Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 46
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
Braz Dent J ; 31(5): 532-539, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33146338

RESUMO

The aim was to evaluate the microtensile bond strength (mTBS) to dentin and interfacial stress in a class II cavity restored with bulk-fill or conventional composite resins and the margin interfaces. Vertical slot class II cavities in the mesial face, with the gingival end in dentin, were prepared in 72 third molars, being divided into groups (n=24): G1-Tetric N-Ceram; G2-Tetric N-Ceram Bulk-Fill; G3-SonicFill. Clearfil SE Bond adhesive system was used in all groups. Half of the teeth in each group (n=12) were submitted to thermo-mechanical cycling (TMC). Restored teeth (n=9) were cut perpendicular to obtain beams, which were submitted to a mTBS test in an EMIC machine. The cervical margins in dentin of the restored teeth (n=3) were assessed using SEM through epoxy resin replicas as well as the section of the restoration. Interfacial stresses after load application were calculated by 2D finite element analysis. The mTBS means-MPa followed by different letters represent statistical difference by ANOVA and Games-Howell's test (p<0.05): Without TMC: G1-15.68±6.10a; G2-10.08±5.21ab; G3-7.98±3.76b. With TMC: G1-9.70±5.52a; G2-5.79±1.42a; G3-4.37±1.87a. Interfacial stress (MPa) was 4.4 for SonicFill, 3.9 for Tetric N-Ceram, and 3.5 for Tetric N-Ceram Bulk-Fill. SEM images showed continuous margins for all composite resin restorations. It was possible to conclude that SonicFill obtained a slightly higher interfacial stress and lower bond strength to dentin in comparison with Tetric N-Ceram and Tetric N-Ceram Bulk-Fill. Continuous margin interfaces were obtained for Tetric N-Ceram, Tetric N-Ceram Bulk-Fill, and SonicFill. However, voids were observed in the SonicFill restorations.


Assuntos
Cárie Dentária , Restauração Dentária Permanente , Resinas Compostas , Dentina , Humanos , Teste de Materiais
2.
Braz Dent J ; 31(5): 540-547, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33146339

RESUMO

The aim of this study was to analyze the influence of orthodontic bracket type (metallic or ceramic) and mouthguard on biomechanical response during impact. Two-dimensional plane-strain models of a patient with increased positive overjet of the maxillary central incisor was created based on a CT scan, simulating the periodontal ligament, bone support, gingival tissue, orthodontic brackets (metallic or ceramic) and mouthguard. A nonlinear dynamic impact finite element analysis was performed in which a steel object hit the model at 1 m/s. Stress distributions (Von Mises and Modified Von Mises) and strain were evaluated. Stress distributions were affected by the bracket presence and type. Models with metallic and ceramic bracket had higher stresses over a larger buccal enamel impact area. Models with ceramic brackets generated higher stresses than the metallic brackets. Mouthguards reduced the stress and strain values regardless of bracket type. Mouthguard shock absorption were 88.37% and 89.27% for the metallic and ceramic bracket, respectively. Orthodontic bracket presence and type influenced the stress and strain generated during an impact. Ceramic brackets generated higher stresses than metallic brackets. Mouthguards substantially reduced impact stress and strain peaks, regardless of bracket type.


Assuntos
Protetores Bucais , Braquetes Ortodônticos , Cerâmica , Análise do Estresse Dentário , Análise de Elementos Finitos , Humanos , Incisivo , Teste de Materiais , Desenho de Aparelho Ortodôntico , Estresse Mecânico
3.
J Adhes Dent ; 22(5): 503-514, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33073781

RESUMO

PURPOSE: To compare shrinkage stress, cuspal strain and fracture load of weakened premolars restored with different conventional and bulk-fill composite resins and restorative techniques. MATERIALS AND METHODS: Fifty premolars received a 4.0 x 3.5mm mesio-occlusal-distal (MOD) class II preparation. The lingual and buccal cups were internally weakened. Specimens were restored according to the following 5 groups: Filtek Z350 XT/10 increments; Filtek Z350 XT/8 increments (both 3M Oral Care); Filtek Bulk Fill Flowable Restorative + Filtek Z350 XT (both 3M Oral Care); SDR + Spectra Basic (Dentsply Sirona); and Tetric N-Ceram Bulk Fill (Ivoclar Vivadent). Cuspal strains were measured using strain gauges (n = 10). After restoration, specimens were submitted to thermal/mechanical cycles and fractured. Post-gel shrinkage of the composites was determined. Additionally, residual shrinkage strains and stresses were analyzed using three-dimensional finite element analysis (3D-FEA). The data were statistically analyzed using one-way ANOVA and Tukey's HSD (α = 0.05). RESULTS: One-way ANOVA revealed statistically significant differences among composite resins (p < 0.001) for the post-gel shrinkage. Filtek Z350 XT had the highest post-gel shrinkage and no difference was found between Spectra Basic and Tetric N-Ceram Bulk Fill (p = 0.110). The Filtek Z350 XT/10 increments, Filtek Z350 XT/8 increments and Filtek Bulk Fill Flowable Restorative/Filtek Z350 XT had statistically significantly higher cuspal deformation values when compared to the SDR/Spectra Basic and Tetric N-Ceram Bulk Fill techniques. 3D-FEA confirmed higher stress levels in the incrementally filled conventional restorations. Fracture loads were not statistically significantly different. CONCLUSION: The bulk-fill restoration techniques resulted in less cuspal strain and stress than the incremental technique with conventional composite resin. Fracture resistance was not affected by the restorative techniques.


