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1.
Braz. dent. sci ; 25(2): 1-8, 2022. tab
Article in English | LILACS, BBO | ID: biblio-1367395

ABSTRACT

Objective: This study evaluated the influence of calcium lactate and sodium fluoride mouthwashes on enamel microhardness and dentin permeability during in-office bleaching. Material and Methods: For the microhardness evaluation, enamel blocks were randomly submitted to different treatments associated with in-office bleaching agent using 40% hydrogen peroxide (Opalescence Boost PF 40%/ Ultradent; 3 sessions x 40-minute each) (n = 10): 1) Control: application of bleaching agent; 2) Calcium lactate: 1-minute immersion before bleaching treatment; 3) Sodium fluoride: immersion for 1 minute before bleaching treatment; 4) Calcium lactate + sodium fluoride: 1 minute immersion in calcium lactate solution, followed by 1 minute immersion in sodium fluoride before bleaching treatment. Dentin discs received the same treatment protocols (n = 10) to evaluate permeability. Knoop microhardness and dentin permeability assessments were performed twice (at baseline and 48 hours after the end of bleaching treatment). Results: The generalized linear model considering the design of repeated measures over time showed that there was no significant difference between treatments (p = 0.9577) and between assessments (p = 0.3267) regarding Knoop microhardness. Kruskal Wallis and Dunn tests showed that calcium lactate immersion before bleaching treatment provided higher dentin permeability than other groups (p = 0.0009). Conclusion: The use of sodium fluoride solution and calcium lactate in association with in-office bleaching treatment did not influence the microhardness of tooth enamel, although calcium lactate may increase dentin permeability. (AU)


Objetivo: Este estudo avaliou a influência dos enxaguatórios bucais com lactato de cálcio e fluoreto de sódio na microdureza do esmalte e na permeabilidade da dentina durante o clareamento em consultório. Material e Métodos: Para avaliação da microdureza, blocos de esmalte foram submetidos aleatoriamente a diferentes tratamentos associados a agente clareador em consultório com peróxido de hidrogênio 40% (Opalescence Boost PF 40% / Ultradent; 3 sessões x 40 minutos cada) (n = 10): 1) Controle: aplicação de agente clareador; 2) Lactato de cálcio: imersão de 1 minuto antes do tratamento clareador; 3) Fluoreto de sódio: imersão por 1 minuto antes do tratamento clareador; 4) Lactato de cálcio + fluoreto de sódio: 1 minuto de imersão em solução de lactato de cálcio, seguido de 1 minuto de imersão em fluoreto de sódio antes do tratamento clareador. Os discos de dentina receberam os mesmos protocolos de tratamento (n = 10) para avaliar a permeabilidade. As avaliações da microdureza Knoop e da permeabilidade dentinária foram realizadas duas vezes (no início do estudo e 48 horas após o término do tratamento clareador). Resultados: O modelo linear generalizado considerando o delineamento de medidas repetidas ao longo do tempo mostrou que não houve diferença significativa entre os tratamentos (p = 0,9577) e entre as avaliações (p = 0,3267) em relação à microdureza Knoop. Os testes de Kruskal Wallis e Dunn mostraram que a imersão de lactato de cálcio antes do tratamento clareador proporcionou maior permeabilidade dentinária do que os outros grupos (p = 0,0009). Conclusão: O uso de fluoreto de sódio e lactato de cálcio associado ao clareamento em consultório não influenciou a microdureza do esmalte dentário, embora o lactato de cálcio possa aumentar a permeabilidade dentinária (AU)


Subject(s)
Sodium Fluoride , Tooth Bleaching , Calcarea Lactica , Dentin , Hardness Tests
2.
Rev. Asoc. Odontol. Argent ; 109(2): 76-80, ago. 2021. tab
Article in Spanish | LILACS | ID: biblio-1348357

ABSTRACT

esumen Objetivo: Comparar la microdureza de dos materiales endodónticos a base de silicato de calcio: MTA Densell Endo Sealer y TotalFill BC Sealer. Materiales y métodos: Se evaluó la microdureza de los selladores MTA Densell Endo Sealer (Grupo 1, n=5) y To- talFill BC Sealer (Grupo 2, n=5) contenidos en cilindros de dentina de vacuno a los 14 días posteriores a su fraguado. La medición se realizó a temperatura ambiente mediante la prue- ba de indentación Vickers. Se realizaron cinco indentaciones por probeta con una carga de 100 g durante 10 s cada una. Las mediciones se convirtieron a valores de dureza Vickers (HV) y los promedios de los valores HV de cada grupo se compararon por medio de la prueba t de Student con un nivel de significación de P <0,05. Resultados: A los 14 días, luego del fraguado, la mi- crodureza de MTA Densell Endo Sealer fue significativamen- te mayor (P=0,001) que la de TotalFill BC Sealer. Conclusiones: Los resultados sugieren que a causa de su dureza la remoción de MTA Densell Endo Sealer puede resultar dificultosa cuando está indicado un retratamiento (AU)


Aim: To compare the microhardness of two silicate-based endodontic materials: MTA Densell Endo Sealer and Total Fill BC Sealer. Materials and methods: Samples of MTA Densell Endo Sealer (Group 1, n=5) and Total Fill BC Sealer (Group 2, n=5) contained into cow dentine cylinders were subjected to the Vickers Microhardness Indentation test at room temper- ature and 14 days after setting. Five indentations per sample were performed under a load of 100 g for 10 s. The indenta- tion measurements were converted into hardness values (HV). Mean HV values of each group were compared using the Stu- dent t test at a significance level of P <0,05. Results: 14 days after setting, the microhardness of MTA Densell Endo Sealer was significantly greater (P=0,001) than that of Total Fill BC Sealer. Conclusions: The results of this study suggest that due to its hardness the removal of MTA Densell Endo Sealer could be difficult to perform when a root canal retreatment is indicated (AU)


Subject(s)
Root Canal Filling Materials , Silicate Cement , Hardness Tests , Materials Testing , Statistical Analysis
3.
Rev. Asoc. Odontol. Argent ; 109(2): 137-143, ago. 2021.
Article in Spanish | LILACS | ID: biblio-1348435

ABSTRACT

El propósito de esta revisión bibliográfica es aportar información actualizada acerca de las características de los dientes bovinos en relación con su uso como sustitutos de dientes humanos en trabajos de investigación. De acuerdo con la información registrada, los dientes bovinos serían excelentes sustitutos de la dentición humana para la realización de ensayos de laboratorio con el esmalte dental como modelo experimental (AU)


The purpose of this bibliographic review is to provide updated information about the characteristics of bovine teeth to be used as substitutes for human teeth in dental research. According to the information recorded, bovine teeth appear to be excellent substitutes for human dentition for conducting laboratory tests, using dental enamel as an experimental model (AU)


Subject(s)
Cattle , Cattle , Dental Research , Dental Enamel/anatomy & histology , Tooth Erosion , Statistical Analysis , Dental Bonding , Physical and Chemical Properties , Dental Enamel/ultrastructure , Hardness Tests
4.
Rev. Cient. CRO-RJ (Online) ; 6(2): 24-30, 2021.
Article in English | LILACS, BBO | ID: biblio-1357504

