Temporomandibular disorder is sometimes associated with otic symptoms such as tinnitis and dizziness. It has been remained to be resolved that temporomandibular disorder causes these symptoms or a common disorder like stress causes temporomandibular disorder and these symptoms simultaneously.
Recent statistic studies have elucidated that temporomandibular disorder accompanies otic symptoms significantly. Other studies have elucidated that a population of patients with temporomandibular disorder improves otic symptoms after therapy of temporomandibular disorder. The causal association between temporomandibular disorder and otic symptoms has been recently re-evaluated. Although many hypotheses have been advocated since Costen reported otic symptoms dependent upon distrubed function of the temporomandibular joint in 1934, none of them have got universal acceptance. The mechanism of tinnitus and dizziness as well as that of temporomandibular disorder has been unclear. Diverse disorders can cause tinnitus and dizziness as well as temporomandibular disorder. These reasons make it difficult to understand the causal association.
We used pure tone audiogram and tympanometry and evaluated patients of temporomandibular disorder with or without tinnitus, because dizziness tends to improve with time. However, our study cannot find any audiometric differences between two groups. To elucidate the causal association between temporomandibular disorder and tinnitus, cooperation between dentist and otolaryngologist will be essential. Dentists need more knowledge of tinnitus and dizziness, while otolaryngologists need more knowledge of temporomandibular disorder. From the standpoint of an otolaryngologist, fundamental knowledge of tinnitus and dizziness is stated to be essential for dentists to diagnose on temporomandibular disorder.

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Chief complaints of Patients with thoracic outlet syndrome (TOS) are pain, numbness, and dullness at their neck, shoulder or upper extremity. Such symptoms result from compression or traction of the neurovascular bundle through the thoracic outlet. The entrapment of the neurovascular bundle may be caused by a cervical rib, by hypertrophy or spasm of the scalenus anterior, by abnormal droop of the shoulder girdle, by spasm of the scalenus medius secondary trauma or abnormal posture, by anomalies of the first rib, by abnormal tension of the pectoralis minor. In tempromandibular disorder (TMD), patients often compliant neck stiffness. The neck muscles of the patients with TMD, for example scalenus anterior and scalenus medius, become so stiff that the thoracic outlet may be narrow. The patients with TMD easily suffer from TOS at the same time. We have to be able to diagnose TOS when the patients with TMD complain of pain, numbness, and dullness at their neck, shoulder or upper extremity. In order to diagnose TOS, useful clinical tests, Adson test, Wright test, Eden test, Allen test, Morley test, and Roos test are explained. And new methods to diagnose TOS, somatosensory evoked potential (SSEP), F-wave, brachial plexus neurography, and MRI are introduced. Conservative treatments of TOS are described, for example muscle exercise around the neck and shoulder, stretching, relaxation, and arthrokinetic approach (AKA) . Surgical methods are rare to treat TOS, and the most effective operation is decompression of the neurovascular bundle by resection of the first rib and anomalous structures.

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It is well known that temporomandibular disorders (TMD) patients often suffer from ear symptoms, including earache, tinnitus, dizziness and deafness. However, only a few reports had documented the prognosis of ear symptoms following therapeutic interventions to TMD. We present a case report of TMD whose ear symptoms as well as TMD symptoms had been improved simultaneously by occiusal treatment.
The patient was a 36-year-old female complaining of right temporomandibular joint (TMJ) pain and noise on jaw opening. She also had earache and tinnitus in the right. She developed tinnitus and TMJ noise simultaneously seven months ago, and earache and TMJ pain on jaw opening a month ago. Her dizziness, which was a sequela of tympanitis in her childhood, deteriorated after the onset of TMD symptoms. There are marked pain on palpation in her right face including TMJ, masseter, temporalis, medial and lateral pterygoid, and posterior digastric muscle regions. Radiographs of TMJs were characterized by superior displacement of bilateral condyles. In occlusal examination, interferrences of upper incisers restored with resin facing crown and insufficient occlusal supports of the lower partial denture that replaced her bilateral molars were found. In the treatment, we performed occlusal adjustment in upper incisors and added self-curing acrylic resin to the occlusal surface in the lower partial denture. TMJ pain and earache vanished immediately after the occlusal treatment. Tnnnitus turned for the better after TMJ noise disappeared. Dizziness rarely occurred after the occlusal treatment, and the results of Stepping test, Positioning Nystagmus test and Caloric test were improved. These findings may suggest that ear symptoms were correlated with TMD symptoms and might have shared the cause in part with TMD.

