Development of a new mouth opening force test using an indirect cervical traction device.

BACKGROUND AND AIMS: There have been few reports of objective jaw opening tests, and such studies have involved devices specifically designed for research. In the present study, in order to conveniently and objectively assess mouth opening movements, we replaced the manual resistance used in Daniels and Worthingham's muscle test (DMT) with an indirect cervical traction device. We examined whether the maximum mouth opening force (MOF) could be reliably quantified using this device. METHODS: The subjects were 12 healthy individuals with a mean age of 28.8 years. The MOF measurement procedure was as follows: 1) the subject sat in the chair, and a head belt was placed under the chin so that a traction force was applied almost parallel to the body axis; 2) the researcher instructed the subject to maintain the maximum mouth opening; 3) as maximum resistance was approached, the rate of increase in the traction force decreased. Maximum opening force was recorded; 4) one measurement was taken per session, for a total of two measurements per subject. Pearson's correlation coefficients were used to assess the reproducibility of MOF values. RESULTS: The average MOF (mean +/- SD) in the first and second tests was 24.2 +/- 1.9 and 24.5 +/- 2.0 kg. There was an extremely high correlation between first and second measurements (r = 0.969). CONCLUSIONS: The presently described indirect cervical traction device can be used to reliably quantify MOF.

Swallowing appliance: intraoral reshaping prosthesis for dysphagia secondary to oral floor cancer: a pilot study.

Patients with oral floor cancer often have difficulty swallowing solid foods. The aim of this study was to improve the propulsion of solid foods using a swallowing appliance (SW-A). Subjects comprised three patients with oral floor cancer who had undergone curative surgery. Each participant was asked to swallow gelatin under three conditions: without an SW-A, with a maxillary SW-A, and with both maxillary and mandibular SW-As. This procedure was repeated thrice with three volumes of gelatin (2.5, 5, and 7.5 ml), with videofluorographic swallowing study. Swallowing was assessed on the basis of whether the participant could propel the gelatin from the oral cavity to the pharynx. No subject could propel 2.5 ml of gelatin to the pharynx without an SW-A or with only a maxillary SW-A in place. When both SW-As were used, all subjects could propel all three volumes of gelatin. The mandibular SW-A complemented the compensatory effects of the maxillary SW-A.