ABSTRACT

Objective: To assess the superficial microhardness of enamel-restorations margins of glass ionomer cement reinforced with silver (RS), modified with resin (RI) and composite resin (CO) after cariogenic biofilm. Materials and Methods: Thirty bovine enamel blocks with standard cavities were divided into three groups according to the materials used: RI (Riva Light Cure™, SDI), RS (Riva Silver™, SDI) and CO (Filtek™ Z350 XT, 3M). Half of each enamel block surface was covered by acid resistant varnish. After that, the blocks were exposed to Streptococcus mutans biofilm. The varnish was removed from the blocks and superficial microhardness (MDS) was measured (Knoop, 50 g, 15 s), with five indentations, 100 µm from each other in three different directions. The data were analyzed by the Shapiro Wilk, Kruskal Wallis and Mann Whitney tests (p<0.05). Results: MDS analysis indicated that in 50 µm distance from the restoration, RS group obtained hardness gain (6.31±0.01), unlike RI (-0.36±0.05) and CO (-11.43±0.02) groups that demonstrated significant loss (p<0.05). In other distances did not observe statistical difference between the groups. Regardless of the distance up to 450 µm, significant high total mineral gain was observed for RS group compared to the CO group; however, RS and RI presented similar enamel microhardness. Conclusion: All glass ionomers increased microhardness of enamel blocks even in contact with cariogenic biofilm. Although only the silver reinforced glass ionomer prevented demineralization at the margin restorations in 50 µm from the margin.


Objetivo: Comparar a desmineralização nas margens da interface dente/restauração utilizando cimento de ionômero de vidro modificado com resina (RI) e reforçado com prata (RS) e com resina composta (CO) após desafio cariogênico. Materiais e Métodos: 30 blocos de esmalte bovino com cavidades padronizadas foram divididos em 3 grupos de acordo com os materiais utilizados: RI (Riva Light CureTM, SDI), RS (Riva SilverTM, SDI) e CO (FiltekTM Z350 XT, 3M). Metade de cada superfície de esmalte restaurada foi protegida com verniz ácido-resistente. Os blocos foram expostos ao biofilme de Streptococcus mutans. O verniz foi removido dos espécimes com algodão e álcool para mensuração da microdureza superficial (MDS - Knoop, 50 g, 15 s), através de 3 linhas com 5 indentações em cada e 100 µm de distância entre elas. Os dados foram submetidos ao programa SPSS 20.0, teste de normalidade de Shapiro Wilk, Kruskal Wallis e Mann Whitney (p<0,05). Resultados: A análise da MDS demonstrou que na distância de 50 µm da restauração, o grupo RS apresentou ganho percentual de dureza (6,31 ± 0,01), diferentemente dos grupo RI (-0,036 ± 0,05) e CO (-11,43 ± 0,02) que apresentaram perda significativa (p<0,05). Nas demais distâncias, não foi observada diferença estatística entre os grupos. Conclusão: Todos os cimentos de ionômero de vidro aumentaram a microdureza superficial total dos blocos de esmalte mesmo após exposição ao biofilme cariogênico. No entanto, apenas o grupo RS impediu a desmineralização a 50 µm das margens de restaurações submetidas a biofilme cariogênico.


Subject(s)
Dental Materials , Composite Resins , Dental Enamel , Glass Ionomer Cements , Hardness Tests
5.
Article in English | LILACS, BBO | ID: biblio-1351206

ABSTRACT

ABSTRACT Objective To compare the capacity of silver diamine fluoride (30%) and the bioactive giomer light-curing varnish for arresting ICDAS score 5 non-retentive caries lesions. Material and Methods An in vitro analytical study was conducted using 36 healthy primary teeth, in which a cavity was created, divided into 3 groups: control (distilled and deionized water), giomer-based light-curing varnish - Barrier Coat, and Silver Diamine Fluoride 30% - Cariestop (SDF). The samples were analyzed for mineral loss as measured by surface microhardness (SMH).The Knoop microhardness test was performed using the HVS-1000 microhardness tester. The data were compared by two-way analysis of variance - treatment and time (before and after treatment) followed by Tukey's post-test. The significance level adopted in all analyzes was 5%. Results The specimens treated with giomer showed higher SMH compared to the untreated group but were similar to those of the SDF group. The SDF group, on the other hand, showed no statistically significant difference from the control group (p=0.010). Conclusion The giomer varnish had a remineralizing effect on artificial dentinal caries.


Subject(s)
Tooth, Deciduous , In Vitro Techniques , Diamines , Hardness Tests/instrumentation , Epidemiology, Experimental , Analysis of Variance , Statistics, Nonparametric , Dental Caries
6.
Article in English | LILACS, BBO | ID: biblio-1180857

ABSTRACT

ABSTRACT Objective: To determine the initial mechanical stabilization of conventional glass ionomer cements (GICs) indicated for the atraumatic restorative treatment (ART) in different storage periods. Material and Methods: Specimens were divided according to the GIC (n=12): IZ - Ion-Z, KM - Ketac Molar Easymix, RS - Riva Self Cure, and GL - Gold Label 9. They were prepared and stored in distilled water. Superficial microhardness (SMH) was evaluated (KHN) in three phases: (A) after 1, (B) 3, and (C) 7 days of storage. Data were submitted to 2-way ANOVA and Tukey tests (α = 5%). Results: The average KHN values for phases A, B, and C were, respectively, 33.05 ± 9.74; 33.21 ± 10.31 and 52.07 ± 11.75 (IZ); 50.35 ± 11.39; 66.05 ± 10.48 and 67.77 ± 13.80 (KM); 89.63 ± 15.59; 71.31 ± 23.86 and 57.70 ± 16.89 (RS); 42.18 ± 9.03; 68.54 ± 6.83 and 57.95 ± 8.24 (GL). Significant differences were observed: GIC, time, and interaction of both (p<0.05). KHN values differed between the groups, except in the GIC parameter for KM and GL. The time parameter values of phase A were lower than those of B and C, except for IZ and RS. Conclusion: The initial mechanical stabilization differed between the types of GIC tested and the storage time, and after the final period, all had similar SMH.


Subject(s)
Dental Atraumatic Restorative Treatment/instrumentation , Glass Ionomer Cements/chemistry , Hardness Tests , Molar , Zinc , Brazil , Analysis of Variance
7.
Rev. Odontol. Araçatuba (Impr.) ; 41(2): 34-39, maio-ago.2020. tab, graf
Article in Portuguese | LILACS, BBO | ID: biblio-1102682

