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published_or_final_version / Dentistry / Master / Master of Dental Surgery

Este estudo objetivou estabelecer condições de irradiação com o laser de Er,Cr:YSGG (de comprimento de onda de 2.79 µm) que propiciassem modificações no esmalte dental e aumentassem sua resistência à desmineralização, associadas ou não à aplicação tópica de flúor fosfato acidulado (FFA). Fluências laser de 2,8 J/cm², 5,6 J/cm² e 8,5 J/cm² foram selecionadas, as quais foram associadas com a aplicação prévia de substância fotoabsorvedora (pasta de pó de carvão) e então com aplicação de FFA posteriormente às irradiações. Inicialmente, foram avaliadas as alterações morfológicas, as modificações na temperatura superficial e os aumentos na temperatura intrapulpar decorrentes das irradiações. Posteriormente, as amostras tratadas foram submetidas a uma ciclagem de pH com duração de 10 dias. Após a produção das lesões de mancha-branca, foi avaliada a perda mineral e as quantidades de flúor fracamente ligado e fortemente ligado. Todas as soluções desmineralizantes e remineralizantes foram avaliadas com relação ao seu conteúdo de cálcio, fósforo inorgânico e flúor. Os dados foram avaliados quanto à normalidade e homogeneidade de sua distribuição para que pudesse ser escolhido o teste estatístico mais adequado, considerando o nível de significância de 5%. As fluências selecionadas promoveram superfícies ablacionadas; as fluências de 5,6 J/cm² e 8,5 J/cm² promoveram aumentos de temperatura superficial superiores a 110º C. A análise da temperatura intrapulpar revelou que as fluências escolhidas não aumentaram as temperaturas pulpares acima do limite estabelecido para pulpite. A pasta de pó de carvão não promoveu modificações morfológicas ou alterações significativas nas temperaturas pulpares; entretanto, aumentou as temperaturas superficiais durante as irradiações. Apenas a irradiação laser sob fluência de 8,5 J/cm² diminuiu significativamente a perda mineral quando comparado ao grupo sem tratamento; embora a associação da pasta de carvão + irradiação laser a 2,8 J/cm² + aplicação de FFA tenha apresentado o menor valor de perda mineral de todos os grupos de tratamento deste estudo, tal valor não diferiu estatisticamente daquele obtido quando apenas o FFA foi aplicado (grupo controle positivo). A análise de flúor fracamente ligado revelou que a irradiação laser proporcionou maior formação e retenção do fluoreto de cálcio formado após aplicação de FFA, provavelmente devido à ablação do esmalte, enquanto que a análise de flúor total mostrou não haver diferenças na quantidade de fluorapatita formada após a irradiação laser quando comparado às amostras não-irradiadas. A avaliação das soluções desmineralizantes e remineralizantes evidenciou não haver diferenças significativas nas concentrações de cálcio e fósforo inorgânico entre as amostras irradiadas ou não irradiadas; contudo, a determinação de flúor nestas soluções mostrou diferenças expressivas no conteúdo de flúor, sugerindo que a irradiação laser pode favorecer a uma maior formação de fluoreto de cálcio. De acordo com os resultados deste estudo, pode-se concluir que a irradiação laser proporciona maior retenção de fluoreto fracamente ligado formado no esmalte decorrente da aplicação tópica de flúor; entretanto, a associação dos tratamentos não proporcionou maior efeito na redução da desmineralização do esmalte do que o efeito da aplicação tópica de FFA isoladamente. / This study aimed to stablish irradiation conditions of Er,Cr:YSGG laser (wavelength of 2.79 µm) which could propitiate changes on human dental enamel and increase its resistance to demineralization, when associated or not with topical application of acidulated phosphate fluoride (APF). Fluences of 2,8 J/cm&sup2, 5,6 J/cm&sup2 e 8,5 J/cm&sup2 were selected; they were associated or not with previous application of a photoabsorber (coal paste) and then APF was applied or not after laser irradiation. In a first step, the morphological findings, the surface temperatures, and the pulpal temperatures were evaluated during laser irradiation. After that, the treated samples were submitted to a a ten-day pH-cycling model. After producing the incipient white-spots lesions, the following aspects were evaluated: the mineral loss, the loosely bound fluoride and the firmly bound fluoride. All the demineralizing and remineralizing pH-cycling solutions were evaluated with respect to their calcium (Ca), inorganic phosphorous (Pi) and fluoride (F-) concentrations. The data had their normality and homogeneity distribution statistically evaluated, and it was chosen an appropriated statistical test for each performed analysis according to the obtained results, considering 5% significant level. The fluences selected for this study created ablated surfaces; the fluences of 5.6 J/cm&sup2 and 8.5 J/cm&sup2 promoted increments in surface temperature above 110º C. The intrapulpal temperature changes revealed that laser irradiation did not increase the pulpal temperatures above the critical threshold for induction of pulpitis. The coal paste did not promote any changes on surface morphology or in the intrapulpal temperature changes; however, this paste increased the surface temperatures during laser irradiation. Only laser irradiation at 8.5 J/cm&sup2 was able to decrease the mineral loss when compared to the no-treatment group; although the association of coal paste + laser at 2.8 J/cm&sup2 + APF application presented the lesser mineral loss of all treatment groups of this study, this value was not statistically different than those revealed in the FFA group (positive control). The analysis of loosely bound fluoride revealed that laser irradiation was able to retain the calcium fluoride formed after APF application due to the ablation process, while the analysis of firmly bound fluoride showed no differences in fluorapatite quantities formed after laser irradiation when compared to the non-irradiated samples. The evaluation of demineralizing and remineralizing pH-cycling solutions evidenced no significant differences in calcium or inorganic phosphorous concentrations between lased or unlased samples; however, the fluoride determination exposed important differences on fluoride contents, which suggested that laser irradiation could induce a higher calcium fluoride formation. According to the results of this study, it was possible to conclude that the laser irradiation can propitiate, on enamel, higher loosely bound fluoride retention formed by topical application of fluoride; however, the association of treatments did not increased the effect obtained by APF application alone on enamel demineralization.

