ABSTRACT: The aim of this study was to evaluate the influence of overtorque on integrity, strength and stress on external hexagonal implants (EH), with two different grades (N=10): conventional (C), grade 4; and modified (M), grade 4 with thermal treatment. The dimensions of EH were 3.75 x 13 mm; the specimens were fixed and submitted to SEM analysis and image acquisition. The abutment was then retained with 70 N/cm, re-analyzed by SEM, and a second image was obtained. The images were analyzed by Image J software (1.44o- NIH, USA) for dimensional variations measurement on surface of the hexagonal area. The finite element method was applied with a similar compliance to calculate the resultant stress (MPa) during the torque. Results were statistically analyzed with t-student test (5 %). The dimensional accuracy of M (0.22 mm2) was statistically significant (p<0.05). Minimum principal stress and von-Mises stress of C (-19.95 MPa, -19.94 MPa), were lower than M values (-55.83 MPa, -55.96 MPa), respectively. However, the M group showed lower deformation than C group. Therefore, more rigid titanium alloy is a promising alternative to avoid plastic deformation of prosthetic connec tions even concentrating higher stress magnitude on its structure.

RESUMEN: El objetivo de este estudio fue evaluar la influencia del sobrepar en la integridad, la fuerza y la tensión en los implantes hexagonales externos (EH), con dos grados diferentes (N = 10): convencional (C), grado 4; y modificado (M), grado 4 con tratamiento térmico. Las dimensiones de EH eran 3,75 de diámetro x 13 mm de longitud; las muestras se fijaron y se sometieron a análisis SEM y adquisición de imágenes. A continuación, el pilar se retuvo con 70 N / cm, se volvió a analizar por SEM y se obtuvo una segunda imagen. Las imágenes se analizaron con el software Image J (1.44o-NIH, EE. UU.) Para medir las variaciones dimensionales en la superficie superior del área hexagonal, que fue causada por un par excesivo. El método de los elementos finitos se aplicó con un cumplimiento similar para calcular la tensión resultante (MPa) durante el par. Los resultados se analizaron estadísticamente con la prueba t-student (5 %). La precisión dimensional de M (0,22 mm2) fue estadísticamente significativa (p <0,05). La tensión principal mínima y la tensión de von-Mises de C (-19,95 MPa, -19,94 MPa), fueron inferiores a los valores de M (-55,83 MPa, -55,96 MPa), respectivamente. Sin embargo, el hexágono del grupo M mostró menor deformación que el grupo C. Por lo tanto, la aleación de titanio más rígida es una alternativa prometedora para evitar la deformación plástica de las conexiones protésicas incluso concentrando una mayor magnitud de tensión en su estructura.

RESUMO Objetivo Avaliar a influência do tratamento térmico do silano na resistência de união entre dois cimentos resinosos e uma cerâmica feldspática CAD/CAM. Métodos Quarenta blocos cerâmicos foram duplicados em resina micro-híbrida. Todas as cerâmicas foram condicionadas com ácido fluorídrico 10% por 20 s e receberam aplicação do silano. Os blocos foram randomizados em oito grupos (n = 5): P-Panavia F; PAg- Panavia F + Envelhecimento; HP-Tratamento térmico + Panavia F;HPAg-Tratamento térmico + Panavia F + Envelhecimento; R-RelyX ARC; RAg-RelyX ARC; HR-Tratamento térmico + RelyX ARC; HRAg - Tratamento térmico + RelyX ARC + Envelhecimento. O tratamento térmico foi realizado em forno a 100 °C durante2 min. Todos os blocos foram cimentados e cortados para obter amostras para microtração. Foram feitos 10000 ciclos térmicos. As amostras foram submetidas a teste de micro-tração. Resultados O teste ANOVA revelou uma interação significativa entre cimento/tratamento térmico (p=0,001) e tratamento térmico/ciclo térmico (p=0,001). Conclusão Dessa maneira, o tratamentotérmico do silano a 100ºC por 2 minutos foi capaz de aumentar a resistência de união entre o cimento resinoso e uma cerâmica feldspática mesmo após o envelhecimento.

