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Uso do laser de 'C'O IND. 2' ('lambda'=10,6 'mu') na prevenção da carie e erosão dentarias : estudos in vitro / Use of 'C'O IND. 2' laser ('lambda'=10,6 'mu') on dental caries and erosio prevention : in vitro estudiesSteiner-Oliveira, Carolina, 1981- 04 July 2009 (has links)
Orientador: Marines Nobre dos Santos Uchoa / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-13T08:04:08Z (GMT). No. of bitstreams: 1
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Previous issue date: 2009 / Resumo: Os efeitos causados pelas modificações promovidas pela irradiação com laser de CO2 podem inibir a desmineralização dos tecidos dentários e podem ser potencializados quando
associados ao fluoreto. Apesar de amplo uso do fluoreto e da redução da prevalência de
cárie, essa doença ainda acomete grupos de alto risco. Por outro lado, tem sido observado
um aumento da prevalência da erosão dentária. Os objetivos dessa tese, composta por 4
manuscritos, foram: (1) descrever as características do laser de CO2 e seus mecanismos de
ação na inibição da desmineralização do esmalte; (2) desenvolver um modelo microbiológico, in vitro, de produção de lesão de cárie em dentina e testar duas hipóteses:
(a) de que não há diferença na produção de cárie artificial em dentina utilizando um modelo
microbiológico com regimes de 3 e 6 imersões ao dia em sacarose, avaliados por contagem
bacteriana da dentina (UFC), análise microrradiográfica (AM) e análise de polissacarídeo
insolúvel (API); (b) de que não há diferença no pH do biofilme antes e após sua imersão em
sacarose; (3) avaliar, in vitro, a efetividade do laser de CO2 (? = 10,6 µm) pulsado,
associado ou não ao fluoreto, na redução da desmineralização da dentina radicular usando
um modelo microbiológico, avaliado por AM; (4) avaliar, in vitro, o efeito do mesmo laser,
associado ou não ao fluoreto, na redução da desmineralização do esmalte e da dentina
submetidos a um desafio erosivo, pela mensuração da perda de superfície e análise da
concentração de cálcio, fósforo e fluoreto das soluções desmineralizadoras. Os dados foram
analisados quanto à normalidade e testes apropriados foram realizados com nível de
significância de 5%. No estudo 1, os efeitos do laser no esmalte, seu mecanismo de ação na
redução da desmineralização, combinados ou não ao fluoreto, foram discutidos. No estudo
2, o pH do biofilme diminuiu imediatamente após a imersão em sacarose, mas aumentou
novamente 5 min depois. Lesões em dentina foram produzidas com sucesso e a adição de
sacarose mostrou as maiores perdas minerais, no entanto não diferiu entre os dois regimes
de sacarose. A UFC não mostrou nenhuma diferença e a API dos tratamentos foram
maiores que a do grupo controle. No estudo 3, os espécimes radiculares foram tratados ou
não com laser de CO2 e com ou sem fluoreto antes ou após a irradiação com laser. O
modelo microbiológico utilizado foi efetivo em produzir lesões dentinárias e as terapias
combinadas mostraram as lesões dentinárias mais rasas. No estudo 4, espécimes de esmalte
e dentina foram tratados com fluoreto, laser e fluoreto/laser e submetidos a um desafio
erosivo. Os resultados de desgaste indicaram que o tratamento combinado interferiu com as
perdas minerais do esmalte e da dentina, mesmo sem mostrar efeito sinérgico. Houve uma
tendência de retenção de fluoreto no esmalte pelo tratamento combinado e também de
liberação de menores quantidades de cálcio, fósforo e fluoreto para as soluções
desmineralizadoras. Em conclusão, o mecanismo de ação do laser de CO2 na inibição da
desmineralização do esmalte ainda não está completamente esclarecido e seu efeito pode
ser aumentado quando associado ao fluoreto. O modelo microbiológico foi efetivo em
produzir lesões de cárie dentinária. A irradiação da dentina radicular com laser inibiu a
desmineralização dessa superfície apenas quando associado com o fluoreto; no entanto, não
foi observado efeito sinérgico. O tratamento isolado com laser não foi capaz de prevenir a
perda de superfície do esmalte e da dentina devido à erosão. Sua combinação com fluoreto
mostrou alguma proteção, mas principalmente devido ao efeito do fluoreto. Não foi
observada interação sinérgica significativa ou proteção duradoura com a terapia de laser. / Abstract: The effects caused by the modifications promoted by the CO2 laser irradiation can inhibit the dental tissues demineralization and may be enhanced when associated with fluoride. Despite the widespread use of the fluoride and the reduction of the caries prevalence, this disease still occurs in the high risk groups. On the other hand, an increase of the dental
