A irradiação com o laser de Er,Cr:YSGG promove aumento da área de superfície do esmalte dental irradiado, o que pode resultar em uma maior retenção e um efeito prolongado do fluoreto (F-) presente em produtos fluoretados de diferentes concentrações. O produto formado na superfície de esmalte originado de uma única aplicação de flúor fosfato acidulado (FFA 12.300 μg F-/g) ou da frequente aplicação tópica de dentifrício contendo 1.100 μg F-/g poderia ter seu efeito cariostático prolongado, pelo aumento de sua retenção na superfície do esmalte dental irradiado. Uma vez que o esmalte dentário livre de biofilme não sofre desmineralização na cavidade bucal, sugerimos um estudo in situ onde se possa avaliar o prolongamento do efeito do destas associações, também na presença de placa. As condições de irradiação do estudo in situ, foram determinadas, in vitro, com laser Er,Cr:YSGG no esmalte de maneira isolada ou combinada com as aplicações tópicas de: 1- dentifrício de concentração 1.100 μg F-/g ou 2- FFA, para posteriores análises da formação e retenção de CaF2. Foram realizadas análises morfológicas por microscopia eletrônica de varredura, determinação da concentração do flúor solúvel em álcali por meio do eletrodo íon específico e análise da microdureza em corte longitudinal. Os resultados por microscopia eletrônica de varredura verificaram qualitativamente a formação de produtos na superfície de esmalte na forma de CaF2. A análise bioquímica para determinação quantitativa do F- solúvel em álcali determinou como sendo estatisticamente diferentes (p≤0,05) os Grupos nos quais o laser foi utilizado previamente à aplicação tópica dos dois tipos de produtos fluoretados de diferentes concentrações (dentifrício e FFA), in vitro. Em seguida, foi realizado o estudo in situ quando voluntários utilizaram dispositivos palatinos, contendo blocos de esmalte humano, previamente tratados, com o objetivo de acúmulo da placa nativa sobre os mesmos. Durante a fase in situ, os voluntários permaneceram utilizando dentifrício F- para verificação da ação do mesmo na presença de biofilme sobre os blocos irradiados. Foram correlacionados os efeitos da formação de F-, decorrentes dos tratamentos propostos, na redução da desmineralização. A análise bioquímica para quantificação do F- solúvel em álcali determinou como sendo estatisticamente diferentes (p0,05) os Grupos nos quais o laser foi utilizado após a aplicação tópica dos dois tipos de produtos fluoretados de diferentes concentrações (dentifrício e FFA), in situ, sugerindo um efeito prolongado da sinergia dos tratamentos na diminuição da desmineralização. / The effect of the Er, Cr: YSGG laser promotes increased surface enamel area, which can result in increased retention and prolonged effects of Fluoride (F-) present in products with different concentrations of fluoride. The cariostatic effect from product formed in the enamel surface originated from a single application of acidulated phosphate fluoride (APF 12 300 μg F-/ g), or frequent topical application of dentifrice containing 1,100 μg F-/ g, could be prolonged by increasing its retention on irradiated enamel surface. Once the biofilm-free enamel does not suffer demineralization within the oral cavity, it is proposed an in situ study where we can evaluate the prolongation of the effect of these associations, also in the presence of plaque. The irradiation conditions of the in situ study were determined in vitro with Er, Cr: YSGG laser irradiation of enamel surface either alone or combined with one of the topical applications: 1 - dentifrice F-1,100 μg / g or 2 - APF For further analysis of the formation and retention of CaF2. Morphological analyzes were performed by scanning electron microscopy, determination of the concentration of alkali-soluble fluoride by specific ion electrode analysis and microhardness. The results of scanning electron microscopy verified qualitatively the formation of products in the enamel surface in the form of CaF2. Biochemical analysis for quantitative determination of F-soluble in alkali determined to be statistically different (p≤0.05) Groups in which the laser was used prior to application of topical fluoride products of two types of different concentrations (APF and dentifrice) in vitro. Then, the study was conducted in situ when volunteers wore palatal appliances containing blocks of human enamel, pretreated aiming native plaque formation. During in situ experiment, the volunteers remained using F-dentifrice. Correlations with the effects of F-formation, resulting from treatments proposed in the reduction of demineralization were made. Biochemical analysis for quantitative determination of F- alkali soluble determined to be statistically different (p 0.05). Groups in which the laser was used after topical application of both types of different fluoride concentrations (APF and toothpaste), in situ, suggested an synergic effect, extending treatment efficiency in reducing demineralization.

