Excessive Mouth Opening Research Articles

A nomogram for predicting the risk of temporomandibular disorders in university students

ObjectivesTemporomandibular disorders (TMDs) have a relatively high prevalence among university students. This study aimed to identify independent risk factors for TMD in university students and develop an effective risk prediction model.MethodsThis study included 1,122 university students from four universities in Changchun City, Jilin Province, as subjects. Predictive factors were screened by using the least absolute shrinkage and selection operator (LASSO) regression and the machine learning Boruta algorithm in the training cohort. A multifactorial logistic regression analysis was used to construct a TMD risk prediction model. Internal validation of the model was conducted via bootstrap resampling, and an external validation cohort comprised 205 university students undergoing oral examinations at the Stomatological Hospital of Jilin University.ResultsThe prevalence of TMD among university students was 44.30%. Ten predictive factors were included in the model, comprising gender, facial cold stimulation, unilateral chewing, biting hard or resilient foods, clenching teeth, grinding teeth, excessive mouth opening, malocclusion, stress, and anxiety. The model demonstrated good predictive ability with area under the receiver operating characteristic curve (AUC) values of 0.853, 0.838, and 0.821 in the training cohort, internal validation cohort, and external validation cohort, respectively. The calibration curves demonstrated that the predicted results were consistent with the actual results, and the decision curve analysis (DCA) indicated the model's high clinical utility.ConclusionsAn online nomogram of TMD in university students with good predictive performance was constructed, which can effectively predict the risk of TMD in university students. The model provides a useful tool for the early identification and treatment of TMDs in university students, helping clinicians to predict the probability of TMDs in each patient, thus providing more personalized and accurate treatment decisions for patients.

Thermal ultrasound, manipulation and exercise on pain and mouth opening in Chronic temporomandibular joint disorder

A 60-year-old female patient reported with a chief complaint of pain in bilateral temporomandibular joints (TMJ) region since 11/2 years. The pain was initially reported to be insidious in onset, moderate in intensity, aggravated on chewing food and during excessive mouth opening. On examination her mouth opening was found to be less than 8mm and standard head and neck examination showed grade 2 tenderness with swelling on bilateral TMJ and forward neck posture with rounded shoulders. The patient reported her pain to be 6 at rest in NPRS (with 0 being no pain and 10 being maximum) and 8 out of 10 on mouth opening. A 4-week Physiotherapy Intervention program, which consisted of Ultrasound Therapy at varying intensity, TMJ manipulation, Cervical Range of Motion Exercises and Manual Cervical traction was administered. Repeated evaluation of pain and other functional outcomes were done on a weekly basis. There was significant improvement in her mouth opening (41mm), restoration of masticatory functions, complete resolution of pain and overall improvement in quality of life after the 4weeks intervention program. A structured Physiotherapy intervention program consisting of Non-thermal Ultrasound, Manipulation and exercise targeting TMJ and Upper quarter, proved to be highly effective in increasing functions and reducing signs and symptoms in Chronic TMJ Dysfunction which can be highly disabling. The recovery observed in this patient, who was not on any standard treatment for almost 18months, hence the severe limitations she encountered, is a testament to the need of designing individualized treatment protocols addressing the many facets of impairment in TMJ Disorders.

Bilateral Dislocation of Mandibular Condyles following General Anesthesia—An Overlooked Problem: A Case Report

Dislocation of mandibular condyles can occur following excessive mouth opening or traumatic injury to the temporomandibular joint. It can also occur during general anesthesia that at times may go un-noticed in the modern-day theater setup. Here, we describe a case of bilateral dislocation of mandibular condyle following orotracheal intubation for general anesthesia. Right condyle was dislocated into temporal fossa.

An Uncommon Upper Gastrointestinal System Endoscopy Complication: Temporomandibular Joint Dislocation

Temporomandibular joint (TMJ) is a vital structure to open mouth for eating and speaking. Dislocation of the TMJ can be occured with a trauma, excessive mouth opening, iatrogenic, endoscopy, transesophageal echocardiography. Gastrointestinal system endoscopy is an uncommon reason for the TMJ dislocation. Hardened bite, excessive mouth opening are the major reasons. Sudden presentation of the malocclusion of the mouth, severe pain can be the symptoms and palpable preauricular depression, lower jaw angle can be the findings of TMJ dislocation. Early diagnosis and performing urgent specific interventions are the main points for its management.

