History Of Temporomandibular Disorders Research Articles

Three-dimensional Assessment of Temporomandibular Joint Volume, and Condylar and Glenoid-fossa Morphology: A Cone-beam Computed Tomography Study.

The condylar and glenoid fossa morphology can alter in patients with temporomandibular disorders (TMD), which can lead to changes in the temporomandibular joint (TMJ) space volume. Volumetric evaluation of TMJ can represent the entire three-dimensional (3D)-joint space between the condyle and glenoid fossa. To perform 3D assessment of TMJ volume, condylar, and glenoid-fossa morphology using cone-beam computed tomography and evaluate the correlation between these parameters. Thirty-four patients (age: 13.50 years) who had no previous history of TMD were included. The volume of TMJ space was measured and divided into anterior, posterior, medial, and lateral TMJ volume. The antero-posterior (AP) and medio-lateral (ML) condylar width, AP and ML glenoid-fossa width, and glenoid-fossa depth were evaluated. Statistical analyses were performed with R software at a 0.05 significance level. Each parameter was compared between the left and right sides using a paired-t test. The correlations between the parameters were obtained by the Pearson correlation coefficient. There was no significant difference between lateral and medial TMJ volume; however, posterior TMJ volume was significantly greater than anterior TMJ volume. A significant correlation was observed between AP glenoid-fossa width and TMJ volume, glenoid-fossa depth and TMJ volume, AP position of the condyle and anterior TMJ volume, ML position of the condyle and medial TMJ volume, glenoid-fossa width and condyle width in AP and ML dimension, glenoid-fossa depth and AP glenoid-fossa width. In addition to the evaluation of condylar and glenoid-fossa morphology, assessment of TMJ space volume is important for comprehensive evaluation of the joint.

Evaluation the relationship between polymorphism of galactose mutarotase gene by creating jaw sound in patients with temporomandibular disorder (TMD)

Objective: One of the concerns of dentists is the referral of patients with temporomandibular prob- lems. Temporomandibular joint disorders (TMD) is a complex multifactorial clinical problem that involves masticatory muscles, temporomandibular joint and related structures. This complication is one of the three common chronic pains after headache and low back pain, which can manifest as pain in the temporoman- dibular region and limitation in joint movements, or even as clicking, crepitus, and popping sounds during temporomandibular joint movements. For the first time, the american association for oral pain (AAOP) proposed the role of genetic factors in the development of TMD. It is thought that a complex disorder such as TMD is multidimensional and can be subjected to environmental conditions as well as multiple gene polymorphisms. Identification of single nucleotide polymorphisms in the human genome can play an important role in clinical setting for diagnosis, prognosis and therapeutic interventions in various diseases including TMD. The aim of this study was to evaluate the relationship between polymorphism of galactose mutarotase gene by creating jaw sound in patients with temporomandibular disorder in a population with high similarity to the whole Iranian population and using the results in prevention and targeted treatment of affected patients.
 Study Design: 101 patients with TMD using DC/TMD criteria among those referred to Tehran University School of Dentistry and 103 healthy subjects for TMD that have age and gender matched were selected to control groupfrom those referring to the Oral and Maxillofacial Diseases and Oral and Maxillo- facial Pain departments. Blood samples were taken in 5cc and DNA extracted from the blood of both groups by applying the technique PCRARMS in terms of polymorphism rs4776783 in Galm gene were Compared.
 Results: 101 patients with TMD along with 103 healthy individuals without a history of TMD were evaluated to investigate rs4776783 polymorphism in GALM gene. The average age of the patients was 35.92, and 21 were men and 80 were women. According to the questionnaire, 61 people felt the sound in their jaw while moving. On the other hand, according to the TMD/DC criterion, the number of people who have crepitus in the right and left jaws is equal. The average age of the patients was 35.92, and 21 were men and 80 were women. According to the questionnaire, 61 people felt the sound in their jaw while moving. On the other hand, according to the TMD/DC criterion, the number of people who have crepitus in the right and left jaws is equal. The low prevalence of crepitation with p=0.734 has a significant relationship with the genotype of people.
 Conclusion: This study showed that there is a significant relationship between the rs4776783 poly- morphism in Galm gene and the occurrence of temporomandibular disorder (TMD), jaw sound and pain in many masticatory muscles such as lateral pterygoid and temporal. Therefore, it can be concluded that TMD has a genetic basis.