ABSTRACT

As resinas Bulk fill surgiram com o intuito de facilitar a restauração de cavidades profundas. A fotoativação adequada é extremamente importante para que a resina bulk fill ofereça propriedades mecânicas satisfatórias e, longevidade na restauração. Este estudo avaliou a influência da espessura do incremento na microdureza Knoop (KHN) de três resinas bulk fill (n = 5). Cinquenta amostras foram divididas de acordo com o material (Filtek Z250, Filtek One Bulk Fill e Filtek Bulk Fill Flow), espessura (2mm e 4 mm) e tempo de fotoativação (20 e 40s) - Z2502mm20s, Z2502mm40s, One2mm20s, One2mm40s, One4mm20s, One4mm40s, Flow2mm20s, Flow2mm40s, Flow4mm20s e Flow4mm40s. As análises KHN foram realizadas no topo e na base de cada amostra. Os dados foram submetidos à ANOVA a 1 critério e ao Teste de Tukey (p< 0,05). A média e desvio padrão (+/-) dos seguintes grupos foram (Z2502mm20s) 0,85 (+/- 0,01); (Z2502mm40s) 0,92 (+/- 0,01); (One2mm20s) 1,05 (+/- 0,08); (One2mm40s) 0,95 (+/- 0,04); (One4mm20s) 0,93 (+/- 0,04); (One4mm40s) 0,97 (+/ - 0,04); (Flow2mm20s) 0,92 (+/- 0,05); (Flow2mm40s) 0,89 (+/- 0,04); (Flow4mm20s) 0,79 (+/- 0,04) e (Flow4mm40s) 0,90 (+/- 0,03). Os grupos da Filtek One Bulk apresentaram um valor significativamente maior, demonstrando uma polimerização suficiente mesmo na base de incrementos com 4 mm. Concluiu-se que o aumento na espessura do incremento de resinas bulk fill não afetou negativamente a fotoativação(AU)


Bulk fill composites emerged, allowing the restoration of deep cavities easily. Appropriate lightcuring is crucial to bulk fill composite presents satisfactory mechanical properties and restoration longevity. This study evaluated the influence of thickness increment on Knoop microhardness (KHN) of three dental bulk fill composites (n=5). Fifty samples were divided according to composite (Filtek Z250, Filtek One Bulk Fill and Filtek Bulk Fill Flow), thickness (2mm and 4 mm) and time lightcuring (20 and 40 s) - Z2502mm20s, Z2502mm40s, One2mm20s, One2mm40s, One4mm20s, One4mm40s, Flow2mm20s, Flow2mm40s, Flow4mm20s e Flow4mm40s. KHN analysis were performed on the top and the base of each specimen. Data were subjected to one-way ANOVA and Tukey test (p< 0,05). The mean and standard deviation (+/-) of following groups were (Z2502mm20s) 0,85(+/-0,01); (Z2502mm40s) 0,92(+/- 0,01); (One2mm20s) 1,05(+/-0,08); (One2mm40s) 0,95(+/-0,04); (One4mm20s) 0,93 (+/-0,04); (One4mm40s) 0,97(+/-0,04); (Flow2mm20s) 0,92(+/- 0,05); (Flow2mm40s) 0,89(+/-0,04); (Flow4mm20s) 0,79(+/-0,04) e (Flow4mm40s) 0,90(+/-0,03) Filtek One Bulk groups present significantly higher value, demonstrating sufficient polymerization even on the base of 4 mm increments. It was concluded that the increase in the thickness increment of Bulk fill composites did not negatively affect the lightcure(AU)


Subject(s)
Composite Resins , Hardness Tests , Dental Materials , Polymerization
8.
Rev. cuba. estomatol ; 57(2): e2901, abr.-jun. 2020. tab, graf
Article in Portuguese | LILACS, CUMED | ID: biblio-1126500

ABSTRACT

RESUMO Introdução: Os estudos científicos acerca das propriedades físicas e mecânicas apresentadas pelas resinas compostas são cada vez mais necessários diante da grande variedade de produtos disponíveis no mercado atual, resultante do aumento de sua demanda dentro da odontologia que preza por preparos minimamente invasivos com a devolução das características estéticas e funcionais do elemento dentário. Objetivo: Avaliar e comparar a microdureza e porosidade das resinas compostas fotopolimerizavéis Filtek Z350 XT 3M e Zirconfill Technew. Métodos: Foram confeccionados 10 corpos de prova por amostra (n= 10) submetidos a teste microdureza Vickers e porosidade por microtomografia computadorizada. Resultados: Com relação à presença de porosidades, dada em porcentagem, o grupo da Filtek apresentou os menores valores médios. Quando comparado estatisticamente, os grupos apresentaram diferença estatística (p= 0,019), com uma magnitude de efeito alta. Com relação aos valores de microdureza, o grupo da Filtek apresentou os maiores valores médios. Quando comparados estatisticamente, os grupos não apresentaram diferença estatística (p > 0,05). Conclusões: A porosidade foi significativamente diferente entre os grupos estudados, sendo o grupo Filtek Z350XT de menor percentual. No entanto, os grupos não apresentaram diferença estatística para microdureza, apesar do grupo Filtek Z350XT ter apresentado maior valor médio(AU)


RESUMEN Introducción: Los estudios científicos sobre las propiedades físicas y mecánicas presentadas por las resinas compuestas son cada vez más necesarios ante la gran variedad de productos disponibles en el mercado actual, resultante del aumento de su demanda dentro de la odontología que aprecia por preparaciones mínimamente invasivas con la devolución de las características estéticas y funcionales del elemento dental. Objetivo: Evaluar y comparar la microdureza y porosidad de las resinas compuestas fotopolimerizables Filtek Z350 XT 3M y Zirconfill Technew. Métodos: Se han confeccionado 10 cuerpos de prueba por muestra (n= 10) sometidos a prueba de microdureza Vickers y porosidad por microtomografía computarizada. Resultados: Con respecto a la presencia de porosidades, dada en porcentaje, el grupo de Filtek presentó los menores valores medios. Cuando se comparó estadísticamente, los grupos presentaron una diferencia estadística (p= 0,019), con una magnitud de efecto alto. Con respecto a los valores de microdureza, el grupo de Filtek presentó los mayores valores medios. Cuando se comparó estadísticamente, los grupos no presentaron una diferencia estadística (p> 0,05). Conclusiones: La porosidad fue significativamente diferente entre los grupos estudiados, siendo el grupo Filtek Z350XT de menor porcentaje. Sin embargo, los grupos no presentaron diferencia estadística para microdureza, a pesar de que el grupo Filtek Z350XT presentó un valor medio más alto(AU)


ABSTRACT Introduction: Scientific studies about the physical and mechanical properties of composite resins are increasingly needed in view of the wide variety of products available in the market today, resulting from the increase in their demand for dental care purposes, with a preference for minimally invasive preparations aimed at restoring the esthetic and functional characteristics of the treated element. Objective: Evaluate and compare the microhardness and porosity of the photopolymerizable composite resins Filtek Z350 XT and Zirconfill Technew. Methods: Ten test bodies were developed per sample (n= 10) and subjected to Vickers microhardness and porosity testing by computerized microtomography. Results: With respect to the presence of porosity, expressed in percentages, the Filtek group had the lowest mean values. When compared statistically, the two groups showed a statistical difference (p= 0.019) with a high effect magnitude. Regarding microhardness, the Filtek group had the highest mean values. Statistical comparison did not find any difference between the groups (p> 0.05). Conclusions: Porosity was significantly different in the groups studied, the Filtek Z350XT group exhibiting the lowest percentage. However, the groups did not show any statistical difference concerning microhardness, despite the fact that the Filtek Z350XT group had a higher mean value(AU)


Subject(s)
Humans , Dental Care/adverse effects , Composite Resins/adverse effects , X-Ray Microtomography/methods , Hardness Tests/methods , Physical Properties
9.
Braz. dent. sci ; 23(3): 1-11, 2020. tab, ilus
Article in English | LILACS, BBO | ID: biblio-1116331

