Hydrofluoric acid concentration, time and use of phosphoric acid on the bond strength of feldspathic ceramics

Abstract The objective of this study was to evaluate the influence of hydrofluoric acid (HF) concentration, etching time, and application of phosphoric acid (PA) followed by neutralization with sodium bicarbonate on the bond strength between a feldspar ceramic and resin cement. Thus, 80 blocks (10 x 12 x 2 mm) of glass ceramic (VM - Vita Mark II - Vita Zahnfabrik) were made and randomly assigned to eight groups (n = 10) according to the factors: HF concentration (5 and 10%), etching time (60 and 120 s), and use of phosphoric acid (PA) (with and without). According to the experimental group, 37% PA (Condac, FGM) was applied after HF etching for 60s. Afterwards, samples were immersed in sodium bicarbonate for 1 min then in an ultrasonic bath in distilled water (5 min) for cleaning. After surface bonding treatment, cylinders (Ø = 2 mm; h = 2 mm) of dual resin cement (AllCem / FGM) were made in the center of each block. The samples were then stored in water (37ºC) for 90 days and submitted to the shear bond test (50 KgF, 1 mm/min). Failure analysis was performed by stereomicroscope and scanning electron microscopy. Data (MPa) were analyzed with 3-way ANOVA and Tukey's test. Only the factor "HF concentration" was significant (p = 0.02). Most failures were of cohesive in ceramic (40%) and mixed types (42.5%). The 10% HF resulted in higher shear bond strength value than the 5% HF. Surface cleaning with phosphoric acid followed by sodium bicarbonate and HF time (60 or 120 seconds) did not influence the resin bond strength to feldspar ceramic.

Does use of silane-containing universal adhesive eliminate the need for silane application in direct composite repair?

Abstract This in vitro study aimed to evaluate the effect of a silane-containing universal adhesive used with or without a silane agent on the repair bond strength between aged and new composites. Forty nanohybrid composite resin blocks were stored in distilled water for 14 d and thermo-cycled. Sandpaper ground, etched, and rinsed speciments were randomly assigned into four experimental groups: silane + two-step etch-and-rinse adhesive system, two-step etch-and-rinse adhesive system, silane + silane-containing universal adhesive system, and silane-containing universal adhesive system. Blocks were repaired using the same composite. After 24 h of water storage, the blocks were sectioned and bonded sticks were submitted to microtensile testing. Ten unaged, non-repaired composite blocks were used as a reference group to evaluate the cohesive strength of the composite. Two-way ANOVA and Tukey's tests were used to analyze average µTBS. One-way ANOVA and Dunnet post-hoc tests were used to compare the cohesive strength values and bond strength obtained in the repaired groups (α = 0.05). The µTBS values were higher for the silane-containing universal adhesive compared to the two-step etch-and-rinse adhesive system (p = 0.002). Silane application improved the repair bond strength (p = 0.03). The repair bond strength ranged from 39.3 to 65.8% of the cohesive strength of the reference group. Using universal silane-containing adhesive improved the repair bond strength of composite resin compared to two-step etch-and-rinse adhesive. However, it still required prior application of a silane agent for best direct composite resin repair outcomes.

Can the application of multi-mode adhesive be a substitute to silicatized/silanized y-tzp ceramics?

Abstract This study evaluated the effectiveness of a multi-mode adhesive (SBU-Scotch Bond Universal/3M) as a substitute for silica coating and silane application on the bonding of zirconia ceramics to resin cement. One-hundred and twenty sintered zirconia ceramic blocks (5 x 5 x 5 mm) were obtained, finished by grounding with silicon carbide paper (#600, #800, #1000 and #1200) and randomly divided into 12 groups (n=10) in accordance with the factors "surface treatment" (ScSi - silicatization + silanization; ScSBU - silicatization + SBU; SBU - SBU without photoactivation and SBUp - SBU photoactivated) and "ceramic" (Lava / 3M ESPE, Ceramill Zirconia / Amann Girrbach and Zirkonzahn / Zirkonzahn). Dual resin cement cylinders (RelyX Ultimate/3M ESPE) were subsequently produced in the center of each block using a silicon matrix (Ø=2 mm, h=5 mm) and photoactivated for 40 s (1200 mW/cm2). The samples were stored for 30 days in distilled water (37ºC) and submitted to shear bond strength test (1 mm/min, 100 KgF). Data (MPa) were analyzed under ANOVA (2 levels) and Tukey test (5%). Complementary analyzes were also performed. ANOVA revealed that only the factor "surface treatment" was significant (p=0.0001). The ScSi treatment (14.28A) promoted statistically higher bond strength values than the other ScSBU (9.03B), SBU (8.47B) and SBUp (7.82B), which were similar to each other (Tukey). Failure analysis revealed that 100% of the failures were mixed. The silica coating followed by the silanization promoted higher bond strength values of resin cement and ceramic, regardless of the zirconia ceramic or SBU.

Resumo Este estudo avaliou a efetividade de um adesivo "multi-mode" (Single Bond Universal/3M) como um substituto para a silicatização e aplicação do silano na resistência de união das cerâmicas de zircônia e um cimento resinoso. Para isso, 120 blocos cerâmicos sinterizados de zircônia nas dimensões de (5 x 5 x 5 mm) foram obtidos, lixados com lixas de granulação decrescente (#600, #800, #1000 e #1200) e divididos aleatoriamente em 12 grupos (n = 10), de acordo com os fatores "tratamento de superfície" (ScSi - silicatização + silanização; ScSBU - silicatização + Single Bond; SBU - SBU sem fotoativação e SBUp - SBU com fotoativação) e "cerâmica" (Lava/3M ESPE, Ceramill Zircônia/ Amann Girrbach e Zirkonzahn/Zirkonzahn). Posteriormente, cilindros de cimento resinoso dual (RelyX Ultimate/3M ESPE) foram confeccionados no centro de cada bloco com auxílio de uma matriz de silicone (Ø=2 mm; h=5 mm) e fotopolimerizados por 40 s (1200 mW/ cm²). Em seguida, as amostras foram armazenadas durante trinta dias em água destilada (37 °C) e submetidas ao ensaio de resistência de união ao cisalhamento (1 mm/min, 100 kgF). Os dados (MPa) foram analisados sob ANOVA (2 fatores) e teste de Tukey (5%). Análises complementares também foram realizadas. ANOVA revelou que apenas o fator "tratamento de superfície" foi significativo (p=0,0001). O tratamento ScSi (14.28A) promoveu valores de adesão estatisticamente superiores aos demais ScSBU (9.03B), SBU (8.47B) e SBUp (7.82B), os quais foram semelhantes entre si (Tukey). A Análise de falhas revelou que 100% da falhas que ocorreram foram mistas. A silicatização seguida da silanização promoveu a melhor resistência de união entre cimento resinoso e a cerâmica, independentemente do tipo da cerâmica ou do SBU.

