Prevalence and association of headaches, temporomandibular joint disorders, and occlusal interferences

Occurrence of Cervical Spine Pain and Its Intensity in Young People with Temporomandibular Disorders

Background: The main aim of this cross-sectional study was to compare the occurrence and severity of cervical spine pain in young adults diagnosed with TMDs with a healthy control group (without TMDs). Methods: The study was conducted from June to July 2023. Inclusion criteria were age (18-30 years), cervical spine pain (for at least 1 month), and consent to participate in the study. The study was conducted based on RDC/TMD protocol, an original questionnaire, and a physiotherapeutic examination focused on detecting TMDs. The cervical pain level was assessed using the Visual Analogue Scale (VAS). Thus, a total of 95 subjects were registered for the trials, 51 people (53.7%) constituted the control group (without TMDs), while 44 (46.3%) people constituted the study group (with TMDs). Results: The mean age of people participating in the study was 22.2 ± 2.2 years in the study group and 22.5 ± 3.1 years in the control group. The largest group was people aged 21-25 (n = 51 people, 53.7%). Patients from the study group more often experienced pain in the stomatognathic system during palpation (both in the muscle, joint, and musculoskeletal groups) and had reduced mobility of the temporomandibular joints in every movement (p < 0.001). People from the study group were also characterized by less mobility of the cervical spine (p < 0.05), apart from extension movement (p > 0.05). The analysis showed that of the 95 people participating in the study, 85.4% reported problems in the cervical spine area (n = 81), of which almost all people in the study group struggled with this problem (n = 43, 97.7%). It was found that cervical spine pain was significantly more common in people with TMDs (p < 0.05, chi2 = 10.118, df = 1, rc = 0.31). The level of pain was significantly higher in people from the study group (p < 0.001, chi2 = 45.765, df = 4, rc = 0.57). Conclusions: Our research has shown that the occurrence of cervical spine pain is more common in the group of young people with temporomandibular disorders (TMDs). In young people, this problem is rarely recognized and properly treated.

Relationship between natural or iatrogenic malocclusions and temporomandibular disorders: A case control study

OBJECTIVE

To investigate the link between malocclusions and temporomandibular disorders (TMD) with a focus on iatrogenic malocclusion. Other etiologies of TMD (oral parafunctions) were also assessed.

METHODS

The prevalence of malocclusions was correlated in two groups: patients with TMD (case group) and patients without TMD (control group). Malocclusions involving dental care were specified. Parafunctions in the case group were assessed.

RESULTS

A statistically significant association between TMD and overbite >4 mm, interferences in laterotrusion, and absence of Angle Class I was shown. A potential deleterious effect of iatrogenic malocclusions was highlighted.

CONCLUSION

The multifactorial etiology of TMD was confirmed because an association between TMD and three malocclusions was found, and all case patients had parafunction(s). Current recommendations advising first a reversible treatment, TMD care should start with a behavioral re-education to remove parafunctions. However, it is essential to avoid creating iatrogenic malocclusion during dental care.

Malocclusion complexity as an associated factor for temporomandibular disorders. A case-control study

OBJECTIVE

To evaluate the association between temporomandibular disorders (TMD) and malocclusion complexity using the Index of Complexity Outcome and Need (ICON) levels.

METHODS

A prospective, cross-sectional, case and control study was done. Cases and controls were matched in a one-to-one relationship (179 subjects each). The Research Diagnostic Criteria was used to evaluate the presence of TMD, and the ICON was used to quantify malocclusion complexity. A binary logistic regression (p < 0.05) was used to identify associations between variables.

RESULTS

TMD presence was associated with gender and malocclusion complexity (p < 0.05). The largest proportion of controls were in the lowest three levels of ICON complexity, while most cases were in the three highest levels (p < 0.001). Higher malocclusion complexity indicated a greater TMD risk.

CONCLUSION

The results indicate that TMD is associated with malocclusion complexity. As malocclusion complexity increases, so do the odds of presenting with TMD.

