RESUMEN

Objective: This in vivo study compared two bleaching techniques with regard to the degree of tooth sensitivity (TS), color change, and treatment stability for a 6-month follow-up period. Materials and methods: Sixty volunteers were selected according to inclusion and exclusion criteria and submitted to in-office bleaching. For group 1, we performed one bleaching session with a 35% hydrogen peroxide gel and a second bleaching session after 7 days; for group 2, we performed two bleaching sessions with two applications per session, each session with a 7-day interval, using a light-emitting diodes (LEDs) device emitting violet light (405-410 nm) without employing peroxide-containing bleaching gel. TS was recorded immediately before and immediately after each bleaching session using the Variance Analogic Scale. The color of upper central incisors and upper canines at baseline was recorded immediately after each bleaching session, after 15, 30, and 180 days, with a value-oriented shade guide used by two well-trained observers. Results: The two whitening protocols results were similar regarding the immediate effectiveness and 6-month stability of tooth whitening. Dental bleaching with violet LED did not promote postoperative pain sensitivity at any of the evaluated times. However, dental bleaching performed with 35% hydrogen peroxide promoted higher postoperative pain sensitivity. Conclusions: The violet light alone provided dental bleaching and had the clinical advantage of promoting less immediate postoperative sensitivity; however, an unwanted repigmentation occurred after dental bleaching with light alone.

Asunto(s)

RESUMEN

Papacarie Duo™ is clinically used and has proven effectiveness; however, it is necessary to improve its antimicrobial action. The combined treatment of Papacarie Duo™ with Urucum (Bixa Orellana) could create a potential tool for dental caries treatment; its extract obtained from the seeds' pericarp contains a water-soluble primary pigment (cis-bixin) with smaller amounts of other carotenoids. The dicarboxylic acid salts of cis-norbixin and trans-norbixin occur in heated alkaline solutions. To analyze the absorption spectra and cytotoxicity (with human dermal fibroblasts) in different concentrations of Urucum, associated or not with Papacarie Duo™, we performed this in vitro study. The effects of pure Urucum, Papacarie Duo™, and PapaUrucum™ on the microstructure of collagen were also analyzed. The application of papain-based gel with Urucum did not present cytotoxicity, its exhibit UV absorption spectrum peak around 460 ± 20 nm. Also, it showed that the compound used did not alter the chemical structure of collagen. Consequently, this product could be used as a chemomechanical method to remove dentin caries as well as being a potential product for antimicrobial photodynamic therapy (aPDT) application.

Asunto(s)

RESUMEN

Viruses can spread to the environment, and it can be challenging to clear it. A direct approach to limit airborne transmission of pathogens in dental clinic offices is to inactivate viruses within a short time of their production and block the person-to-person transmission routes in dental clinics. For this, we can use chemical substances on surfaces and germicidal ultraviolet light (UV), typically at 254 nm, for complementary disinfection of surfaces and air contaminated by aerosols produced by high-speed handpiece or ultrasound scaler. Based on the literature review and the similarity of Sars-Cov-2 with other previously studied corovaviruses, COVID-19 is sensitive to UV irradiation that can break the genome of this virus, inactivating it. In our study, we performed the calculation of the time required to decontaminate a dental care room between each patient change. We can conclude that the use of UVC can be incorporated into the dental care routine to reduce cross contamination. (AU)

Os vírus podem se espalhar para o meio ambiente e pode ser um desafio eliminá-lo. Uma abordagem direta para limitar a transmissão aérea de patógenos nos consultórios de clínicas odontológicas é inativar os vírus o mais rápido possivel após sua produção e bloquear as rotas de transmissão de pessoa para pessoa nas clínicas odontológicas. Para isso, podemos usar substâncias químicas para limpar as superfícies e luz ultravioleta (UV) germicida (UV), normalmente a 254 nm, para desinfecção complementar de superfícies e ar contaminado por aerossóis produzidos pelo altarotação ou ultrassom periodontal. Com base na revisão de literatura e na semelhança do SarsCov-2 com outros corovavirus previamente estudados, o COVID-19 é sensível à irradiação UV que podem quebrar o genoma desse vírus, inativando-o. Em nosso estudo, realizamos o cálculo de tempo necessário para descontaminar uma sala de atendimento odontológico entre cada troca de paciente. Podemos concluir que a utilização de UVC pode ser incorporada à rotina de atendimento odontológico para reduzir a contaminação cruzada entre atendimentos. (AU)

