Journal of oral rehabilitation
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Research is needed to assess the validity of the Clinical Diagnostic Criteria for Temporomandibular Disorders (CDC/TMD). The purpose of this study was to test the reliability of the clinical diagnosis of temporomandibular joint (TMJ) degenerative joint disease (DJD) as compared with the magnetic resonance imaging (MRI) 'gold standard'. The TMJ DJD group comprised 48 joints in 24 consecutive patients who were assigned a clinical bilateral diagnosis of TMJ DJD. ⋯ Most of the disagreement was due to false-negative interpretations of asymptomatic joints. The results suggest CDC/TMD to be predictive for degenerative joint changes but insufficient for determination of OA. Patients assigned a clinical TMJ-related diagnosis of DJD may need to be supplemented by evidence from MRI to determine the presence or absence of OA.
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Comparative Study Clinical Trial Controlled Clinical Trial
Hormone-dependent fluctuations of pressure pain threshold and tactile threshold of the temporalis and masseter muscle.
In order to better objectify reported pain and disturbed sensation, psychophysical parameters as pressure pain threshold (PPT) and tactile threshold (TT) have been introduced in pain research. The present study evaluated fluctuations of these parameters, obtained using an algometer (PPT) and von Frey hairs (TT), in relation to fluctuations in female reproductive hormones. Ten students not using oral contraceptives and eight students using oral contraceptives participated in the study. ⋯ Scores on the left temporalis muscle appeared significantly higher than that on the right side. In all subjects the PPT tended to be higher on the left side, while in students using oral contraceptives, the PPT values of the temporalis muscle were significantly higher in the menstrual phase, and lower in the follicular phase. A significant correlation between the PPT of the temporalis muscle and the TT of the overlying skin was observed.
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The purpose of this study is to provide basic understanding of how the speed of chewing affects masticatory jaw kinematics. Twenty-six healthy subjects (23.6 +/- 2.5 years of age) chewed a standardized bolus of gum at fast (100 cycles s-1), habitual and slow (50 cycles s-1) rates. The rates were controlled with a metronome and the order of rates was randomized for each subject. ⋯ While the shape of 3-D pathway was similar for the three rates, the perimeter of the pathway was significantly shorter for fast chewing cycles. Maximum AP, vertical, lateral and total 3-D jaw velocities were significantly different among the three rates. Between cycle variation in cycle duration and jaw excursion were least during fast chewing and the greatest during slow chewing; variability in maximum velocity was similar for the three rates.
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It has been suggested that occlusal interference results in masticatory muscle dysfunction. In our previous study, occlusal interference reduced the rat masseter energy level during masticatory movements. The purpose of this study was to investigate the histological alterations of rat masseter muscles following experimental occlusal alteration with unilateral bite-raising. ⋯ Most of the muscle fibres in experimental rats remained intact, although partial histological changes were observed, such as extended connective tissue, appearance of inflammatory cells in the muscle fibres and existence of muscle fibres with central nuclei and central cores. Moreover, the fibre area-fibre frequency histograms of experimental muscle indicated a broad pattern than that of controls. These results indicated that occlusal interference caused histological changes in masseter muscles and that this may be related to the fact that the masseter energy level was reduced during masticatory movements in unilateral bite-raised rats.
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The relationship between nocturnal jaw-muscle activity and temporomandibular disorders (TMD) is still controversial. The aim of this study was to investigate the effect of selective slow wave sleep (SWS = non-rapid-eye-movement (NREM) stage 3 + 4) deprivation on jaw-muscle activity using a new automatic system. Ten healthy men without signs of symptoms of TMD participated. ⋯ The results showed that the time spent in SWS was significantly decreased during the first sleep deprivation night, but there were no significant effects on nocturnal EMG activity (i.e. the numbers of bruxism episodes per hour of sleep, bruxism bursts per episodes bruxism bursts per hour of sleep), MVOF, VAS or PPT. Furthermore, the automatic system only deprived the SWS in five subjects for the following two nights although the sound stimulation was given at the maximum intensity. These results suggest that deprivation of SWS may not interact immediately with nocturnal jaw-muscle activity and jaw-muscle pain.