Digitized by Kansas Correctional Industries

Caries of the pits and fissures of permanent teeth continues to be a problem for children. Newly erupted permanent molars are particularly at risk. Oral hygiene measures have been shown to be able to reduce the incidence of caries. The aim of this study was to compare the caries preventive effects of a professional tooth cleaning and oral health education programme (test) with a standard preventive programme (comparison), comprising selective fissure sealing and application of topical fluorides on newly erupted first permanent molars. School Dental Service clinics of the Health Department of Western Australia, in Perth, were assigned to test (4)or comparison (4) clinics. Schoolchildren, mean age 6.3 plus or minus 0.3 (s) yr with, sound, newly erupted first permanent molars were included in the study (n=404; 207 test; 197 control).Children were examined after twelve and twenty-four months by an examiner who was 'blind' to the test or control status of the children. After twelve months, 186 test and 163 control children were examined, and after twenty-four months, 179 test and 156 control children were examined. Three hundred and twenty children were examined in both years. After twenty-four months, 32 children in test and 31 children in control developed caries of the first permanent molars, the estimated risk ratio was 0.90 (95% CI 0.58, 1.41); and children in the test group had an average DFT score of 0.30 plus or minus 0.75 compared with 0.30 plus or minus 0.70 DFT in the control group (t-test, p=0.96). The results suggest that, after two years, there was no statistically significant difference between the caries preventive effects of a professional tooth cleaning and oral health education programme and a programme based on selective fissure sealing and application of topical fluorides.Baseline deciduous caries experience, presence of hypomineralised first ++ / permanent molars and frequency of toothbrushing were statistically significant factors in predicting molar caries. Using baseline deciduous caries experience as a screening criterion to predict permanent molar caries, sensitivity of 0.67 and specificity 0.61 were obtained at a cutpoint of 1 dmfs. Sensitivity and specificity values were maximised at 0.72 by using a combined baseline dmfs and hypomineralisation as screening criteria. Cost-effectiveness analysis indicated an incremental cost-effectiveness ratio of $40/child/year. The test programme was more costly and produced similar outcomes and does not warrant adoption on economic grounds.

The aim of the present thesis was to find a test for prediction of caries activity which would be useful in routine clinical work.Correlations between oral health, general health, food habits and socioeconomic conditions were investigated in 4- and 8-year-old children. It was found that the salivary secretion rate and the prevalence of oral lactobacilli were factors which might be useful in caries prediction.In 5- and 8-year-old children negative correlations between caries frequency and secretion rate, pH and buffer effect of saliva were demonstrated. However, these parameters showed a wide range of variation.A dip-slide test (Dentocult®), for determination of the number of lactobacilli in saliva, were investigated. The test proved to be reliable for determining of the number of lactobacilli in saliva.The clinical use of information on salivary secretion rate and number of lactobacilli in saliva in prediction of caries activity was examined in 115 14-year-old children over a period of 64 weeks. The number of lactobacilli in saliva, but not the salivary secretion rate, was correlated to caries activity. The number of lactobacilli in saliva seems to reflect the frequency of ingested fermentable carbohydrates and indirectly the risk for initiation of carious lesions. However, when the lactobacillus test is used it is important that there are no such areas of microbial retention on the teeth, as open cavities, poorly executed conservations, dentures or orthodontic bands. The lactobacillus test would make it possible to individualize prophylactic caries treatment. / <p>Annan ISSN på omslaget och titelblad (ISSN 0934-7532).</p><p>Härtill 5 delarbeten.</p> / digitalisering@umu

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

No description available.

Bibliography: leaves [165]-178. / xviii, 178, [27] leaves : ill. (some col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Designs and implements a field trial to test the effectiveness of a 10 ppm fluoride co-crystallized sugar in inhibiting caries as a potentially inexpensive public health preventative measure. / Thesis (Ph.D.)--University of Adelaide, Dept. of Dentistry, 1997?

Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 6 uppsatser.