Methods: The guardians of 15 preschool children, gave informed consent to participate in this study. Three-year follow-up data from 3 yrs in 2010 to 5 yrs in 2012 were recorded to obtain the outcome that was caries increment (Δdmft) during years by the change of dmft.
Whole unstimulated saliva samples were collected into pre-weighed tubes for 5 minutes. SFR were calculated (ml/min) after re-weighed. The pH levels and buffer capacities were determined using a pH meter and MS levels were determined with MUCOUNT® (ShowaYakuhinKako, Tokyo). Na+, K+, NH4+, Ca2+, Mg2+, F-, Cl-, NO3-, SO42-, PO43-concentrations were measured by ion chromatography.
Wilcoxon signed-ranks test with Bonferroni correction were used among the data of different age groups.
Results: The mean dmft for children of 3, 4 and 5 yrs were 0.53(SD1.19), 1.73(SD2.34) and 2.80(SD2.73), indicating that Δdmft(4-3yrs), (5-4yrs) and (5-3yrs) were 1.20, 1.07 and 2.27, respectively. Significant differences were found in dmft (p<0.05: 4yrs≠5yrs, 3yrs≠5yrs) and in Δdmft (4-3yrs)≠(5-3yrs) (p<0.05).
SFR(ml/min) of 3, 4 and 5 yrs were 0.31(SD0.20), 0.54(SD0.30) and 0.93 (SD0.42), respectively (p<0.05: 3yrs≠4yrs, 4yrs≠5yrs, p<0.01: 3yrs≠5yrs),in pH as well, 7.97(SD0.41), 7.49(SD0.24) and 7.54(SD0.21),(p<0.01: 3yrs≠4yrs, 3yrs≠5yrs). Statistical differences were found in Na+ between 3 yrs (182.95ppm, SD158.84) and 4 yrs (77.16ppm, SD21.58);(p<0.05), in SO42-among age (3 yrs: 23.28ppm, SD12.76), (4 yrs: 22.32ppm, SD11.93),(5 yrs:10.67ppm, SD7.05);(p<0.05: 3yrs≠5yrs, 4yrs≠5yrs).
Conclusion: Dental caries and SFR showed increase with age in preschool children.