Association between primary headaches and temporomandibular disorders: A systematic review and meta-analysis

BACKGROUND

The primary objective of this systematic review was to answer the following question systematically: Is there any association between primary headaches (PHs) and temporomandibular disorders (TMDs) in adults?

TYPES OF STUDIES REVIEWED

The protocol was registered with the International Prospective Register of Systematic Reviews. The authors performed the search in 7 main databases and 3 gray literature sources. The included articles had to have adult samples. PHs must have been diagnosed using the International Classification of Headache Disorders, and TMDs must have been diagnosed using Research Diagnostic Criteria for Temporomandibular Disorders, Diagnostic Criteria for Temporomandibular Disorders, or International Classification of Orofacial Pain. Risk of bias was evaluated using the Joanna Briggs Institute Meta-Analysis of Statistics Assessment and Review Instrument tools. The meta-analysis was performed using Review Manager software, Version 5.4. Certainty of evidence was screened according to Grading of Recommendations Assessment, Development and Evaluation.

RESULTS

Eight of 2,574 articles reviewed met the inclusion criteria for qualitative analysis and, of these, 6 met the inclusion criteria for quantitative analysis. Odds ratios (ORs) for painful TMD and tension-type headache (OR, 3.16; 95% CI, 1.80 to 5.54 to OR, 13.06; 95% CI, 2.79 to 61.12), migraines (OR, 5.35; 95% CI, 3.04 to 9.40 to OR, 6.22; 95% CI, 3.81 to 10.14), and chronic headaches (OR, 40.40; 95% CI, 8.67 to 188.15 to OR, 95.93; 95% CI, 12.53 to 734.27) were calculated. Articular TMDs without pain were evaluated in only 1 article, in which ORs of 1.78 (95% CI, 0.90 to 3.51) for migraines and 1.04 (95% CI, 0.53 to 2.06) for tension-type headache were reported. Three studies were classified as moderate risk of bias and 5 as low risk of bias. The certainty of evidence varied between very low and low.

CONCLUSIONS AND PRACTICAL IMPLICATIONS

Recognizing the positive association between painful TMD and PHs can help dentists and physicians treat the pain and avoid it, or recommend the patient to a specialist.

Development of a biomechanical model for dynamic occlusal stress analysis

The use of traditional finite element method (FEM) in occlusal stress analysis is limited due to the complexity of musculature simulation. The present purpose was to develop a displacement boundary condition (DBC)-FEM, which evaded the muscle factor, to predict the dynamic occlusal stress. The geometry of the DBC-FEM was developed based on the scanned plastic casts obtained from a volunteer. The electrognathographic and video recorded jaw positional messages were adopted to analyze the dynamic occlusal stress. The volunteer exhibited asymmetrical lateral movements, so that the occlusal stress was further analyzed by using the parameters obtained from the right-side eccentric movement, which was 6.9 mm long, in the stress task of the left-side eccentric movement, which was 4.1 mm long. Further, virtual occlusion modification was performed by using the carving tool software aiming to improve the occlusal morphology at the loading sites. T-Scan Occlusal System was used as a control of the in vivo detection for the location and strength of the occlusal contacts. Data obtained from the calculation using the present developed DBC-FEM indicated that the stress distribution on the dental surface changed dynamically with the occlusal contacts. Consistent with the T-Scan recordings, the right-side molars always showed contacts and higher levels of stress. Replacing the left-side eccentric movement trace by the right-side one enhanced the simulated stress on the right-side molars while modification of the right-side molars reduced the simulated stress. The present DBC-FEM offers a creative approach for pragmatic occlusion stress prediction.

Prevalence of concurrent headache and temporomandibular disorders: a systematic review protocol

OBJECTIVE

The objective of this review is to determine the concurrent prevalence of temporomandibular disorders and headaches in patients.

INTRODUCTION

Temporomandibular disorders affect the temporomandibular joint and associated orofacial structures. It is the second-most common musculoskeletal disorder experienced by adults. Headache is one of the most pervasive neurological disorders and can be an extremely disabling condition. Temporomandibular disorders and headache are known to often occur simultaneously and have a bi-directional relationship due to their close anatomical association.

