RESUMO
PURPOSE: To evaluate early and 24-hour microtensile bond strength (microTBS) and the degree of conversion (DC) of one representative adhesive system from each of the four current bonding approaches. METHODS: 40 human molars were sectioned occluso-gingivally into two halves. Resin composite was bonded incrementally to flat, mid-coronal dentin, using the adhesives Adper Scotchbond MP (MP); Adper Scotchbond 2 (SB); Clearfil SE Bond (SE); and Adper Prompt L-Pop (LP) according to the respective manufacturer's instructions (n = 10). One half was immediately sectioned into sticks and subjected to muTBS test. As the sectioning process took approximately 1 hour, the results were designated as 1-hour bond strengths. The other half was stored in distilled water at 37 degrees C for 24 hours before being sectioned and tested. The DC of these systems was measured using Fourier Transform-Raman spectroscopy in three periods: immediately, 1 and 24 hours after polymerization. Data were analyzed with ANOVA and Tukey's tests. RESULTS: There were no significant differences between the 1-hour and 24-hour bond strengths (P > 0.05), or among the DC measured immediately, 1 hour and 24 hours after polymerization (P > 0.05). However, significant differences were observed among adhesives (P < 0.05). microTBS values obtained, in MPa (1 hour/24 hour), were: SB (48.6 + 1.3/48.4 + 3.5) = SE (51.9 + 4.7/53.3 +/- 2.9) > MP (35.3 +/- 10.9/38.6 + 6.7) > LP (25.5 + 1.1/26.0 + 1.5). The DC, in percentage (immediately/1 hour/24 hour), were: SE (81/82/87) > MP (79/77/81) > SB (60/63/65) > LP (39/37/42).
Assuntos
Condicionamento Ácido do Dente/métodos , Colagem Dentária , Adesivos Dentinários/química , Resinas Compostas/química , Materiais Dentários/química , Dentina/ultraestrutura , Humanos , Teste de Materiais , Polímeros/química , Cimentos de Resina/química , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Estresse Mecânico , Temperatura , Resistência à Tração , Fatores de Tempo , Água/químicaRESUMO
OBJECTIVES: Verify the influence of radiant exposure (dose) on polymerization stress and microleakage of composite restorations using two adhesive systems. METHODS: An experimental composite (1BisGMA:1TEGDMA, 75wt.% filler) was subjected to 3, 6, 12 or 24J/cm(2) under 500mW/cm(2). Stress was measured in 1-mm height specimens placed between two glass rods (Ø=5mm) attached to a testing machine. Microleakage was assessed in cylindrical restorations (Ø=5mm, h=2mm) with enamel margins, using Adper Single Bond 2 (SB) or Adper Prompt (PR). After storage, specimens were subjected to dye penetration (50% AgNO(3)) and sectioned twice, perpendicularly. Microleakage of the 8tooth/composite interfaces was recorded in millimeters. KHN was measured at both surfaces of cylindrical specimens (Ø=5mm, 1 or 2mm height). ANOVA/Tukey test were used (alpha=0.05). KHN top and bottom were compared using paired t-tests. RESULTS: Stress increased significantly with dose (3J/cm(2): 1.4+/-0.3(c); 6J/cm(2): 4.3+/-0.5(b); 12J/cm(2): 9.3+/-0.6(a); 24J/cm(2): 9.9+/-0.7(a), in MPa). For both average and maximum microleakage, interactions were not statistically significant (p>0.05). Tooth average microleakage was influenced by the adhesive system (SBAssuntos
Resinas Compostas/efeitos da radiação
, Infiltração Dentária/classificação
, Restauração Dentária Permanente
, Bis-Fenol A-Glicidil Metacrilato/química
, Bis-Fenol A-Glicidil Metacrilato/efeitos da radiação
, Resinas Compostas/química
, Colagem Dentária
, Esmalte Dentário/ultraestrutura
, Adesivos Dentinários/química
, Adesivos Dentinários/efeitos da radiação
, Dureza
, Humanos
, Luz
, Teste de Materiais
, Organofosfatos/química
, Organofosfatos/efeitos da radiação
, Polietilenoglicóis/química
, Polietilenoglicóis/efeitos da radiação
, Polímeros/química
, Ácidos Polimetacrílicos/química
, Ácidos Polimetacrílicos/efeitos da radiação
, Doses de Radiação
, Coloração pela Prata
, Estresse Mecânico
, Propriedades de Superfície
RESUMO
Este estudo avaliou a resistência de união entre o conjunto resina composta/adesivo e diferentes tipos de substrato dentinário. Quinze molares humanos extraídos foram divididos em três grupos de acordo com o tipo de dentina: 5 dentes com dentina afetada por cárie (C), 5 restaurados com amálgama (R) e 5 dentes hígidos (H). Todos os dentes tiveram suasuperfície oclusal desgastada até expor uma superfície dentinária plana. As diferentes superfícies foram condicionadas com ácido fosfórico a 37% (3M ESPE), seguindo-se a aplicação e fotopolimerização do adesivo Single Bond (3M ESPE)para a imediata inserção de incrementos de 1 mm de resina composta (Z250 û 3M ESPE) até atingir 4 mm de altura.Após 24 horas de armazenagem em água destilada (37ºC), os corpos-de-prova em forma de palito com secção transversal de 1 mm2 de área foram submetidos ao ensaio de microtração (Instron). A análise estatística (ANOVA/Tukey) revelou que o fator substrato interferiu na resistência adesiva (p<0,05), com a dentina hígida (42,0±7,1 MPaa) proporcionandomaiores valores que a dentina restaurada (37,1±4,7 MPab) e que a cariada (37,7±4,8 MPab).