Asunto(s)

RESUMEN

OBJECTIVE: The aim of this in vitro study was to evaluate the degradation of type I collagen fibers after treatment with a papain-based gel associated with a blue dye (PapaMBlue™) for use in antimicrobial photodynamic therapy. MATERIALS AND METHODS: For such, 60 bioabsorbable membrane sponge discs were used. Group 1 was the negative control group. In groups 2, 3, and 4, the papain-based gel PapaMBlue gel was applied all over the samples for 4 min and irradiated using red laser (660 ± 10 nm) with 15, 30, and 40 J/cm2, respectively. In group 5, the papain-based gel was applied all over the samples for 4 min. In group 6, the photosensitizing dye was applied all over the samples for 4 min. The compositional analysis of the samples was performed using ATR-FTIR (attenuated total reflectance-Fourier transformed infrared spectroscopy). The data were statistically analyzed using ANOVA and Tukey's test (p < 0.05). RESULTS: Neither classic Papacarie™ nor the modified product with a photosensitizing agent (PapaMBlue) promoted collagen degradation. CONCLUSIONS: The irradiation of methylene blue added to papain gel with red light did not alter the chemical structure of type I collagen.

Asunto(s)

RESUMEN

This study intended to evaluate the effects of a papain-gel with a red-light absorbing pigment (methylene blue - MB) to mediate photodynamic therapy (PDT) against Streptococcus mutans biofilms. The PapaMBlue was compared with free MB to generate reactive oxygen species using fluorescence probes (SOSG and HPF). PDT (660-nm light) was carried out against S. mutans biofilms grown on either plastic dishes or on collagen membrane and assayed by CFU, live-dead staining using confocal microscopy, transmission electron microscopy and H&E staining for collagen films. Cytotoxicity and subcellular localization was studied in human fibroblasts. Sponges of bioabsorbable type I collagen membrane were exposed to papain based gel, irradiated with laser and analyzed about their integrity by ATR-FTIR. The PapaMBlue produced higher amounts of singlet oxygen and hydroxyl radicals than free MB, possibly due to better disaggregation of the dye in solution. The PapaMBlue antimicrobial effects on biofilms proved to be capable of reducing the S. mutans. Both MTT and PrestoBlue assays showed higher cell viability and metabolism scores in fibroblasts treated with PapaMBlue and MB, possibly due to stimulation of mitochondrial activity and that collagen triple helix is unaffected. The PapaMBlue is equally effective as MB in destroying S. mutans biofilms growing on plastic or collagen without affecting fibroblasts.

Asunto(s)

RESUMEN

Considering the improvement of biomaterials that facilitate atraumatic restorative techniques in dentistry, a papain-based gel can be used in the chemomechanical removal of decayed dental tissue. However, there is no information regarding the influence of this gel on the structure of sound collagen. The aim of the present study was to investigate the adsorption of a papain-based gel (Papacarie(TM)) to collagen and determine collagen integrity after treatment. A pilot study was first performed with 10 samples of type I collagen membrane obtained from bovine Achilles deep tendon to compare the influence of hydration (Milli-Q water) on infrared bands of collagen. In a further experiment, 10 samples of type I collagen membrane were used to evaluate the effects of Papacarie(TM) on the collagen microstructure. All analyses were performed using the attenuated total reflectance technique of Fourier transform infrared (ATR-FTIR). The results demonstrated that the application of Papacarie(TM) does not lead to the degradation of collagen and this product can be safely used in minimally invasive dentistry. As the integrity of sound collagen is preserved after the application of the papain-based gel, this product is indicated for the selective removal of infected dentin, leaving the affected dentin intact and capable of re-mineralization.