Functional orthopedic device type Sn20 – a therapeutic resource in the control of chronic temporomandibular dysfunction – case report

The literature indicates that patients with a history of Temporomandibular Disorder (TMD), who experience sudden occlusal changes, may worsen their parafunctional habits and develop TMD again. In this sense, the aim of this study is to present a clinical case of recurrent chronic TMD after oral rehabilitation (increase of vertical dimension in all teeth) using Simões Network 20 (SN20) functional orthopedic appliance as one of the resources therapies. The patient was female, 62 years old, and complained of disabling pain, anxiety symptoms, hypervigilant and history of TMD. The patient reported failure of other treatment modalities, including use of the smooth stabilizer device. The diagnosis was chronic TMD – primary osteoarthritis of the temporomandibular joint and related myofascial pain and orofacial migraine. Treatment included physical measurements, instructions, peripheral and central medication, AOF type SN20 (night use). After three months of therapy, the patient showed significant improvement with complete pain reduction. The use of the AOF SN20 together with conservative measures represents a valuable therapeutic modality for patients with chronic TMD.

Multidisciplinary team in temporomandibular disorders

Introduction The temporomandibular disorders (TMD) are one of the main concerns regarding orofacial pathologies and there are an ascending number of cases. They are characterised as a group of pathological conditions that may affect the temporomandibular joint (TMJ), the masticatory musculature and/or other adjacent anatomical structures, leading to pain and dysfunction [1]. The multifactorial aetiology of TMD affects a relatively large number of the world population and requires a multidisciplinary evaluation and diagnosis by the clinical team [2]. Among the various elements that constitute the multidisciplinary team we highlight the dentist and the physiotherapist. The dentist as a first-line professional, most of the time is responsible for the identification of patients potentially at risk and for the follow-up of those who already present the disease [3]. On the other hand, the physiotherapist aims to reduce musculoskeletal pain, promote muscle relaxation, reduce muscle hyperactivity, improve function by restoring the quality and quantity of mandibular movements and maximise joint mobility [4]. Description of the clinical case A 24-year-old female patient with a history of temporomandibular disorder and bruxism she presented an non-assisted mouth opening (UMO) of 28 mm and an assisted mouth opening with pain in the masseter and TMJ bilaterally of 29 mm, after the clinical assessment with the DC/TMD protocol we arrived at a diagnosis of disc displacement without reduction (DDwR) with limited opening, degenerative joint disease in the left TMJ, arthralgia (II), myofascial pain (III) in the masseter with pain referred to other anatomical regions. All the assumptions of the Helsinki Declaration have been fulfilled and an informed consent for clinical case of Clinica Dentária Egas Moniz approved by the ethic commission of Instituto Universitário Egas Moniz. The treatment plan consisted of cognitive behavioural therapy (CBT), prescription of muscle relaxants, occlusal splint especially for reduction of overload due to bruxism, infiltration with 1 ml of hyaluronic acid of high molecular weight in the TMJ bilaterally followed by articular mobilisation techniques and neuromuscular and myofascial techniques. The patient was instructed to continue with the physiotherapy. Results The follow up was made 2 months after with 8 sessions of physiotherapy and 1 more hyaluronic acid infiltration bilaterally as protocoled session, we could observe an absence of temporomandibular joint pain, UMO of 42 mm, decreased crepitation, decreased intensity of myofascial pain (I) and (DDwR) without limited opening. Discussion and conclusion The multidisciplinary dentist-physiotherapist team combines inputs from different professions with the aim of promoting the best patient care and represents an added value for the management of the signs/symptoms of patients with temporomandibular dysfunction.

Does the Stomatognathic System Adapt to Changes in Occlusion? Best Evidence Consensus Statement.

