• Fluoride;
  • mouth rinse;
  • pre-school children;
  • Japan

Aim: To determine whether Japanese preschool-aged children swallow fluoride solution while rinsing and how much fluoride was retained in the mouth after rinsing. Methods: The subjects were 769 children who participated in a school-based fluoride mouth rinse programme (FMR) using 0.05% sodium fluoride solution daily. The group of younger, mean age of 4 years and 10 months, experienced the FMR for two months, and the group of older children, mean age of 5 years and 4 months, did it for at least 8 months, rinsing for a minute using 7ml of the solution. The amount of fluoride retained in the mouth was estimated as the amount present in the net rinsing solution prepared minus what returned to the solution expectorated. Results: No child swallowed all the solution. The rate of fluoride retained was 12.0% (mean = 0.19mg) in the younger group and 10.7% (mean = 0.17mg) in the older. Only six children retained over 0.5mg of fluoride. With the extra survey using weekly intervals, the amount retained was below 0.5mg in all children. Conclusion: That Japanese preschool-aged children could perform fluoride mouth rinsing safely and efficiently.