Relationship between emotional state and masticatory system function in a group of healthy volunteers aged 18-21

OBJECTIVE

To determine the role of emotional state in the masticatory system function in a group of young adults.

METHODS

Ninety-six generally healthy randomly selected students aged 18-21 were examined. They were subjected to a questionnaire survey determining their emotional state, clinical examination, and instrumental diagnostics (EMG, Cadiax Compact, JVA).

RESULTS

The stress symptoms group revealed a greater intensity of neck and shoulder muscles pain (p < 0.05) and an increase of electrical potential of the masseter muscles in maximal voluntary clench (p < 0.05). They reported more often headache (p < 0.001), tension/contracture of the head, neck and nape (p < 0.05), and pain while opening the mouth wide (p < 0.05). The values of parameters obtained in the instrumental diagnostics did not reveal differences between the groups.

CONCLUSION

Stressful situations increase muscular tension but do not have a direct impact on the temporomandibular joints function.

Accurate Diagnosis and Treatment of Painful Temporomandibular Disorders: A Literature Review Supplemented by Own Clinical Experience

Introduction

Temporomandibular disorders (TMD) is a multifactorial group of musculoskeletal disorders often with combined etiologies that demand different treatment plans. While pain is the most common reason why patients decide to seek help, TMD is not always painful. Pain is often described by patients as a headache, prompting patients to seek the help of neurologists, surgeons, and ultimately dentists. Due to the unique characteristics of this anatomical area, appropriate diagnostic tools are needed, as well as therapeutic regimens to alleviate and/or eliminate the pain experienced by patients. Aim of the Study. The aim of this study is to collect and organize information on the diagnosis and treatment of pain in TMD, through a review of the literature supplemented by our own clinical experience. Material and Methods. The study was conducted by searching scientific databases PubMed, Scopus, and Google Scholar for documents published from 2002-2022. The following keywords were used to build the full list of references: TMD, pain, temporomandibular joint (TMJ), TMJ disorders, occlusal splint, relaxing splints, physiotherapy TMD, pharmacology TMD, natural therapy TMD, diagnostic criteria for TMD, and DC/TMD. The literature review included 168 selected manuscripts, the content of which was important for pain diagnosis and clinical treatment of TMD.

Results

An accurate diagnosis of TMD is the foundation of appropriate treatment. The most commonly described treatments include physiotherapy, occlusal splints therapy, and pharmacological treatment tailored to the type of TMD.

Conclusions

Based on the literature review and their own experience, the authors concluded that there is no single ideal form of pain therapy for TMD. Treatment of TMD should be based on a thorough diagnostic process, including the DC/TMD examination protocol, psychological evaluation, and cone beam computer tomography (CBCT) imaging. Following the diagnostic process, once a diagnosis is established, a treatment plan can be constructed to address the patient's complaints.

Impact of sports on temporomandibular dysfunction: a comparison of competitive and recreational female athletes as well as female non-athletes

Objectives

The present study was conducted to investigate the correlation between (competitive) sports and the occurrence of temporomandibular dysfunctions (TMD) by comparing the prevalences in competitive, recreational, and non-athletic women.

Materials and methods

A total of 138 women between the ages of 18 and 45 were interviewed about symptoms of TMD by means of a questionnaire. Based on their athletic performance level, the participating women were classified as competitive athletes, recreational athletes, or non-athletes (each group n = 46).

Results

Symptoms of TMD were notably less frequent in competitive female athletes (52.2%) than in recreational female athletes (63.0%) and female non-athletes (60.9%). With increasing training load, the prevalence of TMD decreased in both the competitive and recreational female athlete groups.

Conclusions

Athletic activity in general seems to have a positive effect on the occurrence of TMD. Competitive female athletes appear less likely to suffer from symptoms of TMD than recreational athletes and non-athletes. One possible explanation for this could be the better supervision by qualified trainers and physiotherapists in competitive sports.