The purpose of this Best Evidence Consensus Statement was to evaluate the existing literature on the stomatognathic system's ability to adapt to occlusal changes. The search term stomatognathic system was not useful as it resulted in over 400,000 results nor was the search term temporomandibular joint adaptation with 738 results due to the large number of references not related to the topic. The terms stomatognathic system adaptation to occlusal changes (186 results), teeth flexion (139 results), muscle adaptation to dental occlusion (278 results), and occlusal changes and neuroplasticity (11 results) provided the best selection of articles related to the topic. Limiting the above searches to systematic reviews and randomized controlled clinical trials resulted in multiple publications that were related to the question.9-13 Other literature reviews, data-based publications, and expert opinion resources have been included due to their relationship to the question. From the extensive list of search results, 242 articles were determined to be potentially related to the focus question and were evaluated with 56 being included in this paper. It was determined that the stomatognathic system adapts to occlusal changes through the temporomandibular joint, muscles, teeth and bone. The dynamically modified periosteum on the articulator surfaces of the condyle and fossa has a unique load-bearing morphology with 3 subarticular layers of fibrocartilage that absorb and dissipate both peak (impact) and sustained loads. Adaptability of the TMJs and muscles can be documented through studies where artificially produced occlusal interferences were placed in patients and those study participants with normal temporomandibular joints (TMJs) adapted fairly well whereas those with a previous history of temporomandibular disorders (TMD) did not adapt as well. Available evidence indicates patients generally adapt to the occlusal change inherent in orthodontic treatment, mandibular advancement surgery, and the use of mandibular advancement devices. The head and neck muscles also adapt to occlusal changes in patients without a history of TMD. The dentition adapts to changes through the bone and periodontal ligaments as well as the ability of teeth to undergo slight flexion under masticatory loading. This article is protected by copyright. All rights reserved.

Association between temporomandibular disorders with clinical and sociodemographic features: An observational study.

Temporomandibular disorders (TMD) are the most common orofacial impairment, but the relevance of certain clinical features in TMD is not clear. The main objective of this study was to analyse if temporomandibular disorders (TMD) are associated with sociodemographic (eg age, height, weight, body mass index and gender), psychological (eg anxiety and depression) and clinical features (eg use of dental splints, orthodontics, retainers, bruxism, sleep disturbance, familiar prior history of TMD and dental occlusion). An observational study was conducted to calculate the correlation of TMD, as assessed with DC/TMD criteria, with sociodemographic, psychological and clinical features on 59 voluntary subjects with TMD (n=45) and without TMD (n=14). Sex, height, weight, body mass index, age, use of dental splint, orthodontics, retainers, parafunctional disorders, sleep disturbance, familiar history of TMD, bruxism, anxiety, stress and dental occlusion class data were included in a multivariable correlation analysis to determine which variables are associated with TMD and bruxism. TMD was found to be correlated with none of the features assessed (P>.05), but a negative correlation with the use of dental splint (P<.05). Dental occlusion class showed no statistically significant correlation with any assessed feature (P>.05). The etiology of TMD is not clear and considering certain clinical features including dental occlusion are not justified in the evidence-based TMD practice for making irreversible occlusal treatment decisions.

Association between hypoplastic condyles and temporomandibular joint disc displacements: a cone beam computed tomography and magnetic resonance imaging metrical analysis

This study investigated the association between hypoplastic condyles and disc displacements without reduction (DDw/oR). Consecutive patients with non-syndromic unilateral condylar hypoplasia were recruited and clinical, cone beam computed tomography (CBCT) and magnetic resonance imaging (MRI) data were acquired. Linear measurements including condylar head width, depth, height and condyle length were determined with CBCT while MRI was used to assess disc position, morphology and displacement. A total of 43 patients were enrolled of which 93.02% had a history of temporomandibular disorders (TMDs) and 83.72% presented with TMD signs and symptoms. Depth and height of the condylar head along with condyle length of hypoplastic joints (6.68±1.67mm, 4.97±1.25mm and 14.49±3.02mm, respectively) were significantly lesser than normal joints (7.77±1.26mm, 6.35±1.45mm and 18.20±3.18mm) (P<0.001). The prevalence of DDw/oR was significantly higher in hypoplastic joints (79.07% versus 13.95%) (P<0.001). Joints with hypoplastic condyles had shorter disc lengths (6.99 ± 2.16 mm vs, 8.45 ± 2.26 mm) (P=0.007). Furthermore, disc displacements were significantly more advanced (8.52 ± 2.84 mm) and severe (76.74% with severe translations) when compared to the contralateral side (4.77 ± 2.97 mm and 32.56%) (P<0.05). A significant association was observed between condylar hypoplasia and temporomandibular joint DDw/oR with hypoplastic joints exhibiting more severely displaced and deformed discs. DDw/oR coupled with repaired degenerative joint disease may mimic condylar hypoplasia radiographically.