Asunto(s)

RESUMEN

One possible undesirable consequence of orthodontic therapy is the development of incipient caries lesions of enamel around brackets. The aim of this study was to compare the effects of CO2 (λ = 10.6 µm) and Nd:YAG (λ = 1,064 nm) lasers associated or not with topical fluoride application on the prevention of caries lesions around brackets. Brackets were bonded to the enamel of 65 premolars. The experimental groups (n = 13) were: G1--application of 1.23% acidulated fluoride phosphate gel (AFP, control); G2--Nd:YAG laser irradiation (0.6 W, 84.9 J/cm(2), 10 Hz, 110 µs, contact mode); G3--Nd:YAG laser irradiation associated with AFP; G4--CO2 laser irradiation (0.5 W, 28.6 J/cm(2), 50 Hz, 5 µs, and 10 mm focal distance); and G5--CO2 laser irradiation associated with AFP. Quantitative light-induced fluorescence was used to assess enamel demineralization. The data were statistically compared (α = 5%). The highest demineralization occurred in the Nd:YAG laser group (G2, 26.15% ± 1.94). The demineralization of all other groups was similar to that of the control group. In conclusion, CO2 laser alone was able to control enamel demineralization around brackets at the same level as that obtained with topical fluoride application.

Asunto(s)

RESUMEN

Na era da colaboração, surge o Ensino a Distância (EaD) como poderosa ferramenta de divulgação de realidades, permitindo que a importância do BDH seja divulgada adequadamente. Diversas iniciativas estão sendotomadas de modo articulado, a fim de facilitar a criação e a consolidação de uma rede de colaborativa detrabalho em Telessaúde e Teleodontologia para a divulgação e implementação de Bancos de Dentes Humanosem sua faculdade ou centro de pesquisasbaseado no caminho trilhado pela Faculdade de Odontologia da USP (AU).

In the era of collaboration, arises Distance Education (DE) as a powerful tool for the dissemination of realities, allowing the importance of BDH is disclosed properly. Several initiatives are being taken in an articulate manner in order to facilitate the creation and consolidation of a network of collaborative working in Telehealth and Teledentistry for the dissemination and implementation of Banks Human Teeth at your college or research center based on the path followed by School of Dentistry, USP (AU).

Asunto(s)

RESUMEN

Aim: To evaluate the leakage on Er,Cr:YSGG laser- and bur- prepared Class V cavities restoredwith a silorane-based composite resin using different insertion techniques Methods: 40 cavitieswere outlined according to: the type of instrument [Er,Cr:YSGG laser (3.0 W power, energy perpulse of 150 mJ, fluence of 53.57J/cm2, pulse duration of 140-200 μs, 20 Hz repetition rate and55/65% air/water spray) or diamond bur]; and the type of filling technique (bulk increment orincremental). Four experimental groups were obtained (n=10): G1- diamond bur (DB) andincremental (I); G2- DB and bulk increment (BI); G3- Er,Cr:YSGG and I; and G4- Er,Cr:YSGGand BI. Specimens were restored with a silorane-based composite resin (Filtek P90, 3M/ESPE),subjected to 500 thermal cycles, sealed, infiltrated with 2% (w/v) methylene blue and sectioned inhalves. Specimen analysis was scored based on a scale. Statistical analyses were done usingthe Kruskal-Wallis and Student Newman-Keuls tests (α=0.05). Results: Statistically significantdifferences were observed between G2 and G4 (p=0.003) and between G1 and G2 (p=0.028).The filling technique did not influence the pattern of dye leakage in the cavity walls (p=0.151).Conclusions: Less leakage was observed when Er,Cr:YSGG cavities were restored withsilorane-based composite resin, using the bulk increment technique. Nevertheless, cavities doneusing diamond bur have less leakage only when incrementally restored.