ABSTRACT Objective Evaluate the influence of silane heat treatment in bond durability between two resin cements and CAD/CAM feldspathic ceramic. Methods 40 feldspathic ceramic blocks were obtained, and were duplicated in microhybrid composite. All ceramic blocks were etched with 10% hydrofluoric acid for 20 s and received application of silane agent. The blocks were randomizedinto eight groups (n=5) according to the surface treatments and luting agents: P- Panavia F; PAg- Panavia F + Aging; HP- Heat Treatment + Panavia F; HPAg- Heat Treatment + Panavia F + Aging; R- RelyX ARC; Rag- RelyX ARC + Aging; HR- Heat Treatment + RelyX ARC; HRAg- Heat Treatment + RelyX ARC + Aging. The heat treatment was performed in furnace at 100 °C for 2 min. All blocks were cemented and cut to obtain samples with adhesive area of 1 mm2. Aging was performed with 10000 thermal cycles. The samples were subjected to microtensile bond strength test. Results The three-way ANOVA test revealed a significant interaction between cement versus heat treatment (p=0.001) and heat treatment versus thermal cycling (p=0.001) indicating that there was a change in bond strength due to surface treatment and aging. Conclusion Therefore, the heat treatment of the silane at 100 ºC for 2 minutes obtained higher values of bond strength between the resin cement and a feldspathic ceramicafter aging.

Resumo Introdução Apesar de ser uma das cerâmicas mais estudadas atualmente, a zircônia ainda não possui um protocolo bem definido para uma cimentação adesiva. Objetivo Avaliar a influência de diferentes tempos de condicionamento e concentrações do ácido fluorídrico (AF) na superfície da zirconia e na resistência de união entre uma cerâmica Y-TZP vitrificada e um cimento resinoso. Material e método Os tratamentos de superfície foram: jateamento com óxido de alumínio revestido com sílica (Co); aplicação de glaze + condicionamento com AF 5% por 5s (G5-5s), 10s (G5-10s) ou 20s (G5-20s); aplicação de glaze + condicionamento com AF 10% por 5s (G10-5s), 10 (G10-10s) ou 20s (G10-20s). Em seguida, cilindros de cimento (3,3 × 3,3mm) para teste de cisalhamento foram feitos em todos os espécimes. Os espécimes foram submetidos a 6000 ciclos térmicos antes do teste de adesão. As fraturas foram analisadas por estereomicroscópio. Os dados foram analisados estatisticamente por Kruskal-Wallis e Dunn (5%). Amostras extra de cada grupo foram feitas para realização de perfilometria e microscopia eletrônica de varredura (MEV). Resultado A resistência de união zircônia-cimento foi afetada pelos tratamentos de superfície (p = 0,001). Os grupos G10-5s (2,71 MPa) registraram os maiores valores de resistência de união, seguidos pelos Co (2,05 MPa), enquanto os grupos G5 apresentaram o menor valor de união. Falhas adesivas foram predominantes. As análises por imagem revelaram que os grupos G5 parecem ser menos rugosos quando comparados aos grupos tratados com AF 10%. A criação de poros na superfície vítrea (glaze) ocorreu apenas quando foi utilizado AF 10%. Conclusão A aplicação de camada de vidro de porcelana de baixa fusão foi capaz de superar o jateamento e obter uma maior adesão adesiva ao cimento resinoso, no entanto, somente quando foi utilizado 10% de HF por um intervalo de 5 segundos.

Abstract Introduction Despite being one of the most studied ceramics today, zirconia still does not have a well-defined adhesion protocol. Objective Evaluate the influence of different etching times and hydrofluoric acid (HF) concentrations on the zirconia surface and bond strength between a vitrified Y-TZP ceramic and a resin cement. Materials and method The zirconia surface treatments were: sandblasting with silica-coated alumina (Co); glaze application + 5% HF etching for 5s (G5-5s), 10s (G5-10s) or 20s (G5-20s); glaze application + 10% HF etching for 5s (G10-5s), 10 (G10-10s) or 20s (G10-20s) . Then, cement cylinders (3.3 × 3.3 mm) were built up for shear bond test on all specimens. The specimens were subjected to 6000 thermal cycling before the test. Fractures were analyzed by stereomicroscope. Data were statistically analyzed by Kruskal-Wallis and Dunn statistical tests (5%). Extra samples of each group were made to obtain profilometry and scanning electron microscopy (SEM). Result Zirconia-cement bond strength was affected by the ceramic surface treatments (p = 0.001). G10-5s (2.71 MPa) recorded the highest bond strength values, followed by the Co (2.05 MPa) while G5 groups had the lowest bond value. Adhesive failure of the samples predominated. The image analysis revealed G5 groups seem to have a lower roughness when compared to groups treated by 10% HF. The creation of pores in the low-fusing porcelain glass layer surface occurred only when 10% HF was used. Conclusion The low-fusing porcelain glass layer application was able to overcome the sandblasting and obtain a greater adhesive bond to the resinous cement, however, only when 10% HF was used for an interval of 5 seconds.

