Effect of resin and ionomer sealer materials on demineralization inhibition of occlusal pit and fissures, evaluation of enamel mineral loss and marginal adaptation

Orientadores: Regina Maria Puppin-Rontani, Marines Nobre dos Santos UchoaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: As superfícies oclusais são locais suscetíveis ao acúmulo de biofilme bacteriano favorecendo o desenvolvimento de lesões de cárie. Os selantes de fóssulas e fissuras oclusais vêm sendo proposto na prevenção desta doença multifatorial, principalmente em pacientes de alto risco. Desta forma, os objetivos deste estudo in vitro foram avaliar: 1 - a formação de fendas na interface esmalte/selante (gaps) de diferentes tipos de materiais usados como selantes (Selante resinoso, Cimento de ionômero de vidro, Cimento de ionômero de vidro modificado por resina e Sistemas adesivos) quando submetidos ao severo estresse físico e químico e 2 - o efeito de inibição da perda mineral do esmalte produzida pelos selantes oclusais que contém ou não fluoretos e verificar a capacidade de liberação de flúor destes materiais. Um total de 108 terceiros molares humanos inclusos foi aleatoriamente dividido em grupos de acordo com o material, e selados: Concise (C), FluroShield (F), Helioseal Clear Chroma (H), Vitremer (V), Fuji II-LC (FII), Ketac Molar (KM), Fuji IX (FIX), Single Bond (SB), e Clearfil Protect Bond (CF). Todos os grupos foram submetidos à ciclagem térmica (500 ciclos) e de pH (14 dias). Para a avaliação da formação de fendas e do efeito de inibição à cárie, os espécimes foram constituídos de fragmentos de fissuras oclusais, obtidos a partir de secções longitudinais, no sentido vestíbulo-lingual da fossa central para os molares inferiores, e da fossa mesial para os superiores. Por meio de microscopia eletrônica de varredura, da análise de microdureza (% de volume mineral) e da análise da liberação de flúor destes materiais nas soluções dês-remineralizadoras foram avaliados os efeitos dos materiais quanto à formação de ¿gaps¿ e inibição da perda mineral do esmalte dentário. Os resultados demonstraram que Single Bond e Vitremer foram efetivos na preservação da interface material selador/superfície oclusal do esmalte, suportando as condições de severo estresse físico e químico oferecidos pelo modelo in vitro proposto. Os selantes resinosos não foram capazes de prevenir a perda mineral do esmalte oclusal de dentes permanentes exposto ao desafio cariogênico. Já selantes ionoméricos revelaram os menores valores de perda mineral de esmalte na mesma situação experimental. Deve-se considerar que o flúor liberado pelos selantes ionoméricos foi capaz de prevenir a perda mineral do esmalte. Entretanto, apenas a presença de flúor na composição do material não foi capaz de interferir na inibição da perda mineral do esmalteAbstract: The occlusal surfaces are considered susceptible sites for the biofilm accumulation, which increases caries development. Pit and fissure dental sealants are recognized as an important adjunct approach for caries prevention in high caries risk patients. However, in the search for a material that has a good clinical performance, it should be considered the integration of retention and fluoride-releasing properties in sealant materials. The aims of this in vitro study were to quantitatively evaluate: 1 - the effect of different materials when used as sealants (Resin sealant, Glass-ionomer cements, Resin-modified glass-ionomer cements, and Adhesive systems) on the gap formation in the fissure submitted to physical and chemical stress, and 2 - the effect of enamel mineral loss of fluoride- and non-fluoride-containing occlusal sealants on permanent teeth at different distances from the sealant margin and verify the fluoride releasing capability of these materials. One hundred and eight impacted human third molars were sealed and randomly assigned into: Concise (C), FluroShield (F), Helioseal Clear Chroma (H), Vitremer (V), Fuji II-LC (FII), Ketac Molar (KM), Fuji IX (FIX), Single Bond (SB), and Clearfil Protect Bond (CF) groups. All groups were subjected to thermo cycling (500 cycles) and 14 days of pH cycling. Each tooth was longitudinally sectioned in order to obtain oclusal specimens. It was consist in a perpendicular slice to the fissure orientation in the central fossa of mandibular and mesial fossa of maxillary molars. Scanning Electron Microscopy and cross-section microhardness evaluations assessed marginal adaptation and enamel mineral loss, respectively. The results demonstrated that Single Bond and Vitremer sealants were effective in preserve the marginal adaptation in the enamel occlusal fissure. They were able to support the stress conditions offered by this in vitro model. On the other hand, resin sealant did not prevent the enamel mineral loss in permanent teeth in a situation that simulated a high cariogenic challenge. Considering glass ionomer cements, the fluoride release level of these materials were able to decrease the enamel mineral loss. Moreover, only the presence of fluoride on the material¿s composition cannot predict the material¿s behavior with regard to their capability to interfere with the enamel mineral loss on permanent teethMestradoOdontopediatriaMestre em Odontologi

