[Effects of wearing complete dentures on swallowing in the elderly]

The purpose of this study was to evaluate effects of wearing complete dentures on swallowing in the elderly. Sixteen nondysphagic edentulous volunteers (mean age: 75.0 yrs) were studied in terms of surface electromyography of the anterior belly of digastrics and masseter muscles, tongue pressure toward the hard palate, and the laryngeal movement. The subjects swallowed 2 ml water under four conditions, with upper and lower dentures, without lower denture, without upper denture, and without upper and lower dentures. Dipper-type of swallowing was prescribed. A repeated-measures ANOVA was used for statistical analysis. Total swallowing duration and the latent period until laryngeal elevation were significantly prolonged without upper or lower denture, and without both dentures (p < 0.05). They were significantly shorter without lower denture than those without upper denture, and without both dentures (p < 0.05). Duration of the preparatory stage was significantly prolonged without upper denture, and without both dentures comparing with the others (p < 0.05). Duration of the oral stage was significantly prolonged without upper denture, and without both dentures comparing with the duration with both dentures (p < 0.05). There were no changes in the pharyngeal stage with or without dentures. The prolongation of total swallowing duration was due to the prolongation of the preparatory and oral stages. The prolongation of swallowing would affect the oral-pharyngeal coordination of swallowing, and exacerbate the depression of swallowing functions with aging. These results suggested that wearing complete dentures contributes to maintain physiological procedure of swallowing in the elderly.