Outcomes of Restoring Untreated and SDF-treated Dentine Caries Lesions in Primary Teeth of Preschool Children

The study population of this proposed study is Hong Kong preschool children. Children attending grade 1 or 2 in nine selected kindergartens were invited to join this study. An invitation letter with information on the purpose and procedures of the study was sent to the parents of the children through the kindergarten. The parents were asked to give written consent for allowing their child to receive a free oral examination and ART restorations, if indicated for treating the decayed primary teeth in their child's mouth, provided by dentists in the kindergarten. Parental consent were obtained before inclusion of a child in this study. Cavitated caries lesions in the primary teeth of the study children were restored following the ART procedures (Holmgren et al., 2013). The instruments used were LED illuminated dental mirror, sickle probe, tweezers, hatchet, excavators and flat plastic. The dental restorative material used was a high-strength chemical-cured glass ionomer (Ketac-molar, 3M ESPE, Germany). At the baseline, all children with parental consent were clinically examined in the kindergarten. Disposable dental mirror attached to a handle with an intra-oral LED light and a ball-ended probe was used. The status of each tooth was recorded. Children who had at least one decayed primary tooth with a cavity into dentine were included into the study. All decayed teeth in the children were restored, except those with inadequate access and those with signs of pulpal pathology. The decayed teeth in half of the children received topical application of a SDF solution (Saforide, Toyo Chemical, Japan), through simple random allocation on a child basis using random numbers, around 10 weeks before receiving the restoration. The time used for placement of each restoration was recorded to the nearest minute. The children were examined at 6 and will be examined at 12, 18 and 24 months after placement of ART restorations by calibrated examiners who were not involved in the placement of the restorations. The same instruments used in the baseline examination were used in the follow-up examinations. The status of the restorations and restored teeth were assessed and recorded using codes and criteria commonly adopted in previous clinical studies of ART restorations (Lo et al., 2007). At baseline, information on the children's oral hygiene practice, snacking habit, oral health related quality of life, and parental satisfaction with the appearance of their child's teeth was collected by a self-completed questionnaire. A validated tool for measuring oral health related quality of life of preschool children in Hong Kong, Chinese version of Early Childhood Oral Health Impact Scale (ECOHIS), was used (Lee et al., 2009). The same measurement tool was used at the 6-month and will be used at 24-month follow-up.