Assuntos
Resinas Compostas , Restauração Dentária Permanente , Dente Pré-Molar , Análise do Estresse Dentário , Polimerização
4.
Braz. dent. j ; 31(5): 540-547, Sept.-Oct. 2020. graf
Artigo em Inglês | LILACS-Express | LILACS, BBO - Odontologia | ID: biblio-1132326

RESUMO

Abstract The aim of this study was to analyze the influence of orthodontic bracket type (metallic or ceramic) and mouthguard on biomechanical response during impact. Two-dimensional plane-strain models of a patient with increased positive overjet of the maxillary central incisor was created based on a CT scan, simulating the periodontal ligament, bone support, gingival tissue, orthodontic brackets (metallic or ceramic) and mouthguard. A nonlinear dynamic impact finite element analysis was performed in which a steel object hit the model at 1 m/s. Stress distributions (Von Mises and Modified Von Mises) and strain were evaluated. Stress distributions were affected by the bracket presence and type. Models with metallic and ceramic bracket had higher stresses over a larger buccal enamel impact area. Models with ceramic brackets generated higher stresses than the metallic brackets. Mouthguards reduced the stress and strain values regardless of bracket type. Mouthguard shock absorption were 88.37% and 89.27% for the metallic and ceramic bracket, respectively. Orthodontic bracket presence and type influenced the stress and strain generated during an impact. Ceramic brackets generated higher stresses than metallic brackets. Mouthguards substantially reduced impact stress and strain peaks, regardless of bracket type.


Resumo O objetivo deste estudo foi analisar a influência da presença e tipo de bráquete ortodôntico (metálico ou cerâmico), e a presença de protetor bucal na resposta biomecânica durante impacto. Modelos bidimensionais em estado plano de deformação de paciente com incisivo central superior com overjet positivo acentuado foram criados baseados em tomografia computadorizada, simulando ligamento periodontal, suporte ósseo, tecido gengival, bráquetes ortodônticos (metálico e cerâmico) e o protetor bucal. Análise de elementos finitos não-linear de impacto foi realizada na qual uma esfera de aço atingiu o modelo a 1m/s. A distribuição de tensões (Von Mises e Von Mises modificado) e a deformação foram avaliadas. As distribuições de tensões foram afetadas pela presença e tipo de bráquete. Modelos com bráquete metálico e cerâmico produziram maiores valores de tensões sobre maior área do esmalte vestibular. Modelos com bráquetes cerâmicos geraram maiores tensões do que metálicos. O protetor bucal reduziu as tensões e deformações geradas independentemente do tipo de bráquete. A capacidade de absorção de choques foi de 88.37 e 89.27% para os bráquetes metálicos e cerâmicos, respectivamente. A presença e o tipo de bráquete influenciou a distribuição de tensões e deformações durante o impacto. Bráquetes cerâmicos geraram maiores valores de tensão do que metálicos. Protetor bucal reduziu significativamente os picos de tensão e deformação.

5.
Braz. dent. j ; 31(5): 532-539, Sept.-Oct. 2020. tab, graf
Artigo em Inglês | LILACS-Express | LILACS, BBO - Odontologia | ID: biblio-1132338

RESUMO

Abstract The aim was to evaluate the microtensile bond strength (mTBS) to dentin and interfacial stress in a class II cavity restored with bulk-fill or conventional composite resins and the margin interfaces. Vertical slot class II cavities in the mesial face, with the gingival end in dentin, were prepared in 72 third molars, being divided into groups (n=24): G1-Tetric N-Ceram; G2-Tetric N-Ceram Bulk-Fill; G3-SonicFill. Clearfil SE Bond adhesive system was used in all groups. Half of the teeth in each group (n=12) were submitted to thermo-mechanical cycling (TMC). Restored teeth (n=9) were cut perpendicular to obtain beams, which were submitted to a mTBS test in an EMIC machine. The cervical margins in dentin of the restored teeth (n=3) were assessed using SEM through epoxy resin replicas as well as the section of the restoration. Interfacial stresses after load application were calculated by 2D finite element analysis. The mTBS means-MPa followed by different letters represent statistical difference by ANOVA and Games-Howell's test (p<0.05): Without TMC: G1-15.68±6.10a; G2-10.08±5.21ab; G3-7.98±3.76b. With TMC: G1-9.70±5.52a; G2-5.79±1.42a; G3-4.37±1.87a. Interfacial stress (MPa) was 4.4 for SonicFill, 3.9 for Tetric N-Ceram, and 3.5 for Tetric N-Ceram Bulk-Fill. SEM images showed continuous margins for all composite resin restorations. It was possible to conclude that SonicFill obtained a slightly higher interfacial stress and lower bond strength to dentin in comparison with Tetric N-Ceram and Tetric N-Ceram Bulk-Fill. Continuous margin interfaces were obtained for Tetric N-Ceram, Tetric N-Ceram Bulk-Fill, and SonicFill. However, voids were observed in the SonicFill restorations.


