Sleep bruxism: The past, the present, and the future-evolution of a concept

BACKGROUND

The concept of sleep bruxism (SB) has evolved exponentially over the past several decades. Many theories and hypotheses have been proposed as to the definition, pathophysiology, and management of SB, from the early 1960s through the present. The role of peripheral factors, such as dental occlusion, in the pathogenesis of SB has been discarded.

TYPES OF STUDIES REVIEWED

The authors searched several electronic databases (ie, PubMed, Google Scholar, Web of Science, Embase, and Ovid MEDLINE) for studies on bruxism. The search was conducted from January 1961 through May 2023 and yielded 4,612 articles, of which 312 were selected for comprehensive review after eliminating duplicates and nonfocused articles.

RESULTS

There has been an evident progressive shift from the role of peripheral factors, such as dental occlusion, to more central factors, such as the involvement of a central pattern generator as well as the autonomic nervous system, in the genesis of bruxing movements. There is continued robust interest in the dental community to elucidate the contributing factors involved in SB.

CONCLUSIONS AND PRACTICAL IMPLICATIONS

The neurophysiology of SB appears to be leaning more toward central rather than peripheral factors. There is increasing evidence of the role of the autonomic nervous system, genetics, and comorbidities in the genesis of SB. The scientific literature seems to refute the role of dental occlusion in the causation of bruxing movements. As per the literature, there has been a paradigm shift in the definition and genesis of SB and its possible dental implications and management, which also highlights the need for succinct scientific studies in this regard.

Effects of bruxism on temporomandibular joint internal derangement in patients with unilateral temporomandibular joint pain: The role of magnetic resonance imaging diagnostics

OBJECTIVE

This study compared temporomandibular joint (TMJ) magnetic resonance imaging (MRI) findings between bruxism and control groups with unilateral TMJ pain as well as the TMJ MRI findings for the painful and non-painful sides of individuals in the two groups.

METHODS

Clinical and MRI findings of patients seen at Uşak University, Dentistry Faculty, Department of Oral and Maxillofacial Surgery for unilateral TMJ pain between 2017 and 2020 were analyzed. Bruxism was diagnosed based on clinical findings and patient history. The MRI variables were disc/condyle relationship (normal, disc displacement with reduction, or disc displacement without reduction), disc structure (normal and abnormal), condyle degeneration type (normal, moderate, or severe), and joint effusion (absent or present). Pain was recorded based on a visual analog scale (VAS) numbered between 0 and 10. Statistical analyses were performed using IBM SPSS. The data were distributed non-normally according to the results of Kolmogorov-Smirnov tests. The Mann-Whitney U test was used to compare age and VAS. Chi-square tests were used to compare categorical variables. Statistical significance was defined as p < 0.05.

RESULTS

This study assessed the MRI records of 558 cases of TMJ pain. No significant differences in disc/condyle relation, disc structure, condyle structure, or effusion were observed between the control and bruxism groups (p > 0.05). However, a significant difference in TMJ MRI findings was observed between the painful and non-painful sides of each individual in the control and bruxism groups (p = 0.001, p < 0.001 and p = 0.004, p < 0.001, respectively).

CONCLUSION

The results of this study established a relationship between the painful side for each patient and TMJ MRI findings. In particular, individuals with bruxism had a higher rate of TMJ internal derangement and effusion on the painful side.

Dental Implant Treatment in Bruxers: A Case Report and Literature Review

This case report presents a literature review and a case report of a full-mouth implant rehabilitation for a 65-year-old woman with a history of Bruxism. The patient's oral condition showed dentition with severe occlusal wear, extensive dental work, and missing teeth replaced with bridges and implants. The existing dental work was failing due to recurrent caries and the mechanical failure of long-span bridges. The unique aspect of the treatment presented in this report is the management of existing osseointegrated implants of different systems with different platform designs, which adds to the treatment's complexity. The existing implants were incorporated into the planned treatment, and other implants were added to support maxillary zirconia and mandibular hybrid full-arch prostheses. After 2 years of function, extensive wear was evident on the milled acrylic, even though an occlusal guard was used. New acrylic teeth were processed using the same milled titanium bar of the mandibular hybrid prosthesis, and the occlusal surfaces of the acrylic teeth were protected with gold onlays. The patient is seen regularly for maintenance every 6 months with no further complications. Careful evaluation, planning, and treatment execution are paramount in managing patients with a history of bruxism. Patients should be prepared and informed about possible mechanical failure and seen regularly for maintenance.