Incident injury is strongly associated with subsequent incident temporomandibular disorder: results from the OPPERA study.

Cross-sectional studies confirm, as expected, a positive association between jaw injury and painful temporomandibular disorders (TMDs), but prospective evaluations are lacking. We prospectively assessed incident jaw injury, injury type, and development of TMD in adults aged 18 to 44 years. Data were collected from 3258 individuals from communities surrounding 4 US academic institutes between 2006 and 2008. At enrollment, participants reported no TMD history and no facial injuries in the previous 6 months. Quarterly, follow-up questionnaires assessed incident jaw injury, which was classified as intrinsic (attributed to yawning or prolonged mouth opening) or extrinsic (attributed to other causes). Examiners classified incident TMD during a median follow-up period of 2.8 years (range 0.2-5.2 years). Cox regression models used jaw injury as a time-dependent covariate to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association with incident TMD. Among 1729 participants with complete data, 175 developed TMD. Eighty percent of injuries were intrinsic. Temporomandibular disorder annual incidence was nearly twice as high in those experiencing jaw injury (5.37%) compared with those who did not (3.44%). In the Cox model that accounted for timing of injury, the corresponding HR was 3.94 (95% CI = 2.82-5.50) after adjusting for study site, age, race, and sex. Hazard ratios did not differ (P = 0.91) for extrinsic injuries (HR = 4.03, 95% CI = 2.00-8.12) and intrinsic injuries (HR = 3.85, 95% CI = 2.70-5.49). Jaw injury was strongly associated with incident TMD. If surveillance and intervention after jaw injury is to be effective in preventing TMD, they should focus on both intrinsic and extrinsic injuries.

Laser phototherapy in acute posttraumatic trismus - Case-series study.

There are very few studies on laser phototherapy (LPT) in acute temporomandibular disorders (TMDs). Our objective is to assess the effectiveness of laser phototherapy (LPT) on the limitation of the mouth opening due to an acute mandibular trauma. Fourteen women of 41 ± 3 years and 24 men of 38 ± 3 years, with no history of TMD and having sustained a mandibular trauma within the prior 20 hours, were treated exclusively by using an 810-nm laser beam in a continuous wave mode, with an output power of 1 W. At a speed of 2 cm/s, it scanned twice, for 60 seconds, with a pause in between of 2 minutes, a large cutaneous area (25 cm2), covering the temporomandibular joint (TMJ), the masseter muscle and a part of the temporalis fossa; also, it scanned just once, for 7 seconds, a small mucous area (3 cm2), covering the internal pterygoid muscle. The clinical outcomes were evaluated by comparing the maximum unassisted opening (MUO), measured at the baseline and immediately after the end of the LPT procedure. The MUO improvement of 24.6 ± 4.4 mm represented a highly significant difference (p < .0001) between the measurements, in all the patients, regardless of gender. By scanning with an 810-nm laser beam, within less than 20 hours after the trauma, large areas of all the involved tissues and not just a few points, as described until now, the limited mouth opening in acute posttraumatic trismus was immediately and greatly resolved.

The importance of the posterior joint space for functional mandibular movements: A laboratory cross-sectional study.