Asunto(s)

RESUMEN

AIM: The aim of this study was to analyze and compare the influence of short-term NaOCl-storage and long-term water storage on the microtensile bond strength (µTBS) of etch-and-rinse adhesive system to human dentin. MATERIALS AND METHODS: Thirty-six third human molars were randomly divided into 6 groups (n = 6) according to the aging protocol: G1 (water, 24 hours); G2 (water, 6 months); G3 (water, 12 months); G4 (10% sodium hypochlorite--NaOCl, 1 hour); G5 (10% NaOCl, 3 hours) and G6 (10% NaOCl, 5 hours). A two-step etch-and-rinse adhesive (Adper Single Bond 2) was applied according to the manufacturers' instructions. A composite (Filtek Z250) was applied in four horizontal increments and was individually cured. Specimens were cut following the microtensile test technique, submitted to the different aging protocols, and tested in tension. The fracture pattern was observed in a stereomicroscope (40* magnification) and in a scanning electron microscope. The µTBS data were analyzed by ANOVA and Tukey's test (α = 0.05). RESULTS: The effect of storage in 10% NaOCl for 1 or 3 hours was not significantly different from that of aging in distilled water (DW) for 6 or 12 months (p > 0.05). Beams immersed in DW for 24 hours and in 10% NaOCl for 5 hours showed the highest and lowest µTBS values respectively. CONCLUSION: The aging protocols negatively influenced dentin bond strength. Aging specimens in 10% NaOCl for 1 or 3 hours can be an alternative method for long-term water storage (6 or 12 months) bond strength studies. CLINICAL SIGNIFICANCE: This aging protocol allows a quick achievement of longitudinal bond strength data, so that results are available to the professionals in this area while the materials are yet present at the dental market.

Asunto(s)

RESUMEN

AIM: This study was undertaken to examine the effect of root canal (RT) sealers content and the cleaning procedure of RT walls on bond strength (BS) of a fiber reinforced composite (FRC) post cemented with resin-based or zinc phosphate cement. MATERIALS AND METHODS: Forty bovine roots were divided into 2 groups (n = 20) and obturated with gutta-percha points plus Sealer 26 sealer or gutta-percha points plus N-Rickert sealer. In each group, half (n = 10) of intracanal walls was cleaned with ethanol and the other half with sulfuric ether. In each of these subgroups, half of intracanal posts (n = 5) were cemented with Bistite resin-based cement and half with zinc phosphate cement. Specimens were submitted to pull-out test and tensile force until post dislodgement. The maximum forces required for post removal was expressed in MPa, means were submitted to statistical analysis (Analysis of Variance Test, a = 0.05). RESULTS: Fiber reinforced composite cemented with zinc phosphate were significantly more retentive than those cemented with Bistite (p < 0.05). Regarding the influence of eugenol-based sealer on post retention, there was a statistically significant difference (p < 0.05) only between groups cemented with Bistite, in which canals filled with N-Rickert + gutta-percha showed lower BS than canals filled with Sealer 26 + gutta-percha. CONCLUSION: Despite endodontic cement used, higher pull-out bond strength were obtained when posts were cemented with zinc phosphate. CLINICAL SIGNIFICANCE: The importance of ethanol or sulphuric ether application to properly replace water from intraradicular dentine still requires further investigations, especially to clarify if this technique may reduce the effect of aging and improve the stability of the bond, when used to cement fiber posts into the root canal.