Effects of three silane primers and five adhesive agents on the bond strength of composite material for a computer-aided design and manufacturing system

Abstract Objective The objective of this study was to evaluate the effects of combinations of silane primers and adhesive agents on the bond strength of a composite block for a computer-aided design and manufacturing system. Material and Methods Three silane primers [Clearfil Ceramic Primer (CP), Super-Bond PZ Primer (PZ), and GC Ceramic Primer II (GP)] were used in conjunction with five adhesive agents [G-Premio Bond (P-Bond), Repair Adhe Adhesive (R-Adhesive), Super-Bond D-Liner Dual (SB-Dual), Super-Bond C&B (SB-Self), and SB-Dual without tributylborane derivative (SB-Light)]. The surface of a composite block (Gradia Block) was ground with silicon carbide paper. After treatment with a silane primer, a adhesive agent was applied to each testing specimen. The specimens were then bonded with a light-curing resin composite. After 24 h, the shear bond strength values were determined and compared using a post hoc test (α=0.05, n=8/group). We also prepared control specimens without primer (No primer) and/or without adhesive agent (No adhesive). Results PZ/SB-Dual and GP/SB-Dual presented the highest bond strength, followed by GP/P-Bond, CP/SB-Dual, CP/R-Adhesive, No primer/SB-Dual, GP/R-Adhesive, CP/P-Bond, No primer/R-Adhesive, PZ/R-Adhesive, CP/SB-Self, PZ/P-Bond, PZ/SB-Self, and GP/SB-Self in descending order of bond strength. No primer/P-Bond, No primer/SB-Self, and all specimens in the SB-Light and No adhesive groups presented the lowest bond strengths. Conclusion A dual-curing adhesive agent (SB-Dual) containing a tributylborane derivative in combination with a silane primer (GP or PZ) presents a greater bond strength between the composite block and the repairing resin composite than the comparators used in the study.

One-year aging effects on microtensile bond strengths of composite and repairs with different surface treatments

Abstract The present study aimed to evaluate effects of different surface treatments and aging of composite cylinders on bond strength of composite resin repair. Thirty-two composite cylinders were produced and divided into four groups according to type of surface treatment and storage time of composite cylinder and repair. Cylinder surface of control group (Gcontrol) received no treatment before composite repair. Other groups were sandblasted with aluminum oxide (GAl2O3), followed by silane (GAl2O3sil) or adhesive (GAl2O3ad). Composite cylinders were stored in artificial saliva for either 24 hours or 1 year. Repairs were performed and stored in artificial saliva for 24 hours or 1 year and repair strength was evaluated using microtensile bond strength test. Data were submitted to Student’s t test, two-way ANOVA, and post hoc test for storage time and treatment (α = 0.05). Gcontrol group showed lower values of aging of composite cylinder and storage time of repair (24 hours or 1 year for both) compared with other groups (p < 0.05). GAl2O3ad and GAl2O3sil groups did not exhibit decreased microtensile bond strength with aged repairs (1 year; p > 0.05). Polymer degradation was significant for composite cylinders during the first year of storage in Gcontrol, GAl2O3, and GAl2O3ad groups (p < 0.05). In GAl2O3sil group, storage time of composite cylinders was not significant (p > 0.05). Aging of composite resin influenced bond strength of restoration repair for up to 1 year. Sandblasting with Al2O3, followed by application of silane layer, produced high bond strength after composite or repair aging.

A aplicação de um glaze na superfície de cimentação melhora a adesão da zircônia ao cimento resinoso? / Does the application of a glaze layer in the intaglio surface improve the adhesion between zirconia and resin cement?

Este trabalho teve como objetivo avaliar o efeito de diferentes tratamentos de superfície na resistência adesiva entre a interface zircônia/cimento resinoso. Blocos de zircônia (12 x 11,6 x 1,2 mm) foram divididos em cinco grupos (n=10) e classificados conforme o tratamento de superfície. Nas amostras em que a superfície não foi jateada, os filmes de glaze foram avaliados em função do condicionamento ou não das amostras com ácido fluorídrico (HF). No jateamento das superfícies das cerâmicas foram utilizadas microesferas de alumina, com e sem revestimento de sílica, e avaliada a influência dos tratamentos na resistência adesiva entre a superfície da cerâmica e o cimento resinoso. No teste de resistência de união, as amostras com glaze condicionado e com jateamento (alumina + sílica) apresentaram resultados superiores em relação às amostras não jateadas. As falhas foram classificadas em adesiva, mista e coesiva com a ajuda de um estereomicroscópio. A caracterização das superfícies foi avaliada por microscopia eletrônica de varredura e espectroscopia de energia dispersiva. A espessura dos filmes glaze, obtida pela micrografi a da secção transversal das amostras, apresentou espessuras semelhantes independentemente do tratamento. Os tratamentos de superfície da zircônia com glaze condicionado (com e sem secagem) e jateamento (alumina + sílica) obtiveram os melhores resultados de resistência de união.