erosion prevalence was observed. This thesis, comprised by 4 manuscripts, aimed: (1) to
describe the CO2 laser characteristics and its action mechanisms in the enamel
demineralization inhibition; (2) to develop an in vitro microbial model to produce dentin
caries lesions and test two hypotheses - (a) that there is no difference in the artificial caries
production in dentin using a microbial model with 3 and 6 sucrose bath immersions, as
assessed by bacterial counts on the dentin (CFU), microradiographic analysis (TMR) and
extracellular polysaccharide analysis (EPS); (b) that there is no difference in the biofilm pH
before and after each sucrose bath; (3) to assess, in vitro, the effectiveness of a pulsed CO2
laser (? = 10.6 µm) associated or not with fluoride, in reducing the root demineralization
using a microbial model, as assessed by TMR; (4) to assess, in vitro, the effect of the same
laser, associated or not with fluoride, on the prevention of the enamel and dentin erosions
by means of surface loss measurement and analysis of the calcium, phosphorus and fluoride
concentrations in the demineralizing solutions. The data were checked for normality and
appropriated tests were performed with a significance level of 5%. In study 1, the laser
effects on the enamel and its action mechanisms in the demineralization reduction,
combined or not with fluoride, were discussed. In study 2, the biofilm pH decreased
immediately after the sucrose bath but increased again after 5 min. Dentin lesions were
successfully produced, and the sucrose addition showed the highest mineral losses, even
though there was no difference between the sucrose regimens. The CFU did not show any
difference and the EPS from the treatment groups were higher than for the control. In study
3, root specimens were treated with/without CO2 laser and with/without fluoride prior or
after the laser irradiation. The microbial model utilized was effective in developing dentin
lesions and the combined therapies showed the shallowest dentin lesions. In study 4,
specimens of enamel and root dentin were treated with fluoride, laser and fluoride/laser and
submitted to an erosive challenge. The wear results indicated that the combined treatment
interfered with the enamel or dentin surface losses, although no synergistic effect was
observed. There was a trend for the combined treatment to retain more fluoride in enamel
and release lower amounts of calcium and phosphorus into the demineralizing solutions. In
conclusion, the CO2 mechanism action on the enamel demineralization reduction is still not
elucidated and its effects can be increased when associated with fluoride. The microbial
model was effective in producing dentin caries lesions. However, it did not reproduce the
remineralizing phase of the caries process. Irradiation of the root dentin with laser inhibited
the root surface demineralization only when associated with fluoride; however, no synergic
effect was observed. The laser treatment alone was not able to prevent enamel or dentin
surface losses due to erosion. Its combination with fluoride showed some protection, but
mostly due to the fluoride effect. No significant synergistic interaction or lasting protection
could be observed for the laser therapy. / Doutorado / Odontopediatria / Doutor em Odontologia
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Enhancing Root Caries Lesion Prevention By Combining Two American Dental Association-Recommended Preventive AgentsAlmudahi, Abdulellah January 2022 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Purpose: This in vitro study aims to analyze the effect of combining two ADA-recommended professionally applied 1:1 Chlorhexidine/Thymol varnish ((Cervitec Plus)) and professionally prescribed 5,000 ppm fluoride toothpaste ((PreviDent 5000 Plus)) on reducing lesion depth and increasing mineral content Materials & Methods: Forty-eight dentin specimens were randomly distributed into four treatment groups (n=12 per treatment). Biofilms of Streptococcus mutans and Candida albicans were created on the polished surfaces of bovine root dentin specimens (n=12 per treatment). 