Comparison of inter-twin concordance in symptoms of temporomandibular disorders: a preliminary investigation in an adolescent twin 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.

[Longitudinal follow-up of symptom severity of a patient with continuous neuropathic pain assessed by actual drug consumption record].

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.