Clinical relevance

Patients should be motivated to engage in sports as a protective measure against symptoms of TMD. However, it is important to ensure that they are properly instructed by experienced personnel in order to avoid unphysiological strain and negative consequences.

Effects of competitive sports on temporomandibular dysfunction: a literature review

OBJECTIVES

The German Society of Craniomandibular Function and Disorders recommends that patients suffering from temporomandibular dysfunctions should practice sports in order to compensate for everyday stress. This raises the question as to what extent competitive athletes develop temporomandibular dysfunctions or whether their athletic activities protect them. With the present literature review, the authors intend to give an overview of the currently available publications on this topic.

MATERIALS AND METHODS

A literature research in the PubMed and Google Scholar databases was performed to filter out the currently available publications on the topic 'sports, and temporomandibular dysfunction.

RESULTS

Out of 114 available articles, seven met the inclusion criteria. Two other relevant articles were found in the list of references, so that in total, nine publications were picked for the review. In case numbers ranging from eight to 347 subjects, a temporomandibular dysfunction was detected with a prevalence between 11.7% and 100% for athletes and between 11.11% and 14.3% for non-athletes. Different kinds of sports were evaluated, all of them contact sports: basketball, handball, wrestling, boxing, karate, mixed martial arts, field hockey, water polo, and soccer. One study compared athletes with and without consumption of anabolic steroids, regardless of the type of sport. The level of athletic performance varied across the different studies.

CONCLUSIONS

Currently, studies dealing with the effect of competitive sports on temporomandibular dysfunction are scarce. Inconsistent methodological procedures permit only limited comparability.

CLINICAL RELEVANCE

A general trend, however, can already be discerned: professional athletes suffer from temporomandibular dysfunctions more frequently than non-athletes.

Relationship between Parafunctional Habits and Salivary Biomarkers

Objectives:

Parafunctional habits, as one of the etiological factors of temporomandibular disorders (TMD), are an individual’s response to increased stress. During stress and depression, biomarkers such as cortisol and salivary alpha-amylase (SAA) are secreted in the saliva. The present study aimed to investigate whether there is a correlation between salivary stress biomarkers and parafunctional habits.

Materials and Methods:

Thirty-two cases, from May to September 2015, were selected based on two standard stress questionnaires, namely the depression anxiety stress Scale-21 (DASS-21) and the Beck Anxiety Inventory (BAI). Saliva samples were collected to examine the level of unstimulated salivary cortisol and SAA. The significance of the results was assessed via student’s t-test and Mann-Whitney test (α=0.05).

Results:

The mean concentrations of cortisol and SAA in unstimulated saliva were significantly higher in the case group than in the control group (P=0.01 and 0.44, respectively). The mean scores of anxiety, stress, and depression were significantly higher in the case group than in the control group (P<0.05).

Conclusion:

It seems that the levels of salivary cortisol and SAA, as well as stress, anxiety, and depression scores, are higher in patients with parafunctional habits.

Association between salivary alpha-amylase and subjective and objective oral parafunctions in community-dwelling elderly individuals

Background/purpose

Stress in the elderly is caused by loss of physical and psychological health. Although there have been many reports on the intraoral environment affecting physical health, few reports exist on stress and the intraoral environment in the elderly. The aim of this study was to investigate the relationship between salivary α-amylase as an index of stress value and the intraoral environment.

Materials and methods

Three hundred and nineteen participants were community-dwelling independent individuals over 65 years old. The outcome variable was salivary α-amylase. After measurement, salivary α-amylase was classified into four groups (0 = 0–30, 1 = 31–45, 2 = 46–60, 3 = 61–200). The predictor variables were physical status (which includes age and male body-mass index) and subjective and objective symptoms (which include present teeth, torus palatinus, torus mandibularis, temporomandibular joint noise, bruxism, and dental attrition). These variables were compared among participants using univariate analysis and multiple logistic regression analysis.