BackgroundThe search for the ideal, healthy and reproducible position of the condyles is of utmost importance for dental diagnosis and treatment. Thus, the objective of this laboratory cross-sectional study was to verify the relationship between the posterior joint space and the mandibular lateral movements.Material and MethodsDental casts from 15 women and 15 men with normal mastication, 28 natural teeth and no history of temporomandibular disorders or pain, were fabricated and mounted on a fully adjustable articulator. From the maximum intercuspal position, condylar displacement was evaluated and measured on the working and nonworking sides during mandibular lateral movement, both to the right and left sides.ResultsThe correlation between the measures of interest was assessed with the Pearson correlation coefficient (α=.05). Condylar displacement on the working side and nonworking side condyle was 0.88±0.71 mm and 3.57±1.11 mm (right mandibular lateral movement); and 0.91±0.58 mm and 3.51±0.78mm (left mandibular lateral movement), respectively. No significant correlation in the condylar displacement between the working side condyles on the right and on the left sides was observed (r=.22; P=.248). The condylar poles of the articulator moved posteriorly, simulating the functional movements of the mandible during mastication. In all cases, condylar displacement during mandibular lateral movement both to the right and left occurred posteriorly on the working side condyle.ConclusionsThe condylar poles of the articulator moved posteriorly simulating the functional movements of the mandible during mastication. Moreover, left and right working condyles may require slightly different spaces to function, suggesting minor anatomical asymmetries. Key words:Mastication, dental occlusion, prosthodontics.

Maxillo-facial surgery in skeletal Class II: repercussions on the temporo-mandibular joints

These interventions usually aimed at the correction of the skeletal discrepancy by mandibular retrognatism with an advancement of the distal portion of the mandible after mandibular osteotomy. The position of the condyle is determined during the osteosynthesis with miniplates. Condyles are set back in relation with the supine position of the patient and the weakness of his (her) curarized muscle. All studies show that surgery of mandibular advancement causes a lateral, torque and backward movement of the condyles, all harmful to the condyles. Factors that predispose to condylar resorption are "the patient": a woman, young (between 15 and 40), high mandibular angle, with a history of temporo-mandibular disorders and surgical overload applied to the condyles. What are the possible solutions to avoid failures? Patient preparation before surgery and surgery simulation with an articulator, condylar position control during surgery, working with surgeons to achieve a condylar portion stabilization system (with the CAD), quickly set up a mobilization of the mandible by physiotherapy.

COMT Diplotype Amplifies Effect of Stress on Risk of Temporomandibular Pain

When measured once, psychological stress predicts development of painful temporomandibular disorder (TMD). However, a single measurement fails to characterize the dynamic nature of stress over time. Moreover, effects of stress on pain likely vary according to biological susceptibility. We hypothesized that temporal escalation in stress exacerbates risk for TMD, and the effect is amplified by allelic variants in a gene, catechol-O-methyltransferase (COMT), regulating catechol neurotransmitter catabolism. We used data from the Orofacial Pain: Prospective Evaluation and Risk Assessment prospective cohort study of 2,707 community-dwelling adults with no lifetime history of TMD on enrollment. At baseline and quarterly periods thereafter, the Perceived Stress Scale (PSS) measured psychological stress. Genotyped DNA from blood samples determined COMT diplotypes. During follow-up of 0.25 to 5.2 y, 248 adults developed examiner-verified incident TMD. PSS scores at baseline were 20% greater (P < 0.001) in adults who developed incident TMD compared with TMD-free controls. Baseline PSS scores increased by 9% (P = 0.003) during follow-up in cases but remained stable in controls. This stress escalation was limited to incident cases with COMT diplotypes coding for low-activity COMT, signifying impaired catabolism of catecholamines. Cox regression models confirmed significant effects on TMD hazard of both baseline PSS (P < 0.001), modeled as a time-constant covariate, and change in PSS (P < 0.001), modeled as a time-varying covariate. Furthermore, a significant (P = 0.04) interaction of COMT diplotype and time-varying stress showed that a postbaseline increase of 1.0 standard deviation in PSS more than doubled risk of TMD incidence in subjects with low-activity COMT diplotypes (hazard ratio = 2.35; 95% confidence limits: 1.66, 3.32), an effect not found in subjects with high-activity COMT diplotypes (hazard ratio = 1.42; 95% confidence limits: 0.96, 2.09). Findings provide novel insights into dynamic effects of psychological stress on TMD pain, highlighting that effects are most pronounced in individuals whose genetic susceptibility increases responsiveness to catecholamine neurotransmitters.