Abstract To evaluate the effect of different surface treatments on the marginal misfit and retentive strength between Y-TZP crowns and an epoxy resin. Forty (40) epoxy resin (G10) abutments (height: 5mm, conicity: 60, finish line: large chamfer) with equal dimensions were milled and included in polyurethane to simulate the periodontal ligament. Next, 40 Y-TZP crowns (thickness: 1mm) were milled (Cerec in Lab) and randomly divided into four groups (n=10) according to the surface treatment: GS(glaze spray), GP(glaze powder/liquid), P(zirconia primer) and RS(tribochemical silica coating). The conditioned surfaces were cemented with dual self-adhesive cement, light cured and submitted to thermomechanical cycling (2x106, 100N, 4Hz, 5°/55°C). Marginal misfit was analyzed by a stereomicroscope and SEM. Retentive strength test was performed (1mm/min) until crown debonding. Glaze layer thickness was also performed to GS and GP groups. Marginal misfit data were analyzed by Kruskal Wallis and Dunn tests; one-way ANOVA and Tukey (5%) analyzed the tensile strength data. The marginal misfit of the GS (48.6±19.9μm) and GP (65.4±42.5μm) were statistically lower than the RS (96±62.9μm) and P (156±113.3μm) (p=0.001). The retentive strength of the GP (470.5±104.1N) and GS (416.8±170.2N) were similar to the P (342.1±109.7N), but statistically higher than those of the RS (208.9±110N). The GS and GP glaze layer was 11.64μm and 9.73μm respectively. Thus, glaze application promoted lower marginal discrepancy and higher retentive strength values than conventional techniques.

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.

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.

O objetivo deste estudo foi avaliar o efeito de diferentes tempos de condicionamento ácido na rugosidade de superfície e resistência flexural de uma cerâmica à base de disilicato de lítio. Espécimes cerâmicos em forma de barra (16 mm x 2 mm x 2 mm) foram produzidos a partir de blocos cerâmicos. Todos os espécimes foram polidos e limpos em banho de ultrasom em água destilada. Os espécimes foram aleatoriamente divididos em 5 grupos (n=15). Grupo A (controle) sem tratamento. Grupos B-E condicionamento com ácido fluorídrico 4,9% (HF) por 4 diferentes períodos de condicionamento: 20 s, 60 s, 90 s e 180 s, respectivamente. As superfícies condicionadas foram observadas sob microscopia eletrônica de varredura. Perfilometria de superfície foi utilizada para examinar a rugosidade das superfícies condicionadas, e os espécimes foram carregados até a falha pelo teste de flexão três pontos. Os valores foram analisados usando ANOVA um fator e teste de Tukey (?=0,05). Todos os períodos de condicionamento produziram superfícies significantemente mais rugosas do que o grupo controle (p<0,05). Os valores de rugosidade aumentaram com o tempo de condicionamento. Os valores médios de resistência à flexão foram (MPa): A=417 ± 55; B=367 ± 68; C=363 ± 84; D=329 ± 70; e E=314 ± 62. O condicionamento com HF reduziu significativamente os valores médios de resistência à flexão conforme o tempo de condicionamento aumentou (p=0,003). Os achados deste estudo mostraram que o aumento do tempo de condicionamento ácido influenciou a rugosidade de superfície e resistência flexural de uma cerâmica à base de disilicato de lítio confirmando a hipótese do mesmo.

The aim of this study was to examine the effect of different acid etching times on the surface roughness and flexural strength of a lithium disilicate-based glass ceramic. Ceramic bar-shaped specimens (16 mm x 2 mm x 2 mm) were produced from ceramic blocks. All specimens were polished and sonically cleaned in distilled water. Specimens were randomly divided into 5 groups (n=15). Group A (control) no treatment. Groups B-E were etched with 4.9% hydrofluoric acid (HF) for 4 different etching periods: 20 s, 60 s, 90 s and 180 s, respectively. Etched surfaces were observed under scanning electron microscopy. Surface profilometry was used to examine the roughness of the etched ceramic surfaces, and the specimens were loaded to failure using a 3-point bending test to determine the flexural strength. Data were analyzed using one-way ANOVA and Tukey's test (?=0.05). All etching periods produced significantly rougher surfaces than the control group (p<0.05). Roughness values increased with the increase of the etching time. The mean flexural strength values were (MPa): A=417 ± 55; B=367 ± 68; C=363 ± 84; D=329 ± 70; and E=314 ± 62. HF etching significantly reduced the mean flexural strength as the etching time increased (p=0.003). In conclusion, the findings of this study showed that the increase of HF etching time affected the surface roughness and the flexural strength of a lithium disilicate-based glass ceramic, confirming the study hypothesis.