Results

The participants included 77 men and 242 women, with a mean age of 75.8 ± 5.4 years (65–94 years). Although temporomandibular joint noise and dental attrition were significantly positively correlated with salivary α-amylase, bruxism was significantly negatively correlated with salivary α-amylase (p < 0.05). Stepwise regression analysis revealed a significant relationship between salivary α-amylase and temporomandibular joint noise, bruxism, and dental attrition.

Conclusion

High salivary α-amylase is associated with a high rate of temporomandibular joint noise and dental attrition, and a low rate of bruxism among elderly participants.

Influence of Psychosocial Factors and Parafunctional Habits in Temporomandibular Disorders: A Cross-Sectional Study

INTRODUCTION

Temporomandibular disorders (TMDs) are abnormalities affecting the temporomandibular joint, jaw muscles, or both. An intrinsic relationship reportedly exists between TMDs and psychosocial factors, including stress. Parafunctional habits such as bruxism and clenching are also known to be responsible for TMDs.

OBJECTIVE

To determine the association of anxiety, depression, and bruxism with TMD symptoms and their relationship with age and sex.

METHODS

Patients included in the study reported, as their chief concern, pain lasting for more than a week in the temporomandibular joint area and/or masticatory muscles. The patients were divided into age groups as follows: Younger than 20 years, 21 to 30 years, 31 to 40 years, 41 to 50 years, 51 to 60 years, and above 60 years. Patients were examined clinically and were asked to complete an anamnestic questionnaire (modified version of Helkimo Anamnestic Index) and the Hospital Anxiety and Depression Scale (HADS).

RESULTS

Seventy-five patients (55 women, 20 men) were included in the study. The prevalence of TMDs was higher in female patients, of whom 33 (60%) had moderate to severe TMDs. Of the 20 male patients, 12 (60%) had signs and symptoms of moderate TMDs. Anxiety and depression scores were higher in female patients. No significant correlation was found between degree of malocclusion and TMDs.

DISCUSSION

We found correlations between the degree of TMD with age, sex, parafunctional habits, and psychosocial factors. Symptoms of TMD seemed to increase in patients with parafunctional habits, from younger to older age groups, and with increased anxiety and depression scores.

CONCLUSION

The degree of TMDs is higher in women, and TMDs are associated with higher anxiety and depression scores. Correlation between these factors paves the way for preventive actions aimed at those with moderate and severe signs of TMDs.

Síndrome da disfunção da articulação temporomandibular e o estresse presente no trabalho policial: revisão integrativa

Resumo O estudo objetivou investigar se o estresse presente nas atividades dos trabalhadores da polícia brasileira pode ter relação com o desenvolvimento da síndrome da disfunção da articulação temporomandibular (DTM), uma doença comumente associada a condições estressantes. Realizou-se uma revisão integrativa de literatura sobre os temas estresse, DTM e atividade policial. Foram identificadas diversas fontes estressoras no trabalho do policial brasileiro e observou-se que o estresse influencia no desenvolvimento, agravamento e tratamento dos sintomas da síndrome. Há comprometimento na qualidade de vida e saúde dos portadores de DTM. O fato de estudos terem mostrado associação entre estresse e atividades desenvolvidas pelos policiais brasileiros, bem como relação entre estresse e DTM, levou à suposição de que é possível haver relação entre o estresse gerado pelo trabalho executado por policiais e o risco de desenvolvimento da DTM por essa classe de trabalhadores. É recomendado que o indivíduo portador da síndrome seja avaliado como um todo antes da execução do tratamento e que esse tratamento seja multidisciplinar. A literatura sobre DTM em policiais ainda é incipiente, motivo pelo qual sugere-se o desenvolvimento de estudos sobre o tema.

Relationship between depression and masticatory muscles function in a group of adolescents

OBJECTIVE

The aim of the study is to determine association between depressive symptoms and the electrical activity of muscles in maximum voluntary clench in a group of young adults.

METHODS

A total of 186 volunteers (Females = 98, Males = 88), with a mean age of 19 years, were recruited to the study. All participants took a questionnaire survey stating the level of depression (Beck's scale), clinical examination, and instrumental diagnostics (EMG).

