RESUMO

In recent decades, natural fibers have emerged as an alternative to synthetic fibers due to their renewable nature, lower environmental impact, and comparable strength properties. Agave bagasse, a byproduct of agave juice extraction in Mexico, stands out for its potential in various industrial applications, notably biocomposite production. Bagasse is rich in cellulose, along with hemicellulose and lignin. Cellulose is the most suitable to be converted into valuable products, and it is versatile, renewable, and biodegradable. An effective pre-treatment is crucial to enrich its fraction. This study aims to determine the optimal pre-treatment conditions for the agave bagasse. Three different pre-treatments were tested, acid (H2SO4), enzymatic (Cellic® HTec2 enzymatic preparation), and sequence of acid-enzymatic (sulfuric acid and Cellic® HTec2), to determine which pre-treatment got the optimal cellulose fraction increase. The acid pre-treatment was conducted over three time ranges (5, 10, and 15 min) at different acid concentrations (1%, 1.5%, and 2%). Enzymatic reactions were conducted over 24 h, testing three different enzyme concentrations (1.5%, 3%, 4.5%). The sequential pre-treatment utilized the optimal conditions derived from the acid experiments (1.5% H2SO4 for 10 min), followed by enzymatic reactions carried out over three different durations (6, 12, and 24 h). The findings revealed that a 1.5% acid concentration applied for 10 min was the most efficient pre-treatment method. This pre-treatment resulted in a 1.9-fold increase in the cellulose fraction while reducing hemicellulose content by 30%. The hemicellulose reduction was confirmed through Fourier Transform IR spectroscopy (FTIR) analysis, complemented by scanning electron microscopy (SEM) observations highlighting physical alterations in the fiber structure. Furthermore, thermogravimetric analysis (TGA) demonstrated improved thermal stability, suggesting potential use in biocomposites. Future research should evaluate the environmental impact of optimized pre-treatment methods for agave bagasse.

RESUMO

OBJECTIVE: The aim of this study was to evaluate the effect of four different finishing procedures on the fatigue strength of a fully stabilized zirconia (5Y-FSZ) material. MATERIALS AND METHODS: Disc-shaped specimens of a 5Y-FSZ (Katana UTML, Kuraray Noritake) were made (ISO 6872-2015), grinded with 600- and 1200-grit silicon carbide paper, sintered as recommended, and randomly assigned into four groups according to the finishing technique: C (control, as-sintered), P (polished with polishing rubbers), G (glaze application - powder/liquid technique), and PG (polished with polishing rubbers + glaze application - powder/liquid). Then fatigue strength (staircase method), X-ray diffraction (XRD), and scanning electron microscopy (SEM) analyses were performed. RESULTS: The C group presented the lowest fatigue strength, while the PG group presented the highest. The P and G groups presented intermediate behavior, presenting similar statistical results. XRD showed similar crystalline phase patterns for all groups. SEM images revealed some changes in the zirconia surface, with the P group presenting some scratches on the surface, while the scratches in the PG group were filled with the glaze material. CONCLUSION: None of the techniques analyzed in this study impaired the fatigue strength of fully stabilized zirconia. Importantly, the polishing rubbers combined with glaze application (PG group) improved its fatigue strength. CLINICAL RELEVANCE: The polishing rubbers followed by glaze application improve the fatigue strength in ultra-translucent zirconia.

Assuntos

RESUMO

The purpose of this study was to investigate the tensile bond strength (TBS) and shear bond strength (SBS) between a zirconia core and fluoroapatite-pressed ceramic after the application of glass 46SP6 and AP40 via the ISO-17095:2013 methodology. Sintered zirconia beams (n = 120) were divided into four groups: (a) control: no treatment; (b) ZirL: IPS-E max ceram ZirLiner coating; (c) glass AP40 coating; and (d) glass 46SP6 coating. A fluoroapatite ceramic (IPS e.max Zir Press, Ivoclar Vivadent) beam was injected perpendicularly on top of each zirconia (Zenostar, Wieland Dental) beam forming a cross-bonded specimen. All groups were sub-divided into two for tensile and shear bond strength tests using a universal testing machine. Data were analyzed using the Kruskal-Wallis, Pearson Chi2, and Mann-Whitney U test (α = 0.05). The failure modes were measured using a stereomicroscope for each group. Scanning electron and atomic force microscopy were also employed. Zirconia surface modification with glass AP40 showed higher TBS values followed by the ZirL group with statistical differences (p < 0.05). SBS values showed no statistical differences between the groups. AFM analysis showed higher roughness values (Ra) in the 46SP6 and AP40 groups (p < 0.05). Glass coating AP40 exhibited promising bond strength results between zirconia and fluorapatite veneering ceramic, making it better for chemical and mechanical interlocking which may improve bilayered restorations longevity.