Resumo O objetivo foi avaliar a resistência de união à microtração (RUμT) à dentina e o estresse interfacial em cavidades classe II restauradas com resina composta de incremento único ou convencional e as interfaces marginais. Cavidades classe II na face mesial, com margem gengival em dentina, foram confeccionadas em 72 terceiros molares, sendo divididos em grupos (n=24): Grupo 1-Tetric N-Ceram; Grupo 2- Tetric N-Ceram Bulk-Fill; Grupo 3- SonicFill. O Sistema adesivo Clearfil SE Bond foi usado em todos os grupos. Metade dos dentes de cada grupo (n=12) foram submetidos à ciclagem termo-mecânica (CTM). Os dentes restaurados (n=9) foram cortados perpendicularmente para obter palitos que foram submetidos ao teste de RµT na máquina-EMIC. As margens cervicais em dentina dos dentes restaurados (n=3) foram observados em microscopia eletrônica de varredura (MEV) por meio de réplicas em resina epoxy, assim como os cortes das restaurações. O estresse interfacial após a aplicação da carga foram calculadas por análise de elementos finitos 2D. As médias de RUμT-MPa seguidas de letras distintas apresentam diferença estatística de acordo com ANOVA e teste de Games-Howell (p<0,05): Antes da CTM: G1-15.68±6.10a; G2-10.08±5.21ab; G3-7.98±3.76b. Após CTM: G1-9.70±5.52a; G2-5.79±1.42a; G3-4.37±1.87a. O estresse interfacial (MPa) foi 4,4 para SonicFill, 3,9 para Tetric N-Ceram e 3,5 para Tetric N-Ceram Bulk-Fill. Imagens em MEV mostraram margens contínuas para todas as restaurações em resina composta. Foi possível concluir que o SonicFill obteve um estresse interfacial ligeiramente mais alto e menor resistência de união à dentina em comparação com o Tetric N-Ceram e o Tetric N-Ceram Bulk-Fill. Interfaces de margem contínua foram obtidas para Tetric N-Ceram, Tetric N-Ceram Bulk-Fill e SonicFill. Entretanto, espaços vazios foram observados nas restaurações do SonicFill.

6.
Braz Dent J ; 29(3): 268-274, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29972453

RESUMO

The aim was to evaluate the influence of different dentin preparation mode in the smear layer characteristics (SL), hybrid layer (HL), and microtensile bond strength (µTBS) to dentin with two resin cements. The occlusal dentin of 120 third molars was exposed. The teeth were divided into 4 groups (n=30) according to the dentin preparation mode: 1- fine grain diamond bur; 2- coarse grain diamond bur; 3- multi laminate carbide steel bur; and, 4- ultrasonic CV Dentus diamond bur. Each treated dentin group was divided into 2 sub-groups (n=15) according to the resin cement: (1) RelyX U200 and (2) RelyX ARC. Resin composite blocks were cemented on dentin. After storage at 37o C for 24 h, beams with a cross section area of 1.0 mm2 were obtained, and tested in a universal testing machine at a crosshead speed of 0.5 mm/min. Two additional teeth for each sub-group were prepared to analyze the SL and HL on a scanning electron microscopy. According to Kruskal-Wallis test and Dunn tests, there was no significant difference in µTBS among the rotary instruments within each resin cement group. RelyX ARC obtained higher µTBS values compared to RelyX U200 (p<0.05). RelyX ARC formed evident HL, which was not observed for RelyX U200. The dentin mode preparation did not influence the µTBS of the resin cements. The SL was different for all instruments. The cementing agent is more determinant in the hybrid layer formation and bond strength to dentin than the instruments applied on dentin.


Assuntos
Colagem Dentária , Preparo da Cavidade Dentária/métodos , Adesivos Dentinários/química , Dentina/química , Cimentos de Resina/química , Resistência à Tração , Bis-Fenol A-Glicidil Metacrilato , Análise do Estresse Dentário , Humanos , Microscopia Eletrônica de Varredura , Dente Serotino/química , Polietilenoglicóis , Ácidos Polimetacrílicos , Camada de Esfregaço
7.
Braz. dent. j ; 29(3): 268-274, May-June 2018. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-951545

RESUMO

Abstract The aim was to evaluate the influence of different dentin preparation mode in the smear layer characteristics (SL), hybrid layer (HL), and microtensile bond strength (µTBS) to dentin with two resin cements. The occlusal dentin of 120 third molars was exposed. The teeth were divided into 4 groups (n=30) according to the dentin preparation mode: 1- fine grain diamond bur; 2- coarse grain diamond bur; 3- multi laminate carbide steel bur; and, 4- ultrasonic CV Dentus diamond bur. Each treated dentin group was divided into 2 sub-groups (n=15) according to the resin cement: (1) RelyX U200 and (2) RelyX ARC. Resin composite blocks were cemented on dentin. After storage at 37o C for 24 h, beams with a cross section area of 1.0 mm2 were obtained, and tested in a universal testing machine at a crosshead speed of 0.5 mm/min. Two additional teeth for each sub-group were prepared to analyze the SL and HL on a scanning electron microscopy. According to Kruskal-Wallis test and Dunn tests, there was no significant difference in µTBS among the rotary instruments within each resin cement group. RelyX ARC obtained higher µTBS values compared to RelyX U200 (p<0.05). RelyX ARC formed evident HL, which was not observed for RelyX U200. The dentin mode preparation did not influence the µTBS of the resin cements. The SL was different for all instruments. The cementing agent is more determinant in the hybrid layer formation and bond strength to dentin than the instruments applied on dentin.


Resumo O objetivo deste estudo foi avaliar a influência de diferentes modos de preparação da dentina nas características da smear layer (SL), da camada híbrida (CH) e na resistência de união à microtração (RUµT) à dentina com dois cimentos resinosos. A dentina oclusal de 120 terceiros molares humanos foi exposta. Os dentes foram divididos em 4 grupos (n=30) de acordo com o modo de preparação da dentina: 1 - ponta diamantada de granulação fina; 2 - ponta diamantada de granulação grossa; 3 - ponta de carboneto de aço multilaminada; 4 - ponta diamantada ultrassônica. Cada grupo foi subdividido em dois subgrupos (n=15) de acordo com o cimento resinoso: (1) RelyX U200 e (2) RelyX ARC. Blocos de resina composta foram cimentados na dentina. Após armazenamento a 37 °C por 24 h, as amostras foram cortadas para obter palitos com área de 1,0 mm2, os quais foram testados em máquina de ensaio universal com velocidade de 0,5 mm/min. Dois dentes adicionais por subgrupo foram preparados para analisar as características da SL e da CH em microscópio eletrônico de varredura. De acordo com o teste de Kruskal-Wallis e o teste de Dunn, não houve diferença significativa na RUµT entre os instrumentos rotatórios para cada cimento resinoso. RelyX ARC obteve maiores valores de RUµT em comparação ao RelyX U200 (p<0,05). RelyX ARC formou uma CH evidente, o que não foi observado para o RelyX U200. O modo de preparação da dentina não influenciou na RUµT dos cimentos resinosos. A SL foi diferente para todos os instrumentos. O agente de cimentação foi mais determinante na formação da camada híbrida e na resistência de união do que os instrumentos utilizados para preparar a dentina.