This work aimed to evaluate the effect of different surface treatments on bond strength at the zirconia/resin cement interface. Zirconia blocks (12 x 11.6 x 1.2 mm) were divided into five groups (n=10) and classified according to the surface treatment. In the samples wherein the surface glaze has not been sandblasted the films were assessed for conditioning or not the samples with hydrofluoric acid (HF). Alumina microespheres with and without silica coating were used to blast the surfaces, and also to study the effect of treatments on bond strength between the ceramic surface and the resin cement. In the bond strength test samples with conditioning glaze and sandblasting (alumina + silica) showed higher scores than the non-blasted samples. The flaws were classified as adhesive, cohesive and mixed with the aid of a stereomicroscope. Surface characterization was evaluated by scanning electron microscopy and energy dispersive spectroscopy. The thickness of the glaze film obtained by the micrograph of the cross section of the samples showed similar thicknesses regardless of treatment applied. The zirconia surface treatments with conditioning glaze (with and without drying) and sandblasting (alumina + silica) generated the best bond strength results.

Effects of plasma on polyethylene fiber surface for prosthodontic application

ABSTRACT Plasma technology has the potential to improve the adherence of fibers to polymeric matrices, and there are prospects for its application in dentistry to reinforce the dental particulate composite. Objectives This study aimed to investigate the effect of oxygen or argon plasma treatment on polyethylene fibers. Material and Methods Connect, Construct, InFibra, and InFibra treated with oxygen or argon plasma were topographically evaluated by scanning electron microscopy (SEM), and chemically by X-ray photoelectron spectroscopy (XPS). For bending analysis, one indirect composite (Signum) was reinforced with polyethylene fiber (Connect, Construct, or InFibra). The InFibra fiber was subjected to three different treatments: (1) single application of silane, (2) oxygen or argon plasma for 1 or 3 min, (3) oxygen or argon plasma and subsequent application of silane. The samples (25x2x2 mm), 6 unreinforced and 60 reinforced with fibers, were subjected to three-point loading tests to obtain their flexural strength and deflection. The results were statistically analyzed with ANOVA and the Bonferroni correction for multiple comparison tests. Results SEM analysis showed that oxygen and argon plasma treatments promote roughness on the polyethylene fiber surface. X-ray photoelectron spectroscopy (XPS) analysis shows that both plasmas were effective in incorporating oxygenated functional groups. Argon or oxygen plasma treatment affected the flexural strength and deflection of a fiber reinforced composite. The application of silane does not promote an increase in the flexural strength of the reinforced composites. Conclusions Oxygen and argon plasma treatments were effective in incorporating oxygenated functional groups and surface roughness. The highest strength values were obtained in the group reinforced with polyethylene fibers treated with oxygen plasma for 3 min.

Influence of Light Source, Thermocycling and Silane on the Shear Bond Strength of Metallic Brackets to Ceramic

The objective of this study was to evaluate the effects of different light sources, thermocycling and silane on the bond strength of metallic brackets to ceramic. Cylinders of feldspathic ceramic were etched with 10% hydrofluoric acid for 60 s. Half of the cylinders (Groups 1 to 4) received two layers of silane. Metallic brackets were bonded to the cylinders using Transbond XT and divided into 8 groups (n=20), according to light source (Radii Plus LED - 40 s; Groups 1, 2, 5 and 6 and XL 2500 halogen light - 40 s; Groups 3, 4, 7 and 8) and experimental conditions with (Groups 2, 4, 6 and 8) without thermocycling (Groups 1, 3, 5 and 7). Shear bond testing was carried out after 24 h of deionized water storage (Groups 1, 3, 5 and 7) and thermocycling (Groups 2, 4, 6 and 8; 7,000 cycles - 5°/55 °C). Date were submitted to three-way ANOVA and Tukey's post hoc test (α=0.05). The Adhesive Remnamt Index (ARI) was evaluated at 8× magnification. The application of silane was effective in increasing the shear bond strength of the brackets to ceramic (p<0.05). Significant difference (p<0.05) on the bond strength was observed between light sources with or without thermocycling. The ARI showed a predominance of scores 0 for all groups, with an increase in scores 1, 2 and 3 for the silane groups. In conclusion, silane improved significantly the shear bond strength of the brackets to ceramic. The thermocycling and light sources influence on the bond strength.

Resumo O objetivo neste estudo foi avaliar o efeito de diferentes fontes de luz, termociclagem e silano na resistência de união de bráquetes metálicos a cerâmica feldspática. Cilindros de cerâmica feldspática foram condicionados com ácido fluorídrico a 10% por 60 s. Metade dos cilindros (Grupos 1 a 4) recebeu duas camadas de silano. Bráquetes metálicos foram colados aos cilindros usando Transbond XT (3M Unitek), formando 8 grupos (n=20), dependendo das fontes de luz usadas para fotoativação (Radii Plus LED - 40s; Grupos 1, 2, 5 e 6 e XL 2500 halógena - 40 s; Grupos 3, 4, 7 e 8), nas condições experimentais com (Grupos 2, 4, 6 e 8) e sem ciclagem térmica (Grupos 1, 3, 5 e 7). O ensaio de resistência ao cisalhamento foi realizado após armazenagem por 24 h em água deionizada (Grupos 1, 3, 5 e 7) ou armazenados e submetidos a ciclagem térmica (Grupos 2, 4, 6 e 8; 7.000 ciclos - 5° e 55° C). Os dados foram submetidos à Análise de Variância de três fatores e teste de Tukey (α=0,05). O Índice de Remanescente Adesivo (IRA) foi avaliado com aumento de 8×. O uso do silano foi efetivo no aumento da resistência de união ao cisalhamento de bráquetes à cerâmica. Diferença significante na resistência de união foi observada entre as fontes de luz, e com ou sem ciclagem térmica. O IRA mostrou predominância de escore 0 para todos os grupos, com aumento de escores 1, 2 e 3 para os grupos com silano. Em conclusão, a aplicação do silano melhorou significativamente a resistência de união ao cisalhamento de bráquete à cerâmica. A ciclagem térmica e as fontes de luz influenciaram a resistência da união.

