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This study evaluated the test-retest reliability for determining the temporomandibular joint (TMJ) disk position, diagnosed using magnetic resonance imaging (MRI). These assessments were done as a base-line measurement for a prospective cohort study, which examines the risk factors for precipitation and progression of temporomandibular disorders. Fifteen subjects (mean age, 24.2 ± 0.94 years; male/female = 8/7) were recruited from the students of Okayama University Dental School. Sagittal MR TMJ images were taken with a 1.5-T MR scanner (Magneton Vision, Siemens) in close and maximal open positions twice at about 1-week (6-11 days) interval. The images were displayed using 200% magnification on a computer screen with a commercially available image software package (OSIRIS, UIN/HCUG). Three calibrated examiners diagnosed the disk positions using the standardized criteria. The disk position of each joint was classified as normal, anterior disk displacement with or without reduction, and others. The first and second disk position diagnoses were compared, and the test-retest reliability level was calculated using the kappa index. The second disk position diagnosis was consistent with the first in 27 out of 30 joints. The calculated kappa value representing the test-retest reliability level between the first and second disk position diagnosis was 0.812. These results indicated that the test-retest reliability of MRI-based diagnosis of TMJ disk positions at about 1-week interval was substantially high, even though they were not completely consistent.

We previously reported that nitric oxide (NO) is first detected in the uterus of a pregnant rat on gestational day 13.5 (GD13.5) and that NO levels peak on GD17.5. In addition, NO production in the uterus is mainly derived from the decidua and not the myometrium. The aim of the present study was to reveal the role of NO that peaked on GD17.5 of gestation in the decidua. To inhibit NO production, pregnant rats were continuously administered by an nitric oxide synthase inhibitor, N(G)-nitro-L-arginine-methyl ester (L-NAME) for 48 h. In the control group, saline was infused instead of L-NAME. After treatment, the decidua were obtained from GD13.5, GD17.5 and GD21.5 rats. Apoptosis and activated caspase-3-positive cells were observed by transferase-mediated dUTP nick-end labeling (TUNEL) assay and immunohistochemistry, respectively. The caspase-3 enzyme activity was also measured in the cell lysate from the decidua. The numbers of TUNEL-positive cells and activated caspase-3-positive cells each increased and the amount of caspase-3 activity also increased significantly in rats on GD17.5 than in rats in the control group, but no changes were observed in rats on GD13.5 and GD21.5. Furthermore, enzyme activity regarding the initiator caspases, caspase-8 and -9, upstream factors for caspase-3 in the caspase cascade, was measured simultaneously on GD17.5 under the same treatment. Caspase-8 and -9 enzyme activities increased significantly in the control group; an increment of caspase-8 activity was especially prominent. The present results indicate that an inhibitor of NO production caused apoptosis through typical apoptotic signals in the decidua on GD17.5, suggesting that an NO peak in the decidua is essential to cell survival and the maintenance of uterine formation.

Objective: The objective of this study was to investigate the association between TMJ pain/disk pathosis and the muscle tenderness pattern in the orofacial and neck/shoulder region., Study Design: One hundred seventy-one TMD patients were divided into 4 groups, including group 1: patients with painful unilateral TMJ disk displacement (DD); group 2: patients with painless unilateral TMJ DD; group 3: patients with painless bilateral TMJ DD; and group 4: patients with a bilateral normal TMJ disk position (n = 41). Each subject underwent muscle palpation and the side-by-side number of muscle tenderness points was combined as the number of muscle tenderness points on each side. Within each group, DD with and without reduction subjects were separated into subgroups and then were analyzed., Results: In group 1, the median muscle tenderness points on the side with painful TMJ DD without reduction was significantly higher than on the normal side (P = .019), whereas the palpation scores for painless DD patients showed no significant difference between the DD and normal sides., Conclusions: These results indicated painful disk displacement to possibly be correlated with ipsilateral muscle tenderness., (Copyright 2010 Mosby, Inc. All rights reserved.)