1:1 Chlorhexidine/Thymol varnish was applied once then the tested 5,000 ppm fluoride toothpaste was applied for 120 seconds twice daily over the course of 2 days. Tested groups were: (1) 1:1 Chlorhexidine/Thymol varnish ((Cervitec Plus)) (C/T). (2) 5,000 ppm F toothpaste ((PreviDent 5000 Plus)) (F). (3) Combination of 1:1 Chlorhexidine/Thymol varnish ((Cervitec Plus)) & 5000 ppm F toothpaste ((PreviDent 5000 Plus)) (C/T+F). (4) Deionized water (DIW) as control group. Biofilms were analyzed for biofilm dry weight. Dentin specimens were analyzed using transversal microradiography (TMR) for mineral content change and lesion depth. PH data was analyzed using two-way ANOVA. Total biofilm dry weight data was analyzed using one-way ANOVA. Integrated mineral loss and lesion depth data was analyzed using two-way ANOVA All pair-wise comparisons from ANOVA analysis were made using Fisher’s Protected Least Significant Differences to control the overall significance level at 5%. Results: Treatment with (C/T+F) resulted in higher mean pH values compared to the control group (DIW) and (F) group. The average pH values of group (C/T) were not statistically different than group (C/T+F). the biomass of the combined S. mutans & C. albicans biofilm among all the groups were not significantly different. (DIW) presented significantly deeper lesions for both surfaces (sound &demineralized) when compared to (F) (P=0.0118), (C/T) (P=0.0002), and (C/T+F) (P<.0001). The sound surfaces for the specimens for group (C/T) and Group (F) showed superficial lesion depth. However, the sound surfaces of specimens treated with (C/T+F) showed the most superficial depth. Due to mineral gain, the demineralized surfaces of the specimens of both (C/T) & (C/T+F) showed a decrease in the lesion depth. Conclusion: Within the limitations of our study. The combination of 5,000 ppm fluoride toothpaste and CHX/Thymol had no significant effect on mineral content. However, the combination had a considerable effect on lesion depth reduction.
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The effect of acid etching on remineralization of incipient caries lesions : a micro-ct studyYeslam, Hanin E. January 2009 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Etching of enamel caries lesions has been demonstrated to enhance remineralization. However, this effect reaches a plateau after a period of time. This study aimed at investigating the effectiveness of additional acid etching on remineralization.
Forty 1 mm × 2 mm human enamel blocks with chemically induced artificial incipient lesions were used. Ten specimens were randomly selected at the end of demineralization for transverse microradiography (TMR) analysis. The remaining specimens were then divided into three groups (n = 10). Group A was remineralized by a pH cycling system with 1100 ppm sodium fluoride for 20 days. In group B, the specimens were etched with 35-percent phosphoric acid for 30 s and then remineralized. Group C was remineralized by same procedure as group B plus and given an additional acid etch after 10 days of remineralization. Mineral density was measured by x-ray microtomography (µ-CT). The volumetric mineral content [VM (µm3×105)] was determined between 91 and 0-wt%. The µ-CT % mineral recovery (%) was calculated using the formula 100×(remineralize VM - demineralization VM) / (sound VM - demineralization VM). One-hundred-μm sections of demineralized and remineralized specimens were used to assess the mineral loss (IML: vol%×µm) and lesion depth (µm) using TMR.
The three groups showed no significant difference in mineral change or mineral content for µ-CT or TMR lesion depth. The TMR IML showed a significant difference between the demineralized specimens and the three remineralized groups. The correlation between TMR IML and TMR lesion depth was 0.66 (p < 0.0001). The µ-CT percent mineral recovery from demineralization was correlated with neither TMR IML nor TMR lesion depth. When evaluated with µ-CT, the twice-acid-etched group presented lower mineral gain values than the group etched only once with acid. Also, the twice-etched group presented lower mineral gain and greater TMR IML compared with the non-acid etch group. TMR images revealed reduction of surface layer in the acid-etched groups, especially in the twice-etched group, in which significant reduction or loss of surface layer occurred.
Based on these results, we conclude that additional acid etching with 35-percent phosphoric acid does not enhance remineralization compared with a single application of acid etching. We believe that the viable existence of the surface layer is essential for remineralization of the lesion. Further investigations into the accuracy of µ-CT to detect minute mineral changes in incipient caries lesions are probably needed.
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