Management of Habitual Temporomandibular Joint Dislocation by Eminectomy

Temporomandibular joint (TMJ) dislocation(luxation) occurs when the condyle moves out of the glenoid fossa upon mouth opening and is locked anteriorly to the articular eminence. The dislocation leads to protective contraction or spasm of masticatory muscles, which reinforces the locked state, with or without pain. Usually, the episodes are triggered by any activities that lead to wide mouth opening such as yawning, laughing, and prolonged, excessive mouth opening during a dental or medical exam. It is a distressing and embarrassing situation for the patient. Repetitive dislocation of TMJ is defined as recurrent or habitual TMJ luxation. There are many treatment modalities available ranging from conservative approach to surgical approach. However, conservative approaches usually offer only a temporary solution and they have significant failure rate. Surgical approaches are available with varying degrees of success. Eminectomy is the most predictable surgical treatment for recurrent TMJ luxation. Herein, we report a case of a 47-year old male patient who was diagnosed with bilateral recurrent TMJ luxation that was successfully treated through bilateral eminectomy.

Twenty cases of temporomandibular disorders with warming-needle moxibustion on ginger at Xiàguān (下关ST 7)

ObjectiveTo observe the clinical efficacy of treatment for temporomandibular disorders with warming-needle moxibustion on ginger at Xiàguān (下关ST 7). MethodsTwenty patients with temporomandibular disorders were given acupuncture at ST 7 of the affected side, and then the self-prepared round cake-shaped ginger with moxa was set on the needle closing to skin surface, Ignited moxa, burn out as one cone, three cones were given for once. The treatment was performed once a day, 7 times was 1 course, and the curative effect was evaluated after 1 course of treatment. ResultsAmong 20 patients, 12 were cured, improvement was observed in 7 patients, and 1 case had no response to treatment. The effective rate was up to 95.0%; improvement was observed in 14 patients after treatment for 3 times. According to follow-up visit 1 month after treatment, 1 patient relapsed due to excessive mouth opening, but the symptom was mild and relieved after rubbing. ConclusionThe clinical efficacy of treatment for temporomandibular disorders with warming-needle moxibustion on ginger at ST 7 was ideal.

Temporomandibular joint dislocation in an epileptic and mentally retarded patient: a case report.

Temporomandibular joint (TMJ) dislocation is defined as an excessive forward movement of the condyle beyond the articular eminence with complete separation of articular surfaces and fixation in that position.' Theories regarding the pathogenesis of TMJ dislocation propose laxity of TMJ ligaments or capsule, excessive activity of the lateral pterygoid muscle (LPM)and erosion of the eminence'. TMJ dislocation can occur in an anterior, posterior, lateral and superior direction'. Clinical presentation of dislocated TMJ includes inability to close the mouth, deviation of the mandible away from the affected side in unilateral cases, hollowing in front of the tragus, spasm of muscles of mastication and severe pain of the TMt Radiographs show an empty condylar fossa with the condylar head located anterior to the articular eminence. Anterior TMJ dislocation usually follows excessive mouth opening during yawning, laughing, eclamptic fit and motor vehicle accident (MVA)'. Iatrogenic causes of TMJ dislocation are excessive mouth opening during dental treatment, intubation, and otorhinolaryngological procedures Some drugs are associated with TMJ dislocation, these include antiemetics such as metoclopramide and compazine which produce extrapyramidal effects' and neuroleptic drugs. Systemic connective diseases like Ehlers-Danlos and Marfan syndromes have also been implicated in TMJ dislocations The purpose of this article is to report management challenges of an epileptic and mentally retarded patient with recurrent TMJ dislocation.

Temporomandibular joint dislocation in a post-stroke patient with dysphagia caused by gastroesophageal reflux-related vomiting

Temporomandibular joint dislocation (TMJ) is sometimes found in post-stroke patients, and most cases occurs involuntarily. This report describes a rare case of repeated, voluntary, TMJ in a 73-year-old woman with dysphagia and dysarthria. The cause of dislocation was suspected to be voluntary excessive mouth opening associated with gastroesophageal reflux-related vomiting and the desire to eject oral deposits resulting from hypoglossal and facial nerve paralyses. After an oral hygiene intervention, the frequency of TMJ dislocation decreased and finally disappeared. Thorough oral hygiene seemed to contribute to protection against TMJ dislocation. (J Oral Sci 58, 133-136, 2016).