8.
Odontology ; 106(1): 56-63, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28160094

RESUMO

The purpose of this study was to investigate the marginal adaptation and microleakage of SonicFill composite with different photopolymerization techniques. Class II cavities were prepared in 40 premolars and divided into groups according to the photopolymerization technique (n = 10): G1:1200 mW/cm2 for 20 s; G2:1200 mW/cm2 for 40 s; G3:Soft-start with 650 mW/cm2 for 5 s and 1200 mW/cm2 for 15 s; G4:Soft-start with 650 mW/cm2 for 10 s and 1200 mW/cm2 for 30 s. The cavities were restored with OptiBond FL adhesive and SonicFill. Epoxy resin replicas were obtained before and after thermocycling. The occlusal and cervical margins were analyzed with scanning electron microcopy and expressed as the percentage of continuous margins (%CM). The specimens were submitted to microleakage with silver nitrate. ANOVA and Tukey's test revealed that the %CM at the linguo-occlusal margin for group 1 (83.19%) was significantly different from groups 2, 3 and 4, which had values over 95%. At the cervical margin, there was no statistically significant difference between the groups. After thermocycling, there was a significant decrease in %CM. The predominant score of microleakage was 1 in enamel and 3 in dentin. The SonicFill composite led to gap formation and microleakage, especially in the dentin at the cervical margin, regardless of the photopolymerization technique employed.


Assuntos
Resinas Compostas/química , Preparo da Cavidade Dentária/métodos , Infiltração Dentária , Adaptação Marginal Dentária , Materiais Dentários/química , Processos Fotoquímicos , Dente Pré-Molar , Humanos , Técnicas In Vitro , Teste de Materiais , Microscopia Eletrônica de Varredura , Polimerização , Cimentos de Resina , Propriedades de Superfície
9.
Open Dent J ; 11: 276-283, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28839476

RESUMO

OBJECTIVE: The aim was to evaluate, in vitro, the tensile bond strength to dentin of Scotchbond Universal (SU), All-Bond Universal (AU) and One Coat 7 Universal (OC7) adhesives applied in self-etch mode, after 24 h of storage and after 500,000 loading cycles, using Clearfil SE Bond (SE) as a control. MATERIALS AND METHODS: The adhesives were applied on the dentin of bovine teeth, followed by the application of a composite resin. Thirty specimens were obtained for each adhesive. Half of the specimens were submitted to cyclic loading for 500,000 cycles. All specimens were submitted to a tensile bond strength test in a universal testing machine at a crosshead speed of 0.5 mm/minute. RESULTS: According to two-way ANOVA and Tukey's test (α=5%), the interaction between the adhesive and cyclic loading factors was significant (p=0.001). The means followed by the same letter represent no significant difference in the bond strength (MPa) after 24 h: OC7=7.86A (±2.90), SU=6.78AB (±2.03), AU=5.61BC (±2.32), and SE=3.53C (±1.89). After cyclic loading, SE, SU and AU maintained bond strength comparable to 24 h period. There was a significant decrease only for OC7. CONCLUSION: SU, AU and OC7 had bond strength to dentin comparable to that of SE. Only OC7 had decreased bond strength to dentin after cyclic loading.

10.
Dental Press J Orthod ; 22(1): 82-88, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28444011

RESUMO

INTRODUCTION: Material biodegradation that occurs in the mouth may interfere in the bonding strength between the bracket and the enamel, causing lower bond strength values in vivo, in comparison with in vitro studies. OBJECTIVE: To develop a prototype to measure bracket debonding force in vivo and to evaluate, in vitro, the bond strength obtained with the prototype. METHODS: A original plier (3M Unitek) was modified by adding one strain gauge directly connected to its claw. An electronic circuit performed the reading of the strain gauge, and the software installed in a computer recorded the values of the bracket debonding force, in kgf. Orthodontic brackets were bonded to the facial surface of 30 bovine incisors with adhesive materials. In Group 1 (n = 15), debonding was carried out with the prototype, while tensile bond strength testing was performed in Group 2 (n = 15). A universal testing machine was used for the second group. The adhesive remnant index (ARI) was recorded. RESULTS: According to Student's t test (α = 0.05), Group 1 (2.96 MPa) and Group 2 (3.08 MPa) were not significantly different. ARI score of 3 was predominant in the two groups. CONCLUSION: The prototype proved to be reliable for obtaining in vivo bond strength values for orthodontic brackets.