Assuntos
Humanos , Resinas Compostas , Amálgama Dentário , Adesivos Dentinários , Resistência à TraçãoRESUMO
Cutting procedures conventionally used for microtensile specimens' preparation induce mechanical stress and attrition, leading to cracks in dental structure. Enamel is mainly affected due to its high module of elasticity and brittleness. As an alternative to the conventional diamond saw, a diamond wire was used for cutting. The two techniques were compared in efficacy in the preparation of two different sample shapes. Forty human molars, flattened in dentin or enamel, were used for sample preparation. After bonding procedures, resin block was built incrementally. Half of the teeth were cut using a diamond disc and the other half using a diamond wire, obtaining slabs and stick-shaped specimens. Slabs were then shaped to obtain hourglass samples. Five samples from each subgroup were randomly selected for Scanning electron microscopy (SEM) analysis. Remaining samples underwent microtensile test and the results were analyzed, including/excluding premature failures (pf), with three-way ANOVA and Tukey test, performed separately, by substrate. On dentin, only the exclusion of pf showed a significant higher bond strength values than when pf were included (p < 0.05); however, on enamel, all factors (equipment, shape and including/excluding pf) had a significant effect on bond strength (p<0.05). The most remarkable finding from SEM was the incidence of specimens' cracks and defects when diamond blade was used. Scratches and cracks in the hourglass-shaped specimens were also detected. In both cases, enamel was more affected than dentin.
Assuntos
Diamante , Dente Molar , Manejo de Espécimes/instrumentação , Manejo de Espécimes/métodos , Esmalte Dentário , Dentina , HumanosRESUMO
O objetivo do presente estudo foi avaliar, por teste de microtração, a resitência de união do adesivo com "primer" autocondicionante Clearfil SE Bond (Kuraray Medical Inc.) ao substrato (esmalte ou dentina); e verificar, através de MEV, a integridade da interface entre adesivo e substrato antes do teste de microtração. Quatorze molares humanos hígidos foram aleatoriamente divididos em dois grupos (n=7) de acordo com o substrato a ser usado: dentina ou esmalte. Após a aplicação do sistema adesivo, um bloco de resina composta (Tetric Ceran - Ivoclar Vivadent, Schaan, Liechtenstein) de aproximadamente 5 x 5 x 5 mm foi construído sobre o dente, sendo cada incremento fotoativado por 40 segundos com 60mW/cm² (Optilux 401 - Demetron Research Corporation). Após 24 horas, os blocos dente/adesivo/resina foram seccionados, obtendo-se corpos de prova em forma de palito, com área de união de aproximadamente 0,8mm². Foram obtidos 156 corpos-de-prova, sendo que 120 palitos foram usados para o teste de microtração e 36 foram preparados para análise em microscopia eletrônica de varredura. A média de resistência de união (MPa) em dentina foi de 44,5 (+/-7,7) e em esmalte, 38,9 (+/-4,8), sendo estatisticamente semelhantes entre si. A análise em MEV mostrou presença de bolhas e/ou microtrincas na interface adesiva e no substrato, principalmente em esmalte
Assuntos
Humanos , Esmalte Dentário , Dentina , Adesivos Dentinários , Resinas Compostas , Microscopia Eletrônica de Transmissão e Varredura , Resistência ao CisalhamentoRESUMO