Assuntos

RESUMO

Objective: The purpose of the study was to evaluate the effect of different preparation designs and different surface treatments on the fracture resistance of monolithic zirconia inlay-retained fixed dental prosthesis [IRFDP]. Material and methods: Forty-five translucent zirconia IRFDPs were divided into three groups according to preparation designs (n = 15); group I: proximal box, group II: inlay-box and group III: butterfly wing (modified inlay). Each group was further subdivided into three subgroups according to the surface treatments utilized (n = 5); sandblasting, tribochemical silica coating (Cojet system) and erbium, chromium: Yttrium, scandium, gallium, garnet (Er, Cr: YSGG) laser irradiation. All zirconia IRFDPs were cemented to their respective resin models using selfadhesive resin cement. All cemented IRFDPs were subjected to fracture resistance test using universal testing machine. The initial fracture site was determined by using a stereomicroscope (x6.7magnification). Two-way analysis of variance (ANOVA) was used to evaluate the effect of different designs, different surface treatments and their interaction on the mean fracture resistance. Bonferroni's post-hoc test was used when ANOVA is significant (P ≤ 0.05). Results: Butterfly wings design showed the highest fracture resistance values followed by inlay and box designs respectively (P ≤ 0.05). Sandblasting and Cojet showed significantly the highest mean fracture resistance values than Laser with no significance difference between them. Conclusion: The butterfly wing design increased the fracture resistance of the zirconia IRFDPs. Sandblasting and tribochemical silica coating of zirconia surfaces had a greater effect than Er, Cr: YSGG laser to gain higher fracture resistance of zirconia IRRDPs (AU)

Objetivo: O objetivo do estudo foi avaliar o efeito de diferentes modelos de preparações e diferentes tratamentos de superfície na resistência à fratura de inlays de zircônia monolítica. Material e métodos: Quarenta e cinco inlays translúcidos de zircônia foram divididos em três grupos de acordo com os desenhos de preparação (n = 15); grupo I: caixa proximal, grupo II: inlay convencional e grupo III: asa de borboleta (inlay modificado). Cada grupo foi subdividido em três subgrupos de acordo com os tratamentos de superfície utilizados (n = 5); jateamento de areia, revestimento triboquímico de sílica (sistema Cojet) e érbio, cromo: ítrio, escândio, gálio, granada (Er, Cr: YSGG) irradiação a laser. Todos os inlays de zircônia foram cimentados em seus respectivos modelos de resina usando cimento de resina auto-adesivo. Todos os inlays cimentados foram submetidos a teste de resistência à fratura usando máquina de teste universal. O local inicial da fratura foi determinado usando um estereomicroscópio (ampliação de 6,7x). A análise de variância (ANOVA) de dois fatores foi usada para avaliar o efeito de diferentes desenhos, diferentes tratamentos de superfície e sua interação na resistência média à fratura. O teste post-hoc de Bonferroni foi usado quando a ANOVA foi significativa (P ≤ 0,05). Resultados: O design das asas de borboleta apresentou os maiores valores de resistência à fratura, seguidos pelos designs de inlay convencional e caixa, respectivamente (P ≤ 0,05). O jateamento de areia e o Cojet apresentaram significativamente os maiores valores médios de resistência à fratura do que o Laser, sem diferença de significânc=ia entre eles. Conclusão: O design da asa de borboleta aumentou a resistência à fratura dos inlays de zircônia. O revestimento por jato de areia e triboquímica de sílica das superfícies de zircônia teve um efeito maior que o laser Er, Cr: YSGG para obter maior resistência à fratura dos inlays de zircônia. (AU)

Assuntos

RESUMO

Abstract The purpose of this study was to evaluate the microshear bond strength of ceramic prosthetic structures reinforced by lithium disilicate cemented with resin cement under conditions of different surface treatments and adhesive systems. Seventy-two rectangular blocks of lithium disilicate (6.5 mm long × 5 mm wide × 1 mm thick) were fabricated, air abraded with 50-μm Al2O3 particles and divided into six groups (n=12) depending on the surface pretreatments. The groups were as follows: 10HF/S/SBM: 10% hydrofluoric acid etched for 20 s (10HF) + silane (S) + Adper Scotchbond Multi-Purpose (SBM); 10HF/S/SB: 10HF + S + Single Bond Universal (SB); 10HF/SBM; 10HF/SB; S/SBM and S/SB. Two 1-mm-long plastic tubes were placed on the specimens, filled with RelyX ARC resin cement and cured for 20 s per tube. The plastic tube was removed, and the microshear bond strength was tested. Data were submitted to analysis of variance and Tukey's tests (α=0.05). Fractured specimens were observed under optical microscopy. For both adhesives, the bond strengths (MPa) of groups treated with acid-etching and silane (10HF/S/SB: 24.82, 10HF/S/SBM: 24.90) were higher (p<0.001) than those of groups treated with acid-etching (10HF/SB: 16.47, 10HF/SBM: 19.94) only or only silane (S/SB: 18.42, S/SBM: 13.24). All groups showed a predominance of failure adhesive. The silanization should be a clinical step in cementing ceramic structures reinforced by lithium disilicate, even with the application of universal adhesive that contains silane in its formulation.

