Early childhood caries (ECC) is the most prevalent oral disease of children worldwide. Epidemiological studies reported that most of the ECC are left untreated. While young children may not be co-operative enough for conventional restorative treatments, silver diamine fluoride (SDF) can be topically applied on tooth surfaces as a cariostatic agent. Previous clinical trials have confirmed that annual application of 38% SDF is effective in arresting dentin caries in preschool children. However, information about the effectiveness of SDF with different combinations of concentration and frequency is still lacking. This information is important for the optimal application of SDF in the future public health programs for caries control. This prospective randomized controlled trial aimed to investigate and compare the effectiveness of 12% and 38% SDF when applied annually or biannually in arresting dentin caries of primary teeth of preschool children for 30 months. The two null hypotheses tested were firstly, there is no difference in effectiveness when SDF is applied at 12% or 38% in arresting dentin caries of preschool children; and secondly, there is no difference in effectiveness when SDF is applied annually or biannually in arresting dentin caries of preschool children. A total of 888 healthy and cooperative K1 children aged 3-4 years with at least one dentin caries surface were recruited and randomized into four treatment groups: Group 1 received annual applications of 12% SDF, Group 2 received biannual applications of 12% SDF, Group 3 received annual applications of 38% SDF, and Group 4 received biannual applications of 38% SDF. Group 3 was assigned as the positive control group. Primary outcome was soft dentin caries surface at baseline that became arrested at the follow-up examinations. Clinical examinations were conducted at the kindergartens every 6 months by the same trained examiner. Parental questionnaires were used to collect the children’s demographic information, oral hygiene related habits, parental satisfaction with children’s dental appearance and dental health at baseline, 18- and 30-month examinations. Adverse effects after treatments including increment of non-vital teeth, complaint about tooth or gingival discomfort, gingival discoloration, and black staining over arrested surfaces were also recorded. A total of 798 children with 3,268 caries surfaces were examined at 30-month follow-up. The dropout rates of the four groups were similar. The respective proportions of arrested surfaces in Group 1 to Group 4 were 48.7%, 54.0%, 60.6%, and 66.9%, respectively (p < 0.001). The two null hypotheses were rejected. Both concentration and frequency were significantly related to treatment effectiveness, but no significant interaction between these two factors was found. The effect size of concentration was much greater than frequency. Other than a higher proportion of black staining in groups receiving 38% SDF treatments, there were no significant differences in adverse effects among the children in the four treatment groups. To conclude, SDF is more effective in arresting dentin caries in primary teeth of preschool children at 38% than 12%, and when applied biannually than annually. Clinical significant improvement in effectiveness can be achieved by increasing its concentration. / published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

The use of fluoride involves a balance between the protective effect against caries and the risk of having fluorosis. Fluorosis in Australian children was highly prevalent in the early 1990s. Policy initiatives were introduced to control fluoride exposure so as to reduce the prevalence of fluorosis. Objective: The study aimed of describing the prevalence, severity and risk factors for fluorosis, and to escribe the trend of fluorosis among South Australian children. The study also aimed of exploring the effect of the change in fluoride exposure on dental fluorosis and caries. Methods This research project was nested in a larger population-based study, the Child Oral Health Study (COHS) in Australia 2002-2005. The parent study's sample was chosen using a multistage, stratified random selection with probability of selection proportional to population size. Fluoride exposure history was retrospectively collected by a parental questionnaire. This nested study sample (n=1401) was selected from the pool of South Australian (SA) COHS participants. Children were selected by year of birth to form three birth cohorts: those born in 1989/90; 1991/92; and 1993/94. Children were approached in two further stages: a dental health perception questionnaire, and a clinical examination for fluorosis. Some 898 children took part in the first stage. Among those, one trained dentist examined 677 children for fluorosis under clinic conditions using two indices (the Fluorosis Risk Index (Pendrys, 1990) and the TF Index (Thylstrup and Fejerskov, 1978)). The Dental Aesthetic Index score (DAI) was also recorded. Caries experience extracted from dental records of all previous visits to school dental linics was used to enable calculation of dmfs/DMFS scores at different anchor ages. Data were re-weighted age and sex to represent the South Australian child population. Per cent lifetime exposure to fluoride in water and patterns of discretionary fluoride use were calculated. Fluorosis data were used to calculate the prevalence and severity of fluorosis. Caries dmfs/DMFS scores were calculated at different anchor ages to enable comparison between birth cohorts. Results A higher proportion of children in the later birth cohorts used low concentration fluoride toothpaste, and a smaller amount of toothpaste was used when they commenced toothbrushing. There was a significant decline in the prevalence of fluorosis across the three successive birth cohorts. Risk factors for fluorosis, defined by the two indices, were use of standard fluoride toothpaste, an eating and/or licking toothpaste habit, and exposure to fluoridated water. Means (SD) of the deciduous caries dmfs scores at age six and eight were 1.45 (3.11) and 2.46 (3.93) respectively. Evaluation of the "trade-off" between fluorosis and caries with fluoride exposure indicated that the use of low concentration fluoride toothpaste and preventing an eating/licking of toothpaste habit could reduce the prevalence of fluorosis without a significant increase in caries experience. Conclusion There was a marked decline in the prevalence of fluorosis across the three successive birth cohorts. The decline was linked with the reduction in exposure to fluoride. Exposure to fluoridated water and several components of toothpaste use were risk factors for fluorosis. Establishing an appropriate use of fluoride toothpaste could be successful in reducing fluorosis without a significant increase in caries experience. / Thesis (Ph.D.)--Dental School, 2004.

Thesis (D.P.H.)--University of Michigan.

Thesis (M.S.P.H.)--University of Michigan, 1942.

Thesis (M.S.P.H.)--University of Michigan, 1942.

Thesis (D.P.H.)--University of Michigan.

Thesis (M.S.P.H.)--University of Michigan, 1942.

Thesis (M.S.P.H.)--University of Michigan, 1942.

Thesis--University of Turku, 1987. / "Also published in: Proceedings of the Finnish Dental Society, 1988, Vol. 84, Suppl. II"--T.p. verso. At head of title: From the Department of Cariology, Institute of Dentistry, University of Turku, Turku, Finland, and the Department of Conservative Dentistry, Semmelweis Medical University, Budapest, Hungary. Includes bibliographical references (p. 62-72).

Thesis (M.D.S.)--University of Hong Kong, 2002. / Also available in print.