Asunto(s)

Asunto(s)

RESUMEN

A radiopacidade é um pré-requisito imprescindível para materiais utilizados como base eforramento de restaurações. Possibilita que o profissional identifique a presença do material,permitindo a diferenciação com a estrutura dental adjacente. Objetivo: O objetivo desse estudofoi avaliar a radiopacidade de materiais de base e forramento disponíveis para uso clínico ecomparar com a radiopacidade do esmalte e dentina. Materiais e Métodos: Foram analisados:13 marcas comerciais de cimento de ionômero de vidro, 1 amálgama e 1 resina composta. Foramconfeccionados três corpos de prova com espessura de 1 mm para cada cimento de ionômerode vidro e para cada material restaurador. Obteve-se 1 espécime, com 1 mm de espessura, deesmalte/dentina através de um corte transversal da coroa dental. As tomadas radiográficas foramfeitas com o sistema digital ~VG 5000 Kodak e tempo de exposição de 0,32 segundos. Asimagens obtidas foram trabalhadas no programa Image Tool® obtendo-se os valores médiosde cinza. A análise estatística ANOVA, seguida pelo teste de Tukey (p 0,05) detectou diferençasconsideráveis. Resultados: Alguns cimentos de ionômero de vidro apresentaram radiopacidadeinferior à da dentina e inadequada segundo as normas ISO9917, sendo considerada insuficientepara um correto diagnóstico radiográfico. Conclusão: Conclui-se que existem cimentos de ionômerode vidro indicados como base e forramento de restaurações disponíveis para aquisiçãocom radiopacidade imprópria para serem detectados radiograficamente.

The radiopacity is an essential prerequisite for materiais used as a base liner and restorationsand allows the professional to identify the presence of the material allowing the differentiationfrom the adjacent tooth structure. Objectives: The aim of this study was to evaluate the radiopacityof base and liner materiais available for clinical use and compare to the radiopacity ofenamel and dentin. Materiais and methods: 13 glass ionomer cements, one resin composite andone amalgam were evaluated. Three specimens with 1 mm thickeness for each glass ionomercement and restorative material were prepared. Cross section was made from a third molardental crown to obtain enamel and dentin specimen with thickness of 1 mm. Radiographswere taken with digital system Kodak RVG5000 and exposure time of 0.32 seconds. The imageswere analysed through the programe Image Tool" to obtain the mean grey values. Statisticaltest ANOVA followed by Tukey test (p<0.05) detected considerable differences. Results: Someglass ionomer cements presented radiopacity lower than dentin, considered insufficient for acorrect radiographic diagnosis, according to ISO 9917. Conclusion: It was concluded that somebase and liner materiais available for purchase have an inadequaderadiopacity to be detectedradiographically.

Asunto(s)

RESUMEN

OBJECTIVES: The aim of this study was to describe roughness and gloss alterations of enamel after treatment with 38% hydrogen peroxide (HP) and after polishing with 2% neutral sodium fluoride (SF) or a dental tooth paste containing nanohydroxiapatite particles (nHA) using power spectral density (PSD) description, roughness parameters (Ra, RMS, and Z range) and gloss analysis. METHODS: An atomic force microscope (AFM) and a spectrophotometer were used to analyze eighteen specimens of upper incisors. After initial analyses, all specimens were bleached with 38% HP for 135 min. The specimens were analyzed after bleaching. Nine specimens were polished with SF (Group Fluor) and the other nine specimens were polished with nHA (Group nHA), then all specimens were analyzed after polishing. Roughness and gloss were analyzed with ANOVA and Tukey's t-test. RESULTS: No statistical difference was found for Ra and RMS among initial, after bleaching and after polishing in both groups. For Z range, Group nHA showed a significant decrease after polishing. Bleaching with 38% HP did not increase the PSD in the spatial frequency of the visible light spectrum range in both groups. After polishing, nHA group showed a decrease in PSD for all morphological wavelengths. Gloss did not show statistical difference after bleaching in both groups. Gloss showed significant increase after polishing with nHA. SIGNIFICANCE: bleaching treatment with 38% HP didn't alter enamel surface roughness or gloss. PSD analyses were very suitable to identifying the morphological changes on the surfaces.