Resumo O objetivo neste estudo foi avaliar a resistência de união ao microcisalhamento de estruturas protéticas cerâmicas reforçadas por dissilicato de lítio cimentadas com cimento resinoso sob diferentes tratamentos de superfície e sistemas adesivos. Setenta e duas barras retangulares de dissilicato de lítio (6,5 mm de comprimento × 5 mm de largura × 1 mm de espessura) foram fabricadas, tratados com partículas de Al2O3 (50 μm) e dividido em seis grupos (n=12) dependendo dos pré-tratamentos de superfície. Os grupos foram como se segue: 10HF/S/SBM: condicionamento com ácido fluorídrico 10% durante 20 s (10HF) + silano (S) + Adper Scotchbond Multi-Purpose (SBM); 10HF/S/SB: 10HF + S + Single Bond Universal (SB); 10HF/SBM; 10HF/SB; S/SBM; e S/SB. Dois tubos plásticos cilíndricos de 1 mm de comprimento foram colocados sobre os espécimes, preenchidos com cimento RelyX ARC e fotoativado durante 20 s por tubo. Os tubos plásticos foram removidos e a resistência de união ao microcisalhamento foi testada. Os dados foram submetidos à análise de variância e ao teste de Tukey (α=0,05). Espécimes fraturados foram observados sob microscopia óptica. Para ambos os adesivos, a resistência de união (MPa) dos grupos tratados com condicionamento ácido e silano (10HF/S/SB: 24,82, 10HF/S/SBM: 24,90) foram superiores (p<0.001) aos grupos tratados com condicionamento ácido apenas (10HF/SB: 16,47, 10HF/SBM: 19,94) ou apenas silano (S/SB: 18,42, S/SBM: 13,24). Todos os grupos apresentaram uma predominância de falha adesiva. A silanização deve ser um passo clínico em cimentação de estruturas cerâmicas reforçadas por dissilicato de lítio, mesmo com a aplicação do adesivo universal que contém em sua formulação um silano.

Assuntos

RESUMO

OBJECTIVES: This study investigated the effect of surface treatment (air-abrasion with alumina or hydrofluoric acid-etching) on feldspar ceramic mechanical strength and initial reliability (24h) before/after adhesive luting. METHODS: Ceramic discs (VITA) were tested as monolithic specimens (Acid; Abrasion), luted bilayers (Acid+luting agent; Abrasion+luting agent), or untreated (Control). Luted groups were coated using resin-based agent (RelyX Veneer, 3M ESPE). Biaxial flexural test with ball-on-ring setup was carried out (n=30). Biaxial flexural strength (σbf, MPa), characteristic strength (σ0, MPa), and Weibull modulus (m) were calculated for axial positions z=0 (ceramic surface) and z=-t2 (luting agent surface). For each condition, 95% confidence intervals were calculated. Scanning electron microscopy was used for topography and fractography analyses. RESULTS: At z=0, σbf and σ0 of luted specimens were higher than of monolithic specimens for both surface treatments. Groups Acid and Abrasion had lower σbf and σ0 than Control. Group Abrasion had poorer mechanical strength. Similar structural reliability was observed for all conditions except for the group Abrasion+luting agent, which had lower m than all other groups. At z=-t2, no significant differences between luted groups were observed for mechanical strength and reliability. A more irregular surface topography with more sharp angles was left by air-abrasion than etching. Monolithic specimens failed from surface pores at the tensile area, whereas failure in luted specimens originated from pores below the resin-ceramic interface. SIGNIFICANCE: Air-abrasion yielded lower mechanical strength and initial reliability than acid etching. Presence of a resin-based luting agent layer bonded to ceramic significantly increased its mechanical strength.

Assuntos

RESUMO

The aim of this study was to evaluate the efficacy of different surface conditioning methods on the microtensile bond strength of a restorative composite repair in three types of dental ceramics: lithium disilicate-reinforced, leucite-reinforced and feldspathic. Twelve blocks were sintered for each type of ceramic (n=3) and stored for 3 months in distilled water at 37 °C. The bonding surface of ceramics was abraded with 600-grit SiC paper. Surface treatments for each ceramic were: GC (control) - none; GDB - diamond bur #30 µm; GHF - hydrofluoric acid (10%); GT- tribochemical silica coating (45-μm size particles). Treatments were followed by cleaning with phosphoric acid 37% for 20 s + silane + adhesive. The composite resin was used as restorative material. After repair, samples were subjected to thermocycled ageing (10,000 cycles between 5 °C and 55 °C for 30 s). Thereafter, the samples were sectioned into 1.0 mm2 sticks and tested for microtensile bond strength with 0.5 mm/min crosshead speed. Data were compared by two-way ANOVA and Tukey's test (α=0.05). The superficial wear with diamond bur proved to be suitable for feldspathic porcelain and for leucite-reinforced glass ceramic while hydrofluoric acid-etching is indicated for repairs in lithium disilicate-reinforced ceramic; tribochemical silica coating is applicable to leucite-reinforced ceramic. Predominance of adhesive failures was observed (>85% in all groups). In conclusion, the success of surface treatments depends on the type of ceramic to be repaired.