Morphological And Chemical Changes In Dentin After Using Endodontic Agents: Fourier Transform Raman Spectroscopy, Energy-dispersive X-ray Fluorescence Spectrometry, And Scanning Electron Microscopy Study.

We examine the morphological and chemical changes in the pulp chamber dentin after using endodontic agents by scanning electron microscopy (SEM), Fourier transform Raman spectroscopy (FT-Raman), and micro energy-dispersive x-ray fluorescence spectrometry (μEDXRF). Thirty teeth were sectioned exposing the pulp chamber and divided by six groups (n=5): NT-no treatment; CHX-2% chlorhexidine; CHXE-2% chlorhexidine+17% EDTA; E-17% EDTA; SH5-5.25% NaOCl; SH5E-5.25% NaOCl+17% EDTA. The inorganic and organic content was analyzed by FT-Raman. μEDXRF examined calcium (Ca) and phosphorus (P) content as well as Ca/P ratio. Impressions of specimens were evaluated by SEM. Data were submitted to Kruskal-Wallis and Dunn tests (pNT=SH5E>CHX>E>CHXE). CHXE and E presented the highest Ca/P ratio values compared to the other groups (p<0.05). The SEM images in the EDTA-treated groups had the highest number of open tubules. Erosion in the tubules was observed in CHX and SH5E groups. Endodontic agents change the inorganic and organic content of pulp chamber dentin. NaOCl used alone, or in association with EDTA, was the most effective agent considering chemical and morphological approaches.1707500

Influence of environmental conditions on properties of ionomeric and resin sealant materials

OBJECTIVES: The aim of this study was to determine the effect of environmental conditions on the degradation of ionomeric and resin sealant materials. MATERIAL AND METHODS: FluroShield, Vitremer, and Ketac Molar disc-shaped specimens (n=18/material) were prepared, polished, subjected to initial hardness and roughness readings. Six discs of each material were randomly assigned to one of three different storage solutions: 0.3% citric acid (CA), demineralization solution (DE), and remineralization solution (RE). The specimens were individually immersed in 3 mL of the test solutions, which were daily changed. After 15 days of storage, new surface roughness and hardness readings were done. Fluoride release in the solutions was measured within 15 days. Data were analyzed by ANOVA and Tukey's and Contrast tests (&#945;=0.05). RESULTS: The storage in CA increased the roughness of Vitremer and Ketac Molar. A significant reduction in hardness was observed for all materials after storage in all solutions. For all materials, the greatest amounts of fluoride release occurred during the 1st day. FluroShield presented the same patterns of fluoride release in all solutions. Ketac Molar and Vitremer released the highest amounts of fluoride in the CA solution. CONCLUSIONS: Ionomeric materials are more susceptible to degradation than resin-based materials under acidic conditions. Acidic conditions lead to a higher fluoride release from ionomeric materials

Titanium dioxide nanotubes incorporated into bleaching agents: physicochemical characterization and enamel color change