Investigating activity of masticatory muscles in patients with hypermobile temporomandibular joints by using EMG.

Background Temporomandibular joint hypermobility (TMJH) can manifest higher range of motions in mandible. The aim of this study was to investigate and compare the activity of masticatory muscle of TMJs in healthy individuals and patients with mild, moderate and severe TMJH. Material and Methods In this clinical study, 69 patients (between the ages of 22 to 42) with manifestation of TMJH were included. The patients were divided into three groups based on their maximum mouth opening (MMO): (light) with MMO of 50-55 mm; (moderate) with MMO between 55 to 65 mm; and (severe) with MMO >65 mm. Also, 20 healthy people with profiled tomography in the last 6 months were invited as control group (healthy) with normal MMO (<50 mm). All the groups subjected to electromyogram (EMG) in 2 steps: maximal voluntary clenching (MVC) of the jaws; and during chewing of bread by using one side of the jaws voluntary. The collected data were analyzed by Student T-test and Chi-Square tests using SPSS software version 15 at significant level of 0.05. Results Both TMJs of light, moderate and severe groups showed significant differences in frequency, time of activity and rest in comparison with healthy group during chewing and MVC (all p values < 0.01). Conclusions Masticatory muscles activity reduced in relation with the severity of TMJH and higher excessive mouth opening. Key words:Electromyography, joint hypermobility, mouth opening, tempormandibular joint.

A Novel Treatment of Recurrent Temporomandibular Joint Dislocation with Intermaxillary Fixation Using Microimplant: A Case Report

Dislocation of temporomandibular joint (TMJ) is troublesome condition which was most commonly shown far anteriorly displaced mandibular condyle to the articular eminence, thereby make it impossible to close one’s mouth. It is often referred to as ‘open lock’ in clinically. Although anatomical modification of the articular eminence through eminectomy has been considered most satisfactory and efffective treatment for managing the recurrent dislocation, it seldom performs clinically due to its invasiveness and patient’s reluctance. We thought a shortterm intermaxillary fixation could be of benefit to the patient suffering from recurrent dislocation. A 21-year-old male patient with recurrent TMJ dislocation which had developed after excessive mouth opening, was successfully treated with intermaxillay fixation using microimplant for 2 months. It is more conservative and less complicated method than eminectomy in treating recurrent TMJ dislocation. Transient intermaxillary fixation using microimplant and elastics could be one of treatment options for recurrent TMJ dislocation.

Current status of temporomandibular joint disorders and the therapeutic system derived from a series of biomechanical, histological, and biochemical studies

This article was designed to report the current status of temporomandibular joint disorders (TMDs) and the therapeutic system on the basis of a series of clinical, biomechanical, histological and biochemical studies in our research groups. In particular, we have focused on the association of degenerative changes of articular cartilage in the mandibular condyle and the resultant progressive condylar resorption with mechanical stimuli acting on the condyle during the stomatognathic function. In a clinical aspect, the nature and prevalence of TMDs, association of malocclusion with TMDs, association of condylar position with TMDs, association of craniofacial morphology with TMDs, and influences of TMDs, TMJ-osteoarthritis (TMJ-OA) in particular, were examined. In a biomechanical aspect, the nature of stress distribution in the TMJ from maximum clenching was analyzed with finite element method. In addition, the pattern of stress distribution was examined in association with varying vertical discrepancies of the craniofacial skeleton and friction between the articular disk and condyle. The results demonstrated an induction of large compressive stresses in the anterior and lateral areas on the condyle by the maximum clenching and the subsequent prominent increases in the same areas of the mandibular condyle as the vertical skeletal discrepancy became more prominent. Increase of friction at the articular surface was also indicated as a cause of larger stresses and the relevant disk displacement, which further induced an increase in stresses in the tissues posterior to the disks, indicating an important role of TMJ disks as a stress absorber. In a histological or biological aspect, increase in TMJ loading simulated by vertical skeletal discrepancy, which has already been revealed by the preceding finite element analysis or represented by excessive mouth opening, produced a decrease in the thickness of cartilage layers, an increase in the numbers of chondroblasts and osteoclasts and the subsequent degenerative changes in the condylar cartilage associated with the expression of bone resorption-related factors. In a biochemical or molecular and cellular aspect, excessive mechanical stimuli, irrespective of compressive or tensile stress, induced HA fragmentation, expression of proinflammatory cytokines, an imbalance between matrix metalloproteinases and the tissue inhibitors, all of which are assumed to induce lower resistance to external stimuli and degenerative changes leading to bone and cartilage resorption. Excessive mechanical stimuli also reduced the synthesis of superficial zone protein in chondrocytes, which exerts an important role in the protection of cartilage and bone layers from the degenerative changes. It is also revealed that various cytoskeletal changes induced by mechanical stimuli are transmitted through a stretch-activated or Ca2+channel. Finally, on the basis of the results from a series of studies, it is demonstrated that optimal intra-articular environment can be achieved by splint therapy, if indicated, followed by occlusal reconstruction with orthodontic approach in patients with myalgia of the masticatory muscles, and TMJ internal derangement or anterior disk displacement with or without reduction. It is thus shown that orthodontic treatment is available for the treatment of TMDs and the long-term stability after treatment.

