Correlation between direction and severity of temporomandibular joint disc displacement and reduction ability during mouth opening

The most common temporomandibular joint (TMJ) internal derangement is an abnormal relationship of the disc with respect to the mandibular condyle, articular eminence and glenoid fossa-disc displacement. The aim of our study was to analyse the correlation between partial/complete disc displacement in the intercuspal position (IP) and its reduction in the open-mouth position (OMP) in both oblique sagittal and coronal planes on magnetic resonance imaging (MRI) in patients with temporomandibular disorders. Multisection MRI analysis of 382 TMJs was conducted in 191 patients with disc displacement according to the RDC/TMD criteria (148 women, 43 men; aged 14-60 years). The disc position was evaluated on all oblique sagittal and coronal images in the IP and the OMP. Univariate logistic regression analysis showed that the severity of disc displacement in the sagittal plane is a statistically significant predictor of reduction ability during mouth opening (B = 3.118; P < .001). Moreover, the severity of disc displacement in both planes is also a significant predictor of disc reduction in OMP (B = 2.200; P < .05). In conclusion, reduction ability during mouth opening is associated with the severity of disc displacement in IP, in both sagittal and coronal planes. Multisection analysis of all MR images allows distinguishing the correct disc position from disc displacement and can improve the ability to distinguish between various stages of TMJ internal derangement.

[Investigations on the prevalence of headache associated with mandibular dysfunction]

The role of mandibular dysfunction in the etiology of headache is still underestimated in the medical literature. For this reason an analysis of own questionnaire investigations published in the years 1983 to 1999 was done. These investigations were carried out in 3915 subjects aged 15-66. In order to determine the prevalence of headache associated with mandibular dysfunction in the analysis mandibular parafunctions and clicking in the temporomandibular joints (TMJs) were selected. The comparison of the prevalence of headache in groups with and without mandibular parafunctions and in groups with and without clicking in the TMJs has shown that the prevalence of headache was significantly higher in groups with mandibular parafunctions and with clicking in the TMJs than in groups without these disturbances. The difference in the prevalence of headache in the investigated groups has shown that headaches noted in the population can be associated with mandibular parafunctions in 18.2% and dependent on the age with clicking in the TMJs in 9.7% to 25%.

Investigations on prevalence and treatment of fingernail biting

Numerous investigations indicate that there is a parallel between emotional stress and hyperactivity of the masticatory muscles connected with mandibular parafunctions. Elimination of mandibular parafunctions is difficult and almost impossible, therefore, this paper proposed a treatment whereby nonharmful motor habits are substituted for the parafunction. Questionnaire investigations were carried out in 2905 subjects, with an attempt at treatment in the youngest group of 222 pupils. It was found that good results were obtained through adult supervision and cooperation.