Titanium dioxide nanotubes are nanostructures that can accelerate the oxidation reaction of bleaching procedures and promote a more effective whitening effect. Objective: This study evaluated physicochemical properties of bleaching agents incorporated with titanium dioxide (TiO2) nanotubes, and the effects on tooth color change at different periods. Methodology: 40 premolars were treated according to the following groups (n=10): CP - 10% carbamide peroxide (1 hour daily/21 days); CPN - CP incorporated into TiO2; HP - 40% hydrogen peroxide (three 40-minute sessions/7 days apart); HPN - HP incorporated into TiO2. Color shade was evaluated at five different periods (baseline, after 7, 14 and 21 days of bleaching, and 7 days after end of treatment) according to Vita Classical, CIELab and CIEDE2000 scales. Mean particle size (P), polydispersity (PO) and zeta potential (ZP) were evaluated using dynamic light scattering. Data on the different variables were analyzed by mixed model tests for measures repeated in time (ZP e L*), generalized linear models for measures repeated in time (P, PO, Vita Classical and b*), and Friedman and Mann-Whitney tests (a* and color change/ΔE and ΔE00). Results: CP and CPN presented higher P, higher PO and lower ZP than HP and HPN (p≤0.05). All groups showed a significant decrease in Vita Classical color scores after 7 days of bleaching (p&lt;0.05), and HPN presented a greater significant reduction than the other groups. L* increased in TiO2 presence, in all groups, without any differences (p&gt;0.05) in bleaching time. A significant reduction occurred in the a* and b* values for all the groups, and HPN presented lower a* and b* values (p&lt;0.05) than CPN. ΔE was clinically noticeable after 7 days, in all groups, and all groups resulted in a perceptible color change according to ΔE00. Conclusion:TiO2 did not influence physicochemical properties of the bleaching agents. HPN presented more effective tooth bleaching than CP

Células mesenquimais indiferenciadas em periodontia : novas perspectivas

A engenharia de tecidos é um campo contemporâneo da ciência, que visa criar condições baseadas em princípios de biologia celular e molecular, bioengenharia e biomateriais para regenerar tecidos. As células tronco mesenquimais apresentam altas taxas de proliferação e são capazes de se diferenciar, sob certas condições, em multi-linhagens, sugerindo que elas têm grande potencial para atuar no campo da regeneração. As células tronco derivadas de tecidos dentais são uma fonte alternativa adequada de células mesenquimais uma vez que são de fácil acesso e têm baixa morbidade para o doador. Estudos demonstraram que elas já foram isoladas e caracterizadas a partir de diversos tecidos tais como polpa dentária, dentes decíduos esfoliados, ligamento periodontal, gengiva, folículo dental e papila apical. Entretanto, os estudos demonstram que há heterogeneidade entre essas populações e não existe um método padrão para selecionar as células-tronco dentais mais apropriadas para procedimentos regenerativos. O objetivo desta revisão é apresentar o conhecimento atual dos vários tipos de células-tronco derivadas de dentes e discutir as novas perspectivas para seu uso na engenharia de tecidos periodontais.Tissue engineering is a contemporary field of science, which aims to create conditions based on principles of cell and molecular biology, bioengineering and biomaterials to regenerate tissues. Mesenchymal stem cells present high proliferation rates and are able to differentiate into multilineages under certain conditions, suggesting that they have great potential to act in regeneration field. Tooth derived stem cells are a suitable alternative source of mesenchymal cells once they are easily accessible and have poor morbidity to the donor. Studies showed that they have been isolated and characterized from diverse tissues such as dental pulp, exfoliated deciduous teeth, periodontal ligament, gingiva, dental follicle and apical papilla. However studies show that there is heterogeneity among these populations and there is no standard method to select the most appropriate tooth derived stem cells for regenerative procedures. The aim of this review is to present the current perspective of the multiple types of tooth-derived stem cells and to discuss the basis for their use in periodontal tissue engineering

