Dental fear and anxiety of preschool children and postoperative instructions of silver diamine fluoride therapy

Abstract

This thesis consists of five studies investigating the management of early childhood caries among kindergarten children at the community level, with a focus on dental fear and anxiety (DFA) and the use of silver diamine fluoride (SDF) therapy. The thesis included two parts. The first part is to estimate the global DFA prevalence among young children through published literature by using systematic review and meta-analysis and analyse the factors influencing DFA prevalence. The results showed that the estimated global prevalence of DFA among 2- to 6-year-old children was 30%. Additionally, children had higher odds of DFA if they had no dental visit experience, or if they had caries experience. This thesis also reported a cross-sectional study on the DFA prevalence among Hong Kong children participating a kindergarten-based service. The study employed self-reported Facial Image Scale to measure DFA. The results showed SDF therapy does not generate DFA in Hong Kong young children because 86% of the children exhibited no DFA during SDF therapy. The second part of the thesis provides evidence-based information for SDF therapy, especially in a school-based oral health promotion project. It consists of three studies. The first study is a 30-month cohort study to examine the caries status of Hong Kong children when they studied in kindergarten. The results showed that the children's caries prevalence was 23% and caries experience was 0.7 when they joined kindergarten. Furthermore, their caries incidence was found to be 34% over the 30 months. Their caries incidence was associated with their baseline caries experience, oral hygiene and their family income. The second study reviewed the current postoperative instructions for SDF therapy. Many literatures suggested refraining from eating, drinking or rinsing for 30 minutes after SDF therapy, but such instruction was not evidence-based. We therefore designed a randomised control trial to investigate the caries-arresting effect of not rinsing for 30 min after SDF therapy for young children. The trial recruited 3- to 4-year-old kindergarten children and randomly allocated them into two groups after SDF therapy. Children in the experimental group were instructed to rinse with water immediately, whereas children in the control group were asked to refrain from rinsing, drinking, or eating for 30 minutes. A calibrated examiner performed the baseline, and the 6-month follow up examinations to determine the lesion activity (active/arrest) of the SDF-treated carious tooth surface. The results showed no significant difference (65% vs 61%) in caries-arrest rate between the two groups. Hence, the trial does not support the postoperative instruction to refrain from rinsing, drinking, or eating for 30 minutes when using SDF to arrest caries in young children.