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In this paper, we presented three cases who had some symptoms related to disorder of masticatory muscles, and considered several patterns of relation between temporomandibular disorders (TMD) and their adjacent diseases.
The case 1 had dizziness and disorder of sense of balance and the case 2 had palatal tremor. These symptoms were improved by using occlusal splints and occlusal reconstruction. The case 3 had tremor of hands, stiffness and dullness of masseter muscles, sternocleidomastoid muscles and trapezius muscles, opening limitation of mouth, masticatory disorder, sense of dysphagia and so on. Initially, definite diagnosis for the case 3 could not be made by several departments of medical hospitals, and the case 3 was suspected as TMD. However, the case 3 was finally diagnosed as amyotrophic lateral sclerosis (ALS) but not TMD.
The treatment results of the case 1 and case 2 indicate that some kinds of occlusal treatments have possibility of becoming useful symptomatic therapy for medical diseases related to TMD. On the other hand, the case 3 calls our attention to existence of adjacent diseases which need differential diagnosis from TMD.
There are various patterns of contact between TMD and their adjacent diseases. It is difficult to divide the various patterns clinically. Therefore, it is considered that we must be careful in treating symptoms adjacent to TMD and should make efforts to solve mechanisms of the relation among TMD, occlusion and the related symptoms.

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Two clinical reports are Temporomandibular disorders (TMD) due to Bruxism and clencing during sleeping. The following cases presented the symptomatology of TMD disappeared by occlusal treatment.
[Case 1] The patient was an 18 years-old male with an Angle class III malocclusion who couldn't close his mouth during waking up for almost one year. Clinical inspection showed that the mandibular right second molar was guiding the mandibular eccentric movements. The TMD symptoms disappeared by shifting anteriorly the tooth guidance with splints.
[Case 2] The patient was an 51 years-old female who had pain of left Temporomandibular joint (TMJ) . She could't sleep well due to the TMD symptoms. Clinical inspection showed that the left second premolar was Scissors bite. The symptomatology of the TMD disappeared by treating the contact point of the left second premolar.
We recorded jaw and condylar movements of these two cases with a 6-degree-of-freedom measuring device during lateral excursions with and without wearing of the splints in order to assess the influence of shifting anteriorly the location of tooth guidance on the cure of the symptoms. We found that the direction of condylar movements changed markedly during parafunctional grinding tasks.
We conclude that correction of anterior guidance is a non-invasive alternative therapy in some cases of condylar dislocation.

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The purpose of this experiment was to clarify the effect of the occlusal contact condition of the lateral excursion on the masticatory path patterns. For the 60 healthy subjects, the masticatory movement and the occlusal contact of moving laterally for 1 mm (L1), 2 mm (L2) and 3 mm (L3) were recorded respectively. After classifying the masticatory path patterns of chewing chewing gum, the occlusal contact condition of the lateral excursion were related quantitatively with the masticatory path patterns and the following results were obtained.
1. The frequency of the path patterns from pattern I to VIII were 40.8%, 10.8%, 28.3%, 5%, 4.2%, 4.2%, 5%, and 1.7%, respectively (pattern I: opened towards the working side and closed in a convex manner, II: similar to pattern I but closed in a concave manner, III: opened first towards non-working side then towards working side and closed in a convex manner, IV: similar to pattern III but closed in a concave manner, V: opening and closing paths were convex, VI: a reverse pattern of the regular pattern, VII: opening and closing paths crossed each other, VIII: opening and closing paths were a straight line) . Since pattern VIII had only 1.7%, it was discarded from the following comparisons.
2. For all pattern groups (I-VII) at both working and non-working sides, the number of tooth contact at each lateral position decreased significantly as the excursion moved laterally from L1-L3.
3. The appearance rate of the number of tooth contact: For the working side of L1, group I and II had fewer tooth distribution. For the balancing side of L1, all groups had occluding contacts. For the working side of L2, groups I, II, VI, and VII had fewer tooth distribution. For the balancing side of L2, only group I showed no tooth contact. For the working side of L3, all groups showed fewer tooth distribution. For the balancing side of L3 all groups had a tendency to disappear. Significant differences were found for 4 pairs at L1, for 16 pairs at L2, and for 12 pairs at L3.
4. It was concluded that the occlusal contact condition at the lateral excursion changed according to the distance from centric occlusion. Also the difference in the masticatory path pattern was most evident at 2 mm lateral excursion. And this difference in the occluding condition of the lateral excursion was related to the difference in the masticatory path pattern.