RESULTS

Symptoms of mild or medium depression were found in 35 of the subjects (18.82%). Average electric potentials of the masticatory muscles in maximal voluntary clench were significantly higher among the subjects with depression symptoms in comparison with subjects without those symptoms (85.96 ± 10.25 vs 78.97 ± 15.32, p < . 0.05).

DISCUSSION

An increase in the electrical potentials of masseter muscles in maximal voluntary clench was found in the group with depression symptoms. The study should be continued to confirm this finding.

Sleep and awake bruxism in adults and its relationship with temporomandibular disorders: A systematic review from 2003 to 2014

OBJECTIVE

In order to establish a relationship between bruxism and temporomandibular disorders (TMDs), a systematic review was performed.

MATERIALS AND METHODS

A systematic research was performed based on PubMed, Cochrane Library, Medline, Embase, BIREME, Lilacs and Scielo data bases, between 2003 and 2014 including all languages. Descriptive clinical cases were identified. Two independent authors selected the articles. PICO format was used to analyse the studies and the Newcastle-Ottawa Scale (NOS) was used to verify the quality of the evidence.

RESULTS

Thirty-nine studies (n = 39) were analysed in this review. According to bruxism diagnosis, articles were grouped as follows: polysomnographic diagnosis (PSG) (n = 7), clinical diagnosis (n = 11) and survey/self-report (n = 21). Thirty-three articles (n = 33) established a positive relation between bruxism and TMD and six (n = 6) did not. Quality of evidence was low to moderate. In general, the most part of the studies showed shortcomings on their design with bias risk, and also had a low sensitivity on bruxism diagnosis.

CONCLUSIONS

The evidence based on PSG was not as conclusive as the studies that used surveys and clinical exam to diagnosis bruxism, when bruxism was related to TMD. Sleep bruxism could be associated with myofascial pain, arthralgia and joint pathology as disc displacement and joint noises. Although the evidence at present is inconclusive and does not provide information according to the type of bruxism (bruxism sleep and wakefulness), it is possible to suggest that bruxism would be associated with TMD.

[Masticatory apparatus disorder: how can rehabilitation treatment help?]

INTRODUCTION

The temporomandibular joint is highly adaptive and masticatory apparatus disorders (MAD) can occur when its ability to adapt is overwhelmed. Occlusal etiologies were long pinpointed as the sole culprits. However, a consensus now exists which minimizes their involvement. It is recognized that the etiology of MAD is multifactorial, combining occlusal problems, parafunctions, postural anomalies, orofacial dyspraxia and stress.

MATERIALS AND METHODS

In this article, the authors review the role of physiotherapy in managing these pathologies.

RESULTS

While it remains essential to treat the symptoms in order to relieve pain, optimum treatment requires the underlying pathogenic mechanisms to be identified. Rehabilitation treatment, therefore, offers a physiotherapy-based approach providing an etiological solution. By reeducating function, physiotherapy produces lasting results.

DISCUSSION

Given the multifactorial nature of MAD etiologies, maxillofacial rehabilitation is an indispensible ally for odontologists or orthodontists adopting a multidisciplinary approach in their treatment of this disorder.

The influence of emotional state on the masticatory muscles function in the group of young healthy adults

Stress may affect the function of all the components of the masticatory system and may ultimately lead to differentiated symptoms and finally to systemic and structural dysfunctions. Objective. To determine the effect of stress on the masticatory muscles function in young healthy adults. Material and Methods. A total of 201 young, Angle's first class, healthy volunteers, 103 female and 98 male, in the age between 18 and 21 years were recruited into the study. All the participants underwent clinical examination according to the Slavicek scheme, questionnaire survey according to Perceived Stress Scale, and assessment of masticatory muscles function in central occlusion. Results. Symptoms of masticatory system dysfunction were found in the group of 86 subjects (46,24%). All the muscles activity in central occlusion was comparable in female and male groups. Mean values of masseters activities in the group of low stress subjects (75,52 µV ± 15,97) were statistically different from the groups with medium (82,43 µV ± 15,04) and high (81,33 ± 12,05) perceived stress (P < 0.05). Conclusion. Chronic stress may reveal or exacerbate symptoms of masticatory dysfunction.

