ABSTRACT
The present study compared the duration of the electromyographic silent period (SP) of the masseter muscles elicited by chin-tapping in normal asymptomatic adults (N=39) and in a group with sympstoms of temporomandibular joint dysfunction (TMJD)(N=3).EMG activity was recorded from right (RM) and left (LM) masseter muscles using bipolar surface electrodes coupled to a DISA 1500 EMG-system.During maximal clenching, ten taps were applied downwards to the chin with a reflex hammer. The mean SP durations obtained for the normal group were 25.45ñ4.20 ms (RM) and 25.33ñ4.18ms (LM), whereas the TMJD group presented significantly greater values (P<0.01,Student t-test) of 41.89ñ12.94ms (RM) and 42.40ñ12.99ms (LM).The upper limits of normality calculated for RM and LM were 32.36 ms and 31.21 ms, respectively. Eighty-four percent of patients with TMJD showed SP durations above these limits. The results indicate that the measurement of masseteric SP duration may be used as an objective diagnostic method of TMJ disorders, provided that borderline values are interpreted with caution along with clinical impressions
Subject(s)
Adolescent , Adult , Middle Aged , Humans , Male , Female , Masseter Muscle/physiopathology , Temporomandibular Joint Dysfunction Syndrome/physiopathology , Bite Force , Electromyography , Masticatory Muscles/physiopathology , Pain/physiopathology , Reaction Time , Temporomandibular Joint Dysfunction Syndrome/diagnosisABSTRACT
1. In the present study we measured intraoral air pressure (Po) during the production of the stop consonant/p/, in a syllabic contes, in normal and surgically repaired cleft palate subjects. po was measured by placing a sensing catheter between the lips in the oral cavity. The catheter was connected to a pressure transducer and the output signals were amplified and transmitted to a recorder. 2. When compared to normal individuals, cleft patients with velopharyngeal insufficiency (VPI) and oral articulation for/p/presented significantly lower Po levels (P<0.01) but pressure curves of normal shape. 3. In cleft palate patients with VPI and glottal coarticulation for/p/, Po was absent or markedly reduced; in the latter case, the Po curve was of a characteristically irregular shape. 4. These results suggest thata measurement of Po during the production of a selected consonant appears to be a suitable instrumental method for identifying VPI and discrininating an oral stop from the compensatory glottal stop often observed in postoperative cleft palate speakers