OBJECTIVES: This study assessed the effect of cast rectifiers on the marginal misfit of cast UCLA abutments compared to premachined UCLA abutments. The influence of casting and porcelain baking on the marginal misfit of these components was also investigated. METHODS: Two groups were analyzed: test group - 10 cast UCLA abutments, finished with cast rectifier and submitted to ceramic application; control group - 10 premachined UCLA abutments, cast with noble metal alloy and submitted to ceramic application. Vertical misfit measurements were performed under light microscopy. In the test group, measurements were performed before and after the use of cast rectifiers, and after ceramic application. In the control group, measurements were performed before and after casting, and after ceramic application. Data were submitted to statistical analysis by ANOVA and Tukey's test (a= 5%). RESULTS: The use of cast rectifiers significantly reduced the marginal misfit of cast UCLA abutments (from 25.68mm to 14.83mm; p<0.05). After ceramic application, the rectified cylinders presented misfit values (16.18mm) similar to those of premachined components (14.3 mm). Casting of the premachined UCLA abutments altered the marginal misfit of these components (from 9.63 mm to 14.6 mm; p<0.05). There were no significant changes after porcelain baking, in both groups. CONCLUSION: The use of cast rectifiers reduced the vertical misfit of cast UCLA abutments. Even with carefully performed laboratory steps, changes at the implant interface of premachined UCLA abutments occurred. Ceramic application did not alter the marginal misfit values of UCLA abutments.

Enfermedades como reflujo gastroesofágico y bulimia, provocan alteraciones ácidas en la cavidad bucal que pueden causar erosión dental. El efecto de este medio ácido sobre materiales restauradores y posibles cambios en sus propiedades son poco relatado en la literatura. De esta forma, el objetivo de este trabajo fue evaluar la solubilidad y la microdureza de cerámicas feldespáticas expuestas in vitro a fluido gástrico simulado sin enzimas (pH 1,2). Fueron confeccionados 100 discos, de 8mm de diámetro y 2mm de altura, con las siguientes cerâmicas: Vitadur Alfa (I), Vita Omega 900 (II) Finesse All-Ceramic (III), IPS dSign (IV) y Carmen (V). Estos fueron divididos en tres grandes grupos según la exposición al fluido gástrico: (A) sin exposición, (B) 24 horas de exposición y (C) 7 días de exposición. La solubilidad fue evaluada por medio del pesaje en balanza digital (Metler Toledo), calculándose la cantidad de pérdida de masa (MP). El análisis de microdureza Vickers (MD) fué realizado utilizando un microdurómetro FM-700 (Future Tech). Los resultados obtenidos mostraron valores de pérdida de masa (%) de B, comparado con A, de: 0,1280(I), 0,2143(II), 0,0485(III), 0,1377(IV), 0,0824(V); y para C de: 0,1182(I), 0,2305(II), 0,0773(III), 0,1653(IV), 0,3256(V). Se observaron valores de dureza superficial para A de: 527,53(I), 531,67(II), 519,85(III), 544,72(IV), 523,72(V); para B de: 505,38(I), 529,63(II), 478,60(III), 514,91(IV); 504,97; y C de: 484,96(I), 495,61(II), 493,5(III), 482,76(IV), 488,22(V). El análisis estadístico con el test de ANOVA (p<0,05), mostró influencia del fluido gástrico tanto en la pérdida de masa como en la solubilidad de las cerámicas evaluadas.

Diseases like gastroesofagical ebb tide and bulimia, cause acid alterations in the buccal cavity that can cause dental erosion. The effect of this average acid on restoring materials and possible changes in their properties little are related in Literature. Of this form, the objective of this work was to evaluate the solubility and the micro-hardness of exposed feldespatic ceramics in vitro to simulated gastric fluid without enzymes (pH 1.2). 100 discs were made, of 8mm of diameter and 2mm of height, with the following cerâmic: Vitadur Alpha (i), Bollard Omega 900 (II) Finesse All-Ceramic (III), IPS dSign (IV) and Carmen (v). These were divided in three great groups according to the exhibition to the gastric fluid: (a) without exhibition, (b) 24 hours of exhibition and (c) 7 days of exhibition. The solubility was evaluated by means of the weigh in digital balance (Metler Toledo), calculating the amount of loss of mass (MP). The micro-hardness analysis Vickers (MD) was made using a microdurometer FM-700 (Future Tech). The obtained results showed values of loss of mass (%) of B, compared with A, of: 0,1280 (I), 0.2143 (II), 0.0485 (III), 0.1377 (IV), 0.0824 (V); and for C of: 0,1182 (I), 0.2305 (II), 0.0773 (III), 0.1653 (IV), 0.3256 (V). Values of superficial hardness were observed stops To of: 527,53 (I), 531.67 (II), 519.85 (III), 544.72 (IV), 523.72 (V); for B of: 505,38 (I), 529.63 (II), 478.60 (III), 514.91 (IV); 504,97; and C of: 484,96 (I), 495.61 (II), 493.5 (III), 482.76 (IV), 488.22 (V). The statistical analysis with the ANOVA test (p< 0.05), as much showed influence of the gastric fluid in the loss of mass like in the solubility of the evaluated ceramics.