Purpose: In this study, we clinicostatistically investigated the relationship between joint effusion and joint pain with intermittent closed lock.
Subjects and Methods: The subjects were 49 patients (49 joints) who were diagnosed with having an intermittent closed lock. The controls were 30 patients (33 joints) who were diagnosed with having a capsule-ligament disorder. These patients were examined by MRI. They visited our department between April 2004 and December 2005. Joint effusion was classified according to Larheim's grading system. Visual analog scale (VAS) was used to assess joint pain, and the relationship between joint effusion and joint pain was statistically investigated.
Results: Joint effusion was observed in 20 joints in patients with intermittent closed lock with joint pain, and in 21 joints without joint pain. In patients with capsule-ligament disorders, joint effusion was observed only in one joint. Regarding the incidence of joint effusion, there was a statistically significant difference between intermittent closed lock with joint pain and capsule-ligament disorders.
Conclusions: These results suggest that joint effusion is observed in many cases with intermittent closed lock, however, there is no significant difference between joint effusion level and joint pain intensity.

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Purpose: A measurement system was developed for measuring the dynamic force on a patient's head during massage of the masticatory muscle. The dynamic force during massage by dentists was evaluated.
Methods: The measurement system consists of an anatomical head model, an intelligent force/torque sensor unit, and a pedestal unit. The sensor detected three-dimensional components of force to the head during the massage in each axial direction simultaneously and continuously in real time.
Results: During the massage by skilled dentists, stable wave patterns of three-dimensional load were observed. Differences in the force between right and left hand were minimal. The load of compression was approximately 10 to 15 N.
Conclusions: The Dynamic load measurement system may be useful for massage therapy training and studying the physiological efficacy of massage.

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Objective: We evaluated alteration of the articular disc position at opened mouth after treatment by magnetic resonance imaging findings in patients with temporomandibular joint disease with anterior disc displacement without reduction.
Material and methods: Our study based on 11 joints found that the disc changed from anterior disc displacement without reduction at the initial MRI study to anterior disc displacement with reduction at follow-up MRI study. All of the study subjects were female, with age ranging from 15 to 36 years. One joint underwent interventional radiology (lyses and lavage) and splint therapy, 3 joints underwent pumping manipulation and splint therapy. Three joints underwent splint therapy and 1 joint received only follow-up. Four joints underwent splint therapy after the interventional radiology on the contralateral side. Clinical evaluation focused on temporomandibular pain, joint sound and trismus. MR imaging was performed for the mandibular head position, configuration of articular disc and degree of disc displacement at closed mouth.
Results: Clinical signs observed with alteration of the disc position were disappearance of TMJ pain in 7/9 joints (77.7%), disappearance of TMJ sound in 1/5 joints (20%) and appearance of sound in 3/6 joints (50%). An increase in the distance of opening the mouth was found in all of the 7 joints with trismus. The changes in the MR image findings were mandibular head position changes in 2/11 joints (18.1%), disc configuration in 3/11 joints (27.2%) and degree of displacement in 5/11 joints (45.4%). In the mouth closed position, the mandibular head moved antero-inferiorly after treatment.
Conclusion: It is possible that the articular disc was repositioned at the mouth opening after treatment in the case of younger patients with a few disc deformities of anterior disc displacement without reduction.

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Obsolete dislocation of the temporomandibular joint cannot be repositioned manually due to organic changes in mandibular fossa and so is often treated by open reduction under general anesthesia. This report presents a case of obsolete dislocation of the temporomandibular joint of a patient who cannot endure treatment under general anesthesia.
The patient was a 61-year-old man with severe marginal periodontitis. Since his chronic liver failure made general anesthesia risky, we chose a conservative reduction by lever action using intraoral blocks with built-up heels and elastic traction. Because he had no tight tooth that could resist the traction, we innovated on past reports of conservative reduction. Seventeen days after treatment, the reduction was successful and his jaws were stable. By 12 months after treatment, he had no recurrent dislocation and the outcome was good.

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There have been no questionnaires in epidemiologic studies that estimated cross-validation of question items for screening temporomandibular disorders (TMD). The purposes of this study were to select question items for screening of TMD, and to assess their validity.
Methods: We analyzed 2, 360 dental patients (TMD prevalence rate: 11.7%) who visited any of four dental treatment facilities during one year from October 2005. Cross-validation, criterion-based validation, and estimation of cut-off value for diagnostic accuracy for TMD were calculated.
Results: Four question items (five-point numeric rating scale) were selected from 20 predetermined items by factor analysis followed by Mokken analysis. The validity was confirmed by construct-validity, cross-validity, criterion-related validity, polychotomous item response theory and Cronbach'α. The cut-off value of the total value of the four items was 8.5, indicating that the sensitivity was 0.746 and the specificity was 0.811.

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We experience some cases that are difficult to diagnose as temporomandibular disorders (TMD) or not, even if it is well understood. In this study, we surveyed how medical and dental doctors grasp the concept of TMD, and what kinds of diseases they differentially diagnose. From 12, 518 patients who visited the Oral and Maxillofacial Surgery Department of Saitama Medical University for five years from 2000 to 2004, and 4, 964 patients who visited the Oral and Maxillofacial Surgery Department of Tokyo Medical and Dental University for one year in 2004, which totaled 17, 482 patients, patients who had a letter of introduction regarding TMD were extracted and evaluated as to whether our diagnosis was the same or not, and if it was not the same, what the diagnosis was. The subjects were 359 patients in total, 225 patients in Saitama Medical University and 134 patients in Tokyo Medical and Dental University. In these cases, 39 patients were not diagnosed as TMD: 8 cases were diagnosed such as traumatic arthritis and dislocation of temporomandibular joint (TMJ) classified into diseases of TMJ without TMD and 31 cases such as teeth, periodontitis, psychological disease and somatoform disorder classified into diseases without TMJ diseases.

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