Pressure pain thresholds fluctuate with, but do not usefully predict, the clinical course of painful temporomandibular disorder

Central sensitization elicits pain hypersensitivity and is thought to be causally implicated in painful temporomandibular disorder (TMD). This causal inference is based on cross-sectional evidence that people with TMD have greater sensitivity than controls to noxious stimuli. We tested this inference in the Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA) prospective cohort study of 3258 adults with no lifetime history of TMD when enrolled (visit 1). During 5years of follow-up, 1 group labeled “persistent TMD cases” (n=72) developed first-onset TMD by visit 2 that persisted ⩾6months until visit 3. Another group labeled “transient TMD cases” (n=75) developed first-onset TMD at visit 2, which resolved by visit 3. Randomly sampled “controls” (n=126) remained TMD-free throughout all 3 visits. At each visit, pressure pain thresholds (PPTs) were measured by algometry at 10 cranial and bodily sites. In persistent TMD case patients, mean PPTs reduced 43kPa (P<.0001) between visits 1 and 2 and thereafter did not change significantly. In transient TMD case patients, mean PPTs reduced 41kPa (P<.001) between visits 1 and 2, and then increased 20kPa (P<.001) by visit 3. These patterns were similar after excluding cranial sites symptomatic for TMD. Importantly, visit 1 PPTs had no clinically useful prognostic value in predicting first-onset TMD (odds ratio [OR]=1.07, P=.15). Among first-onset case patients, visit 2 PPTs were modest predictors of persistent TMD (OR=1.36, P=.002). In this longitudinal study, PPTs reduced when TMD developed then rebounded when TMD resolved. However, premorbid PPTs poorly predicted TMD incidence, countering the hypothesis that PPTs signify mechanisms causing first-onset TMD.

The Reliability of the Bilateral Trigeminal Roots-motor Evoked Potentials as an Organic Normalization Factor: Symmetry or Not Symmetry?

Background: In order to achieve a complete clinical evaluation of mastication, an in-depth neurophysiopathological assessment of masticatory muscles control is needed. Electromyography technique (EMG) is widely used for this purpose but failed to give convincing results. The aim of this work was to describe our quantitative objectivation of the motor control of the masticatory muscles and to verify the hypothesis to consider the bilateral Root Motor Evoked Potentials as an electrophysiological normalization factor. Methods: 25 healthy people (15 males, 10 females; mean age 29 years ± 5) with normal occlusion and no history of temporomandibular disorders and orofacial pain underwent a transcranical electrical stimulation that allowed a direct bilateral stimulation of the motor roots of the trigeminal motor system called bilateral Root Motor Evoked Potentials (bRMEPs). The maximal Absolute Neural Evoked Energy, symmetry and synchrony properties of the resulting b R-MEPs were studied using measures like latency, amplitude and integrated area of the collected signal. An Artificial Neural Network computational model was used to estimate the correlation coefficient with the EMG values of each of both sides to predict the values from the right side by inputting values from the left side.

General Health Status and Incidence of First-Onset Temporomandibular Disorder: The OPPERA Prospective Cohort Study

Temporomandibular disorder (TMD) overlaps with other health conditions, but no study has examined which of these conditions increase the risk of developing first-onset TMD. The authors prospectively evaluated the relationship between health status at enrollment and subsequent incidence of TMD in 2,722 men and women. Participants aged 18 to 44 years had no history of TMD and were clinically free of TMD when enrolled in 2006 to 2008 at 4 U.S. study sites in the Orofacial Pain: Prospective Evaluation and Risk Assessment (OPPERA) prospective cohort study. First-onset examiner-classified TMD developed in 260 people over a median 2.8 years of follow-up. Cox regression estimated the association between health conditions and TMD incidence while accounting for potential confounders. Incidence of first-onset TMD was 50% higher for people with low back pain (adjusted hazard ratio [AHR] = 1.50, 95% confidence limits [CLs]: 1.08, 2.10) and 75% higher for people with genital pain symptoms (AHR = 1.75, 95% CLs = 1.04, 2.93) than people without a history of these pain disorders. Digit ratio, a marker of intrauterine exposure to sex hormones, was significantly associated with TMD incidence. Other independent predictors of first-onset TMD were sleep disturbance and cigarette smoking. These findings reveal multiple influences of health status on incidence of first-onset TMD. PerspectiveThis article examines health conditions that commonly overlap with TMD to determine which ones predict first-onset TMD. A history of low back pain and genital pain conditions at baseline were important predictors. Novel findings were that disrupted sleep and conditions in utero may increase incidence of first-onset TMD.