INCLUSION CRITERIA

The systematic review will include all studies with adult participants (>18 years) experiencing headaches (migraine, migraine with/without aura, tension-type, cervicogenic, and chronic headache) with symptoms of temporomandibular disorders occurring concurrently.

METHODS

An initial search of PubMed will be followed by CINAHL, the Cochrane Central Register of Controlled Trials in the Cochrane Library, EBSCO MasterFILE Premier, PEDro, ProQuest Health and Medical Complete, Science Direct, and Scopus. Titles and abstracts of studies will be reviewed, and full text articles will be selected if the inclusion criteria are met. Studies that meet the eligibility criteria will then be assessed by two independent reviewers. Full-text articles will be selected if the inclusion criteria are met. A standardized critical appraisal checklist for studies reporting prevalence data will be used to assess methodological quality and a standardized data extraction tool will be used. The results from the included studies will be analyzed using JBI SUMARI software.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO (CRD42019139689).

Painful temporomandibular disorder, sleep bruxism, anxiety symptoms and subjective sleep quality among military firefighters with frequent episodic tension-type headache. A controlled study

OBJECTIVE

To investigate associations of temporomandibular disorders (TMDs), bruxism, anxiety and sleep quality among military firefighters with frequent episodic tension-type headache (FETTH).

METHODS

The sample comprised two groups (80 individuals): controls (mean age 35.2 years) and study group (mean age 38.5 years). Headache was diagnosed in accordance with the ICHD-III. The Research Diagnostic Criteria for TMDs were used to classify the TMDs; bruxism was diagnosed in accordance with the International Classification of Sleep Disorders; anxiety was classified using the Beck Anxiety Inventory; and sleep quality was assessed using the Pittsburgh Sleep Quality Index. In the statistical models, we used a significance level of 95%.

RESULTS

Associations were found between participants with FETTH and TMDs (p < 0.001) and anxiety (p = 0.002).Poor quality of sleep (p = 0.687) and bruxism (p = 0.670) were not risk factors.

CONCLUSION

The study found that TMDs and anxiety among firefighters were associated with FETTH.

The Association Between Headaches and Temporomandibular Disorders is Confounded by Bruxism and Somatic Symptoms

OBJECTIVES

The objective of this observational study was to establish the possible presence of confounders on the association between temporomandibular disorders (TMD) and headaches in a patient population from a TMD and Orofacial Pain Clinic.

MATERIALS AND METHODS

Several subtypes of headaches have been diagnosed: self-reported headache, (probable) migraine, (probable) tension-type headache, and secondary headache attributed to TMD. The presence of TMD was subdivided into 2 subtypes: painful TMD and function-related TMD. The associations between the subtypes of TMD and headaches were evaluated by single regression models. To study the influence of possible confounding factors on this association, the regression models were extended with age, sex, bruxism, stress, depression, and somatic symptoms.

RESULTS

Of the included patients (n=203), 67.5% experienced headaches. In the subsample of patients with a painful TMD (n=58), the prevalence of self-reported headaches increased to 82.8%. The associations found between self-reported headache and (1) painful TMD and (2) function-related TMD were confounded by the presence of somatic symptoms. For probable migraine, both somatic symptoms and bruxism confounded the initial association found with painful TMD.

DISCUSSION

The findings of this study imply that there is a central working mechanism overlapping TMD and headache. Health care providers should not regard these disorders separately, but rather look at the bigger picture to appreciate the complex nature of the diagnostic and therapeutic process.