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Using a functional method based on the principle of the“Amplitude-Histogram”, the method that divides the electric potential curve of an analog signal into a clock-time, converts a division into digital data and then makes a histogram, we determined the mandibular rest position of a young child in the primary dentition stage and examined age-related three-dimensional changes in this position.The purpose of this study was to obtain new information to help us understand the maturation of the neuromusculature through changes in the mandibular rest position.The subjects were 18 children (6 three-year-olds, 6 four-year-olds and 6 five-year-olds) with normal occlusion.The results were as follows:
1. Vertical component: The mean values of the freeway spaces decreased with age and the rest positions approached the centric occlusion. Also they scattered vertically have converged.
2. Lateral component: The rest positions were scattered around the median line in three-year-old children, but they have converged at the median line with age.
3. Anteroposterior component: The rest positions were scattered anteroposteriorly in three-year-old children, but they have converged below the centric occlusion with age.

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Swallowing function was investigated in 4 oral cancer patients who underwent secondary unilateral radical neck dissection and 3 who underwent radiotherapy of 50 Gy after unilateral radical neck dissection. We studied swallowing function about the relation between resection of suprahyoid muscles, infrahyoid muscles or postoperative radiotherapy. We also examined postoperative changes over time compared to the preoperative swallowing function by video fluorography.
1. Unilateral radical neck dissection cases.
There was no postoperative change in function in the oral phase (lips closing, holding in the oral cavity and the degree of residual test foods in the oral cavity), but in the pharynx phase, amount of residual all test foods in the pharynx was increased 1 month postoperatively. It reduced and recovered to preoperation function 6 months postoperatively, however.
After unilateral resection of the anterior and posterior bellies of the digastricus and omohyoideus muscles, the forward and upward movement of the hyoid bone and closing of the trachea by the epiglottis during swallowing were good on pre and postoperative examinations over time.
2. Postoperative radiotherapy cases.
There was no postoperative change in the function during the oral phase. In the pharynx phase, some patients had increased residual test foods in the pharynx increased 6 months after radiotherapy, but the forward and upward movement of the hyoid bone and closing of the trachea by the epiglottis during swallowing were good on pre and postoperative examinations.
Our findings suggested that there was no significant deterioration of swallowing function or risk of aspiration in patients who underwent secondary unilateral radical neck dissection or radiotherapy of 50 Gy after unilateral radical neck dissection

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In previous report, it has been demonstrated that, during food intake, the range of mouth opening is always larger than food size and the “food space” (difference between mouth opening range and food size) is kept constant. It is assumed that some factors will be involved in this mouth opening movement, such as skeletal frame and jaw condylar movement.
Jaw and head movements during food intake were investigated in four normal subjects (female 3, male 1) and four skeletal class III subjects (female 3, male 1) with edge-to-edge occlusion. Subjects sit on the measuring appliance and their head remained free. They were asked to ingest peaces of apple cut in disk shape (5 mm thick and 3, 6, 9, 12, 15, 18, 21, 24, 27, 30 mm diameter) into their mouths. Head and jaw movements were recorded by means of a 6-degree-of-freedom jaw movement tracking system.
In all subjects, mouth opening range was larger than foods in each size. The food space had no significant difference between normal subjects and class III subjects.
In normal subjects, the range of head movement was smaller than 10 mm and their condyles translated more than 10 mm. In the Skeletal class i group, two subjects who were smaller ( <10 mm) in the range of condyle translation were showed larger ( >10 mm) in quantity of head movement compared with normal subjects. Another two subjects showed same pattern as that of normal subjects.
We speculate that the range of head movement would be involved in jaw movement character in class III subjects. It is necessary to analyze in more skeletal class III subjects in order to reveal connection between the food space, and jaw and head movements.

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