O objetivo deste estudo foi avaliar a eficácia de diferentes condicionamentos de superfície na resistência de união de reparos de compósitos restauradores em três tipos de cerâmicas odontológicas: reforçada por dissilicato de lítio, reforçada por leucita e feldspática. Foram confeccionados 12 blocos para cada tipo de cerâmica (n=3) e armazenados por 3 meses em água destilada a 37 oC. A superfície de união das cerâmicas foi regularizada com lixa de granulação 600 por 15 s e lavadas em ultrassom por 10 min. Os tratamentos de superfície para cada cerâmica foram: GC (controle) - nenhum; GPD - ponta diamantada com 30 µm de granulação; GAF - ácido hidrofluorídrico a 10%; GJ - jateamento com partículas de óxido de alumínio revestido por sílica (45 µm - tamanho das partículas). Após, foi realizada a limpeza da superfície com ácido fosfórico a 7% por 20 s, seguido de silano e adesivo. Como material restaurador foi utilizada resina composta. Após o reparo, as amostras foram submetidas a ciclagem térmica (10,000 ciclos entre 5 °C e 55 °C, por 30 s). Na sequência, as amostras foram seccionadas em palitos de aproximadamente 1,0 mm2 e levadas ao teste de tração em uma máquina de ensaios universal à velocidade de 0,5 mm/min. Os dados obtidos foram comparados estatisticamente por ANOVA de dois fatores e teste de Tukey (α=0,05). Sugere-se que o desgaste da superfície com ponta diamantada é mais indicado para a cerâmica feldspática e cerâmica reforçada por leucita, enquanto o condicionamento com ácido fluorídrico é indicado para reparos em cerâmica reforçada por dissilicato de lítio. O jateamento com partículas de óxido de alumínio revestido por sílica mostrou-se aplicável à cerâmica reforçada por leucita. Predominancia de fraturas adesivas acima de 85% foi observada para todos os grupos. Este estudo demonstrou que o sucesso dos tratamentos de superfície depende do tipo de cerâmica a que são aplicados.

Assuntos

RESUMO

O objetivo deste trabalho foi apresentar uma revisão da literatura sobre superfícies de implantes dentários com tratamento a laser. O laser é uma amplificação da luz que, dependendo de sua intensidade e interação com a matéria, é capaz de gerar mudanças morfológicas e químicas em ligas de metais, como as de titânio, usadas em Odontologia. Diversos tipos de tratamentos a laser vêm sendo estudados para criar superfícies rugosas em implantes dentais osseointegráveis. Atualmente, as superfícies rugosas de implantes dentários, comparadas às superfícies usinadas, apresentam melhor resposta biológica do hospedeiro, diminuindo o período de osseointegração e permitindo ao profissional que realize reabilitações protéticas mais rápidas e seguras.

The aim of this work is to present a literature review regarding dental implants surfaces treated by lasers. Laser is a light amplifi cation that depending of the intensity and matter interaction, is capable to cause morphologic and chemical changes in metal alloys, such as, titanium alloy used in dentistry. Several types of surface laser treatments has been studied to create rough surfaces in osseointegrated dental implants. In the last few years, the rough surfaces of dental implants compared to machined surfaces, presented better biologic response of the host, reducing the osseointegration period, enabling professionals to have a possibility to perform faster and more secure prosthodontic rehabilitation.

Assuntos

RESUMO

O íntimo contato entre osso e implante é considerado um pré-requisito fundamental para o sucesso dos implantes dentários, condição esta conhecida como osseointegração. Devido a isto, um grande número de pesquisas com tratamentos de superfícies de implantes vem sendo desenvolvido por várias empresas nos últimos anos, visando acelerar esse fenômeno. O objetivo deste trabalho é avaliar histomorfometricamente o percentual de contato osso-implante (BIC) e área de osso novo (BA) entre implantes de tratamento de superfície Neoporos (GC - hidrofóbico) e implantes com energia de superfície molhada Acqua (GE - hidrofílicos). Foram utilizados 15 coelhos da raça new zealand, que receberam 30 implantes divididos em cada lado de suas tíbias direita e esquerda, ambos de titânio comercialmente puro grau IV com 3.5x8mm de dimensão, sendo ao final de 15 dias, a região dos implantes coletada e processada histologicamente para obtenção de cortes teciduais não desmineralizados, embora dois implantes do grupo Esm tenham sido excluídos da pesquisa devido à instalação ter ocorrido dentro do canal medular e terem obtido tecido necrosado, não cumprindo as características de osseointegração. Para análise dos dados estatísticos, utilizou-se o teste t de Students para amostras independents e teste Mann-Whitney Rank Sum com nível de significância de p<0.05. Os resultados mostraram que não houve diferença estatisticamente significante entre os grupos para a análise de BIC. O grupo GC apresentou a média de 42.9% de BIC, ligeiramente menor que o grupo GE, que apresentou 49.3% de média. Já para o teste BA houve diferenças de 15%, em que o grupo GC apresentou 58.6% e o grupo GE, 74.4%. A conclusão é que há, ainda, necessidade de maiores estudos a cerca do referido tema.