Assuntos
Descolagem Dentária , Análise do Estresse Dentário/instrumentação , Braquetes Ortodônticos , Adesivos , Animais , Bovinos , Colagem Dentária
11.
Dental press j. orthod. (Impr.) ; 22(1): 82-88, Jan.-Feb. 2017. tab, graf
Artigo em Inglês | LILACS-Express | LILACS | ID: biblio-840206

RESUMO

ABSTRACT Introduction: Material biodegradation that occurs in the mouth may interfere in the bonding strength between the bracket and the enamel, causing lower bond strength values in vivo, in comparison with in vitro studies. Objective: To develop a prototype to measure bracket debonding force in vivo and to evaluate, in vitro, the bond strength obtained with the prototype. Methods: A original plier (3M Unitek) was modified by adding one strain gauge directly connected to its claw. An electronic circuit performed the reading of the strain gauge, and the software installed in a computer recorded the values of the bracket debonding force, in kgf. Orthodontic brackets were bonded to the facial surface of 30 bovine incisors with adhesive materials. In Group 1 (n = 15), debonding was carried out with the prototype, while tensile bond strength testing was performed in Group 2 (n = 15). A universal testing machine was used for the second group. The adhesive remnant index (ARI) was recorded. Results: According to Student’s t test (α = 0.05), Group 1 (2.96 MPa) and Group 2 (3.08 MPa) were not significantly different. ARI score of 3 was predominant in the two groups. Conclusion: The prototype proved to be reliable for obtaining in vivo bond strength values for orthodontic brackets.


RESUMO Introdução: a biodegradação de materiais que ocorre na cavidade bucal pode interferir na resistência de união entre o braquete e o esmalte, causando baixos valores de resistência de união in vivo, em comparação aos valores in vitro. Objetivo: o objetivo do presente estudo foi desenvolver um protótipo para mensurar, in vivo, a força de descolagem de braquetes e avaliar, in vitro, a resistência de união obtida com o uso do protótipo. Métodos: um alicate (3M Unitek) foi modificado por meio da adição de um extensômetro diretamente conectado à garra do alicate. Um circuito eletrônico realizou a leitura do extensômetro, e um software instalado em um computador registrou os valores de força de descolagem do braquete em kgf. Os braquetes ortodônticos foram colados com material adesivo na face vestibular de 30 dentes incisivos bovinos. No Grupo 1 (n = 15), a descolagem foi realizada com o protótipo, enquanto no Grupo 2 (n = 15) foi realizado teste de resistência de união à tração, utilizando-se uma máquina universal de ensaios. O índice de adesivo remanescente (ARI) foi analisado. Resultados: de acordo com o teste de t de Student (α = 0,05), os grupos 1 (2,96 MPa) e 2 (3,08 MPa) não foram estatisticamente diferentes. O escore 3 do ARI foi predominante nos dois grupos. Conclusão: o protótipo mostrou-se confiável para se obter, in vivo, os valores de resistência de união dos braquetes ortodônticos.

12.
Open Dent J ; 10: 268-77, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27347230

RESUMO

OBJECTIVE: The aim of the study was to evaluate the microtensile bond strength (µTBS) of Scotchbond Universal to dentin using the etch-and-rinse or the self-etch technique after 24 h and 6 months of storage. MATERIALS AND METHODS: Flat dentin surfaces were obtained in 24 third molars. The teeth were divided into four groups: G1 - Scotchbond Universal applied in the etch-and-rinse mode; G2 - Scotchbond Universal applied in the self-etch mode; G3 - Scotchbond Multi-Purpose; G4 - Clearfil SE Bond. A block of composite was built on the adhesive area. The tooth/resin sets were cut parallel to the long axis to obtain 40 beams (~0.8 mm(2)) for each group. Twenty specimens were immediately submitted to the µTBS test, and the remaining 20 were stored in water for 6 months. Failures and the adhesive interface were analyzed by SEM. RESULTS: According to two-way ANOVA, the interaction between adhesive and storage time was significant (p=0.015).The µTBS (MPa) means were the following: 24 h - G1 (39.37±10.82), G2 (31.02±13.76), G3 (35.09±14.03) and G4 (35.84±11.06); 6 months - G1 (36.99±8.78), G2 (40.58±8.07), G3 (32.44±6.07) and G4 (41.75±8.25). Most failures were mixed. Evidence of hybrid layer and numerous resin tags were noted for Scotchbond Universal applied with the etch-and-rinse mode and Scotchbond Multi-Purpose. A thinner hybrid layer and fewer resin tags were noted for Scotchbond Universal applied in the self-etch mode and Clearfil SE Bond. CONCLUSION: The results indicate that the µTBS for Scotchbond Universal is comparable to the gold-standard adhesives. Scotchbond Universal applied in the self-etch mode and Clearfil SE Bond revealed higher bond stability compared to the etch-and-rinse mode.

13.
Braz Oral Res ; 29: 54, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25859635

RESUMO

This study evaluated the influence of an alternative surface treatment on the microshear bond strength (µsbs) of zirconia-based ceramic. Thirty-five zirconia disks were assigned to five groups according to the following treatments: Control (CO), glass and silane were not applied to the zirconia surface; G1, air blasted with 100µm glass beads + glaze + silane; G2, a gel containing 15% (by weight) glass beads applied to the ceramic surface + glaze + silane; G3, a gel containing 25% (by weight) glass beads applied to the ceramic surface + glaze + silane; and G4, a gel containing 50% (by weight) glass beads applied to the ceramic surface + glaze + silane. The specimens were built up using RelyX ARC®, according to the manufacturer's recommendations, and inserted in an elastomeric mold with an inner diameter of 0.8 mm. The µsbs test was performed using a testing machine at a crosshead speed of 0.5 mm/min. ANOVA and Tukey's test (p < 0.05) were applied to the bond strength values (in MPa). CO (15.6 ± 4.1) showed the lowest µsbs value. There were no statistical differences between the G1 (24.9 ± 7.4), G2 (24.9 ± 2.3), G3 (35.0 ± 10.3) and G4 (35.3 ± 6.0) experimental groups. Those groups submitted to surface treatments with higher concentrations of glass showed a lower frequency of adhesive failures. In conclusion, the glass application improved the interaction between the ceramic and the luting cement.