ABSTRACT

Objective: To compare the remineralization potential of theobromine and sodium fluoride gels on artificial caries like lesion. Materials and Methods: Forty longitudinal halves of human mandibular premolars were equally divided into 4 groups of 10 samples each: control group (C), samples were stored in distilled water during the experiment period. The remaining 30 specimens were subjected to demineralization protocol to create caries like lesions. samples were immersed for three days in a demineralization solution (pH 5.0) containing 0.2% carbopol and 0.1% lactic acid saturated with calcium phosphate tribasic. The samples were subdivided into 3 equal groups according to the treatment applied during the pH cycle. Demineralization group "D": no treatment applied. Group "F" treated with 2000 mg/liter sodium fluoride gel. Group "T" treated with 200 mg/liter theobromine gel. The specimens of the two studies groups were subjected to Demineralization- Remineralization PH Cycle Protocol for 5 days (Alternating four steps: 1: Treatment material, fluoride or theobromine ˜= 3 minutes. 2: Demineralizing solution 3 hours. 3: treatment material ˜= 3 minutes. 4: Remineralizing solution till the next cycle). The samples were investigated by scanning electron microscope (SEM) and energy dispersive x-ray analysis (EDXA). Results: The enamel of the demineralization group was porous with artificial caries like changes exposing the subsurface enamel rods with severe rod core defects. Theobromine gel and fluoride gel groups showed marked improvement in the surface characteristics in the enamel in both groups. Theobromine gel group showed more observable enamel surface improvement than the fluoride gel group. EDXA revealed that the calcium-phosphorus ratio displayed a descending order: (C > T > F > D). The differences between the two tested groups were not statistically significant. Conclusion: Theobromine gel had more effective remineralizing potential than fluoride gel as a result of its effect in improving the enamel surface characteristics of human teeth. (AU)


Objetivo: Comparar o potencial de remineralização dos géis de teobromina e fluoreto de sódio em lesões de cáries artificiais. Materiais e Métodos: Quarenta metades longitudinais de pré-molares inferiores humanos foram igualmente divididas em 4 grupos de 10 amostras cada: grupo controle (C), as amostras foram armazenadas em água destilada durante o período do experimento. As 30 amostras restantes foram submetidas ao protocolo de desmineralização paracriar lesões artificiais de cárie. As amostras foram imersas por três dias em uma solução de desmineralização (pH 5,0) contendo 0,2% de carbopol e 0,1% de ácido lático saturado com fosfato de cálcio tribásico. As amostras foram subdivididas em 3 grupos iguais, de acordo com o tratamento aplicado durante o ciclo do pH. Grupo de desmineralização "D": nenhum tratamento aplicado. Grupo "F" tratado com 2000 mg / litro de fluoreto de sódio em gel. Grupo & quot;T &q uot; tratado com 200 mg / litro de gel de teobromina. As amostras dos dois grupos de estudo foram submetidas ao protocolo de ciclo de desmineralização - remineralização por 5 dias (quatro etapas alternativas: 1: material de tratamento, flúor ou teobromina ˜= 3 minutos. 2: solução desmineralizante 3 horas. 3: material de tratamento ˜= 3 minutos 4: Solução de remineralização até o próximo ciclo). As amostras foram investigadas por microscopia eletrônica de varredura(MEV) e análise de raios-x dispersivos de energia (EDXA). Resultados: O esmalte do grupo de desmineralização era poroso, com cáries artificiais, como alterações que expunham as hastes de esmalte do subsolo com graves defeitos no núcleo da haste. Os grupos gel de teobromina e flúor apresentaram melhora acentuada nas características da superfície do esmalte nos dois grupos. O grupo gel de teobromina mostrou uma melhoria na superfície do esmalte mais observável do que o grupo gel de fluoreto. A EDXA revelou que a razão cálcio-fósforo exibia uma ordem decrescente: (C> T> F> D). As diferenças entre os dois grupos testados não foram estatisticamente significantes. Conclusão: O gel de teobromina teve um potencial remineralizante mais eficaz que o gel de flúor como resultado de seu efeito na melhoria das características da superfície do esmalte dos dentes humanos. (AU)


Subject(s)
Humans , Sodium Fluoride/therapeutic use , Theobromine/therapeutic use , Dental Caries , Dental Enamel/ultrastructure , Hardness Tests , Microscopy
10.
Article in English | LILACS-Express | LILACS, BBO | ID: biblio-1135499

ABSTRACT

Abstract Objective: To evaluate the effect of immersion and acid challenge with cola drink on color change (ΔE), Vickers hardness (VHN) and surface roughness (Ra) of artificial acrylic resin teeth. Material and Methods: The artificial teeth were divided into 6 groups (n= 8): TC (Trilux/Control), BC (Biotone/Control), TAC (Trilux/Acid challenge), BAC (Biotone/Acid challenge), TI (Trilux/Immersion) and BI (Biotone/Immersion). The teeth were embedded in acrylic resin and the labial side was serially polished to provide appropriate flat surface. The samples of TC, BC, TI, BI groups were immersed in artificial saliva and cola drink (coke) for 7 days, respectively. The acid challenge was performed with immersion of samples in coke for 5 min, and subsequently immersion in artificial saliva for 2h. This cycle was repeated at 4 times/day, during 7 days. The tests of VHN, ΔE and Ra were analyzed before and after the challenge and immersion groups. Data was analyzed by ANOVA, Tukey and T test (α = 0.05). Results: There was no difference in Ra values between groups after treatments. However, there was a decrease in VHN for all groups. BI (19.2 ± 0.3) presented significantly lower hardness than BAC (19.5 ± 0.9) and BC (20.2 ± 0.5). Groups BI (2.18 ± 0.41) and TI (1.50 ± 0.43) had statistically higher ΔE compared to the other groups. Conclusion: The hardness of resin teeth decreased after acid challenges, but the roughness surface was not affected. The color was more affected by the times of exposure in cola beverage and remineralization in artificial saliva, which were associated to the material degradation.


Subject(s)
Tooth, Artificial , Acrylic Resins/chemistry , In Vitro Techniques/methods , Dental Prosthesis , Physical Properties , Beverages , Brazil , Analysis of Variance , Cola/chemistry , Hardness Tests/instrumentation
11.
Braz. oral res. (Online) ; 34: e053, 2020. tab, graf
Article in English | LILACS, BBO | ID: biblio-1132666

ABSTRACT

Abstract The objective was to evaluate the compressive strength (CS), diametral tensile strength (DTS), flexural strength (FS), and Knoop microhardness (KH) of different conventional restorative glass-ionomer cements (GICs) and to correlate these mechanical properties (MP) with the stabilization time (ST) of their chemical bonds. Eighteen GICs were tested: Bioglass [B], Chemfil Rock [CR], Equia Forte [EF], Gold Label 2 [GL2], Gold Label 9 [GL9], Glass Ionomer Cement II [GI], Ionglass [IG], Ion Z[ IZ], Ionomaster [IM], Ionofil Plus [IP], Ionostar Plus [IS], Ketac Molar Easymix [KM], Magic Glass [MG], Maxxion R [Ma], Riva Self Cure [R], Vidrion R [V], Vitro Fil [VF] and Vitro Molar [VM]. The mechanical strength tests were performed in a universal testing machine. KH readings were done with a diamond indenter. STs were examined by Fourier Transform Infrared spectroscopy (FTIR). Data were analyzed with ANOVA and Tukey test (p<0.05). The Spearman rank test was used to evaluate the dependence between the MPs and ST results. The highest MP values were EF, GL2, GL9, GI and KM and the lowest for MG, MA, B, VF and IM. The longest ST was for GL2 and the shortest was for B. ST correlated positively with MP. GICs with longer chemical bonds ST are generally stronger and the ST value obtained from FTIR was useful in predicting the strength of GICs tested.


