Unstimulated salivary flow rates of young children

Objective Studies on salivary flow rates in human beings have mainly been c arried out with adults. The purpose of this study was to determine the unst imulated salivary flow rates of children 4 to 7 years old. In addition, the relative contributions of the variables age, gender, race, height, body we ight, dentition status, use of prescription medication, and health status ( information obtained from parents) to the unstimulated salivary flow rates of children were also studied. Study design. Data were obtained from children (n = 447) at 2 sites in the United States (site 1, southeast Michigan; site 2, northern Michigan) and a t 5 sites in Brazil (site 3, Porto Alegre; site 4, Sao Paulo; site 5, Belem ; and sites 6 and 7, sites in Rio de Janeiro). In northern Michigan (site 2 ) the participants were cognitively or developmentally disabled, or both. I n Rio de janeiro (site 7), a group of 8- to 12-year-olds served as a contro l group. Saliva samples were collected for 3 minutes between 9 AM and noon in the spring or summer, and the saliva rate was determined gravimetrically . Data were analyzed by analysis of variance, bivariate analysis, and regre ssion analysis. Results. The secretion rates at the 7 sites were (in milliliters per minute ) 0.19 +/- 0.15, 0.23 +/- 0.28, 0.34 +/- 0.23, 0.48 +/- 0.37, 0.25 +/- 0.27 , 0.37 +/- 0.28, and 0.61 +/- 0.34, respectively There were significant dif ferences among sites (P < .0001). The older group (site 7) had flow rates t hat were significantly higher than the flow rates of any other group. In ad dition, children from Michigan (sites 1 and 2) had significantly lower rate s than most groups of children in Brazil. Girls had lower unstimulated sali vary flow rates than buys did at all the sites, but the differences were no t statistically significant. Race was shown not to affect the flow rates. T he use of any prescription medication by children in the previous 3 months was associated with lower salivary flow rates than were found in children n ot using prescription medication. Children who were in good health and who had no previous medical conditions had higher flow rates-but not significan tly so. Higher flow rates occurred in children with mixed dentition than in children with primary dentition, although again the differences were not s tatistically significant. Regression analysis revealed weight to be of sign ificance in explaining the variability of the unstimulated salivary flow ra tes at 2 sites, height at 1 site, the use of prescription medication at 2 s ites, and age at 1 site. Conclusions, The unstimulated salivary flow rates in children in the northe rn United States are comparable with those reported for Japanese children, whereas the flow rates of children in Brazil are comparable with those repo rted for North American and European adults. In addition, none of the demog raphic variables/parameters tested contributed consistently to tile variabi lity of the unstimulated salivary flow rates in children at the 7 sites ass essed in this study.