Assuntos
Cimentação/métodos , Cerâmica/química , Cimentos Dentários/química , Vidro/química , Zircônio/química , Análise de Variância , Bis-Fenol A-Glicidil Metacrilato/química , Teste de Materiais , Microscopia Eletrônica de Varredura , Polietilenoglicóis/química , Ácidos Polimetacrílicos/química , Reprodutibilidade dos Testes , Cimentos de Resina/química , Resistência ao Cisalhamento , Estresse Mecânico , Propriedades de Superfície
14.
Braz. oral res. (Online) ; 29(1): 1-2, 2015. tab, ilus
Artigo em Inglês | LILACS | ID: lil-777224

RESUMO

This study evaluated the influence of an alternative surface treatment on the microshear bond strength (μsbs) of zirconia-based ceramic. Thirty-five zirconia disks were assigned to five groups according to the following treatments: Control (CO), glass and silane were not applied to the zirconia surface; G1, air blasted with 100μm glass beads + glaze + silane; G2, a gel containing 15% (by weight) glass beads applied to the ceramic surface + glaze + silane; G3, a gel containing 25% (by weight) glass beads applied to the ceramic surface + glaze + silane; and G4, a gel containing 50% (by weight) glass beads applied to the ceramic surface + glaze + silane. The specimens were built up using RelyX ARC®, according to the manufacturer’s recommendations, and inserted in an elastomeric mold with an inner diameter of 0.8 mm. The μsbs test was performed using a testing machine at a crosshead speed of 0.5 mm/min. ANOVA and Tukey’s test (p < 0.05) were applied to the bond strength values (in MPa). CO (15.6 ± 4.1) showed the lowest μsbs value. There were no statistical differences between the G1 (24.9 ± 7.4), G2 (24.9 ± 2.3), G3 (35.0 ± 10.3) and G4 (35.3 ± 6.0) experimental groups. Those groups submitted to surface treatments with higher concentrations of glass showed a lower frequency of adhesive failures. In conclusion, the glass application improved the interaction between the ceramic and the luting cement.


Assuntos
Cimentação/métodos , Cerâmica/química , Cimentos Dentários/química , Vidro/química , Zircônio/química , Análise de Variância , Bis-Fenol A-Glicidil Metacrilato/química , Teste de Materiais , Microscopia Eletrônica de Varredura , Polietilenoglicóis/química , Ácidos Polimetacrílicos/química , Reprodutibilidade dos Testes , Cimentos de Resina/química , Resistência ao Cisalhamento , Estresse Mecânico , Propriedades de Superfície
15.
Braz. dent. j ; 25(6): 472-478, Nov-Dec/2014. tab, graf
Artigo em Inglês | LILACS | ID: lil-732254

RESUMO

To evaluate the microtensile bond strength (µTBS) of a fluoride-containing adhesive system submitted to a pH-cycling and storage time regimen for primary outcomes. As secondary outcomes the fluoride released amount was evaluated. Twelve dentin surfaces from sound third molar were divided into 2 groups according to adhesive systems: Clearfil SE Protect (PB) and Clearfil SE Bond (SE). Sticks obtained (1.0 mm2) from teeth were randomly divided into 3 subgroups according to storage regimen model: immediate (24h); 5-month deionized water (W); and pH-cycling model (C). All sticks were tested for µTBS in a universal testing machine. Fluoride concentration was obtained from 1-4 days and 30-day in W and 1-4 days in demineralization (DE)/remineralization (RE) solutions from C, using a fluoride-specific electrode. µTBS and fluoride released data were, respectively, submitted to ANOVA in a split plot design and Tukey, and Friedman' tests (a=0.05). There was no significant interaction between adhesive system and storage regimen for µTBS. W showed the lowest µTBS values. There was no significant difference between 24 h and C models for µTBS. There was no significant difference between adhesive systems. Failure mode was predominantly cohesive within composite for the 24 h and W, for the C group it was mixed for SE and cohesive within composite for PB adhesive system. Fluoride concentrations in the DE/RE solutions were less than 0.03125 ppm and not detected in W. In conclusion, the fluoride-containing adhesive system performed similarly to the regular one. Hydrolytic degradation is the main problem with both adhesive systems, regardless of fluoride contents.


O objetivo principal desse estudo foi avaliar a resistência de união à microtração de dois sistemas adesivos (com e sem flúor) após a ciclagem de pH e armazenagem em água deionizada. A quantidade de flúor liberada foi avaliada secundariamente. Doze terceiros molares hígidos foram separados em 2 grupos de acordo com o sistema adesivo: Clearfil SE Protect - com flúor (PB) e Clearfil SE Bond - sem flúor (SE). Os palitos (1 mm2) obtidos do mesmo dente foram aleatoriamente divididos em 3 subgrupos de acordo com o meio de armazenagem: em água deionizada por 24h ou 5 meses e ciclagem de pH. Os palitos foram tracionados em uma máquina de ensaio universal a 0,5 mm/min. A concentração de flúor foi analisada em água deionizada (1-4 dias e 30 dias) e na solução remineralizadora e desmineralizadora (1-4 dias) usando um eletrodo específico. Os dados de resistência de união e liberação de flúor foram, respectivamente, submetidos à Análise de Variância em esquema de parcela subdividida e ao teste de Friedman (a=0,05). Não houve nenhuma interação significativa na resistência de união entre os sistemas adesivos e os meios de armazenagem. Os menores valores de resistência de união à microtração foram encontrados para os palitos armazenados em água deionizada. Não houve nenhuma diferença significativa nos valores de resistência de união após 24h e ciclagem de pH. Nenhuma diferença significativa na resistência de união foi observada entre os 2 sistemas adesivos. O modo de falha foi predominantemente coesivo em compósito para os grupos armazenados em água por 24h ou 5 meses para ambos os sistemas adesivos. No grupo submetido à ciclagem, a falha foi mista para o SE e coesiva em compósito para o PB. A concentração de flúor nas soluções DE/RE foi menor que 0,03125 ppm e não detectada em água deionizada. Concluindo, o sistema adesivo com flúor (PB) apresentou performance similar ao sistema adesivo sem flúor (SE). A degradação hidrolítica foi o principal fator para ambos os sistemas adesivos, independente da adição de flúor.