Silanated Surface Treatment: Effects on the Bond Strength to Lithium Disilicate Glass-Ceramic

Abstract: The aim of this study was to evaluate the effect of silanization protocols on the bond strength of two resin cements to a lithium disilicate glass-ceramic. Thirty-two ceramic discs were assigned to 2 groups (n=16): G1 - dual-cured resin cement and G2 - light-cured resin cement. Four subgroups were evaluated according to the used silanization protocol. The glass-ceramic was etched with 10% hydrofluoric acid for 20 s and silane was applied for 1 min, as follows: CTL - according to the manufacturer's instructions; HA - dried with hot air; NWA - washed and dried with water and air at room temperature; HWA - washed and dried with hot water and hot air. Thereafter, adhesive was applied and light-cured for 20 s. Silicon molds were used to prepare resin cement cylinders (1x1 mm) on the ceramic surface. The specimens were stored in deionized water at 37 °C for 48 h and subjected to a micro-shear test. The data were submitted to statistical analysis (?#61537;=0.05). Group G1 showed higher bond strengths than G2, except for the CTL and NWA subgroups. Differences as function of the silanization protocol were only observed in G1: HWA (25.13±6.83)≥HA (22.95±7.78)≥CTL(17.44±7.24) ≥NWA(14.63±8.76). For G2 there was no difference among the subgroups. In conclusion, the silanization protocol affected the resin cement/ceramic bond strengths, depending on the material. Washing/drying with hot water and/or hot air increased only the bond strength of the dual-cured resin cement.

Resumo: O objetivo do estudo foi avaliar o efeito da técnica de silanização na resistência de união de cimentos resinosos a uma vitrocerâmica. Trinta e dois discos de vitrocerâmica foram distribuídos em 2 grupos (n=16) (G1: cimento dual e G2: cimento fotoativado) e subdivididos em 4 grupos de acordo com a técnica de silanização. A vitrocerâmica foi condicionada com ácido fluorídrico a 10% por 20 s e o silano aplicado por 1 min de acordo com os subgrupos: CTL: de acordo com as instruções do fabricante, HA: secagem do silano com ar quente, NWA: lavagem e secagem com água e ar a temperatura ambiente, HWA: lavagem e secagem com água e ar quente. Após, o sistema adesivo foi aplicado e polimerizado por 20 s, e cilindros (1 x 1 mm) foram confeccionados com os cimentos sobre a superfície da cerâmica. Os espécimes foram armazenados em água destilada por 48 h e submetidos ao ensaio de microcisalhamento. Os dados foram submetidos à análise estatística (?#61537;=0,05). O grupo G1 apresentou maiores valores de resistência do que G2, exceto no subgrupo CTL e NWA. Houve diferença na técnica de silanização apenas para G1: HWA (25,13±6,83)≥ HA (22,95±7,78)≥ CTL (17,44±7,24)≥ NWA (14,63±8,76). Para G2 não houve diferença entre os subgrupos. Conclui-se que a técnica de silanização interferiu na resistência de união cimento/cerâmica dependendo do material utilizado. A lavagem e secagem com água e ar aquecidos promoveu maior valor de resistência apenas para o cimento dual.

Four chemical methods of porcelain conditioning and their influence over bond strength and surface integrity

OBJECTIVE: To assess four different chemical surface conditioning methods for ceramic material before bracket bonding, and their impact on shear bond strength and surface integrity at debonding.METHODS: Four experimental groups (n = 13) were set up according to the ceramic conditioning method: G1 = 37% phosphoric acid etching followed by silane application; G2 = 37% liquid phosphoric acid etching, no rinsing, followed by silane application; G3 = 10% hydrofluoric acid etching alone; and G4 = 10% hydrofluoric acid etching followed by silane application. After surface conditioning, metal brackets were bonded to porcelain by means of the Transbond XP system (3M Unitek). Samples were submitted to shear bond strength tests in a universal testing machine and the surfaces were later assessed with a microscope under 8 X magnification. ANOVA/Tukey tests were performed to establish the difference between groups (α= 5%).RESULTS: The highest shear bond strength values were found in groups G3 and G4 (22.01 ± 2.15 MPa and 22.83 ± 3.32 Mpa, respectively), followed by G1 (16.42 ± 3.61 MPa) and G2 (9.29 ± 1.95 MPa). As regards surface evaluation after bracket debonding, the use of liquid phosphoric acid followed by silane application (G2) produced the least damage to porcelain. When hydrofluoric acid and silane were applied, the risk of ceramic fracture increased.CONCLUSIONS: Acceptable levels of bond strength for clinical use were reached by all methods tested; however, liquid phosphoric acid etching followed by silane application (G2) resulted in the least damage to the ceramic surface.

OBJETIVO: avaliar quatro métodos de condicionamento químico da superfície cerâmica, previamente à colagem de braquetes, e seu impacto sobre a resistência ao cisalhamento e a integridade da superfície ao descolamento.MÉTODOS: quatro grupos experimentais (n = 13) foram delineados de acordo com o método de condicionamento da superfície cerâmica empregado: G1 = ácido fosfórico a 37%, seguido da aplicação de silano; G2 = ácido fosfórico líquido a 37%, seguido da aplicação de silano sem lavagem prévia do ácido; G3 = ácido fluorídrico a 10%; e G4 = ácido fluorídrico a 10%, seguido da aplicação de silano. Após o condicionamento da superfície, braquetes metálicos foram colados à porcelana utilizando-se o sistema Transbond XP (3M Unitek). As amostras foram submetidas a ensaios de resistência ao cisalhamento, em máquina de ensaio universal, e as superfícies cerâmicas foram posteriormente avaliadas em microscópio, com magnitude de 8X. Testes ANOVA/Tukey foram realizados para verificar-se a diferença entre os grupos (α = 5%).RESULTADOS: os maiores valores de resistência ao cisalhamento foram encontrados nos grupos G3 e G4 (22,01 ± 2,15MPa e 22,83 ± 3,32Mpa, respectivamente), seguidos por G1 (16,42 ± 3,61MPa) e G2 (9,29 ± 1,95MPa). Quanto à avaliação da superfície após a descolagem do braquete, a utilização de ácido fosfórico líquido seguido da aplicação de silano, sem lavagem do ácido (G2), produziu menores danos à porcelana. Quando ácido fluorídrico e silano foram aplicados, o risco de fraturar a cerâmica aumentou.CONCLUSÕES: níveis aceitáveis de resistência de união para uso clínico foram alcançados por todos os métodos testados. No entanto, o condicionamento com ácido fosfórico líquido, seguido da aplicação de silano (G2), resultou em menor dano à superfície cerâmica.