Novel Nanotechnology of TiO 2

The aim of this study was to assess the performance of glass ionomer cement (GIC) added with TiO2 nanotubes. TiO2 nanotubes [3%, 5%, and 7% (w/w)] were incorporated into GIC’s (Ketac Molar EasyMix™) powder component, whereas unblended powder was used as control. Physical-chemical-biological analysis included energy dispersive spectroscopy (EDS), surface roughness (SR), Knoop hardness (SH), fluoride-releasing analysis, cytotoxicity, cell morphology, and extracellular matrix (ECM) composition. Parametric or nonparametric ANOVA were used for statistical comparisons (α≤0.05). Data analysis revealed that EDS only detected Ti at the 5% and 7% groups and that GIC’s physical-chemical properties were significantly improved by the addition of 5% TiO2 as compared to 3% and GIC alone. Furthermore, regardless of TiO2 concentration, no significant effect was found on SR, whereas GIC-containing 7% TiO2 presented decreased SH values. Fluoride release lasted longer for the 5% and 7% TiO2 groups, and cell morphology/spreading and ECM composition were found to be positively affected by TiO2 at 5%. In conclusion, in the current study, nanotechnology incorporated in GIC affected ECM composition and was important for the superior microhardness and fluoride release, suggesting its potential for higher stress-bearing site restorations

Performance of sealer materials and infiltrants in the enamel white spot lesion under cariogenic challenge - study in vitro : Mechanical and micro-morphological analysis

Orientadores: Regina Maria Puppin-Rontani, Cinthia Pereira Machado TabchouryTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: Os selantes de fossas e fissuras oclusais vêm sendo propostos na prevenção de cárie em pacientes de alto risco. As lesões iniciais de cárie em esmalte necessitam de atenção preventiva especial e de um diagnóstico preciso. A decisão se o selante deve ser realizado na superfície hígida, com lesão inicial de cárie ou remineralizada pode gerar dúvidas. No intuito de facilitar a apresentação desta Tese, a mesma foi dividida em dois capítulos, como descrito a seguir. Capítulo 1: teve como objetivo revisar a literatura a respeito do efeito dos infiltrantes e materiais seladores na inibição da desmineralização do esmalte em lesões de cárie não cavitadas. Dezoito estudos foram selecionados na avaliação crítica realizada. Dois artigos foram classificados como grau A (estudos in vivo), nove como grau B (estudos in vitro) e sete com grau C (estudos in vitro). Capítulo 2: teve como objetivo avaliar a resistência de união à micro-tração (uTBS) de materiais seladores (FluroShield® - F e Helioseal Clear Chroma® - H) aplicados em diferentes substratos de esmalte (hígido - H, lesão inicial de cárie - C e lesão inicial de cárie + aplicação tópica de verniz de flúor - CF) após desafio cariogênico (ciclagem de pH). Baseado no estudo experimental, a resistência de união à micro-tração foi influenciada pelos diferentes substratos de esmalte. O grupo do substrato de esmalte com lesão inicial de cárie + aplicação tópica de verniz de flúor mostrou maior valores de resistência da união esmalte/material à micro-tração, seguido do hígido e da lesão inicial de cárie. Além disso, os valores de resistência da união esmalte/material à micro-tração foram dependentes do material selador e da ciclagem de pH. Observou-se que os valores de uTBS foram maiores para FluroShield que Helioseal Clear Chroma associados à ciclagem de pH. A fratura tipo mista foi predominante em todos os grupos. Pôde-se concluir que enquanto o selamento da superfície externa do esmalte das fóssulas e fissuras age como uma barreira à difusão dos ácidos na superfície de lesão de mancha branca, a técnica de infiltração cria uma barreira dentro da lesão inicial de cárie, por meio da substituição do ar dos espaços da área de perda mineral por uma resina fotopolimerizável de baixa viscosidade. Os valores mais altos foram encontrados para o substrato com lesão inicial de cárie associado a aplicação de verniz fluoretado. Quando os materiais seladores foram expostos ao desafio cariogênico (ciclagem de pH), FluroShield demonstrou os maiores valores de resistência de união ao esmalte. A resistência de união foi substrato dependente.Abstract: Pit and fissure dental sealants are recognized as an important adjunct approach for caries prevention in high caries risk patients. The caries-like lesions enamel need special preventive action and accurate diagnosis. The decision whether the sealant must been made on the sound, inicial carious enamel or remineralized enamel may lead to uncertainties. In order to facilitate the accomplishment of this Thesis, it was divided into two chapters, as described on the following descriptions. Chapter 1: to present a literature review on the effects of infiltrants and sealers on the inhibition of enamel demineralization of non-cavitated enamel lesions. Eighteen studies identified were included in the project critical appraisal. Two papers were classified as grade A (in vivo studies), nine as grade B (in vitro studies), and seven as grade C (in vitro studies). Chapter 2: to evaluate the microtensile bond strength (uTBS) of resinous sealant materials (FluroShield e Helioseal Clear Chroma) on different enamel substrates (sound, caries-like lesion, and caries-like lesion + varnish topical fluoride appication) after a cariogenic challenge (pH-cycling). The caries-like lesion + varnish topical fluoride showed the highest values, following sound and caries-like lesion enamel. Additionally, uTBS values were dependent on both materials and pH-cycling. FluroShield presented the highest uTBS values, when the materials were submitted to pH-cycling. Mixed failure was the most frequently observed failure for all groups. It could be concluded that while fissure sealing act as a diffusion barrier on the top of the lesion surface, the infiltration technique creates a barrier inside the lesion, replacing lost mineral with low-viscous light-curing resin. The highest values were found for caries-like lesion + varnish topical fluoride enamel. When sealer materials were submitteted to cariogenico challenge (pH-cycling), FluroShield showed the highest microtensile bond strength values. The sealant/enamel microtensile bond strength (uTBS) was enamel substrate dependent.DoutoradoOdontopediatriaDoutor em Odontologi