The near contact between bone and implant is considered an essential pre-requisite for the success of dental implants, a condition known as osseointegration. Due to it, a great amount of researches on implants surface treatments has been developed by several companies in recent years to accelerate the phenomenon of osseointegration. The aim of the present study is to evaluate histomorphometrically the percentage of bone-implants contact (BIC) and the area of new bone (BA) between implants with surfaces treatment Neoporos (GC - hydrophobic) and implants with wets surface energy Acqua (GE - hydrophilic). It was used fifteen (n=15) New Zealand rabbits, which received thirty implants installed dividing them between its right and left tibias. Implants were commercially pure titanium grade IV with 3.5x8mm dimension. After fifteen days, the implants area were collected and processed histologically in order to obtain not demineralized tissue sections. For statistical data analysis, it was used the t test for independents samples and Mann-Whitney Rank Sum test. The significance level was p<0.05. Results showed no statistical significant difference between groups for BIC analysis. The control group showed a mean of 42.9% of BIC, slightly lower than the GE group, which showed a mean of 49.3%. For BA test, there was a significant difference of more than 15% in the control group (58.6% for the GC group and 74.4% for GE group). It was concluded that futher studies is needed on this topic of osseointegration and hydrophobic /hydrophilic implants.

Assuntos

RESUMO

This study investigated the effect of the filler particle size (micron or submicron) of experimental resin cements on the microtensile bond strength to a glass-ceramic pretreated with hydrofluoric acid (HFA) etching or alumina airborne-particle abrasion (AA). Cements were obtained from a Bis-GMA/TEGDMA mixture filled with 60 mass% micron-sized (1 ± 0.2 µm) or submicron-sized (180 ± 30 µm) Ba-Si-Al glass particles. Ceramic blocks (PM9; VITA) were treated with 10% HFA for 60 s or AA for 15 s. Silane and adhesive were applied. Ceramic blocks were bonded to resin composite blocks (Z250; 3M ESPE) using one of the cements. Bonded specimens were sectioned into beams (n = 20/group) and subjected to microtensile bond strength tests. Data were analyzed using ANOVA and Student-Newman-Keuls' tests (5%). Failure modes were classified under magnification. Morphologies of the treated ceramic surfaces and bonded interfaces were evaluated by scanning electron microscopy. The HFA-submicron group had lower bond strengths than the other groups. All AA-submicron specimens debonded prematurely. Mixed failures were predominant for HFA groups, whereas interfacial failures predominated for AA groups. SEM revealed a honeycomb-like aspect in the HFA-treated ceramic, whereas the AA-treated groups showed an irregular retentive pattern. Continuity of cement infiltration along the bonded interface was more uniform for HFA-treated compared to AA-treated specimens. Cracks toward the bulk of the ceramic were observed in AA-treated specimens. Particle size significantly influenced the ceramic bond strength, whereas surface treatment had a minor effect.

Assuntos

RESUMO

A superfície dos implantes dentais é um fator determinante para o sucesso da osseointegra­ção, sendo caracterizada principalmente por parâmetros de rugosidade. Objetivos: caracterizar a topografia da superfície do implante Titaoss. Material e métodos: cinco implantes Titaoss com plataforma de hexágono externo e diâmetro 4,1 mm e 13 mm de com­primento de diferentes lotes foram analisados por microscopia eletrônica de varredura (MEV) e interferometria, para avaliação da morfologia e rugosidade da superfície. Resultados: as imagens de MEV demonstraram uma alta frequência de pequenas estruturas, que são características do tratamento de duplo ataque ácido. A quantificação numérica da rugosidade demonstrou uma altura média das estruturas (Sa) de 0,55 ± 0,16 μm com um incremento da área de superfície (Sdr) de 15,14 ± 3,78% e concentração de picos (Sds) de 0,102 ± 0,010/μm2. Conclusão: a superfície do implante Titaoss apresenta microestruturas decorrentes do tratamento com duplo ataque ácido compatíveis com outros sistemas de implantes já consolidados no mercado internacional. Estudos posteriores são necessários para comprovação clínica longitudinal do sistema.

The surface of dental implants, which is characterized by roughness parameters, is a key factor to determine the success of osseointegration. Objectives: to characterize the surface topography of Titaoss dental implant. Material and methods: five implants with external hexagon connection in 4.1 mm diameter platform and length of 13 mm from different batches were evaluated by scanning electron microscopy (SEM) and by interferometry to identify the surface morphology and quantify roughness. Results: SEM images exhibited high frequency of short structures, which are common in dual acid-etched surfaces. The numerical analysis of roughness reported a mean height deviation of the structures (Sa) of 0.55 ± 0.16 μm and an increase of surface area (Sdr) of 15.14 ± 3.78% with summit concentration (Sds) of 0.102 ± 0.010/μm2. Conclusion: the Titaoss implant presented surface microstructures due to dual acid treatment compatible with other implants already established in the international market. Further studies are necessary to ensure the long-term clinical success of this new implant system

Assuntos

RESUMO

This study evaluated the influence of the surface treatments of fiberglass posts on bond strength to root dentin using push-out test. Forty bovine incisor roots were endodontically treated. The surface of the fiberglass posts (Exacto #2, Angelus) were treated using 4 different protocols (n=10): Control - 70% ethanol for 1 min; 37% phosphoric acid for 1 min; 10% hydrofluoric acid for 1 min; and 24% hydrogen peroxide for 1 min. After a silane coupling agent was applied for 1 min and all posts were cemented using self-adhesive resin cement (RelyX Unicem, 3M-ESPE). The roots were sectioned and two 1-mm-thick slices were obtained from each third: cervical, middle and apical. The specimens were subjected to the push-out test with a crosshead speed of 0.5 mm/min. Data were analyzed by repeated measures ANOVA followed by Tukey's HSD tests (=0.05). The surface treatment (p<0.001) and root third region (p=0.007) factors were significant. The retention to root canal was affected by surface treatment type. The post surface treatment with 24% hydrogen peroxide for 1 min yielded significantly higher bond strength when the fiberglass posts were cemented with RelyX Unicem.