Asunto(s)

RESUMEN

OBJECTIVE: The aim of this study was to assess by atomic force microscopy (AFM) the effect of Er,Cr:YSGG laser application on the surface microtopography of radicular dentin. BACKGROUND: Lasers have been used for various purposes in dentistry, where they are clinically effective when used in an appropriate manner. The Er,Cr:YSGG laser can be used for caries prevention when settings are below the ablation threshold. MATERIALS AND METHODS: Four specimens of bovine dentin were irradiated using an Er,Cr:YSGG laser (λ = 2.78 µm), at a repetition rate of 20 Hz, with a 750-µm-diameter sapphire tip and energy density of 2.8 J/cm(2) (12.5 mJ/pulse). After irradiation, surface topography was analyzed by AFM using a Si probe in tapping mode. Quantitative and qualitative information concerning the arithmetic average roughness (Ra) and power spectral density analyses were obtained from central, intermediate, and peripheral areas of laser pulses and compared with data from nonirradiated samples. RESULTS: Dentin Ra for different areas were as follows: central, 261.26 (±21.65) nm; intermediate, 83.48 (±6.34) nm; peripheral, 45.8 (±13.47) nm; and nonirradiated, 35.18 (±2.9) nm. The central region of laser pulses presented higher ablation of intertubular dentin, with about 340-760 nm height, while intermediate, peripheral, and nonirradiated regions presented no difference in height of peritubular and interperitubular dentin. CONCLUSION: According to these results, we can assume that even when used at a low-energy density parameter, Er,Cr:YSGG laser can significantly alter the microtopography of radicular dentin, which is an important characteristic to be considered when laser is used for clinical applications.

Asunto(s)

RESUMEN

O objetivo deste trabalho foi avaliar a microinfiltração de restaurações classe V em preparos de cavidades obtidos com diferentes potências do laser Er; Cr: YSGG e as cavidades preparadas convencionalmente (ponta diamantada em alta rotação). Sessenta amostras de dentina foram divididas em seis grupos (n = 10). O primeiro grupo serviu como um controle padronizado com preparo de ponta diamantada (G1) e os demais grupos foram irradiados com laser de Er; Cr:YSGG com diferentes parâmetros: G2 - 2,0W; G3- 2,25W; G4- 2,5W; G5- 2,75W; G6- 3,0W. Este laser emite comprimento de onda de 2,78 µm e tem largura de pulso de 140 µm e taxa de repetição fixa de 20Hz. A energia do laser foi entregue através de um sistema de fibra óptica para um terminal de ponta de safira de 6 mm de comprimento e 600 µm de diâmetro, utilizando modo não-contato. O sistema adesivo autocondicionante (Clearfil SE Bond) e a resina composta micro-híbrida (Z-250) foram utilizados para compor os corpos de prova. Após as restaurações, os espécimes foram submetidos a teste de microinfiltração com solução de azul de metileno a 2% em pH 7,0 durante 4 horas, a 37ºC. Os resultados mostraram não haver diferença estatística (p = 0,203) entre grupos experimentais em que os preparos das cavidades foram realizados com ponta diamantada ou com diferentes parâmetros de energia do laser de Er; Cr: YSGG. A partir do presente estudo, pode-se concluir que a microinfiltração foi semelhante em todos os grupos experimentais independentemente do método de preparo cavitário de Classe V usado - laser Er; Cr:YSGG ou ponta diamantada

Asunto(s)