Effect of water-soluble titanium microparticle-permeated tape on temporomandibular disorders-related pain: a preliminary study

OBJECTIVE

Recent research has focused on the applicability of titanium particle-impregnated materials in healthcare and medical products. This preliminary study was undertaken to investigate the effect of water-soluble titanium microparticle-permeated (WSTi) tape on temporomandibular disorder (TMD)-related pain.

MATERIALS AND METHODS

The study included 32 patients (41.5 ± 14.4 years, 26 women) who had visited the Temporomandibular Joint Clinic, Tokyo Medical and Dental University, for treatment of TMD-related pain. The subjects were instructed to apply the WSTi tape (AquaTitan tape) on the most painful area before going to sleep and remove the tape on awakening daily for 2 weeks. Seven outcome variables were statistically analyzed: maximum mouth-opening ranges with and without pain, spontaneous pain intensity, mouth-opening pain intensity, chewing pain intensity, TMD-related limitation of daily functions (LDF-TMD) and subjective evaluation of any change in TMD-related pain.

RESULTS

The mean maximum mouth-opening ranges with (p = 0.011) and without (p = 0.002) pain were significantly greater and mean pain intensities on mouth opening (p < 0.001) and chewing (p = 0.001) were significantly lower at the 2-week follow-up than at the baseline. The mean LDF-TMDQ scores were also significantly lower at the 2-week follow-up (p = 0.004). After 2 weeks of using the WSTi tape, 53.1% and 12.5% of the subjects reported a slight improvement and an improvement, respectively, in TMD-related pain.

CONCLUSION

WSTi tape seems to have beneficial effects on TMD-related pain and LDF.

Evaluation of the non-functional tooth contact in patients with temporomandibular disorders by using newly developed electronic system

The aims of this study were to introduce a novel electronic system for reliable evaluation of the non-functional tooth contact in patients with temporomandibular disorders (TMDs) and investigate the possible associations between the non-functional tooth contact and some characteristics of the patients with TMD. We designed and installed a software program to send emails regarding the non-functional tooth contact to the subjects' preregistered cellular phones at intervals of 20 ± 9 min daily for 10 consecutive days. Twelve patients with TMD and 12 gender- and age-matched healthy subjects responded via emails to one of 3 choices: no tooth contact, tooth contact during oral functions or tooth contact not associated with oral functions. The influence of subjective stress, anxiety, depression, personality and daily activities on tooth contact was then assessed. The frequency of the non-functional tooth contact was significantly higher in the patients with TMD than in the healthy subjects (35·0% vs. 9·6%, P < 0·001), while no significant group difference was found for the frequency of functional tooth contact, the stress, anxiety, depression and personality.

Time-dependent analysis of nociception and anxiety-like behavior in rats submitted to persistent inflammation of the temporomandibular joint

Temporomandibular disorder (TMD) is prevalent in dental clinics and can involve problems with the masticatory muscles or the temporomandibular joints (TMJ). The pain of TMD is frequently associated with inflammation in the TMJs, but it's etiology is considered to be multifactorial and includes biologic, behavioral, environmental, social, emotional and cognitive factors. The purpose of this investigation was to evaluate the anxiety-like behavior in rats exposed to temporomandibular inflammation via injection of Freund's Adjuvant (CFA) with the elevated plus maze (EPM) and light/dark box (LDB) tests and to evaluate nociceptive behavior with the von Frey test at different periods. Moreover, this study measured TMJ inflammation using plasma extravasation (Evans blue test) and the intraarticular infiltration of polymorphonuclear neutrophils (myeloperoxidase quantification). The results showed that rats that were submitted to TMJ inflammation exhibited a decreased number of entries into the open arms of the EPM and a decrease in the time spent in the light compartment and in the number of transitions in the LDB. Additionally, the number of entries in closed arms in the EPM, used as indicator of locomotor activity, did not alter between treatments. Furthermore, increases in mechanical sensitivity and increases in plasma extravasation in the joint tissue occurred throughout the inflammation process, along with an increase in myeloperoxidase in the synovial fluid of TMJ. Our results suggest that the temporomandibular inflammation induced by CFA produced anxiety-like behaviors in rats and induced nociceptive behavior across different periods of inflammation.