Este estudo avaliou a influência de tratamentos de superfície de pinos de fibra de vidro na resistência de união à dentina radicular por meio do teste de push-out. Quarenta raízes de incisivos bovinos foram submetidas a tratamento endodôntico. A superfície dos pinos de fibra de vidro (Exacto #2, Angelus) foram tratadas com 4 protocolos diferentes (n=10): Controle - 70 % de etanol durante 1 min; 37 % de ácido fosfórico durante 1 min, 10% de ácido fluorídrico durante 1 min e 24 % de peróxido de hidrogênio durante 1 min. Depois foi aplicado agente de união silano por 1 min e todos os pinos foram cimentados com cimento resinoso auto-adesivo (RelyX Unicem, 3M- ESPE). As raízes foram seccionadas e foram obtidas duas fatias de 1 mm de espessura em cada terço: cervical, médio e apical. Os espécimes foram submetidos ao teste de push-out com uma velocidade de 0.5 mm/min. Os dados foram analisados pelo teste ANOVA com medidas repetidas, seguido pelo teste de Tukey HSD (=0,05). Os fatores tratamento de superfície (p<0,001) e região do terço radicular (p=0,007) foram significantes; no entanto, a interação entre os dois fatores não foi significante (p=0,827). A retenção ao canal radicular foi afetada pelo tipo de tratamento de superfície. O tratamento de superfície com 24% de peróxido de hidrogênio por 1 min rendeu significativamente maior resistência de união quando os pinos de fibra de vidro foram cimentados com RelyX Unicem.

Assuntos

RESUMO

An important parameter for the clinical success of dental implants is the formation of direct contact between the implant and surrounding bone, whose quality is directly influenced by the implant surface roughness. A screw-shaped design and a surface with an average roughness of Sa of 1-2 µm showed a better result. The combination of blasting and etching has been a commonly used surface treatment technique. The versatility of this type of treatment allows for a wide variation in the procedures in order to obtain the desired roughness. OBJECTIVES: To compare the roughness values and morphological characteristics of 04 brands of implants, using the same type of surface treatment. In addition, to compare the results among brands, in order to assess whether the type of treatment determines the values and the characteristics of implant surface roughness. MATERIAL AND METHODS: Three implants were purchased directly from each selected company in the market, i.e., 03 Brazilian companies (Biomet 3i of Brazil, Neodent and Titaniumfix) and 01 Korean company (Oneplant). The quantitative or numerical characterization of the roughness was performed using an interferometer. The qualitative analysis of the surface topography obtained with the treatment was analyzed using scanning electron microscopy images. RESULTS: The evaluated implants showed a significant variation in roughness values: Sa for Oneplant was 1.01 µm; Titaniumfix reached 0.90 µm; implants from Neodent 0.67 µm, and Biomet 3i of Brazil 0.53 µm. Moreover, the SEM images showed very different patterns for the surfaces examined. CONCCLUSIONS: The surface treatment alone is not able to determine the roughness values and characteristics.

Assuntos

RESUMO

PURPOSE: In the treatment of superficial lesions with proton Pencil Beam Scanning (PBS), spot size is dominated by the nozzle contribution. Accuracy of phase-space modeling is therefore paramount. IBA's Dedicated (DN) and Universal Nozzles (UN) have different designs and, consequently, characteristics. Here we report the phase spaces of these two nozzles, without and with a range shifter (RS). METHODS: In-air spot fluence measurements were made for five proton energies: 225, 210, 180, 150 and 115 MeV and at five distances from isocenter pertinent to SAD-type treatments: +33, +20, +10, 0 and -10 cm ('+' implies upstream), without and with a 7.5 cm water-equivalently-thick RS (sufficient to pull back the lowest energy Bragg peak to patient surface), fixed with its upstream side 41 cm from isocenter. Data collected on a fixed horizontal beam-line with a DN and a gantry-mounted UN were compared. The full-width-at-half-maximum (FWHM) of a Gaussian fit to each spot fluence profile was extracted along the two principal axes. RESULTS: With no RS, the proton spots are ∼20-70% larger at isocenter in the UN than in the DN. Spots are less asymmetric, and eccentricity increases more slowly with energy, in the UN than in the DN. Over the 33 cm in-air travel upstream of isocenter, the spot FWHM varies by less than ∼2 mm. However, spot asymmetry becomes more severe upstream (for 115 MeV spots, 30-40% compared to <20% at isocenter for DN, but similar and <10% for UN). With an RS, spot FWHM at isocenter increases by 12.7 mm from 8.3 mm (DN) and 10.7 mm from 13 mm (UN) for 150 MeV protons (typical for brain treatments). With no RS, relatively distance-independent spot size facilitates SAD-type treatments. For patients with superficial lesions, where an RS is required and the phase space varies rapidly with distance, the RS should be permitted at two additional locations. US Army Medical Research and Materiel Command under Contact Agreement No. DAMD17-W81XWH-04-2-0022.