Subject(s)
Self-Curing of Dental Resins/methods , Glass Ionomer Cements/chemistry , Reference Values , Tensile Strength , Time Factors , Materials Testing , Reproducibility of Results , Analysis of Variance , Spectroscopy, Fourier Transform Infrared , Compressive Strength , Flexural Strength , Hardness Tests
12.
J. appl. oral sci ; 28: e20190005, 2020. tab, graf
Article in English | LILACS | ID: biblio-1056579

ABSTRACT

Abstract Chitosan is a natural, biocompatible chelating substance with potential for dental use. This study compared the effects of final canal irrigation with chitosan and EDTA on dentin microhardness, sealer dentin tubules penetration capacity, and push-out strength. Methodology: Fifty canine roots were distributed according to the final irrigation protocol (n=10): G1- 15% EDTA with conventional irrigation; G2- 15% EDTA with Endovac; G3- 0.2% chitosan with conventional irrigation; G4- 0.2% chitosan with Endovac; and G5- without irrigation. Specimens were obturated (AH Plus) and sectioned in 3 slices per root third. The first slice was used for microhardness and sealer penetration assessments under a laser confocal microscope. The second was utilized in a push-out strength test. The third slice was discarded. Data were analyzed using 2-way ANOVA and Tukey's post hoc test (α<0.05). Failure mode was determined at x40 magnification. Results: Microhardness reduction was more significant in groups G2 and G4 (p<0.05). Sealer penetration through dentin was significantly greater in group G2 (p<0.05). There was no significant difference between groups G1, G3, and G4 (p>0.05). In general, all experimental groups presented similar bond resistance (p>0.05) that significantly differed from the control (p<0.001). Mixed type failures were predominant. Conclusions: In general, 0.2% chitosan and 15% EDTA solutions act in a similar manner with regard to the variables studied. The use of Endovac potentiates the effect of these solutions.


Subject(s)
Humans , Root Canal Irrigants/chemistry , Chelating Agents/chemistry , Dental Bonding/methods , Edetic Acid/chemistry , Dentin/drug effects , Chitosan/chemistry , Reference Values , Root Canal Filling Materials/chemistry , Surface Properties/drug effects , Materials Testing , Reproducibility of Results , Analysis of Variance , Microscopy, Confocal , Shear Strength , Epoxy Resins/chemistry , Hardness Tests , Middle Aged
13.
J. oral res. (Impresa) ; 8(4): 310-315, nov. 5, 2019. tab
Article in English | LILACS | ID: biblio-1145353

ABSTRACT

Purpose: This in vitro study aimed to evaluate the influence of the manual manipulation of two composite resins: Filtek™ Z350XT (3M ESPE) and Herculite Précis® (Kerr), with latex gloves contaminated with powder, human saliva and alcohol, on the microhardness values. Material and Methods: Manual manipulation was evaluated using latex gloves with powder, latex gloves without powder, latex gloves without powder with saliva, latex gloves without powder with alcohol, and without hand manipulation or contaminants (control). Each resin was manually manipulated for 10 seconds and photoactivated for 20 seconds with a light intensity of 1000mW/cm2 using a VALO ­Ultradent LED light­ cured unit, and then each sample was evaluated on the microhardness Vickers tester Leitz (Wetzlar). The collected data were analyzed using Kruskal ­Wallis and Mann ­ Whitney post-test (p<0.05). Results. Microhardness values showed a significant difference between the evaluated and control groups, showing lower microhardness values in the group of latex glove with powder for Filtek™ Z350XT and the group of latex glove without powder with saliva for Herculite Précis®. Conclusion. The manual manipulation of composite resins decreases their surface microhardness.


Propósito: Este estudio in vitrotuvo como objetivo evaluar la influencia de la manipulación manual de dos resinas compuestas: Filtek ™ Z350XT (3M ESPE) y Herculite Précis® (Kerr), con guantes de látex contaminados con polvo, saliva humana y alcohol, sobre los valores de microdureza. Material y Métodos: La manipulación manual se evaluó utilizando guantes de látex con polvo, guantes de látex sin polvo, guantes de látex sin polvo con saliva, guantes de látex sin polvo con alcohol, y sin manipulación manual o contaminantes (control). Cada resina fue manipulada manualmente durante 10 segundos y fotoactivada durante 20 segundos con unaintensidad de luz de 1000mW/cm2 usando una unidad de fotocuración LED VALO - Ultradent, y luego cada muestra fue evaluada en el tester de microdureza Vickers Leitz (Wetzlar). Los datos recopilados se analizaron utilizando Kruska ­Wallis y post-test Mann­ Whitney (p<0.05). Resultados: Se observó una diferencia significativa en los valores de microdureza entre los grupos evaluados y el grupo control, con valores más bajos de microdureza en el grupo de guantes de látex con polvo para Filtek™ Z350XT y el grupo de guantes de látex sin polvo con saliva para Herculite Précis®. Conclusión. La manipulación manual de resinas compuestas disminuye su microdureza superficial.


Subject(s)
Humans , Composite Resins , Dental Materials/adverse effects , Gloves, Surgical , Hardness Tests , Permeability , In Vitro Techniques , Physical Contaminants/adverse effects , Environmental Pollutants/adverse effects , Latex/chemistry
14.
Pesqui. bras. odontopediatria clín. integr ; 19(1): 4073, 01 Fevereiro 2019. tab
Article in English | LILACS, BBO | ID: biblio-997964

ABSTRACT

Objective: To evaluate the impact of radiotherapy on enamel around restorations of glass ionomer cement (GIC) and fluoride tooth paste (FTP). Material and Methods: Eighty enamel blocks were made and randomly distributed into two groups, according to the fluoride therapy, non-fluoride tooth paste (NFTP) and FTP (n=40) and in subgroups in conformity with radiation dose (0, 10, 30 and 60 Gy). Roughness and microhardness enamel analyses were conducted before radiotherapy. Enamel cavities were made and restored with two GIC (Ketac Molar Easy Mix or Vitremer). Enamel blocks were submitted to 10, 30 and 60 Gy. Then, artificial enamel caries lesions were created by a pH-cycling procedure and FTP or NFTP were used as treatment. The restored enamel blocks were submitted to final roughness and microhardness analyses. Roughness increase (ΔR) and hardness loss (ΔH) values of enamel were submitted to ANOVA and Tukey test (p=0.05). Results: The irradiated enamel group showed statistically higher ΔR (0.44 ±0.2) and ΔH (99.26±7.0) values compared to non-irradiated group (ΔR = 0.051±0.02; ΔH=66.16±12.7) when a resin-modified GIC and NFTP were used. Conclusion: Higher radiation dose increased dissolution of bovine enamel. The use of GIC associated with FTP decreased roughness and increased enamel hardness after radiotherapy.