RESUMEN

Este estudo objetivou analisar, por meio de microscopia eletrônica de varredura (MEV), a interface adesiva de restaurações realizadas com sistema adesivo autocondicionante de dois passos (Clearfill SE Bond, Kuraray Co., Ltd., Osaka, Japão), contaminadas por sangue em dois momentos diferentes, recebendo essa contaminação dois tratamentos distintos. Quinze molares humanos foram divididos em cinco grupos experimentais (n = 3): G1 - controle (sem contaminação); G2 - contaminação antes do primer, com lavagem e secagem; G3 - contaminação antes do primer com secagem; G4 - contaminação após bond fotopolimerizado com lavagem e secagem; G5 - contaminação após bond fotopolimerizado com secagem. Os dentes tiveram sua superfície oclusal seccionada e lixada para obtenção de dentina plana. Os espécimes foram contaminados, de acordo com os grupos experimentais, e então foram restaurados e preparados para análise em MEV. Os resultados obtidos foram descritos de duas formas: análise morfológica, na qual foram observadas alterações na formação da camada híbrida (CH) em grupos com a presença do contaminante, e análise morfométrica, em que os dados foram analisados estatisticamente, e pode-se constatar uma relação entre a presença do contaminante e a diminuição do tamanho de tags, em µm, quando comparados ao grupo controle (p ≤ 0, 05). Adicionalmente, foi observado que o tratamento de lavagem com água não foi suficiente para restabelecer a formação de CH semelhante à observada em G1.

Asunto(s)

RESUMEN

Aim: To evaluate the influence of saliva contamination on the short- and long-term bond strength of a self-etch adhesive system. Methods: One hundred and twelve non-carious human molars were randomly divided according to: substrate (enamel/dentin); presence of saliva [none (control- C), before primer (BP), after primer (AP) and after bonding agent (AB)]; treatment of the contamination [none (1), rinsing + drying (2), drying (3) and primer re-application (4)] and specimen storage (24 h or 6 months). A self-etch adhesive system was applied to the dental surfaces followed by incremental insertions of composite resin. After storage in water at 37oC, the specimens were perpendicularly cut into beams for microtensile bond strength testing. Data in MPa were compared by A NOVA followed by Tukey’s test (p< 0.05). Micrographs were obtained by low vacuum scanning electron microscopy. Results: Control groups (G1 and G8) presented higher bond strength than all other groups. The factors presence of saliva, treatments of the contaminant and specimen storage showed no statistically significant results for the two dental substrates. Contaminants could be detected by LV-SEM. Six-month storage did not affect bond strength. Conclusions: The presence of saliva during the application of the self-etch system was deleterious to the bond to enamel and dentin, irrespective of the operative step in which the contamination occurred.

Asunto(s)

RESUMEN

Tendo em vista a necessidade de inibir a atividade enzimática das metaloproteinases (MMPs) para postergar a durabilidade de restaurações de resina composta, aliada à escassezde conhecimento sobre os efeitos destas substâncias na estrutura do colágeno, o presente estudo objetivou, em um primeiro momento, caracterizar quimicamente diferentes extratosde proantocianidina comercialmente disponíveis, buscando-se selecionar aquele que apresentasse características mais favoráveis para adsorção em colágeno. Em um segundomomento, objetivou-seavaliar as interações químicas do extrato selecionado, correlacionando-se com outras soluções inibidoras de MMPs e diferentes agentes condicionadores teciduais, na estrutura molecular e integridade do colágeno. Em umterceiro momento, objetivou-se avaliar os efeitos das diferentes substâncias testadas anteriormente na durabilidade de restaurações de resina composta, por meio de teste demicrotração em diferentes tempos de armazenamento, além de se testar o uso do hipoclorito de sódio como uma alternativa para envelhecimento dos corpos-de-prova. Para aprimeira fase experimental, os extratos MegaNatural-BP, MegaNatural Gold, Leucoselect e GNC foram caracterizados por cromatografia líquida de alta eficiência em fase reversa(HPLC-RF), espectrometria de massas com ionização por spray de elétrons (ESI-MS) e por espectroscopia de absorção no Infravermelho por transformada de Fourier (FTIR). Foipossível analisar os diferentes constituintes químicos dos extratos, por meio da identificação de monômeros e oligômeros de proantocianidinas, além de quantificar o teor deproantocianidina e dos demais constituintes dos produtos avaliados. Desta forma, determinou-se que o produto MegaNatural-BP foi o que apresentou melhores característicaspara uso clínico, sendo o extrato selecionado para as fases posteriores deste estudo, com poucas quantidades de lipídios e açúcares e com teor de proantocianidina aproximado de91%. Em seguida, foram avaliadas diferentes soluções inibidoras de MMPs (clorexedina 2%, extrato MegaNatural:'BP e solução inibidora com íons metálicos), assim como dois agentes condicionantes superficiais (ácido fosfórico a 35% e solução de EDTA O,lM), na integridade da tripla hélice do colágeno por meio da técnica da reflexão total atenuada da espectroscopia de absorção no infravermelho por transformada de Fourier (ATR-FTIR). Observou-se, por meio da análise das bandas 1235 cm-l e 1450 cm-l de membranas detendão profundo de Aquiles bovino, que nenhuma das substâncias testadas modificou significativamente a estrutura helicoidal da molécula de colágeno, sendo indicadas para posterior uso clínico em dentina.

