Effect of Gum Chewing on Saliva Volume in the mouth

Objectives: When the salivary flow rate is unstimulated, the volume of saliva in the mouth before (VMAX) and after swallowing (RESID) has been studied (Lagerlof, 1984). Although, the research on the volume of saliva in the mouth during gum chewing has not been carried out. The aim of this study was to investigate the effect of gum chewing on the VMAX and RESID. Methods: The RESID was measured by a dilution method. It was computed by measuring the potassium concentrations in unstimulated saliva and in the expectorated after a five-second rinse with 10 ml of water immediately following a swallow. The volume swallowed was calculated as salivary flow rate divided by the swallowing frequency, and the VMAX was estimated as the sum of RESID and the volume of saliva swallowed. Swallows were registered by placing over the larynx an electrode which was connected to an EMG. The subjects were 3 males and 3 females who were all in good health and in age from 21 to 35 (mean, 29 years). Results: When saliva was stimulated for the gum chewing, there was an increase in VMAX and RESID. The mean value for the RESID was 0.97±0.22 ml and for the VMAX was 1.35 ± 0.17 ml. Swallowing frequency and the volume of fluid swallowed were also increased as comparing with the values when the salivary flow rate was unstimulated. Conclusion: The results confirm the theoretical study of oral sugar clearance (Dawes, 1983), and suggest the effect for the tooth of the gum component. This study was supported by Grant-in-Aid from the Ministry of Education, Science and Culture(15592172)