Purpose: The relationship between sleep bruxism (SB) and temporomandibular disorders (TMD) is unclear. This study aimed to estimate SB prevalence in an adolescent population and to investigate the relationship between SB frequency and prevalence of TMD signs/symptoms., Materials and Methods: First-year students at a high school in Okayama, Japan, were recruited in 2005, with 195 subjects responding. The SB detection device was a miniature disposable device (BiteStrip, SLP) that indicated the total SB events per night on a 4-grade score. The subjects were divided into severe and nonsevere SB groups with SB frequency cutoffs. The subjects were examined for temporomandibular joint (TMJ) noise during mouth opening/closing, tenderness of the masticatory/cervical muscles, and range of TMJ condylar movement. The presence/absence of headache and shoulder stiffness was also determined by the interview. The odds ratio (OR) and confidence interval (CI) were calculated to test the relationship between SB frequency, gender difference, and presence of the TMD signs/symptoms by multiple regression analysis., Results: Severe SB (more than 125 events per night) was significantly related to the presence of TMJ clicking (OR: 3.74, CI: 1.22-11.49, P = .02), while gender (male) was not related to the presence of TMJ clicking. Severe SB was not related to headache, though gender (male) was significantly related to headache (OR: 2.52, Cl: 1.04-6.11, P= .04) in these subjects., Conclusion: These results suggest that the presence of TMJ clicking was closely related to severe SB in an adolescent population.

There is controversy as to the genetic contribution to the pathogenesis of temporo-mandibular disorders (TMD). Several reports reveal a marked familial aggregation in the signs and symptoms of TMD, while others do not. Therefore, our goal was to investigate the hypothesis using a sophisticated research design, which was a well-known genetic survey inter-twin concordance assessment in the symptoms of TMD. This study is the first step to survey TMD symptoms of a twin group in junior and high schools as a preliminary trial. The 63 twins were asked to participate in this study in junior and senior high schools affiliated with the University of Tokyo, Japan, schools which kept ten twins in each grade for the purpose of several genetic survey programs. After excluding incomplete filling out of questionnaire sheets and data from male-female pairs, 43 monozygotic (MZ) (15.3+/-1.7 yrs, male/female = 17/26 pairs) and nine dyzygotic (DZ) (15.2+/-1.8 yrs, male/female = 6/3 pairs) twins were studied. Outcomes consisted of a prevalidated 14-item self-administered questionnaire, which assessed proband- and pair-wise concordance levels in the MZ and DZ twins. These results demonstrated that the MZ twins had a higher tendency of inter-twin concordance than DZ twins in terms of jaw pain in wide mouth opening (proband-wise concordance = 66.7% in MZ, 0% in DZ), difficulty in mouth opening (20% in MZ, 0% in DZ) and difficulty in mouth closing (50.0% in MZ, 33.3% in DZ), while there was no significant difference between the MZ and DZ concordance levels in other general health-related and behavior-related items, except toothache. However, the pair-wise concordance rates of jaw pain in wide mouth opening and difficulty in mouth opening in the MZ twins were not significantly higher compared to the DZ rate. Possibly, a genetic factor contributed to the pathogenesis of TMD in an adolescent population. The sample size needs to be increased, and there are plans to survey the next sample in the same schools.

Patient: The patient was a 56-year-old female, suffering from severe burning pain in the left maxillary alveolar area. The pain was initiated by periodontal curettage under no local anesthesia. No abnormal local findings in dental X-ray images and no abnormal central nervous system findings in brain magnetic resonance images were observed. Extraction of the tooth temporarily abated her pain, however the pain recurred gradually. Since the observed signs and symptoms of the patient agreed well with the diagnostic standard for continuous neuropathic pain (atypical alveolar pain) of Graff-Radford & Solberg (1992), medications (tricyclic antidepressant, non-steroidal anti-inflammatory drug (NSAID), anxiolytics, topical application of capsacin cream) and supportive psychological therapy have been administered continuously. To measure symptom severity over a long term, daily amounts of taken NSAID and anxiolytics were recorded continuously by the patient in a simple table diary for 7 years. As a result, the total amount of the drugs per month gradually decreased with the passage of time., Discussion and Conclusions: Clinical evidence regarding the prognosis of continuous neuropathic pain in the orofacial region is obviously insufficient, making it difficult to inform such patients of their prognosis of the disorder on the basis of clinical evidence. In this report, we have plotted the total amount of drugs taken per month by the patient as a good reference for the pain severity and the results clearly suggest that pain severity decreased with time. This kind of information may help both clinicians and patients for case-based explanation of the disorder.