PURPOSE: The aims of this in vitro study were to: (1) compare bond strength of different adhesive systems to primary and permanent dentin using microtensile test; and (2) evaluate the interaction of these materials to primary and permanent dentin by means of scanning electron microscopy (SEM). METHODS: Middle-coronal dentin surfaces of 18 exfoliated primary and 18 extracted permanent molars were exposed and teeth were randomly divided, according to their adhesive system, into 3 groups (N=6 per group): (1) Clearfil SE Bond (SE); (2) One Up Bond F (OU); and (3) Single Bond (SB). Then, 5-mm high composite blocks were constructed. After bonding procedures, the teeth were stored in distilled water at 37 degrees C for 24 hours prior to the specimens' preparation. For the microtensile test, teeth (N=5 per group) were longitudinally sectioned into 2 axes rendering beam-specimens that were glued to special devices, which were mounted in a Universal Testing Machine to be loaded under a crosshead speed of 1 mm/min until fracture. One tooth of each group was prepared for SEM. RESULTS: Microtensile bond strength mean values (MPa) to primary/permanent dentin were: (1) SE=60.0/61.4; (2) OU=54.5/53.3; and (3) SB=70.1/64.9. Two-way analysis of variance (ANOVA) showed no significant differences (P>.05) for the bond strength values among primary and permanent dentin groups, neither among groups SExSB and SExOU. SEM images of SE and SB showed a well-defined, uniform, and continuous hybrid layer. A continuous hybrid layer, however, was not found for OU. CONCLUSIONS: Bond strength and micromorphologic characteristics of the adhesive systems evaluated were not influenced by the substrate. OU achieved worse results.
Assuntos
Adesivos , Colagem Dentária , Adesivos Dentinários , Cimentos de Resina , Análise de Variância , Bis-Fenol A-Glicidil Metacrilato , Distribuição de Qui-Quadrado , Análise do Estresse Dentário , Dentina , Permeabilidade da Dentina , Humanos , Teste de Materiais , Metacrilatos , Microscopia Eletrônica de Varredura , Dente Molar , Resistência à Tração , Dente DecíduoRESUMO
PURPOSE: To evaluate the immediate microtensile bond strengths achieved with representative adhesive systems from each of the four current bonding approaches. MATERIALS AND METHODS: Resin composite was bonded incrementally to flat, midcoronal dentin from 33 human molars, using the adhesives (Adper Scotchbond MP; Adper Scotchbond 1; Optibond Solo Plus; Clearfil SE Bond; AdheSE; Tyrian SPE + One Step Plus; Optibond Solo Plus self-etching; One-Up Bond F; iBond; Adper Prompt L-Pop; Xeno III) according to the respective manufacturer's instructions. The bonded specimens were immediately sectioned into sticks and underwent microtensile bond testing either immediately or after 24 h. Data were analyzed with two-way ANOVA and LSD tests. RESULTS: No significant differences were found between immediate and 24-h bond strengths (p > 0.05). However, significant differences were observed among adhesives (p = 0.001). The all-in-one adhesive iBond showed statistically lower values when compared to all the other adhesives. Adper Prompt L-Pop, Xeno III, Tyrian SPE + One Step Plus and One-Up Bond F, all self-etching adhesives, were significantly weaker than AdheSE, Optibond Solo Plus, Adper Scotchbond 1, Optibond Solo Plus self-etching, Clearfil SE Bond, and Adper Scotchbond MP, which did not differ statistically from each other. CONCLUSION: Microtensile bond strengths of representative adhesive systems from the four categories of bonding agents were not equivalent, with the lowest values recorded for the one-step self-etching adhesives. There were no differences in the bond strengths when measured immediately and after 24 h.
