termes d’intensité douloureuse et de récupération fonctionnelle. Il est donc impératif que les études futures incluent des groupes témoins pour distinguer les effets spécifiques de la SMTr des effets non spécifiques (p. ex., évolution naturelle de la condition) et de l’effet placebo. Cette étude met aussi en lumière la nécessité d’améliorer les soins en orthopédie, tout en appelant à des recherches supplémentaires pour comprendre le rôle des différents facteurs impliqués (p. ex., utilisation du placebo, cadre thérapeutique, etc.). Le second objectif portait sur la faisabilité et l’efficacité d’un protocole de SMTr (actif vs sham), bonifié par une procédure de conditionnement, dans le cadre d’une douleur expérimentale induite chez des individus en bonne santé. Ce protocole visait à optimiser la réponse à la SMTr en modulant à la fois le seuil de douleur et les attentes de soulagement des participants, un facteur clé influençant la réponse aux interventions analgésiques. Néanmoins, les résultats se sont révélés peu concluants en raison de limitations méthodologiques (p. ex., la procédure de conditionnement utilisée, absence de suggestions verbales, etc.). Ainsi, des études futures pourraient apporter des améliorations au protocole et l’appliquer auprès d’une population souffrant de douleurs cliniques, dont l’expérience douloureuse et les attentes diffèrent de celles des individus en bonne santé. En effet, les individus souffrant de douleurs chroniques ou aiguës sont plus souvent réceptifs aux interventions thérapeutiques, ce qui pourrait améliorer les résultats futurs. / Pain is a common issue in the medical field, and optimal management during the acute phase is critical to preventing chronic pain. Among various clinical conditions, pain is a predominant symptom in orthopedic trauma patients, which persists for several days after the injury, with a high risk of complications. However, managing pain in this population proves to be a significant challenge, as pharmacological treatments such as opioids and non-steroidal anti-inflammatory drugs are frequently used despite their potential adverse effects on bone healing and patients’ overall health. Therefore, exploring alternative intervention methods, such as repetitive transcranial magnetic stimulation (rTMS), is necessary. While rTMS has shown analgesic potential in chronic and experimental pain, its effectiveness in managing acute pain remains uncertain. Moreover, the analgesic placebo effect involved in all pain interventions seems to have been underestimated, if not neglected, in previous rTMS studies. Additionally, the response rate to rTMS varies widely among individuals, such that any endeavour aiming to deepen our understanding of the specific effects of rTMS and associated placebo effects could reveal to be fruitful in optimizing its efficacy. Therefore, this thesis aimed to address these gaps through two main objectives. The first study investigated the placebo effect of a multi-session sham rTMS protocol in the context of acute pain in patients with an upper limb fracture, by comparing their clinical outcomes to a group receiving standard orthopedic care. The results showed a significant placebo effect in the group receiving sham rTMS, suggesting that the placebo intervention benefited the healing trajectory in terms of pain level and functional recovery. This underscores the importance of including control groups in future rTMS studies to better distinguish between the specific effects of rTMS, non-specific effects (such as natural recovery), and the placebo effect. Furthermore, the study indicates that current orthopedic care models could be enhanced by subacute, multi-session interventions, although further validation is needed. The second study focused on the feasibility and effectiveness of an rTMS protocol (active vs sham) enhanced with a conditioning procedure in healthy individuals experiencing experimental pain. This protocol aimed to optimize the response to rTMS by modulating participants' pain thresholds and their expectations of pain relief, a factor known to influence outcomes in analgesic interventions. However, the results of this study were inconclusive, likely due to various methodological limitations (e.g., ineffective conditioning procedure, number of rTMS sessions, crossover design, absence of verbal suggestions, etc.). Although the design of our protocol did not prove effective, future studies could make methodological adjustments and apply this protocol to a population suffering from clinical pain. Thus, it is important to bear in mind that the painful experience of a clinical population differs from that of healthy individuals. Indeed, patients with clinical pain may have different expectations regarding treatments, which could influence their responsiveness to interventions.