Assuntos
Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Antineoplásicos/administração & dosagem , Floxuridina/administração & dosagem , Antineoplásicos/toxicidade , Esquema de Medicação , Avaliação de Medicamentos , Tolerância a Medicamentos , Floxuridina/toxicidade , Isomerismo , Neoplasias/tratamento farmacológico
16.
J Int Oral Health ; 6(3): 50-5, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25083032

RESUMO

BACKGROUND: This study evaluated in vivo the accuracy of metal (Smart®) and plastic (Triple Tray®) dual-arch trays used with vinyl polysiloxane (Flexitime®), in the putty/wash viscosity, as well as polyether (Impregum Soft®) in the regular viscosity. MATERIALS AND METHODS: In one patient, an implant-level transfer was screwed on an implant in the mandibular right first molar, serving as a pattern. Ten impressions were made with each tray and impression material. The impressions were poured with Type IV gypsum. The width and height of the pattern and casts were measured in a profile projector (Nikon). The results were submitted to Student's t-test for one sample (α = 0.05). RESULTS: For the width distance, the plastic dual-arch trays with vinyl polysiloxane (4.513 mm) and with polyether (4.531 mm) were statistically wider than the pattern (4.489 mm). The metal dual-arch tray with vinyl polysiloxane (4.504 mm) and with polyether (4.500 mm) did not differ statistically from the pattern. For the height distance, only the metal dual-arch tray with polyether (2.253 mm) differed statistically from the pattern (2.310 mm). CONCLUSION: The metal dual-arch tray with vinyl polysiloxane, in the putty/wash viscosities, reproduced casts with less distortion in comparison with the same technique with the plastic dual-arch tray. The plastic or metal dual-arch trays with polyether reproduced cast with greater distortion. How to cite the article: Santayana de Lima LM, Borges GA, Burnett LH Jr, Spohr AM. In vivo study of the accuracy of dual-arch impressions. J Int Oral Health 2014;6(3):50-5.

17.
Braz Dent J ; 25(6): 472-8, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25590191

RESUMO

To evaluate the microtensile bond strength (µTBS) of a fluoride-containing adhesive system submitted to a pH-cycling and storage time regimen for primary outcomes. As secondary outcomes the fluoride released amount was evaluated. Twelve dentin surfaces from sound third molar were divided into 2 groups according to adhesive systems: Clearfil SE Protect (PB) and Clearfil SE Bond (SE). Sticks obtained (1.0 mm2) from teeth were randomly divided into 3 subgroups according to storage regimen model: immediate (24h); 5-month deionized water (W); and pH-cycling model (C). All sticks were tested for µTBS in a universal testing machine. Fluoride concentration was obtained from 1-4 days and 30-day in W and 1-4 days in demineralization (DE)/remineralization (RE) solutions from C, using a fluoride-specific electrode. µTBS and fluoride released data were, respectively, submitted to ANOVA in a split plot design and Tukey, and Friedman' tests (a=0.05). There was no significant interaction between adhesive system and storage regimen for µTBS. W showed the lowest µTBS values. There was no significant difference between 24 h and C models for µTBS. There was no significant difference between adhesive systems. Failure mode was predominantly cohesive within composite for the 24 h and W, for the C group it was mixed for SE and cohesive within composite for PB adhesive system. Fluoride concentrations in the DE/RE solutions were less than 0.03125 ppm and not detected in W. In conclusion, the fluoride-containing adhesive system performed similarly to the regular one. Hydrolytic degradation is the main problem with both adhesive systems, regardless of fluoride contents.


Assuntos
Adesivos Dentinários/química , Fluoretos/química , Cimentos de Resina/química , Análise do Estresse Dentário , Concentração de Íons de Hidrogênio , Dente Serotino , Distribuição Aleatória , Autocura de Resinas Dentárias , Resistência à Tração
18.
J Adhes Dent ; 15(6): 561-8, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23653900

RESUMO

PURPOSE: To evaluate the influence of resin cements and aging on cuspal deflection, fracture resistance, and mode of failure of endodontically treated teeth restored with composite resin inlays. MATERIALS AND METHODS: Seventy-two maxillary premolars were divided into 6 groups: 1: sound teeth as control (C); 2: preparations without restoration (WR); 3: inlays luted with RelyX ARC (ARC); 4: inlays luted with RelyX Unicem (RLXU); 5: inlays luted with Maxcem Elite (MCE); 6: inlays luted with SeT (ST). Groups 2 to 6 received mesio-occlusal-distal preparations and endodontic treatment. Stone casts were made for groups 3 to 6. Composite resin inlays were built over each cast and luted with the resin cements. A 200-N load was applied on the occlusal aspect and the cuspal deflection was measured using a micrometer before and after 500,000 cycles of fatigue loading (200 N; 500,000 cycles). The specimens were then submitted to an axial load until failure. RESULTS: The median cuspal deflection (µm) and median fracture resistance (N) were calculated and statistically analyzed using Kruskal-Wallis and Mann-Whitney tests (p < 0.01). Values followed by the same letter represent no statistically significant difference. Cuspal deflection before cyclic loading: C = 3 µma; ARC = 4 µmab; RLXU= 5 µmab; MCE = 21 µmb; ST = 51 µmbc; WR = 69 µmc. Cuspal deflection after cyclic loading: ARC = 6 µma; RLXU = 19 µmab; MCE = 33 µmb; ST = 62 µmb. Fracture resistance in N: C = 1902a; ARC = 980b; RLXU = 670c; MCE = 533c; ST = 601c; WR = 526c. According to the Wilcoxon test, there was no statistical difference between the cuspal deflection before and after cyclic loading only for ARC (p = 0.015). There was a predominance of recovery fractures for the restored groups. CONCLUSION: Composite resin inlays luted with RelyX ARC maintained cuspal deflection stability and showed higher fracture resistance of the teeth than did inlays luted with the other cements tested.