Signs and Symptoms of First-Onset TMD and Sociodemographic Predictors of Its Development: The OPPERA Prospective Cohort Study

Although cross-sectional studies of temporomandibular disorder (TMD) often report elevated prevalence in young women, they do not address the risk of its development. Here we evaluate sociodemographic predictors of TMD incidence in a community-based prospective cohort study of U.S. adults. Symptoms and pain-related disability in TMD cases are also described. People aged 18 to 44 years with no history of TMD were enrolled at 4 study sites when they completed questionnaires about sociodemographic characteristics. During the median 2.8-year follow-up period, 2,737 participants completed quarterly screening questionnaires. Those reporting symptoms were examined clinically and 260 had first-onset TMD. Additional questionnaires asked about severity and impact of their symptoms. Univariate and multivariable Cox regression models quantified associations between sociodemographic characteristics and TMD incidence. First-onset TMD developed in 3.9% of participants per annum, typically producing mild to moderate levels of pain and disability in cases. TMD incidence was positively associated with age, whereas females had only slightly greater incidence than males. Compared to whites, Asians had lower TMD incidence whereas African Americans had greater incidence, although the latter was attenuated somewhat after adjusting for satisfaction with socioeconomic circumstances. PerspectiveIn this study of 18- to 44-year-olds, TMD developed at a higher rate than reported previously for similar age groups. TMD incidence was positively associated with age but weakly associated with gender, thereby differing from demographic patterns of prevalence found in some cross-sectional studies. Experiences related to aging merit investigation as etiologic influences on development of TMD.

Application of neuromuscular electrical stimulation in the management of hip and knee extensor weakness in children with cerebral palsy: A pilot study

electromyographic trace, comparingpre andpost therapeutic bilaterally behavior of the masseter muscle and the anterior portion of the temporal muscle during the bilateral masticatory activity. Patients/materials and methods: Male and female individuals aging between 18 and 40 years oldwere assessed. All subjectswere submitted to the EMG assessment. The volunteers were divided in four groups.Group I: 12youngwith signs and/or symptomsofmyogenic TMD. They were submitted massage therapy. Group II: 12 young with signs and/or symptoms of myogenic TMD. They were submitted occlusal splint. Group III: 12 young with signs and/or symptoms of myogenic TMD. They were submitted massage therapyandocclusal splint.Group IV:12subjectswithnormo-occlusion and no history of temporomandibular disorder. They were submitted to the EMG exams, but not to the physiotherapeutic and odontologic treatment. It is important to mention that only partial results will be presented in this study. Results: Considering the data obtained and the statistical analysis performed in each studied groups, and noticed that with the techniques applied on theGroups I, II, III and IV, no significant result of EMG activity of all the muscles in study was collected. But, the results point out thedifference (p=0.0026)between theAVSscores, which was taken before and after the treatment (analyzed by the ANOVA statistical test). Discussion and conclusions: There was a significant decrease in pain in Group I, after Group III, after group II and Group IV do not have differences. The data collected in this study demonstrated that the massage therapy was efficient in decreasing the pain [2]. Even though it is not possible to draw a comparison with the literature that deals with the effect of massage therapy in patients with bruxism because this partial results. The physiotherapeutic treatment (massage) and odontologic treatment (occlusal splint) and both treatment together can reduce and eliminate pain. However, the physiotherapeutic and both treatment together can reduce and eliminate pain more.