Effect of composite surface treatment and aging on the bond strength between a core build-up composite and a luting agent

Objective The purpose of this study was to assess the influence of conditioning methods and thermocycling on the bond strength between composite core and resin cement. Material and Methods Eighty blocks (8×8×4 mm) were prepared with core build-up composite. The cementation surface was roughened with 120-grit carbide paper and the blocks were thermocycled (5,000 cycles, between 5°C and 55°C, with a 30 s dwell time in each bath). A layer of temporary luting agent was applied. After 24 h, the layer was removed, and the blocks were divided into five groups, according to surface treatment: (NT) No treatment (control); (SP) Grinding with 120-grit carbide paper; (AC) Etching with 37% phosphoric acid; (SC) Sandblasting with 30 mm SiO2 particles, silane application; (AO) Sandblasting with 50 mm Al2O3 particles, silane application. Two composite blocks were cemented to each other (n=8) and sectioned into sticks. Half of the specimens from each block were immediately tested for microtensile bond strength (µTBS), while the other half was subjected to storage for 6 months, thermocycling (12,000 cycles, between 5°C and 55°C, with a dwell time of 30 s in each bath) and µTBS test in a mechanical testing machine. Bond strength data were analyzed by repeated measures two-way ANOVA and Tukey test (α=0.05). Results The µTBS was significantly affected by surface treatment (p=0.007) and thermocycling (p=0.000). Before aging, the SP group presented higher bond strength when compared to NT and AC groups, whereas all the other groups were statistically similar. After aging, all the groups were statistically similar. SP submitted to thermocycling showed lower bond strength than SP without thermocycling. Conclusion Core composites should be roughened with a diamond bur before the luting process. Thermocycling tends to reduce the bond strength between composite and resin cement. .

Effect of Different Surface Treatments for Ceramic Bracket Base on Bond Strength of Rebonded Brackets

The aim of this study was to evaluate the shear bond strength of rebonded ceramic brackets after subjecting the bracket base to different treatments. Seventy-five premolars were selected and randomly distributed into five groups (n=15), according to the type of the bracket surface treatment: I, no treatment, first bonding (control); II, sandblasting with aluminum oxide; III, sandblasting + silane; IV, silica coating + silane; and V, silicatization performed in a laboratory (Rocatec system). The brackets were fixed on an enamel surface with Transbond XT resin without acid etching. The brackets were then removed and their bases were subjected to different treatments. Thereafter, the brackets were fixed again to the enamel surface and the specimens were subjected to shear bond strength (SBS) test. The adhesive remnant index (ARI) was then evaluated for each specimen. Data were subjected to ANOVA and Tukey's tests (α=0.05). A statistically significant difference was observed only between Rocatec and the other groups; the Rocatec group showed the lowest SBS values. The highest SBS values were observed for group 1, without any significant difference from the values for groups II, III and IV. Most groups had a higher percentage of failures at the enamel-resin interface (score 1). It was concluded that the surface treatments of rebonded ceramic brackets were effective, with SBS values similar to that of the control group, except Rocatec group.

O objetivo do estudo foi avaliar o efeito de tratamentos da base de bráquetes cerâmicos monocristalinos na resistência de união ao esmalte após recolagem. Setenta e cinco pré-molares foram selecionados e aleatoriamente distribuídos em 5 grupos (n=15) de acordo com o tratamento da base do bráquete: I - sem tratamento, primeira colagem (controle), II - jateamento com óxido de alumínio, III - jateamento seguido da aplicação de silano, IV - jateamento com partículas de dióxido de sílica (silicatização) seguido de silano, V - silicatização realizada em laboratório (Sistema Rocatec). Os bráquetes foram colados no esmalte com Transbond XT sem condicionamento ácido. Em seguida, os bráquetes foram removidos e suas bases foram submetidas aos diferentes tratamentos. Os bráquetes foram recolados, armazenados por 24 h e submetidos ao ensaio mecânico de cisalhamento com velocidade de 0,5 mm/min. Após, o índice de remanescente adesivo (IRA) foi avaliado em cada espécime. Os dados foram submetidos à análise de variância e teste de Tukey (α=0,05). Pode-se observar que houve diferença significativa apenas entre o sistema Rocatec e os demais grupos, o qual apresentou os menores valores de resistência. Os maiores valores de resistência foram observados para o grupo I (controle), sem diferença significativa dos grupos II, III e IV. A maioria dos grupos apresentou maior porcentagem de falhas na interface esmalte/resina (escore 1). Pode-se concluir que os tratamentos da base do bráquete cerâmico foram efetivos, apresentando valores similares ao grupo controle, exceto para o grupo em que foi usado Rocatec.