Inhibition of fibrous adhesion formation in the temporomandibular joint of tenascin-C knockout mice.

Tenascin-C (TNC) is a large hexameric extracellular matrix glycoprotein that is expressed in developing organs and tumors. It has been reported that TNC is expressed in inflamed synovial membranes and deformed discs of temporomandibular joint (TMJ) disorder. However, the role of TNC in TMJ is not fully known. In this study, the role of TNC in fibrous adhesion formation of TMJ was examined using TNC knockout (TNCKO) mice. Hypermobility was produced by excessive mouth opening method on the TMJ of both wild-type (WT) and TNCKO mice. TMJ wound healing was compared histologically, and the expression of TNC, fibronectin (FN), and α-smooth muscle actin (α-SMA) in the wounded TMJ was examined by immunohistochemical and immunoblot analyses. Based on histologic analysis, fibrous adhesions were observed in the TMJ of both TNCKO and wild-type (WT) mice after excessive mouth opening. However, fibrous adhesion formation in TNCKO mice occurred later than in WT mice. TNC was expressed in the wounded TMJ disc and mandibular fossa. Although FN and α-SMA expression in the TMJ of TNCKO and WT mice was up-regulated after excessive mouth opening, FN and α-SMA protein levels were higher in WT mice at the same time points. In the wounded TMJ, TNC appears to enhance the expression of FN and α-SMA, and a lack of TNC may reduce fibrous adhesion formation in the TMJ. TNC plays an important role in TMJ wound healing, especially for wounds generated by mechanical stress.

Condylar distances in hypermobile temporomandibular joints of patients with excessive mouth openings by using computed tomography.

Objectives: hypermobility in Temporomandibular joint (TMJ) can manifest higher range of motions in mandible. The aim of this study was to compare the position and distances of the head of condyle to glenoid fossa in TMJs of healthy individuals and patients with mild, moderate and severe TMJ hypermobility. Material and Methods: In this clinical study, 69 patients (between the ages of 22 to 42) with manifestation of joint hypermobility were included and Computed tomography were administered for both TMJs. The patients were divided into three groups based on their maximum mouth opening (MMO): (A) with MMO of 50-55 mm; (B) with MMO between 55 to 65 mm; and (C) with MMO >65 mm. Also, 15 healthy people with profiled tomography in the last 6 months were assumed as control group (N) with normal MMO (<50 mm). The position of condyle from articular eminence while MMO; and the distances from anterior, superior and posterior border of condyle and facing wall of glenoid fossa were measured in closed mouth from the tomography of all contributors. The collected data were analyzed by one-way ANOVA, Post Hoc and Chi-Square tests using SPSS software version 15 at significant level of 0.05. Results: The superior and posterior distances were significantly higher in groups A, B and C than healthy individuals (all P values<0.01). The anterior distance was significant between groups B and N only in right TMJ (P=0.013). Conclusions: TMJ hypermobility showed the characteristic of increased condylar distance in posterior and superior specially in higher excessive mouth opening. Key words:Computed tomography, joint hypermobility, mandibular condyle, mouth opening.