Orthodontic correction of a skeletal Class II malocclusion with severe gummy smile by total intrusion of the maxillary dentition

A 22-year-old woman visited the hospital complaining of lip protrusion, crowded teeth, and a gummy smile. The clinical examination showed a convex profile with a hyperdivergent mandible and a severe gummy smile in both anterior and posterior regions. The unstable mandible position was considered during treatment planning, and a targeted mechanic system was carefully designed. Temporary skeletal anchorage devices in the posterior dental region and a transpalatal arch were introduced as anchorage for the intrusion of the entire maxillary dentition and controlled retraction of the anterior teeth. Based on effective and simple mechanisms, we successfully eliminated the severe gummy smile and improved the facial aesthetics with the aid of conventional appliances. This approach provided an alternative option to orthognathic surgery or bulky invasive miniscrews for treatment of skeletal Class II malocclusion with severe gummy smile.

Evaluation of condyle-fossa relationships in skeletal Class I malocclusion with variable degrees of deep overbite and open bite

OBJECTIVE

To compare the temporomandibular joint (TMJ) position and shape between skeletal Class I subjects with different degrees of deep overbite or open bite and unaffected peers.

METHODS

Cone beam computed tomography (CBCT) images of 90 participants, equally divided into deep bite, open bite, and control groups (DBG, OBG, and CG, respectively), were analyzed. The DBG and OBG were further subdivided into three subgroups based on the severity. Linear and angular measurements were used to determine the positional and morphological characteristics of the TMJ.

RESULTS

DBG showed significantly larger superior joint space, anterior inclination of the condyle, and articular eminence inclination than CG and OBG. The severity of deep bite and open bite significantly influenced the TMJ position and morphology.

CONCLUSION

In severe deep overbite and open bite cases, there were considerable alterations in TMJ components, most likely as a result of functional demands.

Magnetic Resonance Imaging Evaluation of Closed-Mouth TMJ Disc-Condyle Relationship in a Population of Patients Seeking for Temporomandibular Disorders Advice

Objective

To characterize the closed-mouth temporomandibular joint (TMJ) disc-condyle relationship in a population of individuals who sought hospital services for temporomandibular disorders (TMD).

Methods

Two hundred and twenty-four TMJ magnetic resonance images (MRIs) of 112 patients were assessed in all spatial planes to classify disc position with respect to the condyle in a closed-mouth position.

Results

Disc displacement (DD) was present in 62.1% and superior disc position in 29.9% of the patients. Position could not be determined in 8% of the cases. Among DD, pure anteriorized position was the most common condition (34.4%), with different combined translational and rotational displacements in all the other joints (27.7%).

Conclusion

There is a wide biological variability in disc position in closed mouth among patients seeking for TMD advice. Getting deeper into the correlation with clinical symptoms is recommended to refine the potential relevance of any diagnostic and management strategies based on the imaging evaluation of TMJ disc position.

Oral behaviors, bruxism, malocclusion and painful temporomandibular joint clicking: is there an association?