Includes bibliographical references (leaves 232-247). Obtained information on dental caries and fluorosis among a representative sample of Vietnamese children. Also collected information on factors likely to influence caries experience and dental fluorosis and undertook statistical analyses to examine the relationship between fluoride in drinking water, dental caries and dental fluorosis

Background: The World Health Organization defines probiotics as ‘live microorganisms which, when administered in adequate amounts, confer a health benefit to the host’. Traditionally, probiotic microorganisms have been used to prevent or treat gastrointestinal tract diseases. In the last 15 years, there has been increasing interest of a possible probiotic impact on the oral microbiota and dental caries. Dental caries is a multifactorial disease, and the causative factor in the oral microbiota includes a shift from a balanced microflora to a microflora that includes more aciduric species such as mutans streptococci (MS), non-mutans streptococci, and Actinomyces. MS is considered an opportunistic pathogen although several other bacteria also contribute to the disease. Early acquisition of MS is associated with early development of caries; therefore a desirable complement to other prophylactic measures would be a MS colonization inhibitor. Objective: To better understand how selected strains of probiotic lactobacilli interact with MS in vitro and in vivo and to study the impact of probiotic lactobacilli on caries development during childhood. Material and methods: The in vitro properties of probiotic lactobacilli were studied with regard to (i) acid production from sugars and sugar alcohols, (ii) growth inhibition capacity on clinical isolates and reference strains of MS as well as Candida albicans and (iii) the capacity to co-aggregate with MS. A randomized controlled trial (RCT) tested the short-term effect of intervention with two Lactobacillus reuteri strains on MS, which was evaluated after treatment with chlorhexidine. The re-growth patterns of MS and 19 other selected strains were also evaluated. In the second clinical study  we investigated the long-term effect on MS prevalence and dental caries after an intervention with Lactobacillus paracasei ssp. paracasei F19 (LF19) between 4 and 13 months of age. Results: The results from the in vitro testing showed that strains of probiotic lactobacilli differed in their fermentation patterns, inhibition capacity and their capacity to co-aggregate, which should be kept in mind in the translation to clinical research. The clinical study on short-term effects of two L. reuteri strains on MS and other oral strains showed no effect on re-growth patterns after intervention. The clinical study on long-term effects of LF19 showed no effect on the prevalence of MS. Furthermore, the clinical follow-up at 9 years of age showed no differences in either decayed, missing, and filled surface (dmfs) or DMFS between the probiotic and placebo groups. Evaluation of saliva samples showed no signs of oral colonization with LF19 in the study group. Conclusion: The in vitro testing showed potentials of the selected probiotic Lactobacillus strains for interference with MS and C. albicans. The results from the clinical studies showed no such effect on MS or dental caries. Evidence regarding the effectiveness of specific probiotic applications in the prevention of dental caries is limited and does not allow for conclusions concerning the use of probiotic bacteria as a preventive measure.

published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

published_or_final_version / Paediatric Dentistry / Master / Master of Dental Surgery

published_or_final_version / Paediatric Dentistry / Master / Master of Dental Surgery

OBJECTIVES: The primary objective of this study was to evaluate the efficacy of fluoride varnish in caries prevention and arrest on coronal and root surfaces of teeth over a 24-month period in Chinese Sjögren’s syndrome (SS) patients. Secondary objective was to investigate the effect of fluoride varnish on oral microorganism (Candida and lactobacilli). METHODS: This study was a randomized, double-blind, placebo-controlled clinical trial. A total of 85 SS patients participated in this study. They were randomly assigned to two groups to receive either fluoride varnish or placebo gel quarterly. Dental examination, and assessment of the sicca symptoms, oral hygiene, salivary flow / pH / buffering capacity and oral microbiological profiles were carried out at the baseline, 12-month and 24-month visits. RESULTS: Seventy-eight patients (92%) completed the 24-month trial. At the 24-month visit, no statistically significant differences (Mann-Whitney test, P > 0.05) were found between the fluoride and the placebo groups regarding their mean numbers of coronal surfaces with new enamel caries lesions (fluoride: 1.6; placebo: 1.6), arrested caries lesions (fluoride: 0.6; placebo: 0.7), and also root surface caries lesions (fluoride: 0.3; placebo: 0.1). SS patients who had received application of fluoride varnish were significantly less likely to develop dentin caries in coronal surfaces over the 24-month study period (P = 0.035). The mean numbers of coronal surfaces with new dentin caries lesions found at the 24-month visit in the fluoride and placebo groups were 1.4 and 2.7, respectively (Mann-Whitney test, P > 0.05). The caries prevented fraction of fluoride varnish for coronal dentin caries was 33.3%. No significant differences in the mean counts of Candida and lactobacilli between fluoride and placebo groups were detected (Mann-Whitney test, P > 0.05). Results of the logistic regression analysis showed that SS patients who had high baseline DMFS scores (P = 0.050), harbored more species of Candida in the dental plaque samples (P = 0.019), or had low pH of unstimulated whole saliva (P = 0.005) were significantly more likely to develop dentin caries in coronal surfaces over the 24-month study period. CONCLUSIONS: Fluoride varnish may be efficacious in preventing coronal dentin caries in Chinese patients with SS. However, it may not be efficacious in preventing root caries and has no effect on oral microorganism. / published_or_final_version / Dentistry / Doctoral / Doctor of Philosophy

published_or_final_version / abstract / toc / Dentistry / Doctoral / Doctor of Philosophy

<p>Dental caries is a huge problem among the previously disadvantaged population. Early childhood caries is a problem with infants. This thesis contained information concerning the parents knowledge about their children's oral health and their own personal details. These children were all in the age group 2-5 years. The study findings suggest that parent and parents-to-be, need to be informed on oral health issues concerning their children. This should not solely be the task of dentists but other health care workers as well.</p>

Bibliography: leaves 268-281. / xviii, 281 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--Adelaide University, Dept. of Public Health, 2001