Assuntos
Resinas Compostas/química , Materiais Dentários/química , Restaurações Intracoronárias , Cimentos de Resina/química , Coroa do Dente/patologia , Fraturas dos Dentes/fisiopatologia , Condicionamento Ácido do Dente/métodos , Dente Pré-Molar/patologia , Bis-Fenol A-Glicidil Metacrilato/química , Luzes de Cura Dentária/classificação , Preparo da Cavidade Dentária/instrumentação , Preparo da Cavidade Dentária/métodos , Análise do Estresse Dentário/instrumentação , Humanos , Teste de Materiais , Metacrilatos/química , Polietilenoglicóis/química , Ácidos Polimetacrílicos/química , Poliuretanos/química , Obturação do Canal Radicular/métodos , Preparo de Canal Radicular/métodos , Estresse Mecânico , Fatores de Tempo , Dente não Vital/fisiopatologia , Dente não Vital/terapia
19.
J Adhes Dent ; 15(3): 221-7, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23560256

RESUMO

PURPOSE: To examine the influence of 11.5% polyacrylic acid pretreatment on the interface and bond strength of self-adhesive resin cements (Maxcem Elite, RelyX Unicem, SeT) to dentin. MATERIALS AND METHODS: Fifty-six third molars were randomly divided into seven groups: RelyX ARC as control (ARC), RelyX Unicem (RLXU), Maxcem Elite (MCE), SeT (ST), polyacrylic acid+RelyX Unicem (RLXU-P), polyacrylic acid+Maxcem Elite (MCE-P), and polyacrylic acid+SeT (ST-P). Resin composite blocks were luted to flat dentin. After storage in distilled water for 24 h, sticks with a cross-sectional area of ca 0.80 mm2 were obtained (n = 24 per group) and submitted to a microtensile bond strength (µTBS) test in a universal testing machine at a crosshead speed of 0.5 mm/min. Two sets from each group were sectioned mesiodistally in the center of the crown and observed with a scanning electron microscope at 4000X magnification. RESULTS: The mean results of the µTBS test (MPa) followed by the same letter do not differ statistically significantly according to ANOVA and Tukey's post-hoc test (p < 0.05): ARC = 24.19 (± 6.90)a, RLXU-P = 23.12 (± 6.18)a, MCE-P = 13.09 (± 5.87)b, RLXU = 10.23 (± 2.88)b,c, and MCE = 8.14 (± 4.63)c. All SeT specimens failed during the cutting procedure. The hybrid layer was not observed for the self-adhesive resin cements, and resin tags were observed for RelyX Unicem and Maxem Elite when dentin was pretreated with polyacrylic acid. CONCLUSION: Pretreatment with 11.5% polyacrylic acid was effective for bonding RelyX Unicem and Maxcem Elite to dentin.


Assuntos
Condicionamento Ácido do Dente/métodos , Resinas Acrílicas/química , Colagem Dentária , Dentina/ultraestrutura , Cimentos de Resina/química , Bis-Fenol A-Glicidil Metacrilato/química , Resinas Compostas/química , Cimentos Dentários/química , Análise do Estresse Dentário/instrumentação , Vidro/química , Humanos , Teste de Materiais , Metacrilatos/química , Microscopia Eletrônica de Varredura , Polietilenoglicóis/química , Ácidos Polimetacrílicos/química , Poliuretanos/química , Estresse Mecânico , Propriedades de Superfície , Resistência à Tração , Fatores de Tempo , Água/química
20.
Eur J Dent ; 7(4): 474-483, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24932124

RESUMO

OBJECTIVES: The objective of this study is to evaluate, in vitro, the thickness of immediate dentin sealing (IDS) materials on full crown preparations and its effect on the fracture load of a reinforced all-ceramic crown. MATERIALS AND METHODS: SIXTY PREMOLARS RECEIVED FULL CROWN PREPARATION AND WERE DIVIDED INTO THE FOLLOWING GROUPS ACCORDING TO THE IDS TECHNIQUE: G1-control; G2-Clearfil SE Bond; and G3-Clearfil SE Bond and Protect Liner F. After the impressions were taken, the preparations were temporized with acrylic resin crowns. IPS empress 2 restorations were fabricated and later cemented on the preparations with Panavia F. 10 specimens from each group were submitted to fracture load testing. The other 10 specimens were sectioned buccolingually before the thicknesses of Panavia F, Clearfil SE Bond and Protect Liner F were measured in 10 different positions using a microscope. RESULTS: According to analysis of variance and Tukey's test, the fracture load of Group 3 (1300 N) was significantly higher than that of Group 1 (1001 N) (P < 0.01). Group 2 (1189 N) was not significantly different from Groups 1 and 3. The higher thickness of Clearfil SE Bond was obtained in the concave part of the preparation. Protect Liner F presented a more uniform range of values at different positions. The thickness of Panavia F was higher in the occlusal portion of the preparation. CONCLUSIONS: The film thickness formed by the IDS materials is influenced by the position under the crown, suggesting its potential to increase the fracture load of the IPS empress 2 ceramic crowns.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...