Given the need to inhibit the enzymatic activity of matrix metalloproteinases (MMPs) to postpone the longevity of composite resin restorations, combined with the lack ofknowledge about the effects of these substances on the collagen structure, this study aimed, at first to chemically characterize different commercially available proanthocyanidinextracts, aiming to select the one with the more favorable characteristics for adsorption on collagen. In a second step, aimed to evaluate the chemical interactions of the selectedextract and to correlate with other inhibitors of MMPs and different tissue conditioners inthe molecular structure and integrity of collagen. In a third step, aimed to evaluate the effects of different substances previously tested on the longevity of composite restorationsby microtensile test at different storage periods, in addition to test the use of sodium hypochlorite as an alternate specimens aging. For the first phase, the extracts MegaNatural¬BP, MegaNatural Gold, Leucoselect and GNC were characterized by reverse phase high performance liquid chromatography (HPLC-RF), mass spectrometry with electron sprayionization (ESI-MS) and by absorption spectroscopy by Fourier transform infrared (FTIR). It was possible to analyze the chemical constituents of different extracts, throughidentification of monomers and oligomers of proanthocyanidins, as well as quantify the amount of proanthocyanidin and other constituents of the tested products. Thus, the selected extract for the later phases of this study was MegaNatural-BP that showed the best characteristics for clinical use, with lesse r amounts of fats and sugars and approximately 91%of proanthocyanidin contento In the second phase, we evaluated different MMPs inhibitors (chlorhexidine 2%, proanthocyanidin extract and inhibitor solution with metal ions) and twosurface conditioning agents (phosphoric acid 35% and EDTA 0.1 M) in the integrity of the collagen triple helix by the technique of attenuated total reflection spectroscopy absorptionby Fourier transform infrared (ATR-FTIR). It was observed through the analysis of the bands 1235 cm-l and 1450 cm-l from membranes of bovine deep Achilles tendon, that none of thecompounds tested significantly altered helical structure of collagen molecule, being recommended for clinical use in dentin.

Asunto(s)

RESUMEN

The aim of this study was to investigate whether distinct cooling of low fluence erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser irradiation would influence adhesion. Main factors tested were: substrates (two), irradiation conditions (three), and adhesives (three). A 750 microm diameter tip was used, for 50 s, 1 mm from the surface, with a 0.25 W power output, 20 Hz, energy density of 2.8 J/cm(2) with energy per pulse of 12.5 mJ. When applied, water delivery rate was 11 ml/min. The analysis of variance (ANOVA) showed that laser conditioning significantly decreased the bond strength of all adhesive systems applied on enamel. On dentin, laser conditioning significantly reduced bond strength of etch-and-rinse and one-step self-etch systems; however, laser irradiation under water cooling did not alter bonding of two-step self-etching. It may be concluded that the irradiation with Er,Cr:YSGG laser at 2.8 J/cm(2) with water coolant was responsible for a better adhesion to dentin, while enamel irradiation reduced bond strength, irrespective of cooling conditions.

Asunto(s)