Subject(s)
Radiotherapy/methods , Tooth Remineralization/adverse effects , In Vitro Techniques/methods , Dental Enamel , Glass Ionomer Cements/radiation effects , Brazil , Analysis of Variance , Hardness Tests/methods
15.
J. appl. oral sci ; 27: e20180593, 2019. tab, graf
Article in English | LILACS, BBO | ID: biblio-1019973

ABSTRACT

Abstract There is growing evidence that C. albicans is associated with dental caries, but its role on caries development needs to be better clarified. Objective: To evaluate at the hard tissue level the effect of C. albicans on the cariogenic potential of S. mutans biofilms focusing on the mineral profile of induced carious lesions. This study also aimed to evaluate the effect of C. albicans on the acidogenic potential of S. mutans biofilms. Methodology: Dual-species (CA+SM) and single-species biofilms (CA or SM) were grown on the surface of enamel slabs in the presence of glucose/sucrose supplemented culture medium for 24, 48 and 72 hours. Demineralization was evaluated through percentage of surface microhardness change (%SMC) and transversal microradiography analysis (ILM and LD) and pH of the spent medium was recorded daily. Data were analyzed by two-way ANOVA followed by Bonferroni correction. Results: %SMC was statistically different among the biofilms at each time point being the highest for SM biofilms and the lowest for CA biofilms which also differed from CA+SM biofilms [SM (24 h: 47.0±7.3; 48 h: 66.3±8.3; 72 h: 75.4±3.9); CA (24 h: 7.3±3.3; 48 h: 7.1±6.4; 72 h: 6.6±3.6); CA+SM (24 h: 35.9±7.39.1; 48 h: 47.2±9.5; 72 h: 47.6±9.5)]. pH of spent medium was statistically lower for SM biofilms compared to the other biofilms at each time point and remained constant over time while pH values increased from 24 to 72 h for both CA and CA+SM biofilms [SM (24 h: 4.4±0.1; 48 h: 4.4±0.1; 72 h: 4.5±0.1); CA (24 h: 6.9±0.3; 48 h: 7.2±0.2; 72 h: 7.5±0.2); CA+MS (24 h: 4.7±0.2; 48 h: 5.1±0.1; 72 h: 6.1±0.6)]. IML and LD for SM biofilms increased over time while no difference was observed from 24 to 72 h for the other biofilms. Conclusions: The present data suggest that C. albicans has low enamel demineralization potential and the presence of C. albicans can reduce both the cariogenic and acidogenic potentials of S. mutans biofilms.


Subject(s)
Animals , Cattle , Streptococcus mutans/metabolism , Candida albicans/physiology , Tooth Demineralization/microbiology , Biofilms/growth & development , Dental Enamel/microbiology , Reference Values , Surface Properties , Time Factors , Acids/metabolism , Microradiography/methods , Colony Count, Microbial , Dental Enamel/chemistry , Hardness Tests , Hydrogen-Ion Concentration
16.
J. appl. oral sci ; 27: e20180262, 2019. tab
Article in English | LILACS, BBO | ID: biblio-1019969

ABSTRACT

Abstract The incorporation of antimicrobials in the composites as an attempt to reduce bacterial adhesion without jeopardizing mechanical properties is a challenge for Dentistry. Objective: To evaluate the bacterial adhesion and physical properties of a composite containing the methacrylate triclosan- derivative monomer (TM). Methodology: TM was synthesized and added to an experimental composite. Samples were divided into two groups: Control and TM (13.4 wt%). Antibacterial Activity: Three specimens of each material were prepared and placed on bacterial suspensions of Streptococcus mutans for 1, 5 and 10 days. After these periods the counting of the colonies (log10) was performed. Assays was performed in triplicate. Physical Properties: Three-body Abrasion (TBA): Ten specimens of each material were prepared and stored at 37°C/24 h. The surface roughness (Ra) and hardness (KHN) were analyzed. Next, the specimens were submitted to abrasive wear (30,000 cycles) and re-evaluated for Ra and KHN; Sorption/solubility (SS): cylindrical specimens (n=10) were prepared and weighted. The specimens were immersed in deionized water for 7 days at 37°C and then their weight was verified again. SS were calculated using accepted formulas; Diametral tensile strength (DTS): specimens (n=10) underwent test performed in an Instron universal testing machine at a crosshead speed of 1 mm/min. Data were submitted to appropriate statistical tests according to data distribution and assay (p<0.05). Results: Bacterial Adhesion: TM showed a significant reduction on biofilm accumulation in the evaluated periods: 1 day (1.537±0.146); 5 days (2.183±0.138) and 10 days (4.469±0.155) when compared with Control: 1 day (4.954±0.249); 5 days (5.498±0.257) and 10 days (6.306±0.287). Physical Properties: For TBA, SS and DTS no significant difference was found between groups Control and TM. The incorporation of methacrylate triclosan-based monomer in the experimental composite reduce bacterial adhesion of S. mutans and did not affect important polymer properties.


Subject(s)
Triclosan/chemistry , Composite Resins/chemistry , Methacrylates/chemistry , Anti-Bacterial Agents/chemistry , Reference Values , Solubility , Streptococcus mutans/drug effects , Surface Properties , Tensile Strength , Time Factors , Toothbrushing , Triclosan/pharmacology , Bacterial Adhesion/drug effects , Materials Testing , Colony Count, Microbial , Reproducibility of Results , Composite Resins/pharmacology , Hardness Tests , Methacrylates/pharmacology , Anti-Bacterial Agents/pharmacology
17.
Rev. odontol. UNESP (Online) ; 48: e20190052, 2019. tab, graf
Article in Portuguese | LILACS, BBO | ID: biblio-1043172

ABSTRACT

Resumo Introdução Dentes artificiais têm sido empregados para a prática de ensino pré-clínico. Porém, não se sabe o comportamento dos mesmos frente aos diferentes procedimentos realizados durante um tratamento endodôntico simulado. Objetivo Avaliar a microdureza de réplicas de dentes humanos, frente a diferentes soluções irrigadoras. Material e método Quarenta e cinco incisivos centrais superiores artificiais de três marcas comerciais nacionais (dentes "A", "B" e "C") e 15 incisivos humanos foram utilizados. As amostras foram seccionadas a 5 mm do ápice dentário. Os fragmentos radiculares foram fixados em resina para posterior teste de microdureza. Os ensaios da microdureza Knoop foram realizados em dois momentos: momento 1 - microdureza inicial; momento 2 - microdureza final, que foi feita após o uso das soluções irrigadoras (Cloreto de Sódio a 0,9%, Hipoclorito de Sódio a 2,5% e Gluconato de Clorexidina a 2%). As endentações deixadas na superfície da amostra foram mensuradas. O valor obtido para microdureza de cada amostra foi feita com base na média de três endentações. Para análise estatística, foram utilizados os testes ANOVA e Teste t pareado, com nível de significância de 5%. Resultado Os dentes artificiais "A" e "C" apresentaram valores inferiores de microdureza quando comparados ao dente humano (P = 0,05). Não houve diferença estatística entre os dentes artificiais "B" e o dente humano (P = 0,2428). Quanto ao uso das diferentes soluções irrigadoras, também não houve diferença na microdureza das peças dentárias. Conclusão Embora a solução irrigadora não tenha influenciado a microdureza, os dentes artificiais apresentaram valores de dureza inferiores aos do dente humano.


