No Relationship of Salivary Flow Rate or Secretory Immunoglobulin A to Dental Caries in Children

To investigate the relationship between dental caries and the salivary flow rate, secretory immunoglobulin A (sIgA) or other components in children, nonstimulated whole saliva was collected and teeth status was examined in 138 boys and 134 girls aged 11-12 years. The subjects were apparently healthy. The mean salivary flow rate was faster in boys than in girls (0.29 vs 0.18 ml/min, p < 0.001). In both sexes, secretion of salivary sIgA and three other components (total protein, calcium and amylase activity) was markedly dependent on salivary flow rates. These results suggest that basal components of resting saliva are secondarily secreted with the flow of saliva fluid. The mean erupted permanent teeth was 21.0 teeth (range: 10-28 teeth) in boys, and 23.0 teeth (13-28 teeth) in girls (sex-difference: p < 0.001). The means of DMFT, the DMFT ratio (% of DMFT to erupted permanent teeth) and DT+dt (sum of decayed permanent and milk teeth, an index for active caries) were 3.4 DMFT (range: 0-11 DMFT), 16.0% (0-40.0%) and 0.5 DT+dt (0-7 DT + dt) in boys, and 3.8 DMFT (0-12 DMFT), 16.2% (0-44.4%) and 0.8 DT+dt (0-5 DT+dt) in girls, respectively (sex-differences: p>0.05 in all). The salivary flow rate or the four salivary components (either concentration or secretion rate) used here had no relationship to the DMFT ratio or to DT+dt in either sex. Variation in the flow rate or in the basal components of resting saliva may not influence caries development in healthy children.