Temporomandibular Disorders and Headache: A Retrospective Analysis of 1198 Patients

Aim. Headache is one of the most common diseases associated with Temporomandibular Disorders (TMDs). The aim of this study was to evaluate, retrospectively, if headache influences TMD's symptoms. Material and Methods. A total sample of 1198 consecutive TMD patients was selected. After a neurological examination, a diagnosis of headache, according to the latest edition of the International Classification of Headache Disorders, was performed in 625 subjects. Patients were divided into two groups based on presence/absence of headache: Group with Headache (GwH) and Group without Headache (GwoH). Descriptive statistics and Chi-square index were performed. Results. Sociodemographic (gender, marital status, and occupation) and functional factors, occlusion (occlusal and skeletal classes, dental formula, and occlusal abnormalities), and familiar pain did not show a statistically significant correlation in either group. Intensity and frequency of neck pain, arthralgia of TMJ, and myalgia showed higher correlation values in GwH. Conclusion. This study is consistent with previous literature in showing a close relationship between headache and TMD. All data underlines that headache makes pain parameters more intense and frequent. Therefore, an early and multidisciplinary treatment of TMDs should be performed in order to avoid the overlay of painful events that could result in pain chronicity.

Symptoms and signs of temporomandibular disorders among elderly Vietnamese

Background:

To assess the prevalence of the symptoms and signs of temporomandibular disorders (TMDs) and determine the prevalence of TMDs among elderly Vietnamese aged 65–74 years old.

Methods:

A cross-sectional study was conducted among 258 participants aged 65–74 years old (128 females and 130 males) using two strategies for TMD diagnosis: a clinical examination of the temporomandibular joint and its associated structures using the Diagnostic Criteria for Temporomandibular Disorders Axis I; and a set of 14 questions regarding TMD symptoms to obtain anamnestic data.

Results:

The prevalence of TMD symptoms was: headache 49.6%; temporomandibular joint noise 28.0%; orofacial pain 25.2%; jaw locking 3.1%; 62.5% of participants had at least one TMD symptom. Headaches were more prevalent in females than males ( p=0.009) and rural than urban residents ( p<0.001). The most frequent signs were temporomandibular joint crepitus (50.4%), clicking (48.1%) and mouth-opening deviation (37.6%). Temporomandibular joint crepitus and mouth-opening deviation were more frequent among rural than urban ( p=0.024 and p<0.001, respectively). TMD was found in 56.6% of the total sample. Of the TMD sufferers, 37.6% were diagnosed with disc displacement, 34.9% with degenerative joint disease, 3.5% with myalgia and 1.2% with arthralgia.

Conclusions:

More than half of elderly Vietnamese have at least one TMD symptom. TMD sounds were the most common clinical sign of TMD. There were no differences between the genders or place of residence and TMD diagnosis. Disc displacement and degenerative joint disease were most prevalent among elderly Vietnamese.

Grinding patterns in migraine patients with sleep bruxism: a case-controlled study

OBJECTIVES

Details on grinding patterns and types of contact during sleep bruxism in association with migraine headache have not yet been elucidated. This study compared the characteristics of sleep bruxism between patients with migraine and controls.

METHODS

The study included 80 female patients who had been diagnosed with migraine and 52 women with no history of migraine. Grinding patterns were measured using the BruxChecker® (Scheu Dental, Iserlohn, Germany).

RESULTS

There was a significant difference between the two groups in the distribution of grinding patterns at the laterotrusive side (p < 0.001). When the anterior teeth and premolar and molar regions in the two groups were compared, the proportion of the grinding area at all sites was significantly larger in the migraine group than in the control group (p < 0.001).

DISCUSSION

The BruxChecker® showed that there was substantial grinding over a large area among migraine patients, particularly in the molar region.

Association Between Harmful Oral Habits and Sign and Symptoms of Temporomandibular Joint Disorders Among Adolescents

CONTEXT

Temporomandibular disorder (TDM) is defined as a heterogenous group of psychophysiological disorders commonly characterised by orofacial pain, chewing dysfunction or both. Various Epidemiological studies had shown occurrence of TMD in all age groups including children. Also research had shown that non nutritional oral habits to be associated with TMD.

AIM

Present study aimed to find whether harmful oral habits are associated with sign and symptoms of TMD among adolescents in Greater Noida.

SETTING AND DESIGN

Schools in Gautam Buddha district and descriptive study.