Psychological stress alters microstructure of the mandibular condyle in rats

Psychological stress plays an important role in the occurrence and development of temporomandibular joint disorder (TMD). The correlation between psychological factors and TMD has been clinically shown, but the influence of psychological stress on the temporomandibular joint (TMJ) structure still lacks direct evidence. Here, we used communication box to establish the rat model of psychological stress. The stress level of animals was estimated by the elevated plus maze (EPM) test and hormonal assays. The histomorphology and three-dimensional microstructure of the rat condyles were observed by hematoxylin-eosin (HE) staining and Micro-CT, respectively. Compared with control rats, the anxious state of the stressed rats was evidenced by higher plasma adrenocorticotropic hormone (ACTH) and corticosterone (CORT), as well as lower ratios of open arm entries and time and lower time spent in open arms after 1, 2, 3, 4 and 5 week(s) post-exposure to psychological stimuli. HE staining and histomorphometric data analysis showed decreased thicknesses of the central and posterior condylar cartilages in stressed rats at weeks 3, 4 and 5, with the most obvious changes in the posterior part characterized by debonding and thinned fibrous layer, thickened proliferative layer, thinned mature layer and hypertrophic layer. Moreover, Micro-CT scanning revealed local lesion of the subchondral bone in the posterior condylar cartilages of stressed rats at week 5. Our findings indicate that pathologic changes of the histomorphology and three-dimensional microstructure occur in the condyles of stressed rats, hinting us a potential link between psychological factors and the pathogenesis or progression of TMD.

Influence of psychosocial factors and habitual behavior in temporomandibular disorder-related symptoms in a working population in Japan

Background:

The symptoms of temporomandibular disorders (TMD) are directly influenced by numerous factors, and it is thought that additional factors exert indirect influences. However, the relationships between TMD-related symptoms (TRS) and these contributing factors are largely unknown. Thus, the goal of the present study was to investigate influences on TRS in a working population by determining the prevalence of TRS, analyzing contributing factors, and determining their relative influences on TRS.

Materials and Methods:

The study subjects were 2203 adults who worked for a single company. Subjects completed a questionnaire assessing TRS, psychosocial factors (stress, anxiety, depressed mood, and chronic fatigue), tooth-contacting habit, and sleep bruxism-related morning symptoms, using a 5-point numeric rating scale. Our analysis proceeded in 2 phases. First, all variables of the descriptor were divided into parts by using an exploratory factor analysis. Second, this factorial structure was verified by using a confirmatory factor analysis with structural equation modeling.

Results:

Of 2203 employees, 362 reported experiencing TRS (16.4%). Structural equation modeling generated a final model with a goodness of fit index of 0.991, an adjusted goodness of fit index of 0.984, and a root mean square error of approximately 0.021. These indices indicate a strong structural model. The standardized path coefficients for “habitual behavioral factors and TRS,” “psychosocial factors and habitual behavioral factors,” “psychosocial factors and TRS,” and “gender and habitual behavior factors” were 0.48, 0.38, 0.14, and 0.18, respectively.

Conclusions:

Habitual behavioral factors exert a stronger effect on TRS than do psychosocial factors.