Heat Treatment of Pre-hydrolyzed Silane Increases Adhesion of Phosphate Monomer-based Resin Cement to Glass Ceramic

This study evaluated the influence of different forms of heat treatment on a pre-hydrolyzed silane to improve the adhesion of phosphate monomer-based (MDP) resin cement to glass ceramic. Resin and feldspathic ceramic blocks (n=48, n=6 for bond test, n=2 for microscopy) were randomly divided into 6 groups and subject to surface treatments: G1: Hydrofluoric acid (HF) 9.6% for 20 s + Silane + MDP resin cement (Panavia F); G2: HF 9.6% for 20 s + Silane + Heat Treatment (oven) + Panavia F; G3: Silane + Heat Treatment (oven) + Panavia F; G4: HF 9.6% for 20 s + Silane + Heat Treatment (hot air) + Panavia F; G5: Silane + Heat Treatment (hot air) + Panavia F; G6: Silane + Panavia F. Microtensile bond strength (MTBS) test was performed using a universal testing machine (1 mm/min). After debonding, the substrate and adherent surfaces were analyzed using stereomicroscope and scanning electron microscope (SEM) to categorize the failure types. Data were analyzed statistically using two-way test ANOVA and Tukey's test (=0.05). Heat treatment of the silane containing MDP, with prior etching with HF (G2: 13.15±0.89a; G4: 12.58±1.03a) presented significantly higher bond strength values than the control group (G1: 9.16±0.64b). The groups without prior etching (G3: 10.47±0.70b; G5: 9.47±0.32b) showed statistically similar bond strength values between them and the control group (G1). The silane application without prior etching and heat treatment resulted in the lowest mean bond strength (G6: 8.05±0.37c). SEM analysis showed predominantly adhesive failures and EDS analysis showed common elements of spectra (Si, Na, Al, K, O, C) characterizing the microstructure of the glass-ceramic studied. Heat treatment of the pre-hydrolyzed silane containing MDP in an oven at 100 °C for 2 min or with hot air application at 50±5 ºC for 1 min, was effective in increasing the bond strength values between the ceramic and resin cement containing MDP.

Este estudo avaliou o efeito de diferentes formas de tratamento térmico de um silano pré-hidrolisado na adesão de um cimento resinoso à base de monómeros fosfatados (MDP) à uma cerâmica vítrea. Blocos em resina e cerâmica feldspática (n=48, n=6 para teste de união, n=2 para microscopia) foram divididos aleatoriamente em 4 grupos e submetidos a tratamentos de superfície: G1-ácido fluorídrico (HF) 9,6% por 20 s + Silano + cimento resinoso com MDP (Panavia F) ; G2-HF 9,6% por 20 s + Silano + Tratamento Térmico (forno) + Panavia F; G3-Silano + Tratamento Térmico (forno) + Panavia F; G4-HF 9,6% por 20 s + Silano + Tratamento Térmico (ar quente) + Panavia F; G5-Silano + Tratamento Térmico (ar quente) + Panavia F; G6-Silano + Panavia F. Teste de microtração (MTBS) foi realizado utilizando máquina de ensaios universal (1 mm/min). Após o descolamento, substrato e superfícies aderentes foram analisadas utilizando estereoscópico e microscópio eletrônica de varredura (MEV) para classificação dos tipos de falha. Os dados foram analisados estatisticamente utilizando o teste ANOVA dois fatores e o teste de Tukey (=0,05). O tratamento térmico do silano contendo MDP, com condicionamento prévio com HF (G2:13,15±0,89a e G4:12,58±1,03a) resultou em valores de resistência de união significativamente superiores aos do grupo controle (G1:9,16±0,64b). Os grupos sem condicionamento prévio (G3:10,47±0,70b e G5:9,47±0,32b), apresentaram valores de resistência de união estatisticamente semelhantes entre eles e ao controle (G1). O silano utilizado sem condicionamento prévio e tratamento térmico apresentou os menores valores de resistência de união (G6:8,05±0,37c). As análises em MEV mostraram predominância de falhas adesivas e as análises em EDS demonstraram espectros com elementos semelhantes (Si, Na, Al, K, O, C) caracterizando a microsestrutura da vitro-cerâmica estudada. O tratamento térmico do silano pré-hidrolisado contendo MDP, realizado em forno a 100 °C durante 2 min ou com ar quente a 50±5 °C durante 1 min, foi eficaz no aumento dos valores de união entre cimento resinoso contendo MDP e cerâmica.

Effect of Silane Type and Air-Drying Temperature on Bonding Fiber Post to Composite Core and Resin Cement

This study evaluated the influence of silane type and temperature of silane application on push-out bond strength between fiberglass posts with composite resin core and resin cement. One hundred and sixty fiberglass posts (Exacto, Angelus) had the surface treated with hydrogen peroxide 24%. Posts were divided in 8 groups according to two study factors: air-drying temperature after silane application (room temperature and 60 ºC) and silane type: three pre-hydrolyzed - Silano (Angelus), Prosil (FGM), RelyX Ceramic Primer (3M ESPE) and one two-component silane - Silane Coupling Agent (Dentsply). The posts (n=10) for testing the bond strength between post and composite core were centered on a cylindrical plastic matrix and composite resin (Filtek Z250 XT, 3M ESPE) that was incrementally inserted and photoactivated. Eighty bovine incisor roots (n=10) were prepared for testing the bond strength between post and resin cement (RelyX U100, 3M ESPE) and received the fiberglass posts. Push-out test was used to measure the bond strength. Data were analyzed by two-way ANOVA followed by Tukey's test (a=0.05). ANOVA revealed that temperature and silane had no influence on bond strength between composite core and post. However, for bond strength between post and resin cement, the temperature increase resulted in a better performance for Silane Coupling Agent, Silano and RelyX Ceramic Primer. At room temperature Silane Coupling Agent showed the lowest bond strength. Effect of the warm air-drying is dependent on the silane composition. In conclusion, the use of silane is influenced by wettability of resinous materials and pre-hydrolyzed silanes are more stable compared with the two-bottle silane.

