Search

Summary Objective A gender difference in the unstimulated whole saliva flow rate (UWSFR) may be due to a difference in the sizes of the salivary glands. In this study, we investigated the relationships among the UWSFR, gland sizes and body sizes of healthy young adult males and females. Design Unstimulated whole saliva was collected for 5 min by the spitting method in 50 healthy young adults, and the flow rate of the saliva was measured. Heights and weights were measured, and body mass indices (BMI) were calculated. The sizes of the salivary glands were measured by use of a magnetic resonance imaging technique. Results Parotid and submandibular gland sizes and flow rates in females were significantly smaller than those in males, as were also the weights, heights and BMI. In both males and females, there were significant positive correlations between gland sizes and the flow rates, weights and BMI. The variations of the flow rates were reduced by standardizing them with gland sizes, weights and BMI. Conclusions These results suggest that the lower UWSFR in females as compared with males is due to the smaller gland sizes due to the smaller body sizes.

Summary Objective The aim of this study was to examine the relationships between gland sizes and the flow rate and composition of the unstimulated whole saliva in humans. Design In 28 healthy young adults, the sizes of the three major salivary glands were estimated by use of a magnetic resonance (MR) imaging technique. Unstimulated whole saliva was collected for 5 min by the spitting method, and the flow rate and the concentrations of total protein, Na + and K + and pH were measured. Results The estimated sizes of the parotid and submandibular glands showed a significant positive correlation with the flow rate and the secretion rate of total protein in the unstimulated whole saliva, but that of the sublingual glands did not. Concerning the concentrations of Na + and K + and pH, there were no correlations with the salivary gland sizes. Conclusions The results suggest that the larger the sizes of the parotid and submandibular glands, the faster the fluid flow and protein secretion rates in unstimulated whole saliva.

Objective We have recently reported that flow rates of whole saliva in young healthy humans correlate positively with salivary gland sizes. The low rate of salivary secretion in xerostomia patients may be related to the small size of the salivary glands. To investigate this possibility, relationships between salivary secretions and salivary gland sizes were investigated in unknown-etiology xerostomia patients and healthy controls. Design The sizes of the three major salivary glands in seven xerostomia patients and seven age- and gender-matched healthy controls who have no previous disease history and prescription medication related to xerostomia, were measured by use of a magnetic resonance imaging technique. The salivary glands of all subjects failed to show any pathological aspects in magnetic resonance images. The flow rates of unstimulated and chewing-stimulated whole saliva were also measured. Results Flow rates of unstimulated and chewing-stimulated whole saliva and the sizes of the parotid and submandibular glands were significantly lower and smaller in xerostomia patients of unknown etiology when compared with healthy controls. In addition, salivary flow rates per size of the combined three major salivary glands were also significantly lower in the xerostomia patients of unknown etiology. Conclusions The smaller salivary gland size in xerostomia patients of unknown etiology may be one of the causes of the reduced salivary secretion. The secretion rates as a function of gland sizes were also lower, and so it is likely that functional impairments of the salivary gland are also present in patients with xerostomia of unknown etiology.

Objective We have recently reported that unstimulated whole saliva flow rates (UWSFR) correlate positively with salivary gland sizes and body profiles of weight and body mass indices. In the present study, the correlations of chewing-stimulated whole saliva flow rates (CWSFR) with salivary gland sizes and the body profiles were investigated, and the results were compared with those of UWSFR. Design Saliva samples were collected from 24 healthy young males and 26 females by the spitting method while chewing paraffin and the CWSFRs were measured. UWSFR and the estimated sizes of the three major salivary glands in our previous study were used. Results The CWSFRs in all subjects and in males correlated positively with UWSFR, but not in females. The CWSFRs in all subjects correlated positively with parotid and/or submandibular gland sizes, weights and body mass indices, just as with UWSFR; however, the correlation coefficients with salivary gland sizes were smaller than those of UWSFR. In contrast to the results of UWSFR, the correlation coefficients of the CWSFRs with parotid gland sizes in all subjects were larger than those with the sizes of the submandibular glands. The CWSFRs in males correlated only with parotid gland sizes, and those in females did not correlate with any of the parameters. Conclusions The results suggest that the larger the size of the salivary glands, the greater the CWSFR, at least in males.