METHODS: The questionnaire was translated into Mandarin. Upon enrollment, caregivers completed the Mandarin PEDS and answered four questions about its acceptability and usefulness, and its ease of understanding and completion. The Mandarin PEDS was independently evaluated by a pediatrician and a community nurse, and classified as high risk (≥two predictive concerns), medium risk (one predictive concern), low risk (any non-predictive concerns) or no risk (if no concern) for developmental delays. The caregivers repeated Mandarin PEDS at a 2 week interval for test-retest reliability, while the children underwent testing for accuracy using a developmental assessment test.

MATERIALS AND METHODS: One hundred and twenty primary school children were included. They were divided into caries and caries-free groups. Unstimulated whole saliva was collected from each participant using spitting method. The salivary elements were measured using an Atomic Absorption Spectrophotometer. Descriptive statistics, bivariate and Pearson's correlation analysis were performed.

RESULTS: Salivary Cu and Zn levels were significantly higher in children with dental caries compared to those caries-free (p < 0.05). Moreover, these elements had a positive correlation with dental caries (Cu: r=0.698, p<0.001; Zn: r=0.181, p<0.05). No significant variations in Mn and Fe were observed between caries and caries-free group (p>0.05). Additionally, there were significant differences in salivary Zn and Fe among different age groups (p<0.05) and highly significant differences in salivary Cu, Mn and Fe among different ethnic groups (p<0.001). However, all elements exhibited no significant differences between males and females.