Reduced joint distance during TMJ movement in the posterior condylar position

Biomechanical loading reduces joint distance and has a causative relationship with disc displacement in temporomandibular joint and/or osteoarthritis. Condylar movement and pathways during mouth opening and closing are different depending on the condylar position in the glenoid fossa. Therefore, physical loading on the articular disc or condylar head would also be different in different condylar positions. The aim of this study was to evaluate the 3-dimensional changes of joint distance in different anterior–posterior condylar positions. We divided 52 temporomandibular joints into anterior, concentric, and posterior condylar positions using transcranial radiographs. We traced the condylar movements by simulating mandibular movement with 3-dimensional computed tomography data and a position-tracking camera. The joint distance during temporomandibular joint movement was significantly narrower, and the length of condylar pathways with narrower joint distance was longer in the posterior condylar position than in the concentric (p < 0.05) or anterior condylar positions (p < 0.01). Our study suggests that the posterior condylar position experiences more physical loading than other positions. Therefore, the position may have an accelerating or worsening effect on biomechanical loading-related temporomandibular joint disorder in cases of harmful parafunctional activities such as excessive mouth opening, clenching, and bruxism.

The Relationship between Dental Treatment and Temporomandibular Disorder

The risk of temporomandibular joint disorder (TMD) can be increased during dental treatment due to excessive mouth opening and change of occlusion. The aim of this study is to find the relationship between dental treatment and TMD in the patients who developed TMD after dental treatment. The subjects of this study were 21 patients, who developed TMD after dental treatment and were treated with active TMD therapy in Seoul National University Bundang Hospital from June 2003 to February 2007. The subjects were examined with preceding dental treatment, symptom, diagnosis, treatment method of TMD and prognosis of TMD. The obtained results were as follows. 1. Preceding dental treatments were : Implant treatment, 14 cases ; Tooth extraction, 3 cases and others. 2. TMD symptoms were : pain on TMJ, 12cases : Sound on TMJ, 3cases ; Mouth opening limitation, Headache and others. 3. Diagnoses of TMD were : Synovitis and/or capsulitis, 10 cases ; 8 cases of Internal derangement and others. 4. Most TMD were treated by stabilization splint. 5. Prognoses of TMD were : Improvement, 6cases ; sustained 11 cases. In conclusion, the risk of TMD is increased during implant treatment. Prognoses of TMD after dental treatment were bad. It might be that these patients were non-cooperative and have distrust of dental treatment. Because the overloading on TMJ is possible in dental treatment of patients with underlying TMD, prior explanation and knowledge TMJ treatment are very important in these cases.

A survey of temporomandibular joint dislocation: aetiology, demographics, risk factors and management in 96 Nigerian cases

A retrospective study of 96 cases of temporomandibular joint dislocation was undertaken. Patients’ ages ranged from 9 to 85 years (mean ± SD, 35.3 ± 17.4 years) and peak incidence was at 20–29 years. Mean duration was 7.9 weeks (range, 1 h to 3 years). Acute, chronic and recurrent dislocations were seen in 46 (47.9%), 29 (30.2%) and 21 (21.9%) patients, respectively. Males dominated in all three categories but this was not statistically significant ( P = 0.8). Excessive mouth opening while yawning (44 cases) was the commonest cause of dislocation, followed by road traffic accidents (13 cases). Ten patients (10.4%) had an underlying systemic disease, the commonest being epilepsy (four cases); those with acute dislocation recorded the highest incidence of underlying illness. Bilateral anterior (86 cases) dislocations were the most frequent. Of the 96 patients, 89 (92.7%) were available for treatment. Manual reduction with or without anaesthesia proved effective for 38/45 acute, 5/24 chronic and 14/20 recurrent cases. Chronic dislocations were treated mainly by surgical osteotomy (13/24). Vertical subsigmoid and oblique ramus osteotomies were the commonest surgical techniques recorded. Treatment was satisfactory for all patients surgically handled except for one case of anterior open bite postoperatively. This study has shown that excessive mouth opening while yawning is the commonest cause of temporomandibular joint dislocation in Nigerians, and conservative approaches to management remain quite effective irrespective of the duration and clinical subtype. The best choice of surgical technique should be determined by proper clinical evaluation and the need to avoid or minimize postoperative morbidity.