MATERIALS AND METHODS

Cross sectional study was carried out among 240 adolescents (10 - 19 years) studying in schools of Greater Noida. Study population were selected by random sampling to whom screening questionnaires recommended by American Academy of Orofacial Pain (AAOP) were distributed. Patient history and clinical examination was used to determine harmful oral habits. Data analysis was done in SPSS version 21 and Chi-square test was applied.

RESULTS

Sixty one participants (25.4%) displayed no sign and symptoms of TMD, 34 (14.2%) responded affirmatively to atleast one item on the questionnaire and 108(46%) gave at least three affirmative responses. Headache, Neckpain and Toothache were most frequent reported sign and symptoms of TMD (46.2%). There was statistically significant association between gender and sign and symptoms of TMD on three items of the questionnaire (p < 0.05). Nail Biting (45.8%), Biting Lips/objects (37%) were most common habits among the study group. There was statistically significant association between Nail Biting (p = 0.001), Lip Biting/ object biting (p=0.001), Grinding of teeth (p = 0.01) and sign and symptoms of TMD.

CONCLUSION

A statistically significant association was found between nail biting, lip/ object biting and grinding of teeth with signs and/or symptoms of TMD. Thus there is need for preventive dental treatment and community dental education so that young adults realize importance of early diagnosis and treatment of TMJ disorders.

Sleep and Headache

The interaction between sleep and headache or migraine is powerful and an elevated comorbidity between these 2 disorders has been reported in either adults or children. This comobidity is linked to common neurophysiological and neuroanatomical substrates that are genetically based strongly. The first reports on this relationship were related to the prevalence of parasomnias and sleep-disordered breathing in headache but recent research has expanded the comorbidity to several other sleep disorders, such as restless legs syndrome, periodic limb movements during sleep, and narcolepsy. The assessment of children with headache should always include an accurate anamnesis for the presence of sleep problems either in the child or in the relatives; no correct approach for treating children and adolescents is possible without an integrated method of evaluation and management.

Electromyographic and patient-reported outcomes of a computer-guided occlusal adjustment performed on patients suffering from chronic myofascial pain

Objectives: Muscular hyperactivity is a potential source of symptoms in patients with temporal-mandibular disorders. An adequate occlusal adjustment may relieve such symptoms. This study aims to measure the effect of shortening the protrusive disclusion time (DT) and balancing the center of occlusal forces (COF) on the EMG recordings and assess the pain reported by chronic patients one month after the computer-guided occlusal adjustment. Study Design: The sample studied comprised 34 patients suffering from chronic facial pain in which the EMG activity of both masseters was recorded by electromyography. By selective grinding we alleviated all the occlusal interferences during the mandibular protrusion from the habitual closure position in order to establish an immediate posterior disclusion and an equilibration of the COF. Results: At follow-up 76.5% of the patients reported no facial pain. Moreover, the EMG activity and protrusive DT were significantly reduced, and occlusal and muscular function were significantly more symmetric than at baseline. Conclusions: According to this EMG study, this computer-guided occlusal adjustment is able to reduce the activity of the masseters and the self-reported muscular pain of patients one-month after treatment.

Key words:Myofascial pain, occlusal adjustment, electromyography, T-Scan III, occlusal interferences.

Risk factors associated with incidence and persistence of frequent headaches

OBJECTIVE

Headaches represent a significant public health problem, but the knowledge of factors specifically related to incidence and persistence of headaches is still limited. The aim of this study was to evaluate whether gender, self-reported bruxism and variations in the dental occlusion contribute to onset and persistence of frequent headaches.

MATERIALS AND METHODS

The study population comprised 280 dental students, examined annually in a 2-year prospective study with a questionnaire and a clinical examination of the jaw function. In the analysis subjects were dichotomized into cases with frequent (once a week or more) or without frequent headaches (controls). The 2-year cumulative incidence was based on subjects without frequent headaches at baseline. Cases with 2-year persistent headaches reported such symptoms at all three examinations. Self-reported bruxism and factors in the dental occlusion at baseline were used as independent variables in logistic regression analyses.