RESUMO

As cerâmicas à base de zircônia (Y-TZP) apresentam propriedades mecânicas superiores às das demais cerâmicas odontológicas. Entretanto, o aumento do conteúdo cristalino modificou suas características de adesão a cimentos resinosos, tornando necessário o desenvolvimento de métodos mais efetivos de união a estes materiais. Este trabalho in vitro pretende, portanto, avaliar a influência de diferentes tratamentos de superfície e de diferentes agentes de união na resistência ao cisalhamento entre uma zircônia estabilizada por ítrio e um agente cimentante autoadesivo (RelyX U100®/3M ESPE). Para tal, cilindros de PROCERA® Allzircon receberam como tratamento de superfície jateamento com óxido de alumínio (Al2O3 - 50 µm) ou jateamento com o sistema Rocatec. Sobre a superfície tratada dos cilindros foram aplicados, de acordo com os diferentes grupos experimentais, o sistema adesivo Clearfil SE Bond® (Kuraray Co.), e os primers Metal Zirconia Primer (Ivoclar Vivadent) e Alloy Primer (Kuraray Co.) e, finalmente, o cimento resinoso adotado. Cada espécime foi, então, submetido ao teste de cisalhamento (0,05 mm/min), por meio da ação de uma alça de fio ortodôntico passando o mais próximo possível da interface adesiva. A análise de variância a um critérios (ANOVA) e o teste de Tukey (p < 0,05) mostraram que a realização do tratamento de superfície aumentou os valores de resistência de união entre a cerâmica e o cimento resinoso.

O jateamento com o sistema Rocatec (15,33 MPa) apresentou valores significantemente maiores que o jateamento com Al2O3 (11,93 MPa). A aplicação dos agentes de união resultou em uma maior resistência adesiva, sendo que o sistema adesivo Clearfill SE Bond (17,07 MPa) teve um comportamento estatisticamente superior aos demais materiais. Entre os primers, o Metal Zircônia Primer (11,26 MPa) apresentou maior valor de resistência de união que o Alloy Primer (10,01 MPa). Portanto, a associação de um tratamento superficial com um agente de união é valida, já que promoveu os maiores valores de resistência adesiva.

Yttrium-stabilized tetragonal zircon polycrystal (Y-TZP) ceramics show better mechanical properties than other dental ceramics. However, the high crystalline content modified their adhesiveness to resin cements, making it extremely necessary to develop a more effective adhesive strategy between them. This in vitro study intends to evaluate the influence of different surface treatments and different bond agents on the shear bond strength between a Y-TZP and self-adhesive resin cement. PROCERA® Allzircon cylinders (3.5 mm in diameter) received a surface airborne abrasion treatment with 50 µm aluminum-oxide (Al2O3) particles or with the Rocatec system. According to the experimental groups, the adhesive system Clearfil SE Bond® (Kuraray Co.), and the primers Metal Zirconia Primer (Ivoclar Vivadent) and Alloy Primer (Kuraray Co.) were applied on the treated surface of the cylinders, before the application of the adopted resin cement (RelyX U100®/3M ESPE). Each specimen was submitted to the shear bond strength test (0.5 mm/min), by the action of an orthodontic stainless steel ligature wire (0.5 mm in diameter) loop, wrapped around the resin cement, as close as possible to the adhesive interface. One way- ANOVA and Tukey´s post hoc tests (p < 0.05) revealed that surface treatment increased bond strength between the ceramic and the resin cement. Silica coating with the Rocatec system (15.33 MPa) showed significantly higher values than airborne abrasion with Al2O3 (11.93 MPa). Application of all bond agents improved shear bond strength: adhesive system Clearfil SE Bond (17.07 MPa) showed better performance than the other evaluated materials, and Metal Zirconia Primer (11.26 MPa) showed higher bond strength values than Alloy Primer (10.01 MPa). Therefore, the association of a surface treatment with a bond agent is suitable, once it resulted in higher values of adhesive strength.

