Background
Temporomandibular disorder (TMD) incidences are believed to be related to parafunctional behaviors like teeth clenching.
Objectives
This pilot study aimed to (i) develop an automated clench-detection algorithm, and (ii) apply the algorithm to test for differences in nocturnal clenching in women with and without TMD.
Methods
Subjects gave informed consent to participate. Adult women were categorized using Diagnostic Criteria for TMD according to presence/absence (+/-) of both TM joint disc placement (DD) and chronic pain (P) into two groups (+DD+P, -DD-P) with 12 subjects each. Surface temporalis electromyography was recorded during oral tasks performed by subjects at two laboratory sessions. The data were used to characterize muscle activity per N of bite-force (μV/N) for each subject, develop the clench-detection algorithm and test its accuracy. Ambulatory surface temporalis electromyography was self-recorded by each subject over three nights and analyzed using the algorithm and bite-force (N) vs muscle activity μV/N calibrations. Bonferroni-adjusted homoscedastic t-tests assessed for significant between-group differences in clenching (p<0.05).
Results
Sensitivity, specificity, and accuracy of algorithm-detected laboratory clenches were all ≥96%. During self-recordings 95% of clenches had durations of <4 seconds and peak forces of <10 N in both groups. Mean clench durations were significantly longer (p=0.042) in +DD+P (1.9±0.8 seconds) than -DD-P subjects (1.4±0.4 seconds). Mean temporalis duty factors (%clench time/total recording time) were significantly larger (p=0.041) in +DD+P (0.47±0.34%) than -DD-P (0.26±0.22%) subjects.
Conclusions
Nocturnal temporalis muscle activities detected by a validated algorithm were longer per clench and recording time in +DD+P compared to -DD-P women.
Chronic degeneration of connective tissue components can be produced by a variety of autoimmune mechanisms. The designations connective tissue disease and collagen-vascular disease are commonly used to describe such conditions when a patient exhibits chronic, immune-mediated deterioration of connective tissue structures in a systemic distribution. Recognized conditions that fit this definition include rheumatoid arthritis, lupus erythematosus, progressive systemic sclerosis, CREST syndrome, and mixed connective tissue disease. Several characteristic oral manifestations of these conditions are recognized. Xerostomia associated with any of these conditions in addition to dryness of the eyes is the definition of secondary Sjögren's syndrome. Fibrosis of facial skin and the resulting limited jaw opening are diagnostic features of progressive systemic sclerosis. Several periodontal manifestations are associated with these connective tissue disorders. Dramatic periodontal ligament space widening that is associated with some cases of progressive systemic sclerosis has been appreciated for more than five decades. However, it has been more recently reported that the majority of progressive systemic sclerosis patients exhibit at least subtle generalized periodontal ligament widening when intraoral radiographs are carefully evaluated. This finding is, however, of limited periodontal significance because the teeth are typically not mobile. Comparisons of periodontitis indices such as pocket depth between healthy subjects and patients with progressive systemic sclerosis do not reveal significant differences (21). In addition, recent evidence suggests a tendency for more severe or progressive manifestations of periodontitis as a consequence of xerostomia that may result from these diseases.
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