RESULTS

The 2-year cumulative incidence of frequent headaches was 21%. Female gender (OR = 2.6; CI = 1.3-5.4), self-reported bruxism (OR = 2.3; CI = 1.2-4.4) and mandibular instability in intercuspal position (OR = 3.2; CI = 1.4-7.5) were associated with incidence of frequent headaches. Persistent headaches during the observation period were present in 12 individuals (4%) and significantly related to mandibular instability in intercuspal position (OR = 6.1; CI = 1.6-22.6).

CONCLUSIONS

The results indicate that female gender, self-reported bruxism and mandibular instability in intercuspal position are of importance in the development of frequent headaches. In management of these patients a multidisciplinary approach including dentists may be important and, thus, advocated.

Headache and oral parafunctional behaviors

This study tested the hypotheses that individuals with headaches would show significantly more oral parafunctional behaviors than non-headache controls, be diagnosed with one or more temporomandibular disorders (TMD) significantly more frequently than controls, and would report significantly less pain and other symptoms of headache after participating in a habit reversal treatment to reduce oral parafunctional behaviors, compared to a wait list control. In Phase I, individuals with and without self-reported headaches were examined by a blinded examiner and participated in a week-long experience sampling protocol (ESM) to assess oral parafunctional behaviors, pain, and emotional states. In Phase II, those with headaches were randomly assigned to either a habit reversal treatment or to a wait list control group. In the last, sixth week of the program, participants again completed an ESM protocol. Results showed that headache patients were significantly more likely to report oral parafunctional behaviors than non-headache controls and to receive a Research Diagnostic Criteria/TMD diagnosis. Results from Phase II showed general improvement in both groups on pain and parafunctions. Individuals with headaches engage in significantly higher rates and intensities of oral parafunctional behaviors. Treatment of these behaviors using habit reversal techniques appears to have the same effect on pain as waiting.

Influence of functional head postures on the dynamic functional occlusal parameters

Background:

The dentist utilizes supine position during therapeutic procedures, while the patients assumes extended head posture during mastication. It is critical for the restorative dentist to evaluate and understand the possible effect of change in head posture on occlusal contacts. An understanding of the possible effect will help in better restorative rehabilitation.

Aim:

The aim of the following study is to evaluate the influence of head postures on the dynamic occlusal parameters.

Subjects and Methods:

Study group consisted of 50 students from College of Dentistry, King Khalid University. The students were selected randomly from the college student body; they were in the age group of 18-25 years. The head posture evaluated were supine position, upright sitting position and alert feeding position. The head postures were standardized by goniometer and dynamic occlusal contacts were analyzed with Tscan. The data obtained was subjected to statistical analysis with repeated measures of ANOVA to identify the changes in occlusal contacts.

Results:

The occlusion time was 1.366 (0.484), 1.226 (0.562) and 0.997 (0.429) s for supine, upright and alert feeding position respectively. Disclusion time was for right lateral movement was 0.872 (0.372), 0.629 (0.290) and 0.831 (0.369) s for corresponding head postures. Left lateral disclusion time was 0.621 (0.274), 0.274 (0.345) s for upright and alert feeding posture. Repeated measures of ANOVA showed statistically significant difference between occlusal contacts in different head postures.

Conclusion:

Within the limitation of the study, it was concluded that there were significant changes in initial occlusal contact, occlusion and disclusion time at all the head postures evaluated in the study.

The role of occlusal factors on the occurrence of temporomandibular disorders

AIMS

The aim of this study was to investigate the relationship between occlusal factors and temporomandibular disorders (TMD).

METHODOLOGY

One hundred patients were selected among those who sought medical or dental care in public practice in Recife, Brazil. The presence of malocclusions and absence of five or more posterior teeth were evaluated by the clinical exam. TMD diagnosis was given using Research Diagnostic Criteria (RDC/TMD). Statistics were carried out using Fisher and Mann-Whitney methods with 5% significance level, as well as multiple logistic regression analysis.

