Swallowing threshold parameters of subjects with shortened dental arches

摘要

Objectives: To quantify swallowing threshold parameters of subjects with a moderate shortened dental arch dentition (SDA: missing molar teeth, but premolar teeth in occluding position and uninterrupted anterior regions) compared to subjects with a complete dental arch dentition (CDA). Methods: Fourteen females with SDA (3-4 occlusal premolar units) and 14 females with CDA were instructed to chew silicone test 'food' (cubic particles with a total volume of 3 cm 3). They spit it out the moment they felt the urge to swallow and the pulverized particles were collected. Swallowing threshold parameters were number of chewing cycles, time until 'swallowing', and median particle size of the pulverized particles as determined by sieving the food. Chewing tests were performed twice and outcomes were averaged. Results: The number of chewing cycles until 'swallowing' of subjects with SDA was approximately 1.7 times (p 0.005) that of the controls and this took approximately 1.6 times more time (p 0.01). The median particle size until 'swallowing' did not differ significantly between the groups, but demonstrated large individual differences. Regression analyses indicated that the ratio of median particle size until 'swallowing' of SDA and CDA becomes progressively unfavourable for SDA with increasing numbers of chewing cycles. Conclusions: Subjects with SDA pulverized test 'food' particles to sizes comparable to subjects with CDA, but chewed longer with more chewing cycles until 'swallowing'. Higher numbers of chewing cycles were associated with increasing difference between SDA and CDA regarding the median particle size until 'swallowing'. Clinical significance: Compared to subjects with CDA, subjects with moderate SDA pulverize test food particles to comparable size by chewing longer before "swallowing". Therefore, overloading the digestive system by swallowing courser food particles is unlikely in SDA. Consequently, replacement of absent molars just to optimize chewing function is not advised.