Stimulated parotid salivary flow rate in patients with Down syndrome

Saliva is essential for oral defense against infections. Decreased salivary secretion may result in increased dental caries, oral mucosal changes, an altered sense of taste, difficulty in swallowing, and oral pain. A review of the literature reveals sporadic and contradictory reports on the use of sialometry and sialochemistry to explain the role of saliva in the oral health and well-being of subjects with Down syndrome. The present study documents parotid gland saliva secretion at different ages in a group of subjects with Down syndrome. Saliva was collected from 39 patients 11 to 62 years old, by means of a parotid salivary gland cup and under standardized conditions of stimulated secretion. The rate of salivary secretion in the entire group of patients with Down syndrome was lower than that of healthy controls and lower in the older study group compared with the younger group. Institutionalized subjects or those living in hostel-like apartments had a lower secretion rate than those living at home. No difference in salivary flow was found between those patients with Down syndrome with normal thyroid output and those with hypothyroidism who were receiving replacement therapy. In a four-way ANOVA with flow as the dependent variable and Down syndrome, hypothyroidism, institutionalization, and age as factors, Down syndrome was found to be the only variable significantly related to flow (p = 0.017). Our findings indicate that stimulated parotid salivary hypofunction in Down syndrome subjects is mainly related to their genetic disorder.