RESULTS

The sample was mainly comprised of women (83%), individuals over 30 years old (57%) and singles (53%). The percentage of TMD and malocclusion in total sample was 42% and 50%, respectively, while in TMD subjects, malocclusion was present in 38.1%. There was no association between TMD and the occlusal factors studied.

CONCLUSION

It can be concluded that malocclusion and loss of five or more posterior teeth does not contribute to TMD.

Influence of temporomandibular disorder on temporal and masseter muscles and occlusal contacts in adolescents: an electromyographic study

Background

The aim of the present study was to analyse the influence of temporomandibular disorder (TMD) on electromyographic activity in the masseter and temporal muscles of adolescents and investigate a possible association with the number of occlusal contacts.

Methods

The Helkimo Index was administered for the diagnosis of TMD and classification of the adolescents into three groups: without TMD; with mild TMD; and with moderate/severe TMD. Carbon paper was used for the determination of occlusal contact points. A standardised electromyographic evaluation was performed on the masticatory muscles at rest, during habitual chewing and during maximum voluntary clenching. The readings were normalised to maximum voluntary clenching. Statistical analysis involved the chi-squared test and Fisher’s exact test. The Kruskal-Wallis test and one-way analysis of variance with Dunn’s post hoc test were used to compare differences between groups. Pearson’s correlation coefficients (r) were calculated for the determination of correlations between the number of occlusal contacts and RMS values.

Results

Electromyography revealed significant differences in the right and left masseter and temporal muscles at rest and during chewing among the three groups. These differences were not observed during maximum voluntary clenching. No statistically significant differences were found between the groups with and without TMD regarding the number of occlusal contacts.

Conclusion

Electromyographic activity in the masseter and temporal muscles was greater among adolescents with moderate to severe TMD.

Are occlusal characteristics, headache, parafunctional habits and clicking sounds associated with the signs and symptoms of temporomandibular disorder in adolescents?

[Purpose] To assess the association between the oclusal characteristics, headache, parafunctional habits and clicking sounds and signs/symptoms of TMD in adolescents. [Subjects] Adolescents between 14 and 18 years of age. [Methods] The participants were evaluated using the Helkimo Index and a clinical examination to track clicking sounds, parafunctional habits and other signs/symptoms of temporomandibular disorder (TMD). Subjects were classified according to the presence or absence of headache, type of occlusion, facial pattern and type of bite. In statistical analyse we used the chi-square test and Fisher's exact test, with a level of significance of 5%. [Results] The sample was made up of 81 adolescents with a mean age of 15.64 years; 51.9% were male. The prevalence of signals/symptoms of TMD was 74.1%, predominantly affecting females. Signals/symptoms of TMD were significantly associated with clicking sounds, headache and nail biting. No associations were found between signals/symptoms of TMD and angle classification, type of bite and facial pattern. [Conclusion] Headache is one of the most closely associated symptoms of TMD. Clicking sounds were found in the majority of cases. Therefore, the sum of two or more factors may be necessary for the onset and perpetuation of TMD.

Pattern of electromyographic activity in mastication muscles of adolescents with temporomandibular disorder

[Purpose] The aim of the present study was to assess the behavior of the mean and median frequencies of the electromyography signal of the mastication muscles of adolescents with different degrees of TMD severity. [Subjects] Forty-two adolescents aged 14 to 18 years. [Methods] The adolescents were classified according to severity using the Helkimo Index. The control group consisted of 14 subjects with no signs or symptoms of TMD. Three readings were taken in during maximum intercuspation and mandibular rest, with each reading lasting 10 seconds. [Results] Significant differences (p=0.0001) were found in the mean frequency (Hz) between the control group (CG), mild TMD group (MG) and moderate/severe TMD group (MSG), especially during mandibular rest, for all muscles evaluated: right temporal: CG (137.5), MG (194.2), MSG (291.7); left temporal: CG (106.9), MG (200.6), MSG (294.2); right masseter: CG (155.7), MG (242.8), MSG (278.3); left masseter: CG (125.0), MG (214.6), MSG (316.7). Greater differences among groups were found under the condition of mandibular rest.