Abstract Introduction Artificial teeth have been used for preclinical teaching practice. However, the behavior of the same is not known in relation to the different procedures performed during a simulated endodontic treatment. Objective To evaluate the microhardness of replicates of human teeth, in front of different irrigating solutions. Material and method Forty-five artificial upper central incisors of three national trade marks (teeth "A", "B" and "C") and fifteen human incisors were used. Samples were sectioned 5 mm from the apex. The root fragments were fixed in resin for later microhardness test. The Knoop microhardness tests were performed in two moments: moment 1 - initial microhardness; moment 2 - final microhardness, which was done after the use of the irrigating solutions (0.9% sodium chloride, 2.5% sodium hypochlorite and 2% chlorhexidine gluconate). The indentations left on the sample surface were measured. The obtained value for microhardness of each sample was made based on the average of three indentations. ANOVA and Paired t-test were used for statistical analysis. Significance level of 5%. Result Artificial teeth "A" and "C" presented lower values ​​of microhardness when compared to human teeth (P = 0.05). There was no statistical difference between the artificial teeth "B" for the human (P = 0.2428). Regarding the use of different irrigation solutions, there was also no difference in the microhardness of dental pieces. Conclusion Although the irrigating solution did not influence the microhardness, the artificial teeth presented values ​​of hardness inferior to the human tooth.


Subject(s)
Sodium Hypochlorite , Tooth, Artificial , Sodium Chloride , Chlorhexidine , Hardness Tests , Education, Dental , Endodontics
18.
Belo Horizonte; s.n; 2019. 138 p. ilus, tab.
Thesis in English, Portuguese | LILACS, BBO | ID: biblio-1016737

ABSTRACT

Dentes bovinos têm sido utilizados como substitutos aos humanos em pesquisas odontológicas. Entretanto, faltam dados que suportem o uso da dentina radicular bovina, sobretudo, que analisem o efeito da idade nas propriedades do substrato. Assim, analisou-se o efeito da idade nos aspectos morfológicos, químicos e físicos das dentinas radiculares humana e bovina, em função dos terços da raiz. Trata-se de um estudo experimental, in vitro, aprovado pelo Comitê de Ética em Pesquisa (COEP-UFMG 1.803.933) e pela Comissão de Ética no Uso de Animais (CEUAUFMG 372/2016). A amostra foi composta por dentes unirradiculares, cujas dentinas radiculares foram categorizadas em: humana jovem (HJ, 20-30 anos); humana madura (HM, acima de 60 anos); bovina jovem (BJ, 24-36 meses); e bovina adulta (BA, acima de 48 meses). Os dentes foram seccionados abaixo da junção amelocementária e ao longo eixo da raiz, para a obtenção de hemisecções. Uma hemisecção foi escolhida e cortes foram feitos para a obtenção dos espécimes, conforme cada método de análise. Para as análises dos aspectos morfológicos ­ número, diâmetro e área dos túbulos dentinários ­ os espécimes foram analisados em Microscópio Eletrônico de Varredura. A composição química foi analisada por Espectroscopia de Raios X por Dispersão em Energia, Espectroscopia por Comprimento de Onda Dispersivo e Espectroscopia Raman por Transformada de Fourier. Na análise das propriedades mecânicas, os espécimes foram submetidos aos testes de nanoindentação, resistência à flexão em três pontos e compressão. Para a análise da resistência ao cisalhamento por extrusão, as raízes receberam tratamento endodôntico e foram fixados pinos de fibra de vidro com cimentos resinosos (dual convencional e autoadesivo). As raízes foram seccionadas nos terços radiculares e os espécimes testados em máquina universal de ensaios. Adicionalmente, avaliou-se o grau de conversão dos cimentos resinosos. Os dados foram analisados em software estatístico, nível de significância de 5%. A HM apresentou os menores valores para número, diâmetro e área de túbulos dentinários (p<0,05). A HM apresentou maiores valores de cálcio, razão Ca/P e concentração mineral relativa, com diminuição na organização e qualidade do colágeno (p<0,05). A HM apresentou os maiores valores de nanodureza, módulo de elasticidade e resistência à compressão, mas os menores valores de resistência à flexão e módulo de elasticidade à flexão (p<0,05). A HM apresentou os menores valores de resistência de união, com diferenças entre os terços radiculares (p<0,05). O grau de conversão dos cimentos apresentou uma diminuição ao longo dos terços radiculares (p<0,05). Concluiu-se que a idade possui um efeito nos aspectos morfológicos, químicos e físicos da dentina radicular humana, sem efeito na dentina bovina. Assim, quando da necessidade de substituição da dentina radicular humana pela bovina em pesquisas, é necessário considerar o efeito da idade nos desfechos analisados.


Bovine teeth have been used as a substitute for human teeth in dental research. However, there is a lack of data that support the use of bovine root dentin, mainly, that analyze the effect of age on the properties of the substrate. Thus, the effect of age on the morphological, chemical and physical aspects of human and bovine root dentin was analyzed, in function of the root thirds. This is an in vitro experimental study, approved by the Research Ethics Committee (protocol number: 1.803.933) and the Ethics Committee on the Use of Animals (protocol number: 372/2016). The sample was composed of single-rooted teeth and root dentin was categorized into: young human (YH, 20-30 years); old human (OH, above 60 years); young bovine (YB, 24-36 months); and adult bovine (AB, over 48 months). The roots were sectioned below the cement-enamel and longitudinally to produce two hemi-sections. One hemi-section was chosen and sections were made to obtain the specimens, according to each method of analysis. For the analyzes of the morphological aspects - number, diameter and area of the dentinal tubules - the specimens were analyzed in Scanning Electron Microscope. The chemical composition was analysed by Energy Dispersive Spectroscopy, Wavelength Dispersive Spectroscopy and Fourier Transformed Raman Spectroscopy. In the analysis of the mechanical properties, the specimens were submitted to nano-indentation, three-point flexural and compression tests. For the analysis of the push-out bond strength test, the roots received endodontic treatment and fiber post with resin cements (conventional and selfadhesive dual) were fixed. The roots were sectioned in the root thirds and the specimens tested in a universal testing machine. Additionally, the degree of conversion of the resin cements was evaluated. The data were analyzed in statistical software, level of significance of 5%. The OH presented the lowest values for number, diameter and area of dentinal tubules (p<0.05). OH showed higher values of calcium, Ca/P ratio and relative mineral concentration, with decrease in the organization and quality of the collagen (p<0.05). The OH showed the highest values of nano-hardness, elastic modulus and compressive strength, but the lowest values of flexural strength and flexural modulus (p<0.05). The OH presented the lowest values of bond strength, with differences among the root thirds (p<0.05). The degree of conversion of the cements showed a decrease along the root thirds (p<0.05). It was concluded that age has an effect on the morphological, chemical and physical aspects of human root dentin, with no effect on bovine dentin. Thus, when it is necessary to replace the human root dentin by the bovine in research, it is necessary to consider the effect of age on the analysed outcomes.