Assuntos
Colagem Dentária/métodos , Adesivos Dentinários/química , Resinas Acrílicas , Resinas Compostas/química , Dentina/ultraestrutura , Humanos , Teste de Materiais , Metacrilatos , Cimentos de Resina/química , Estresse Mecânico , Resistência à Tração , Fatores de TempoRESUMO
OBJECTIVE: The aim of this study was to compare the behavior of two new, low-shrinkage hybrid composites (Aelite LS and Inten-S) with a microfilled (Heliomolar) and a hybrid composite (Filtek Z250), in terms of polymerization contraction stress and microleakage. METHODS: Maximum contraction stress after 10 min was recorded in a "tensilometer", using a C-factor (C) of 2.5 and energy density of 26 J/cm(2). For the microleakage test, cylindrical cavities with enamel margins prepared in bovine incisors (4 mm diameter, 1.5 mm depth, C = 2.5) were restored in bulk, applying the same energy density used in the contraction stress test. After immersion in 0.5% methylene blue for 4 h, specimens were sectioned twice, perpendicularly, and the highest dye penetration score was recorded. Contraction stress results were analyzed by one-way ANOVA/Tukey's test and microleakage was analyzed by Kruskal-Wallis test. Regression analysis between the two variables was also performed. RESULTS: Aelite LS showed significantly higher stress than the other composites tested. Inten-S and Filtek Z250 had similar stress levels, statistically higher than Heliomolar. In the microleakage test, a significant difference was observed between Aelite LS and Heliomolar only. Regression analysis showed a good linear correlation between the two variables (R2(adjusted) = 0.811). CONCLUSIONS: The low-shrinkage materials exhibited contraction stress values similar or higher than the hybrid composite. A direct relationship between contraction stress values and microleakage for the composites evaluated was verified. SIGNIFICANCE: The low-shrinkage composites tested did not seem to represent an improvement in terms of reducing contraction stress or microleakage.
Assuntos
Resinas Compostas/química , Preparo da Cavidade Dentária/classificação , Infiltração Dentária/classificação , Restauração Dentária Permanente/classificação , Resinas Acrílicas/química , Análise de Variância , Animais , Bis-Fenol A-Glicidil Metacrilato/química , Bovinos , Fenômenos Químicos , Físico-Química , Esmalte Dentário/ultraestrutura , Adaptação Marginal Dentária , Teste de Materiais , Metacrilatos/química , Polímeros/química , Poliuretanos/química , Análise de Regressão , Estatísticas não Paramétricas , Estresse Mecânico , Propriedades de SuperfícieRESUMO
O objetivo da pesquisa foi estudar a influência do tempo de armazenamento (24hs e três meses) na resistência adesiva de dois tipos de adesivo dental, sendo um convencional, Single Bond (SB) e outro com primer autocondicionante, ABF experimental (ABF), e também a influência das variações regionais do abstrato dentário. O esmalte oclusal de 16 terceiros molares foi removido, expondo uma superfície dentinária plana. Nesta, foi criada uma camda de smear através de lixas de papel de granulações decrescentes. Após a aplicação dos sistemas adesivos, blocos de resina Z250 de 5 mm de altura foram construídos sobre a superfície dentinária. Os dentes foram divididos em quatro grupos (n=4) de acordo com o material e o tempo de armazenamento, os dentes foram seccionados, longitudinalmente, em cortes perpendiculares entre si, a fim de se obterem corpos-de-prova (cp) em formato de palito de aproximadamente 0,8 mm quadrados de secção transversal, constituídos por resina-adesivo-dentina. Esses cp foram mapeados, com esmaltes de diferentes cores, conforme suas localizações no dente: mais periférica ou interna, no sentido horizontal. Os espécimes foram submetidos ao teste de microtração. A análise de variância demonstrou não haver diferença significante entre os valores médios de sistência dos dois adesivos com diferentes idades de armazenamento, nem entre as diferentes regiões do dente.
Assuntos
Dentina , Adesivos Dentinários , Resistência à TraçãoRESUMO
The aim of this study was to evaluate the influence of storage periods of 24 hours and 3 months on the microleakage of class II cavities. Two methods of assessing microleakage were also compared. Class II cavities were prepared in sound human molars. MO cavities were restored using ABF experimental (Kuraray Medical Inc.) + Z250 composite resin (3M ESPE), and DO cavities were restored using Single Bond (3M ESPE) + Z250. After different storage periods, specimens were thermocycled, immersed in a dye (0.5 percent methylene blue solution for 4 h) and longitudinally sectioned. Dye penetration was scored according to a 0-4 scale. The extent of microleakage was measured using the ImageLab 2000 program. A statistically significant correlation was verified between both evaluation methods (r = 0.978, p < 0.001). ANOVA revealed a statistically significant difference between the tested adhesive systems regarding microleakage (p < 0.001), although it was not influenced by the different storage periods