Temporomandibular joint-evoked responses by spinomedullary neurons and masseter muscle are enhanced after repeated psychophysical stress

Psychological stress is a risk factor for the development of musculoskeletal pain of the head and neck; however, the basis for this relationship remains uncertain. This study tested the hypothesis that psychophysical stress alone was sufficient to alter the encoding properties of spinomedullary dorsal horn neurons and masseter muscle activity in male rats. Repeated forced swim conditioning increased markedly both the background firing rate and temporomandibular joint (TMJ)-evoked activity of neurons in deep dorsal horn, while neurons in superficial laminae were less affected. Stress also increased the responses to stimulation of facial skin overlying the TMJ of neurons in deep and superficial dorsal horn. TMJ-evoked masseter muscle activity was enhanced significantly in stressed rats, an effect that was reduced by prior blockade of the spinomedullary junction region. These data indicated that repeated psychophysical stress induced widespread effects on the properties of medullary dorsal horn neurons and masseter muscle activity. The effects of stress were seen preferentially on neurons in deep dorsal horn and included enhanced responses to chemosensory input from the TMJ and mechanical input from overlying facial skin. The stress-induced elevation in TMJ-evoked masseter muscle activity matched well with the changes seen in dorsal horn neurons. It is concluded that the spinomedullary junction region plays a critical role in the integration of psychophysical stress and sensory information relevant for nociception involving deep craniofacial tissues.

Behavioral problems and emotional stress in children with bruxism

Bruxism has a multifactorial etiology, and psychosocial factors have been considered to increase the risk of occurrence of this parafunction. The aim of this study was to evaluate the behavior profile of a group of children diagnosed with bruxism. Eighty 7-11-year-old children of both genders (mean age 8.8 years) first recruited as eligible participants. Twenty-nine children (18 males and 11 females) whose parents/guardians reported to present frequent episodes of tooth grinding/clenching while awake or during sleep (at least 3 nights a week) in the previous 3 months were enrolled in the study. The diagnosis of bruxism was established based on the parents/guardians' report about the children's behavior, habits and possible discomforts in the components of the stomatognathic system allied to the presence of signs and symptoms such as pain on the masticatory muscles, masseter muscle hypertrophy, wear facets, fractures of restorations, dental impressions on the cheek mucosa and tongue. As part of the psychological evaluation, the Rutter's Child Behavior Scale-A2 was applied to the parents/caregivers (one for each child) and the Child Stress Scale was applied to the children. Data were analyzed descriptively based on the frequency of each studied variable. Twenty-four (82.76%) children needed psychological or psychiatric intervention; 17 of them presented neurotic disorders and 7 children presented antisocial disorders. Six (20.70%) children presented significant physical and psychological manifestations of stress. The findings of the present study suggest that behavioral problems and potential emotional problems can be risk factors to bruxism in children.

Psychological stress induces alterations in temporomandibular joint ultrastructure in a rat model of temporomandibular disorder

OBJECTIVE

The objective of this study was to investigate the effects of psychological stress on temporomandibular disorder (TMD).

STUDY DESIGN

A communication box was used to induce psychological stress (PS) in rats. Then, the ultrastructure of temporomandibular was observed using scanning electron microscopy. Interleukin-1 (IL-1) and IL-6 were measured with reverse transcription polymerase chain reaction.

RESULTS

The PS group showed evidence of ultrastructural changes in the condyle and articular disk after stimulation, i.e., incomplete gelatinlike material was observed on the condyle after 1 week of PS, wider waves on the articular disk and exposed condylar collagen were observed after 3 weeks of PS, and cracks were apparent on the surface of the condyle. The expression of IL-1 and IL-6 in the condyle cartilage significantly increased after exposure to psychological stress.

CONCLUSIONS

These results indicate that psychological stress induces ultrastructure alterations in the temporomandibular joint and plays an important role in TMD.

Day-to-day variations in salivary cortisol measurements

PURPOSE

The purpose of this study was to clarify the day-to-day variations of salivary cortisol to discuss the appropriate timing for collecting saliva in a day for stress evaluation.

MATERIALS AND METHODS

Saliva samples from twelve healthy adults were collected by means of Salivette(®) (SARSTEDT Co.) three times per day, immediately after awakening (Time1), 6:00 PM (Time2) and 30 min before going to bed (Time3), on 5 nonconsecutive days. Cortisol concentration was measured using a radioimmunoassay.