The present cross-sectional case-control study aimed to determine if there is an association between specific oral behaviors, sleep bruxism (SB), awake bruxism (AB), and painful temporomandibular joint (TMJ) clicking. Ninety individuals were dived into three groups; Group 1 (n = 30): painful TMJ clicking; Group 2 (n = 30): painless TMJ clicking; and Group 3 (n = 30): control group. The following clinical data were studied: oral behaviors (unilateral chewing, gum chewing, nail biting, foreign objects biting, leaning with jaw against the hand, and sleeping in a position that pressures the jaw), SB, AB (including the frequency in 10 days, evaluated by ecological momentary assessment), and malocclusions investigated based on clinical inspections (anterior open bite, posterior cross-bite, abnormal overbite/overjet, occlusal guidance, mediotrusive and/or laterotrusive interferences, retruded contact position to maximum intercuspation slide, missing posterior teeth). All statistical tests (Kolmogorov-Smirnov, chi-square, and one-way ANOVA) were performed with a 5% significance level. Group 1 had the highest frequency of and a significant association with leaning with jaw in the hand, sleeping position that pressures the jaw, gum chewing, nail biting, and AB (p<0.05). Gum chewing, nail biting, and AB were associated with Group 2 only when compared to Group 3 (p<0.05). No significant difference among groups was found for other behaviors (unilateral chewing and foreign objects biting), SB, and all malocclusions (p>0.05). It can be concluded that patients with painful TMJ clicking had a higher frequency of and a significant association with some specific harmful behaviors and AB.

Clinical characteristics of temporomandibular disorders presenting posterior open bite - A report of 12 cases

Background/purpose

There is a paucity of comprehensive information about posterior open bite (POB) in patients with temporomandibular disorders (TMD) because of its rare prevalence. The purpose of this study was to investigate the etiologies, clinical characteristics, and treatment outcomes of patients with TMD presenting POB.

Materials and methods

This study includes a careful review of medical records and imaging findings of 12 patients with TMD (seven men and five women, 50.9 ± 19.2 years, 15–72 years) complaining of POB.

Results

In total, 11 had unilateral POB, whereas 1 had bilateral POB. In 11 patients, POB was caused by inflammatory disorders of temporomandibular joint (TMJ). In the remaining one patient, TMJ medial disc displacement (MDD) was responsible for POB. Of 11 patients with inflammatory conditions of TMJ, four patients had unilateral TMJ internal derangement (ID), two had bilateral TMJ ID, and one had rheumatism. POB was resolved in 10 of 11 patients with TMJ inflammation following the administration of non-steroidal anti-inflammatory drugs and self-management instructions. Prosthodontic treatment was needed in one patient to resolve POB. POB was resolved in the patient with TMJ MDD after stabilization splint therapy.

Conclusion

POB in patients with TMD was mostly caused by inflammatory disorders of TMJ. TMJ MDD could also be a reason. Although almost all POB was resolved by conservative treatments including medications, the possibility of prosthodontic, orthodontic, or surgical treatments also must be considered.

Indexes of jaw muscle function in asymptomatic individuals with different occlusal features

This study aims to assess the correlation between indexes of jaw muscle function and dento-skeletal morphology. A sample of 35 temporomandibular disorders-free healthy individuals (10 males, mean age 26.7 ± 9.8 years) underwent surface electromyographic (sEMG) assessment of bilateral masseter and temporalis muscles, to evaluate sEMG activity during maximum voluntary clenching (MVC) with a dedicated device (Easymyo®, T.F.R. Technology, Udine, Italy). Four outcome parameters were assessed for each individual: MCV on cotton rolls; MVC on teeth; chewing on right and left sides; clench/relax test. Electromyographic recordings were assessed based on five standardized indexes of muscle function, to evaluate the degree of muscle asymmetry during static and dynamic function (i.e., percentage overlapping coefficient [POC], Impact, Asymmetry, Activation, and Torque). For each individual, the presence of a number of occlusal and skeletal features was assessed: asymmetry of molar class; deviated incisor midline; deep bite; open bite; and crossbite. Skeletal class and vertical dimension of occlusion were also evaluated. Based on normality distribution of data, t test and analysis of variance, when needed, were used to compare muscle function indexes between individuals with and without the different dento-skeletal features. None of the muscle function indexes (POC, Impact, Asymmetry, Activation, and Torque) was significantly different between individuals with or without the various dental and skeletal features. Gender differences were also not significant (p > 0.05). Despite some minor differences were observed, none of them was significant. Thus, the interaction between form and function is too complex for hypothesizing a simple one-to-one relationship between interarch tooth relationship and muscle function patterns.

Temporomandibular disorder: otologic implications and its relationship to sleep bruxism

Introduction

Temporomandibular disorder is an umbrella term for various clinical problems affecting the muscles of mastication, temporomandibular joint and associated structures. This disorder has a multifactor etiology, with oral parafunctional habits considered an important co-factor. Among such habits, sleep bruxism is considered a causal agent involved in the initiation and/or perpetuation of temporomandibular disorder. That condition can result in pain otologic symptoms.