Este estudo avaliou a influência do tipo de silano e a aplicação de temperatura no silano na resistência de união por push-out entre pinos de fibra de vidro com núcleo de preenchimento em resina composta e cimento resinoso. Cento e sessenta pinos de fibra de vidro (Exacto, Angelus, Londrina, PR, Brasil) receberam tratamento de superfície com peróxido de hidrogênio a 24%. Os pinos foram divididos em 8 grupos com dois fatores em estudo: temperatura de secagem de ar após a aplicação do silano (temperatura ambiente e 60 ºC) e o tipo de silano: três pré-hidrolisados - Silano (Angelus), Prosil (FGM), RelyX Ceramic Primer (3M ESPE) e um silano de dois frascos - Silane Coupling Agent (Dentsply). Para o teste de resistência de união entre pino e núcleo de preenchimento, os pinos (n=10) foram centralizados em uma matriz plástica cilíndrica e a resina composta (Filtek Z250 XT, 3M ESPE) foi incrementalmente inserida e fotopolimerizada. Para o teste de resistência de união entre pino e cimento resinoso (RelyX U100, 3M ESPE) 80 raízes de incisivos bovinos (n=10) foram preparadas e receberam os pinos de fibra de vidro. Teste de push-out foi usado para mensurar a resistência de união. Os dados foram analisados por ANOVA fatorial seguido do teste de Tukey (a=0,05). Temperatura e silano não tiveram influência na resistência de união entre núcleo de preenchimento e pino. Entretanto, para a resistência de união entre pino e cimento resinoso, o aumento da temperatura resultou em um melhor desempenho para Silane Coupling Agent, Silano e RelyX Ceramic Primer. Além disso, na temperatura ambiente Silane Coupling Agent teve a menor resistência de união. O efeito da secagem de ar quente é dependente da composição do silano. Concluindo, o uso do silano é influenciado pela molhabilidade dos materiais resinosos e os silanos pré-hidrolisados são mais estáveis comparados ao silano de dois frascos.

Adhesive bonding of resin composite to various titanium surfaces using different metal conditioners and a surface modification system

Objective: This study evaluated the effect of three metal conditioners on the shear bond strength (SBS) of a prosthetic composite material to cpTi grade I having three surface treatments. Material and Methods: One hundred sixty eight rivet-shaped specimens (8.0x2.0 mm) were cast and subjected to polishing (P) or sandblasting with either 50 mm (50SB) or 250 mm (250SB) Al2O3. The metal conditioners Metal Photo Primer (MPP), Cesead II Opaque Primer (OP), Targis Link (TL), and one surface modification system Siloc (S), were applied to the specimen surfaces, which were covered with four 1-mm thick layers of resin composite. The resin layers were exposed to curing light for 90 s separately. Seven specimens from each experimental group were stored in water at 37ºC for 24 h while the other 7 specimens were subjected to 5,000 thermal cycles consisting of water baths at 4ºC and 60ºC (n=7). All specimens were subjected to SBS test (0.5 mm/min) until failure occurred, and further 28 specimens were analyzed using scanning electron microscope (SEM) and X-ray energy-dispersive spectroscopy (EDS). Data were analyzed by 3-way ANOVA followed by post-hoc Tukey's test (α=0.05). Results: On 50SB surfaces, OP groups showed higher SBS means than MPP (P<0.05), while no significant difference was found among OP, S, and TL groups. On 250SB surfaces, OP and TL groups exhibited higher SBS than MPP and S (P<0.05). No significant difference in SBS was found between OP and TL groups nor between MPP and S groups. The use of conditioners on 250SB surfaces resulted in higher SBS means than the use of the same products on 50SB surfaces (P<0.05). Conclusion: Sandblasting associated with the use of metal conditioners improves SBS of resin composites to cpTi. .

Tensile Strength of Glass Fiber Posts Submitted to Different Surface Treatments

The aim of this in vitro study was to evaluate the tensile strength of glass fiber posts submitted to different surface treatments. Forty-eight maxillary canines had their crowns sectioned and root canals endodontically treated. The roots were embedded in acrylic resin and distributed into 3 groups according to the surface treatment: Group I: the posts were treated with silane agent for 30 s and adhesive; Group II: the posts were cleaned with alcohol before treatment with silane agent and adhesive; Group III: the posts were submitted to conditioning with 37% phosphoric acid for 30 s before treatment with silane agent and adhesive. Each group was divided into 2 subgroups for adhesive polymerization or not before insertion into the canal: A - adhesive was not light cured and B - adhesive was light cured. All posts were cemented with Panavia F and the samples were subjected to tensile strength test in a universal testing machine at crosshead speed of 1 mm/min. Data were submitted to one-way ANOVA and Tukey's test at 5% significance level. There was statistically significant difference (p<0.01) only between group GIII-B and groups GI-A and GI-B. No significant difference was found among the other groups (p>0.05). It was concluded that the products used for cleaning the posts influenced the retention regardless of adhesive light curing.

O objetivo deste estudo in vitro foi avaliar a resistência à tração de pinos de fibra de vidro submetidos a diferentes tratamentos de superfície. Quarenta e oito caninos superiores tiveram suas coroas seccionadas e as raízes tratadas endodonticamente. As raízes foram incluídas em resina acrílica e distribuídas em 3 grupos de acordo com o tratamento de superfície aplicado aos pinos: Grupo I: os pinos receberam agente silano por 30 s e adesivo; Grupo II: os pinos foram limpos com álcool e então receberam o agente silano e adesivo; Grupo III: os pinos foram submetidos ao condicionamento com ácido fosfórico a 37% por 30 s, seguido de agente silano e adesivo. Cada grupo foi dividido em 2 subgrupos de acordo com fotoativação do adesivo antes da inserção do pino no interior do canal: A – adesivo não foi fotoativado, B: o adesivo foi fotoativado. Todos os pinos foram cimentados com Panavia F e as amostras foram submetidas a teste de tração utilizando máquina universal de ensaios, com velocidade de 1 mm/min. Os dados obtidos foram submetidos à ANOVA a um critério e ao teste de Tukey com nível de significância de 5%. Houve diferença estatisticamente significante (p<0,01) entre o grupo GIII-B e os grupos GI-A e GI-B. Os demais grupos não apresentaram diferenças significantes entre si (p>0,05). Pode-se concluir que as substâncias utilizadas para a limpeza dos pinos interferiram em sua retenção, independente da fotopolimerização do adesivo.