RESULTS

Salivary cortisol concentration showed the larger value at Time1 than that at Time2. The mean value of %CV for day-to-day variation showed the smallest value at Time1 (mean: 43.1%) and the largest value at Time3 (mean: 100.3%). There were significant differences in %CV value between Time1 and Time3, Time2 (mean: 64.1%) and Time3.

CONCLUSIONS

There are considerable day-to-day variations in salivary cortisol concentration measurements. From the viewpoint of day-to-day variation, collecting saliva immediately after awakening in the morning is thought to be more advantageous for evaluating cortisol concentration.

Repeated muscle injury as a presumptive trigger for chronic masticatory muscle pain

skeletal muscles sustain a significant loss of maximal contractile force after injury, but terminally damaged fibers can eventually be replaced by the growth of new muscle (regeneration), with full restoration of contractile force over time. After a second injury, limb muscles exhibit a smaller reduction in maximal force and reduced inflammation compared with that after the initial injury (i.e., repeated bout effect). In contrast, masticatory muscles exhibit diminished regeneration and persistent fibrosis, after a single injury; following a second injury, plasma extravasation is greater than after a single injury and maximal force is decreased more than after the initial injury. Thus, masticatory muscles do not exhibit a repeated bout effect and are instead increasingly damaged by repeated injury. We propose that the impaired ability of masticatory muscles to regenerate contributes to chronic muscle pain by leading to an accumulation of tissue damage, fibrosis, and a persistent elevation and prolonged membrane translocation of nociceptive channels such as P2X(3) as well as enhanced expression of neuropeptides including CGRP within primary afferent neurons. These transformations prime primary afferent neurons for enhanced responsiveness upon subsequent injury thus triggering and/or exacerbating chronic muscle pain.

Prevalence of parafunctional habits and temporomandibular dysfunction symptoms in patients attending a tertiary headache clinic

OBJECTIVE

To investigate the most prevalent forms of headache in a tertiary outpatient service, and to assess the frequency of associated parafunctional habits and temporomandibular dysfunction symptoms (TMD).

METHOD

All new patients referred to the Headache Outpatient Service in UNIMES during 2008 were prospectively assessed by the neurologist and the dental surgeon.

RESULTS

Eighty new patients were assessed; chronic migraine and episodic migraine without aura were the most prevalent conditions, accounting for 66.3% of all cases. There was significantly higher use of analgesics/days for the chronic migraine patients. The prevalence of parafunctional habits was 47.5% and the prevalence of TMD symptoms was 35%.

CONCLUSION

The high prevalence of primary headaches, parafunctional habits and TMD symptoms and the inadequate use of analgesic drugs suggest that primary healthcare units need further training in the field of headache and orofacial pain.

Psychophysical stress increases the expression of phospho-CREB, Fos protein and neurokinin-1 receptors in superficial laminae of trigeminal subnucleus caudalis in female rats

Psychological stress and estrogen status are risk factors to develop painful temporomandibular joint disorders (TMJD); however, the neural basis for this relationship is not known. This study tested the hypothesis that repeated forced swim stress and estradiol treatment alter the phosphorylation of cAMP responsive element-binding protein (pCREB) in trigeminal subnucleus caudalis (Vc), the initial site of sensory input from the TMJ. Ovariectomized female rats were given low or high dose estradiol and subjected to repeated forced swim stress for 3 days and on day 4 an intra-TMJ injection of mustard oil or vehicle was given. Forced swim alone increased the number of pCREB-positive neurons, independent of estradiol treatment or TMJ stimulation, in superficial and deep laminae of Vc. Forced swim also increased the number of Fos-positive neurons in superficial laminae and neurokinin-1 receptor mRNA in whole dorsal Vc, independent of estradiol treatment. These results indicated that persistent psychophysical stress alone was sufficient to increase the expression of pCREB and downstream regulated genes associated with enhanced excitability in the caudal medullary dorsal horn, a brainstem region thought to be critical for TMJD pain.