Objective

The aim of the present study was to investigate the relationship between temporomandibular disorder and both otologic symptoms and bruxism.

Methods

A total of 776 individuals aged 15 years or older from urban areas in the city of Recife (Brazil) registered at Family Health Units were examined. The diagnosis of temporomandibular disorder was determined using Axis I of the Research Diagnostic Criteria for temporomandibular disorders, addressing questions concerning myofascial pain and joint problems (disk displacement, arthralgia, osteoarthritis and osteoarthrosis). Four examiners had previously undergone training and calibration exercises for the administration of the instrument. Intra-examiner and inter-examiner agreement was determined using the Kappa statistic. Individuals with a diagnosis of at least one of these conditions were classified as having temporomandibular disorder. The diagnosis of otologic symptoms and bruxism was defined using the same instrument and a clinical exam.

Results

Among the individuals with temporomandibular disorder, 58.2% had at least one otologic symptom and 52% exhibited bruxism. Statistically significant associations were found between the disorder and both otologic symptoms and bruxism (p < 0.01 for both conditions; OR = 2.12 and 2.3 respectively). Otologic symptoms and bruxism maintained statistical significance in the binary logistic regression analysis, which demonstrated a 1.7 fold and twofold greater chance of such individuals have temporomandibular disorder, respectively.

Conclusion

The logistic regression analysis demonstrated strong associations between the disorder and both otologic symptoms and bruxism when analyzed simultaneously, independently of patient age and gender.

Headaches and facial pain in rhinology

"Sinus headache" is a common chief complaint that often leads patients to an otolaryngologist's office. Because facial pain may or may not be sinogenic in origin, the otolaryngologist should be equipped to evaluate and treat or to appropriately refer these patients. Analysis of current data indicates that the majority of patients who present with sinus headaches actually have migraines. Furthermore, the downstream effect of the cytokine cascade initiated in migraine physiology can cause rhinologic symptoms, including rhinorrhea, congestion, and lacrimation, which may also confound diagnosis. Other causes of sinus headache include the following: cluster headaches, Sluder neuralgia, trigeminal neuralgia, myofascial trigger point pain (tension headaches, temporomandibular joint dysfunction), and contact point headaches. The diagnostic dilemma for an otolaryngologist occurs when a patient has facial pain and symptoms that may indicate chronic rhinosinusitis but with nondiagnostic endoscopy. Traditionally, these patients have been primarily managed with empiric antibiotics. An alternative strategy is to first screen these patients with an upfront computed tomography. This algorithm may ultimately decrease cost; avert unnecessary antibiotics prescriptions; and prompt more timely referrals to other, more appropriate, disciplines, such as neurology, dentistry, and/or pain management specialists.

Association of malocclusion, self-reported bruxism and chewing-side preference with oral health-related quality of life in patients with temporomandibular joint osteoarthritis

OBJECTIVES

The aim of this study was to evaluate the association of oral health-related quality of life (OHRQoL) with malocclusion and self-reported bruxism and chewing-side preference (CSP) in patients with temporomandibular joint osteoarthritis (TMJ-OA).

METHODS

This study involved 511 patients diagnosed with TMJ-OA. Each participant completed the Chinese version of the 14-item Oral Health Impact Profile (OHIP-C14) questionnaire and received a clinical examination concerning malocclusion (posterior crossbite, overbite, overjet and anterior open bite). Also patients' self-reported awake bruxism (AB), sleep bruxism (SB) and CSP based on the Oral Behavior Checklist (OBC) were recorded. The associations of OHIP-C14 with malocclusion and self-reported bruxism and CSP were assessed using multiple linear regression analysis.

RESULTS

Posterior crossbite, overbite, overjet and anterior open bite were not significantly associated with either the total OHIP-C14 score or the scores of each domain of OHIP-C14. AB was significantly associated with both the total OHIP-C14 score and the scores of each domain with the largest standardised coefficients. CSP was significantly associated with both the total OHIP-C14 score and the scores of the psychological and social domains. SB was significantly associated with the scores of both the function limitation and psychological disability domains.