Subject(s)
Tooth Root , Resin Cements , Dental Pins , Dentin/anatomy & histology , Fractures, Compression , Flexural Strength , Hardness Tests , In Vitro Techniques , Microscopy, Electrochemical, Scanning , Microscopy
19.
Belo Horizonte; s.n; 2019. 138 p. ilus, tab, graf.
Thesis in English, Portuguese | LILACS, BBO | ID: biblio-1016420

ABSTRACT

Dentes bovinos têm sido utilizados como substitutos aos humanos em pesquisas odontológicas. Entretanto, faltam dados que suportem o uso da dentina radicular bovina, sobretudo, que analisem o efeito da idade nas propriedades do substrato. Assim, analisou-se o efeito da idade nos aspectos morfológicos, químicos e físicos das dentinas radiculares humana e bovina, em função dos terços da raiz. Trata-se de um estudo experimental, in vitro, aprovado pelo Comitê de Ética em Pesquisa (COEP-UFMG 1.803.933) e pela Comissão de Ética no Uso de Animais (CEUAUFMG 372/2016). A amostra foi composta por dentes unirradiculares, cujas dentinas radiculares foram categorizadas em: humana jovem (HJ, 20-30 anos); humana madura (HM, acima de 60 anos); bovina jovem (BJ, 24-36 meses); e bovina adulta (BA, acima de 48 meses). Os dentes foram seccionados abaixo da junção amelocementária e ao longo eixo da raiz, para a obtenção de hemisecções. Uma hemisecção foi escolhida e cortes foram feitos para a obtenção dos espécimes, conforme cada método de análise. Para as análises dos aspectos morfológicos ­ número, diâmetro e área dos túbulos dentinários ­ os espécimes foram analisados em Microscópio Eletrônico de Varredura. A composição química foi analisada por Espectroscopia de Raios X por Dispersão em Energia, Espectroscopia por Comprimento de Onda Dispersivo e Espectroscopia Raman por Transformada de Fourier. Na análise das propriedades mecânicas, os espécimes foram submetidos aos testes de nanoindentação, resistência à flexão em três pontos e compressão. Para a análise da resistência ao cisalhamento por extrusão, as raízes receberam tratamento endodôntico e foram fixados pinos de fibra de vidro com cimentos resinosos (dual convencional e autoadesivo). As raízes foram seccionadas nos terços radiculares e os espécimes testados em máquina universal de ensaios. Adicionalmente, avaliou-se o grau de conversão dos cimentos resinosos. Os dados foram analisados em software estatístico, nível de significância de 5%. A HM apresentou os menores valores para número, diâmetro e área de túbulos dentinários (p<0,05). A HM apresentou maiores valores de cálcio, razão Ca/P e concentração mineral relativa, com diminuição na organização e qualidade do colágeno (p<0,05). A HM apresentou os maiores valores de nanodureza, módulo de elasticidade e resistência à compressão, mas os menores valores de resistência à flexão e módulo de elasticidade à flexão (p<0,05). A HM apresentou os menores valores de resistência de união, com diferenças entre os terços radiculares (p<0,05). O grau de conversão dos cimentos apresentou uma diminuição ao longo dos terços radiculares (p<0,05). Concluiu-se que a idade possui um efeito nos aspectos morfológicos, químicos e físicos da dentina radicular humana, sem efeito na dentina bovina. Assim, quando da necessidade de substituição da dentina radicular humana pela bovina em pesquisas, é necessário considerar o efeito da idade nos desfechos analisados.


Bovine teeth have been used as a substitute for human teeth in dental research. However, there is a lack of data that support the use of bovine root dentin, mainly, that analyze the effect of age on the properties of the substrate. Thus, the effect of age on the morphological, chemical and physical aspects of human and bovine root dentin was analyzed, in function of the root thirds. This is an in vitro experimental study, approved by the Research Ethics Committee (protocol number: 1.803.933) and the Ethics Committee on the Use of Animals (protocol number: 372/2016). The sample was composed of single-rooted teeth and root dentin was categorized into: young human (YH, 20-30 years); old human (OH, above 60 years); young bovine (YB, 24-36 months); and adult bovine (AB, over 48 months). The roots were sectioned below the cement-enamel and longitudinally to produce two hemi-sections. One hemi-section was chosen and sections were made to obtain the specimens, according to each method of analysis. For the analyzes of the morphological aspects - number, diameter and area of the dentinal tubules - the specimens were analyzed in Scanning Electron Microscope. The chemical composition was analysed by Energy Dispersive Spectroscopy, Wavelength Dispersive Spectroscopy and Fourier Transformed Raman Spectroscopy. In the analysis of the mechanical properties, the specimens were submitted to nano-indentation, three-point flexural and compression tests. For the analysis of the push-out bond strength test, the roots received endodontic treatment and fiber post with resin cements (conventional and selfadhesive dual) were fixed. The roots were sectioned in the root thirds and the specimens tested in a universal testing machine. Additionally, the degree of conversion of the resin cements was evaluated. The data were analyzed in statistical software, level of significance of 5%. The OH presented the lowest values for number, diameter and area of dentinal tubules (p<0.05). OH showed higher values of calcium, Ca/P ratio and relative mineral concentration, with decrease in the organization and quality of the collagen (p<0.05). The OH showed the highest values of nano-hardness, elastic modulus and compressive strength, but the lowest values of flexural strength and flexural modulus (p<0.05). The OH presented the lowest values of bond strength, with differences among the root thirds (p<0.05). The degree of conversion of the cements showed a decrease along the root thirds (p<0.05). It was concluded that age has an effect on the morphological, chemical and physical aspects of human root dentin, with no effect on bovine dentin. Thus, when it is necessary to replace the human root dentin by the bovine in research, it is necessary to consider the effect of age on the analysed outcomes.


Subject(s)
Tooth Root , Resin Cements , Dental Pins , Dentin , Fractures, Compression , Elastic Modulus , Flexural Strength , Hardness Tests , Microscopy
20.
Braz. oral res. (Online) ; 33: e053, 2019. tab, graf
Article in English | LILACS | ID: biblio-1019610

ABSTRACT

Abstract Self-adhesive resin cements (RCs) activate matrix metalloproteinase (MMP) and cathepsin-related collagen degradation, and gallic acid (GA) inhibits the activity of both MMPs and cysteine cathepsins. The purpose of this study was to evaluate the setting time, biaxial flexural strength, and Vickers hardness of self-adhesive RCs after the addition of two different concentrations of GA. RelyX U200 (3M ESPE) and Panavia SA (Kuraray) were modified with 0.5 and 1 wt% GA. The setting time of five samples in each RC group was assessed using a thermocouple apparatus as described in the ISO 4049 test. Biaxial flexure strength was measured using a universal testing machine until failure. Vickers hardness was measured with three randomized indentations on the surface of each resin disc. RCs without GA were used as control. Data were analyzed using a one-way analysis of variance and Tukey's HSD test (α = 0.05). The setting times ranged from 2.4 to 4.6 min for RelyX and from 4.9 to 6.0 min for Panavia. The biaxial flexure strength ranged from 76.5 to 109.7 MPa for RelyX and from 73.3 to 108.2 MPa for Panavia. Vickers hardness values ranged from 41.6 to 58.6 for RelyX and 27.2 to 33.6 for Panavia. The addition of 0.5 and 1 wt% GA to improve durability of resin-dentin bonds had no adverse effects on setting time, whereas the biaxial flexure strength and Vickers hardness values for the tested materials were significantly reduced.


Subject(s)
Resin Cements/chemistry , Gallic Acid/chemistry , Reference Values , Surface Properties , Time Factors , Materials Testing , Reproducibility of Results , Analysis of Variance , Statistics, Nonparametric , Matrix Metalloproteinases/chemistry , Flexural Strength , Hardness Tests
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