Effect of silica coating and silane surface treatment on the bond strength of soft denture liner to denture base material

OBJECTIVE: This study investigated the effects of different surface treatments on the tensile bond strength of an autopolymerizing silicone denture liner to a denture base material after thermocycling. MATERIAL AND METHODS: Fifty rectangular heat-polymerized acrylic resin (QC-20) specimens consisting of a set of 2 acrylic blocks were used in the tensile test. Specimens were divided into 5 test groups (n=10) according to the bonding surface treatment as follows: Group A, adhesive treatment (Ufi Gel P adhesive) (control); Group S, sandblasting using 50-µm Al2O3; Group SCSIL, silica coating using 30-µm Al2O3 modified by silica and silanized with silane agent (CoJet System); Group SCA, silica coating and adhesive application; Group SCSILA, silica coating, silane and adhesive treatment. The 2 PMMA blocks were placed into molds and the soft lining materials (Ufi Gel P) were packed into the space and polymerized. All specimens were thermocycled (5,000 cycles) before the tensile test. Bond strength data were analyzed using 1-way ANOVA and Duncan tests. Fracture surfaces were observed by scanning electron microscopy. X-ray photoelectron spectrometer (XPS) and Fourier Transform Infrared spectrometer (FTIR) analysis were used for the chemical analysis and a profilometer was used for the roughness of the sample surfaces. RESULTS: The highest bond strength test value was observed for Group A (1.35±0.13); the lowest value was for Group S (0.28±0.07) and Group SCSIL (0.34±0.03). Mixed and cohesive type failures were seen in Group A, SCA and SCSILA. Group ...

Heat treatment following surface silanization in rebonded tribochemical silica-coated ceramic brackets: shear bond strength analysis

OBJECTIVE: This study aimed to evaluate the effects of heat treatment on the tribochemical silica coating and silane surface conditioning and the bond strength of rebonded alumina monocrystalline brackets. MATERIAL AND METHODS: Sixty alumina monocrystalline brackets were randomly divided according to adhesive base surface treatments (n=20): Gc, no treatment (control); Gt, tribochemical silica coating + silane application; Gh, as per Gt + post-heat treatment (air flux at 100ºC for 60 s). Brackets were bonded to the enamel premolars surface with a light-polymerized resin and stored in distilled water at 37ºC for 100 days. Additionally, half the specimens of each group were thermocycled (6,000 cycles between 5-55ºC) (TC). The specimens were submitted to the shear bond strength (SBS) test using a universal testing machine (1 mm/min). Failure mode was assessed using optical and scanning electron microscopy (SEM), together with the surface roughness (Ra) of the resin cement in the bracket using interference microscopy (IM). 2-way ANOVA and the Tukey test were used to compare the data (p>0.05). RESULTS: The strategies used to treat the bracket surface had an effect on the SBS results (p=0.0), but thermocycling did not (p=0.6974). Considering the SBS results (MPa), Gh-TC and Gc showed the highest values (27.59±6.4 and 27.18±2.9) and Gt-TC showed the lowest (8.45±6.7). For the Ra parameter, ANOVA revealed that the aging method had an effect (p=0.0157) but the surface treatments did not (p=0.458). For the thermocycled and non-thermocycled groups, Ra (µm) was 0.69±0.16 and 1.12±0.52, respectively. The most frequent failure mode exhibited was mixed failure involving the enamel-resin-bracket interfaces. CONCLUSION: Regardless of the aging method, Gh promoted similar SBS results to Gc, suggesting that rebonded ceramic brackets are ...

Chemical treatment of the intra-canal dentin surface: a new approach to modify dentin hydrophobicity

Objective: This study evaluated the hydrophobicity of dentin surfaces that were modified through chemical silanization with octadecyltrichlorosilane (OTS). Material and Methods: An in vitro experimental study was performed using 40 human permanent incisors that were divided into the following two groups: non-silanized and silanized. The specimens were pretreated and chemically modified with OTS. After the chemical modification, the dentin hydrophobicity was examined using a water contact angle measurement (WCA). The effectiveness of the modification of hydrophobicity was verified by the fluid permeability test (FPT). Results and Conclusions: Statistically significant differences were found in the values of WCA and FPT between the two groups. After silanization, the hydrophobic intraradicular dentin surface exhibited in vitro properties that limit fluid penetration into the sealed root canal. This chemical treatment is a new approach for improving the sealing of the root canal system.

In vitro comparative evaluation of the effect of two different fiber reinforcements on the fracture toughness of provisional restorative resins.

Background: Fracture of provisional fixed partial denture (FPD) may jeopardize the success of provisional prosthodontic treatment phase and cause patient discomfort. Aim: The aim of this study was to compare the fracture toughness of the Polymethyl Methacrylate (PMMA) resin and Bis-Acryl Composite (BAC) resin reinforced with the Polyethylene and Glass fibers. Materials and Methods: Three groups (N=10) of each of the two materials were prepared for the fracture toughness test. Two groups had the different reinforcements and group without reinforcement served as the control. The mean fracture toughness (MPa.m½ ) was compared by One-way ANOVA, followed by the Scheffe analysis. Fracture toughness between fiber-reinforced PMMA and BAC resin was compared by the independent samples t test. Results: For the controls, the fracture toughness for PMMA resin (0.91) was significantly lower than for the BAC resin (1.19). Glass fiber reinforcement produced significantly higher fracture toughness for both, PMMA (1.48) and BAC (1.82) resin, but the Polyethylene fibers did not (0.95 for PMMA and 1.23 for BAC resin). Among the reinforced groups, Silane impregnated Glass fibers showed highest fracture toughness for the BAC resin (1.82). Conclusion: Of two fiber reinforcement methods evaluated, Glass fiber reinforcement for the PMMA and BAC resin produced highest fracture toughness. Clinical Implications: On the basis of this in--vitro study, the use of Glass and Polyethylene fibers tested may be an effective way to reinforce resins used to fabricate fixed provisional restorations.