CONCLUSIONS

Malocclusion is not significantly associated with OHRQoL in patients with TMJ-OA. Self-reported AB is highly associated with OHRQoL in patients with TMJ-OA, while self-reported SB and CSP are both moderately associated with OHRQoL in patients with TMJ-OA.

Do patients with malocclusion have a higher prevalence of temporomandibular disorders than controls both before and after orthognathic surgery? A systematic review and meta-analysis

PURPOSE

The aim of this study was to identify, through meta-analysis, whether patients who require orthognathic surgery have a higher prevalence of temporomandibular disorders (TMDs) than controls, both before treatment and after.

MATERIAL AND METHODS

A systematic review and meta-analysis were conducted based on PRISMA guidelines, to address the study purposes. A search of major databases through PubMed, EMBASE, and Cochrane CENTRAL was performed to locate all pertinent articles published from inception to June 2016. Inclusion criteria were controlled clinical studies, either prospective or retrospective, and case-control studies comparing preoperative and postoperative signs and symptoms of TMDs in patients who undergo orthognathic surgery to those of a healthy volunteer population with no dentofacial deformities. The predictor variables were patients with dentofacial deformities who underwent orthognathic surgery and patients with no dentofacial deformities and with good maxillomandibular relations and normal occlusion. The outcomes variables were the weighted, prevalence rate (proportion) in signs and symptoms of TMDs in patients with dentofacial deformities and risk ratio (RR) of signs and symptoms of TMDs before and after orthognathic surgery, compared to the control group.

RESULTS

A total of 542 patients enrolled in 6 studies were included in this analysis. The overall pooled weighted rate or prevalence of TMDs for orthognathic surgery patients preoperatively was 32.5% (95% CI = 26.7%-38.9%). There was a significant difference between the 2 groups with respect to TMDs before surgery, but no significant difference in TMDs after surgery. The RR for patients who had dentofacial deformities before orthognathic surgery compared with a control group was 1.634 (95% CI = 1.216-2.194; P = 0.001). The RR for patients after orthognathic surgery compared with a control group was 1.262 (0.718; 95% CI = 0.805-1.979; P = 0.311).

CONCLUSION

The results of this study show that patients who are going to have a correction of their malocclusion by orthodontics and orthognathic surgery have a significant incidence of TMDs when compared to a control population, but that after treatment, the incidence of TMDs does not differ from a control population. The reasons for these findings are not clear.

Dental Angle class asymmetry and temporomandibular disorders

OBJECTIVES

The aim of this study was to determine whether there is an association between the presence of asymmetric molar or canine Angle classes on the two sides and the presence of temporomandibular joint dysfunction (TMD).

MATERIALS AND METHODS

Participants to the study were divided into two groups: TMD group (90 patients) or a control group (58 patients). In the TMD group, clinical assessment for TMD was performed according to the Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) guidelines by the same two trained examiners. In both groups, all subjects underwent an assessment of dental occlusion, focusing on the assessment of bilateral canine and molar Angle class relationship. The study protocol was reviewed and approved by the Institutional Review Board of the University of Padova, and each participant gave written consent to take part in the investigation.

RESULTS

TMJ pain was diagnosed in 58, disk displacement in 96, arthrosis in 17, and muscle pain in 46 individuals. Molar Angle class was symmetrical in 86 individuals and asymmetrical in 62 subjects. Molar Angle class was not correlated with any of the TMD diagnoses. Canine Angle class was correlated with TMJ arthrosis. Correlation values with the other TMD diagnoses were low and were not significant.

CONCLUSIONS

It can be suggested that an association between dental Angle class asymmetry and TMDs does not exist and that the role of dental asymmetries as a factor correlated with the presence of TMD signs and symptoms is minimal.

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.

Jaw clenching effects in relation to two extreme occlusal features: patterns of diagnoses in a TMD patient population

OBJECTIVE

The aim of this investigation was to compare the pattern of temporomandibular disorder (TMD) diagnoses in clenching patients with different occlusal features, the null hypothesis being that no between-group differences exist.