Influence of cleansers and irrigation methods on primary and permanent root dentin permeability:a literature review

per review is key issue to known that the adequate endodontic techniques accomplished on primary and permanent teeth regarding the root dentin permeability. Therefore, it was discussed the efficacy of some cleansers and the influence of two irrigation systems used during endodontic preparation of primary and permanent teeth (manual or ultrasonic activation). The literature was searched for original papers relating cleansers characteristics, cleansers effect of root dentin permeability and the influence of manual irrigation or ultrasonic activation systems regarding primary and permanent endodontic therapy. The articles were selected using Bireme and Medline databases. Manual tracing of references cited in key papers otherwise was not elicited. It can be concluded that regarding cleansers and irrigation systems, there are not enough papers focusing primary teeth to establish patterns of change in the root dentin permeability. However, among the solutions used to treat permanent teeth, all solutions and associations studied increased the root dentin permeability. There was no difference in the root dentin permeability for permanent teeth when compared manual and ultrasonic preparatio

Permeability And Smear Layer Removal: Effects Of Different Chemical Agents On The Primary Root Dentin.

The purpose of this study was to evaluate the effects of chemical agents on the permeability and removal of the smear layer in the primary root dentin. Fifty roots were distributed into 6 groups: (1) 5.25% sodium hypochlorite (SH); (2) 5.25% SH+17% ethylenedia-minetetraacetic acid (SHE); (3) 2% chlorhexidine (CHX); (4) 2% CHX+17% ethylenediaminetetraacetic acid (CHXE); (5) 17% EDTA (E); and (6) saline solution (SS). The canals were instrumented and irrigated. The roots were dyed, washed, and sectioned, and the permeability index was measured. The amount of smear layer was scored. Data were submitted to analysis of variance, Kruskal-Wallis, Student-Newman-Keuls and t tests (P<.05). Significant differences were observed in the cervical and apical thirds for the CHX (P=.03), CHXE (P=.027), SS (P=.038), and SH (P<.001) groups. The SS group showed a heavy smear layer in all thirds. Root canals treated with SHE showed great cleaning in the cervical, middle, and apical thirds. Sodium hypochlorite associated with ethylenediaminetetraacetic acid produces the best root canal cleaning and the highest permeability in all thirds.34e81-