The difficult relationship between occlusal interferences and temporomandibular disorder – insights from animal and human experimental studies

The aetiology of temporomandibular disorder (TMD) is multifactorial, and numerous studies have addressed that occlusion may be of great importance. However, whether occlusion plays a crucial role in the pathogenesis of TMD remains controversial. Study designs utilising animal models have been used to study the effects of artificial occlusal alterations. Experimental traumatic occlusion affects blood flow in the temporomandibular joint and results in changes in the condylar cartilage, and artificial occlusal interference induces masticatory muscle nociceptive responses that are associated with peripheral sensitisation and lead to central sensitisation, which maintains masticatory muscle hyperalgesia. The possibility that occlusal interference results in TMD has been investigated in humans using a double-blind randomised design. Subjects without a history of TMD show fairly good adaptation to interferences. In contrast, subjects with a history of TMD develop a significant increase in clinical signs and self-report stronger symptoms (occlusal discomfort and chewing difficulties) in response to interferences. Meanwhile, psychological factors appear meaningful for symptomatic responses to artificial interferences in subjects with a history of TMD. Thus, individual differences in vulnerability to occlusal interferences do exist. Although there are advantages and disadvantages to using human and animal occlusal interference models, these approaches are indispensable for discovering the role of occlusion in TMD pathogenesis.

The dental occlusion as a suspected cause for TMDs: epidemiological and etiological considerations

The relationship between the dental occlusion and temporomandibular disorders (TMDs) has been one of the most controversial topics in the dental community. In a large epidemiological cross-sectional survey - the Study of Health in Pomerania (Germany) - associations between 15 occlusion-related variables and TMD signs or symptoms were found. In other investigations, additional occlusal variables were identified. However, statistical associations do not prove causality. By using Hill's nine criteria of causation, it becomes apparent that the evidence of a causal relationship is weak. Only bruxism, loss of posterior support and unilateral posterior crossbite show some consistency across studies. On the other hand, several reported occlusal features appear to be the consequence of TMDs, not their cause. Above all, however, biological plausibility for an occlusal aetiology is often difficult to establish, because TMDs are much more common among women than men. Symptom improvement after insertion of an oral splint or after occlusal adjustment does not prove an occlusal aetiology either, because the amelioration may be due to the change of the appliance-induced intermaxillary relationship. In addition, symptoms often abate even in the absence of therapy. Although patients with a TMD history might have a specific risk for developing TMD signs, it appears more rewarding to focus on non-occlusal features that are known to have a potential for the predisposition, initiation or perpetuation of TMDs.

Single step approach to make diagnostic impressions of both the arches and face bow transfer: A novel technique

Mounting the maxillary and mandibular dentulous casts for Diagnostic purpose requires many steps (including making maxillary and mandibular impressions, face-bow transfer, and bite registration) or many appointments. A simple new technique of doing all of this together without compromising on the accuracy can save time over the conventional mounting procedure. To compare the accuracy of a new technique of a single-step diagnostic mounting procedure with that of the conventional diagnostic mounting procedure. Ten dentulous patients with the full complement of teeth and without any history of temporomandibular disorder and orthodontic treatment were selected for this study. A detachable metal triple tray to replace the fork part of the face bow fork that further could be attached to face bow was fabricated. Dual-arch impressions and face-bow transfer were made in these subjects using this modified triple tray. These mountings were compared with the ones done with the conventional mounting procedure. Five linear measurements (using stable reference points on the articulator and the cast) were made and the values obtained by both the methods were compared. The Student's 't' test for statistical analysis was used in this study. The measurement values obtained by the single-step method were almost similar to the ones obtained by the conventional method. The various mean measurements for the single step and conventional methods were 37.7 ± 6.8 and 38.5 ± 6.5 mm; 70.0 ± 4.4 and 70.1 ± 4.2 mm; 57.0 ± 4.9 and 57.3 ± 4.2 mm; 71.3 ± 4.5 and 71.0 ± 4.6 mm; and 58.7 ± 2.5 and 58.3 ± 2.3 mm; respectively. The differences between the values obtained by the conventional and single-step methods were not statistically significant. The single-step procedure of diagnostic mounting can be used as an alternative to the conventional method, without compromising the quality of mounting.