The purpose of this study was to propose newly defined parameters of finite helical axis (FHA) analysis for mandibular kinematics. One subject without signs and symptoms of temporomandibular disorders and with normal occlusion was selected. The opening and closing movement of the mouth was recorded by an opto-electric system (TRIMET system). Subsequently, the FHA parameters were calculated. In this study, the direction vector and position vector of the FHA, the rotation angle of the FHA and the translation along the FHA were used as the FHA parameters. The newly defined FHA parameters demonstrated the existence of translational movement of the condyle at the beginning of the opening phase. Furthermore, the FHA position vector clarified the ratio of rotation component to translation component during opening and closing movement. The FHA parameters developed in this study provide detailed information mandibular kinematics.

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A case of acute suppurative arthritis of the temporomandibular joint (TMJ) in a 63-year-old man is reported.
The patient visited our hospital because of severe pain in the right TMJ. On examination, trismus and slight deviation of the mandible to the opposite side were found. MR imaging of the joint revealed a high-intensity area in the upper joint cavity of the right joint, which suggested the diagnosis. Approximately 0.8ml of pus was aspirated by puncture from the upper joint cavity, however, bacterial culture of the pus was negative. Treatment with antiinflammatory drugs and opening mouth exercises yielded excellent results.

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In the past decade, the strategy in conservative treatment for TMDs has markedly changed in our clinic.
Recently, we are actively using physical exercise to treat temporomandibular disorders (TMDs), and instruction for self-correction of habitual behavior. Management of psychological contributing factors such as anxiety and depression is simultaneously conducted individually.
Through our clinical experiences using the above-mentioned therapy, it has appeared that recent post-treatment outcomes have been better than with the previous treatment strategy for TMDs.
In this study, treatment results obtained from 363 TMD patients in 2003 were compared with 382 patients in 1993 in order to confirm the difference between the two periods and to consider the future treatment tactics for TMDs.
In 1993, NSAIDs, oral appliances, mouth opening exercise and disc repositioning manipulation were used to treat TMDs. On the other hand, corrective instruction for each behavioral contributing factor observed in patients, manipulative mobilization under anesthesia of TMJ, administration of anti-anxiety agents or anti-depressants and consultation with psychosomatic medicine were newly adopted in 2003.
As a result, the treatment cases by means of mobilization exercise and NSAIDs administration increased, while the cases by means of oral appliances and the disc repositioning manipulation reduced in 2003. Based on the outcome criteria used at the investigation in 1993, the excellent rate showed a significantly (p<0.001) larger value in 2003 (61.0%) than in 1993 (39.8%). In contrast, the treatment period significantly (p=0.030) decreased from 11.5 weeks in 1993 to eight weeks in 2003.
These results suggested that detecting and correcting the contributing factors of TMDs may be effective for the treatment of TMD patients, and further study to verify the effects of exercise therapy needs to be carried out in the near future.

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The number of visiting patients with temporomandibular disorders (TMD) forms a peak at 20-30 years old, and gradually decreases afterward.
To consider the factors that influence this tendency, we investigated the numbers of patients in four age groups of teens, 20-30, 40-50 and 60 or more years old, and compared these groups in terms of symptoms, disorders, psychological and behavioral contributing factors as recorded in a multi-dimensional survey of patients with painful TMD carried out during one year from September 2003.
As a result, there were 40 cases of teens, 290 cases of 20-30 years, 129 cases of 40-50 years and 75 cases of 60 or more years old, respectively. In comparison between the groups, there was no significant difference for symptoms and disorders, except for the total VAS scores on pain expression terms, the score of restricted mouth opening at getting up. On the other hand, there were significant differences for the neuroticism score on personality trait and several behavioral factors between the groups.
In teens, several behavioral factors in life were outstanding. Work-related factors increased in 20-30s. Thereafter, factors gradually decreased with aging.
It was suggested that these contributing factors in generations might influence the numerical trend of visiting patients with TMD.

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Background: Many clinical practice guidelines now include frequently asked “patient questions (PQ)” and their answers. Typically a PQ is of the form “If I have a temporomandibular disorder with symptom A, what prognosis can I expect if I receive treatment B?”
Purpose: To determine whether the internet can provide useful information to practitioners formulating PQ pertaining to temporomandibular disorders.
Method: On March 17, 2007, we searched three internet consultation/question websites using the keyword__??__??__??__??__(temporomandibular disorders), and we used a blog search engine to identify occurrences of the same keyword in blogs.
Results: There were several thousand hits on the search keyword in the three consultation/question websites. A large number of questions about temporomandibular disorders were associated with these hits. The symptoms most frequently reported by people with a temporomandibular disorder were impaired mouth opening and pain. Blogs with the keyword contained many instances of patients who used mouthpieces (splints) provided by their dentists. Based on this study, we formulated the PQ “Does wearing a mouthpiece effectively treat a temporomandibular disorder?”
Conclusion: Searching the internet provides information that helps to formulate PQ.

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There is no question which tests the validity for screening temporomandibular disorders (TMD) targeting the population.
Purpose: To select one from four fixed questions, which validated screening TMD for dental patients, and to test the crossvalidation and diagnostic accuracy.
Methods and Subjects: A total of 1, 245 dental patients (TMD prevalence rate: 12.4%) who visited either of four dental offices during one year were asked to answer the four screening questions on a five-point numeric rating scale and binary scale (yes/no). The patients were classified into two groups using the random selection method in SPSS (SPSS, Tokyo, ver. 14). We used ROC curves and the non-parametric dichotomous item scalability test for item selection, and calculations of diagnostic accuracy and Bayesian statistics for reliability.
Results: The question ‘When you open your mouth widely and/or close it, do you feel pain in your jaw?’ was selected, and the crossvalidation was proved. The diagnostic accuracy was 0.701 (sensitivity), 0.871 (specificity), and 0.130 (false positive rate). In the false positive group of the question, pericoronitis, dental caries, and periodontal disease were included; these need to be diagnosed by close inspection.

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In habitual luxation of the mandible, luxation occurs repeatedly during normal mouth-opening activities, such as eating, yawning, and conversation. It is often difficult to conservatively treat habitual temporomandibular joint (TMJ) luxation. This paper reports the results of using the Dautrey procedure for preventing habitual luxation of the mandible.
We report 10 cases of habitual luxation who were successfully treated using anterior blocking by the procedure. The patients consisted of 4 males and 6 females with a mean age of 69.2 years. Eight patients showed bilateral luxation, and 2 had unilateral luxation. These patients underwent anterior blocking of the TMJ by the procedure, since they did not respond to conservative methods such as limitation of mouth opening using an elastic bandage and control of artificial dentition, which have been found to be ineffective methods in our department.
All patients had good outcomes without postoperative complications or the development of reluxation that could not be reduced by the patients themselves. It is suggested that the Dautrey procedure is useful for the treatment of habitual luxation of the mandible in patients for whom conservative treatment is difficult.

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