CONCLUSIONS

Adolescents with TMD especially those with more severe symptoms exhibit hyperactivity of the mastication muscles.

Primary headaches and trigeminal neuralgia: neuropathic pain yes or not? Evidences from neurophysiological procedures

Despite the fact that neurophysiological evaluation is not useful for primary headache diagnosis, the nociceptive system exploration through reflexes and evoked potentials procedures may give an aid in understanding the pathophysiological mechanism subtending pain. Neuropathic pain is caused by a lesion or disease of the somatosensory nervous system, which is supported by clinical evaluation and instrumental assessment by trigeminal and nociceptive reflexes and laser evoked potentials. The same methods, applied to migraine and cluster headache, together with evidences coming from structural and functional neuroimaging, excluded the neuropathic origin of pain, which is attaining to symptomatic and idiopathic trigeminal neuralgia, but confirmed a complex dysfunction of pain processing. Tension-type headache fits with a model of non-nociceptive and non-neuropathic pain, subtended by a complex interaction of peripheral muscular and central neuronal factors. The presence of altered modulation of pain concurs with migraine and tension-type headache, and should be taken into account for the choice of the best therapeutic approach.

Fatigue-enhanced hyperalgesia in response to muscle insult: induction and development occur in a sex-dependent manner

Chronic muscle pain affects 20-50% of the population, is more common in women than men, and is associated with increased pain during physical activity and exercise. Muscle fatigue is common in people with chronic muscle pain, occurs in response to exercise, and is associated with release of fatigue metabolites. Fatigue metabolites can sensitize muscle nociceptors, which could enhance pain with exercise. Using a mouse model we tested whether fatigue of a single muscle, induced by electrical stimulation, resulted in enhanced muscle hyperalgesia and if the enhanced hyperalgesia was more pronounced in female mice. Muscle fatigue was induced in combination with a sub-threshold muscle insult (2 injections of pH 5.0 saline) in male and female mice. We show that male and female mice, fatigued immediately prior to muscle insult in the same muscle, develop similar muscle hyperalgesia 24 hours later. However, female mice also develop hyperalgesia when muscle fatigue and muscle insult occur in different muscles, and when muscle insult is administered 24 hours after fatigue in the same muscle. Further, hyperalgesia lasts significantly longer in females. Finally, muscle insult with or without muscle fatigue results in minimal inflammatory changes in the muscle itself, and sex differences are not related to estradiol (ovariectomy) or changes in brainstem activity (pNR1). Thus, the current model mimics muscle fatigue-induced enhancement of pain observed in chronic muscle pain conditions in the human population. Interactions between fatigue and muscle insult may underlie the development of chronic widespread pain with an associated female predominance observed in human subjects.

Gender difference in prevalence of signs and symptoms of temporomandibular joint disorders: a retrospective study on 243 consecutive patients

BACKGROUND

This study evaluated the prevalence of the signs and symptoms of temporomandibular joint disorder (TMD) among patients with TMD symptoms.

METHODS

Between September 2011 and December 2011, 243 consecutive patients (171 females, 72 males, mean age 41 years) who were referred to the Department of Prosthodontics, Faculty of Dentistry, Karadeniz Technical University, Trabzon were examined physically and completed a questionnaire regarding age, gender, social status, general health, antidepressant drug usage, dental status, limited mouth opening, temporomandibular joint (TMJ) sounds, and parafunctions (bruxism, clenching). The data were analyzed using the chi-square test and binary logistic regression model (alpha = 0.05).

RESULTS

With a frequency of 92%, pain in the temporal muscle was the most common symptom, followed by pain during mouth opening (89%) in both genders. TMJ pain at rest, pain in the masseter muscle, clicking, grinding, and anti-depressant use were significantly more frequent in females than males. Age (p=0.006; odds ratio 0.954; 95% CI 0.922-0.987) and missing teeth (p=0.003; odds ratio 3.753; 95% CI 1.589-8.863) had significant effects on the prevalence of TMD.

CONCLUSION

Females had TMD signs and symptoms more frequently than males in the study population. The most common problem in both genders was pain.