MATERIALS AND METHODS

Two groups of subjects receiving a jaw clenching diagnosis and having large overjet or anterior open bite (Group A; N=45, 75.5% females, mean age: 38.1 +/- 15.9 years) or normal occlusion (Group B; N=69, 71% females, mean age: 34.6 +/- 13.8 years) were recruited among a TMD patient population and were given Research Diagnostic Criteria for TMD (RDC/TMD) axis I diagnoses, namely, group I muscle disorders, group II disc displacements, and group III arthralgia/osteoarthritis/osteoarthrosis.

MAJOR FINDINGS

The distribution of RDC/TMD single and combined group diagnoses was significantly different between the two groups (P<0.05), with Group A subjects showing a higher prevalence of multiple diagnoses (60% versus 43.3%), as well as a higher prevalence of combined RDC/TMD axis I group II and III diagnoses (37.8% versus 20.2%). All TMD signs and symptoms were more frequent in the patients with large overjet or anterior open bite with respect to the patients with normal occlusion.

CONCLUSION

In a TMD patient population, jaw clenching may have different consequences in subjects with large overjet or anterior open bite with respect to subjects featuring normal occlusion.

Dental malocclusion is not related to temporomandibular joint clicking: a logistic regression analysis in a patient population

OBJECTIVES

To assess the association of several dental malocclusion features with temporomandibular joint (TMJ) click sounds in a population of temporomandibular disorder (TMD) patients.

MATERIALS AND METHODS

Four hundred forty-two TMD patients (72% female; 32.2 ± 5.7 years, range 25-44 years) were divided into a TMJ clicking and a no-TMJ clicking group, based on the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) assessment. Seven occlusal features were recorded for each patient: (1) posterior crossbite, (2) overbite, (3) open bite, (4) overjet, (5) mediotrusive and (6) laterotrusive interferences and (7) retruded contact position to maximum intercuspation (RCP-MI) slide length. A logistic regression model was created to estimate the association of occlusal features with TMJ clicking.

RESULTS

The difference between the groups as for the prevalence of the various occlusal features was generally not statistically significant, with minor exceptions. Mediotrusive interferences (P  =  .015) and RCP-MI slide ≥2 mm (P  =  .001) were the two occlusal features that were associated with the probability of having TMJ clicking, even if the adjusted odds ratios for TMJ clicking were low for both variables (1.63 and 1.89, respectively). Moreover, the amount of variance in the prevalence of TMJ clicking that was predicted by the final model was as low as 4.5% (R(2)  =  0.045).

CONCLUSIONS

Findings from the present investigation suggested that in a population of TMD patients, the contribution of dental malocclusion features to predict TMJ click sounds is minimal with no clinical relevance.

Dental occlusion, body posture and temporomandibular disorders: where we are now and where we are heading for

The aim of this investigation was to perform a review of the literature dealing with the issue of relationships between dental occlusion, body posture and temporomandibular disorders (TMD). A search of the available literature was performed to determine what the current evidence is regarding: (i) The physiology of the dental occlusion-body posture relationship, (ii) The relationship of these two topics with TMD and (iii) The validity of the available clinical and instrumental devices (surface electromyography, kinesiography and postural platforms) to measure the dental occlusion-body posture-TMD relationship. The available posturographic techniques and devices have not consistently found any association between body posture and dental occlusion. This outcome is most likely due to the many compensation mechanisms occurring within the neuromuscular system regulating body balance. Furthermore, the literature shows that TMD are not often related to specific occlusal conditions, and they also do not have any detectable relationships with head and body posture. The use of clinical and instrumental approaches for assessing body posture is not supported by the wide majority of the literature, mainly because of wide variations in the measurable variables of posture. In conclusion, there is no evidence for the existence of a predictable relationship between occlusal and postural features, and it is clear that the presence of TMD pain is not related with the existence of measurable occluso-postural abnormalities. Therefore, the use instruments and techniques aiming to measure purported occlusal, electromyographic, kinesiographic or posturographic abnormalities cannot be justified in the evidence-based TMD practice.