Assuntos

RESUMO

A substituição de ossos, articulações e dentes por biomateriais é usualmente feita em cirurgias para aliviar a dor e recuperar a função dos tecidos afetados. Adequada resistência mecânica, boa resistência à corrosão no meio corpóreo, não provocar toxicidade ao corpo e longa permanência no local são algumas das principais características que um biomaterial deve possuir para ter sucesso na aplicação. Porém, no corpo humano a degeneração óssea, inflamações nas articulações, bem como o desgaste ou corrosão das próteses e implantes, freqüentemente ocorrem e trazem complicações clínicas (HE e HAGIWARA, 2006). Mo presente trabalho, amostras de titânio comercialmente puro e implantes dentários osseointegráveis na forma de cilindro com roscas, fabricados com titânio comercialmente puro (Ti cp) ASTM grau 4 foram analisados com quatro tipos de superfícies usadas comercialmente: Master Screw (usinada), Master Porous (Superfície tratada com ácido), Master Vulcano Actives (Superfície anodizada) e tratado com flúor. O objetivo deste estudo foi avaliar a bioatividade e a influência do tratamento da superfície do Ti cp mediante imersão em solução de fluído corpóreo simulado (SBF). Após imersão em SBF por 10, 20 e 30 dias, as amostras foram observadas no microscópio eletrônico de varredura caracterizadas por difração de raio X. Os resultados mostraram que entre as superfícies analisadas, a superfície com melhor biocompatibilidade avaliada pela deposição de íons da solução SBF foi a Vulcano; apesar dos tempos de imersão terem sido relativamente baixos, obteve-se um resultado significantivamento positivo após os tratamentos Porous e com flúor

The replacement of bones, articulations and tooth for biomaterials are usually made in sugeries to relieve the pain and to recover the function of the affected tissue. Suitable mechanical properties, high corrosion resistance in the human body environment, no toxicity and long time in the place are some characteristics that a biomaterial should present to have success in the application. However, in the human body the bone degeneration, inflammations problems, as well as the wear or corrosion of the prostheses and implants, frequently happens and brings clinical complications (HE and HAGIWARA, 2006). In the present work, samples of discs and dental implants with cylinder shape were machined with commercial pure titanium (Ti cp) ASTM grade 4 were machined with commercial pure titanium (Ti cp) ASTM grade 4 were analyzed. Four implant surfaces were used: Master Screw (machined), Master Porous (acid etched), Master Vulcano Actives (anodized) and immersed in fluorine. The goal of this study was to evaluate the bioactivity and the influence of the surface treatment on Ti cp 4 immersed in Simulated Body Fluid (SBF). After immersion in SBR for 10, 20 and 30 days, the samples were observed by scanning electron microscopy (SEM) and characterized by X ray diffraction. The results showed that among the studied surface, the best surface result of deposition of ions from the SBF solution was the Vulcano one. In spite of the immersion times have been relatively low, a significantly positive result was obtained with Porous and fluorine treatments

Assuntos

RESUMO

O objetivo deste estudo foi avaliar a resistência de união ao cisalhamento dos materiais restauradores amálgama de prata e resina composta, em função de diferentes tratamentos da superfície, e de três sistemas adesivos (Sa1 - Scotchbond; Sa2 - Panavia 21; Sa3 - Alloybond). Cento e trinta e cinco corpos-de-prova de amálgama (Permite C) em forma de cilindro foram confeccionados e armazenados em estufa a 37º+- 2ºC por 24 horas. Posteriormente, procedeu-se um sorteio aleatório, formando três grupos com 45 corpos-de-prova cada (T1 - Polimento metalográfico - grupo controle; T2 - Microjateamento com óxido de alumínio a 50 um; T3 - Macroretenção com fresa 331/2). Também foram formados 3 subgrupos de 15 elementos cada (Sa1, Sa2, Sa3). Após a realizaçao dos tratamentos superficiais, a resina foi unida ao amálgama, armazenada em água por 7 dias, sendo realizada a ciclagem térmica (550 ciclos entre 5º e 55ºC) e teste de cisalhamento. Os dados em Mpa foram submetidos a análise de variância e teste de Kruskal Wallis (5% de significância). Em uma superfície de amálgama não tratada, o adesivo Panavia 21 foi o que apresentou a maior resistência de união (5,19+-1,07). Quando a superfície foi microjateada, o Alloybond foi o que mostrou os melhores resultados (10,38+-1,95) e, quando submetida à macroretenção, o adesivo Scotchbond apresentou o melhor comportamento (6,64+-1,44). Independentemente do adesivo usado, o tratamento da superfície por microjateamento foi o que apresentou a maior resistência de união

The objective of this study went evaluate the effect of different surface treatments in the shear bond strength between amalgam and composite resin, mediated by three adhesive systems (Sa1 - Scotchbond; Sa2 - Panavia 21; Sa3 - Alloybond) hundred and thirty five amalgam specimens (it Allows C) in cylinder form, they were made and stored in stove at 37º+- 2º C for 24 hours. Later on, it was proceeded a I raffle aleatory, forming three groups with 45 specimens each (T1 - group controls; T2 - Sandblasting with oxide of aluminum for 50um; T3 - Retentive macromechanical with bur 33 1/2). Was also formed 3 subgroups of 15 each (Sa1, Sa2, Sa3), after the accomplishment of the superficial treatments, the resin was united to the amalgam, stored in water by 7 days, being accomplished the thermocycled (550 cycles between 50 and 550C) and bond strength test. The data in Mpa, the variance analysis and test of Kruskal Wallis were submitted (5% of significance). In a surface of non treated amalgam, adhesive Panavia 21 went what presented to largest union resistance (5,19+-1,07). When the surface was sandblasted, Alloybond it was what showed the best results (10,38+-1,95) and when submitted the retentive macromechanical, adhesive Scotchbond presented the best behavior (6,64+-1,44). Independent of the used sticker, the treatment of the surface with sandblasting went what presented to largest union resistance

Assuntos