Influence of number and position of porcelain specimens in the furnace on flexural strength and translucency

The aim of this study was to investigate the influence of the quantity and positioning of feldspathic ceramic specimens inside the furnace on their flexural strength and translucency. The tested hypotheses were that the arrangement of specimens in the furnance would not influence 1) the translucency or 2) the biaxial strength of the porcelain. Methods: Ninety porcelain specimens were made (1.2 mm thickness and 13.5 mm diameter) and assigned into two main groups (n=15): G1 group - 15 firing cycles containing only one specimen each, always at the center of the refractory; and G5 group - 15 firing cycles containing five specimen each, where one specimen was at the center of the refractory and four specimens positioned equidistantly on the periphery. The translucency test was performed using a spectrophotometer, followed by the flexural strength test, according to ISO 6872:2015. T-student test was performed for both the mechanical and optical obtained data. Results: The flexural strength of the porcelain was not affected by the positioning (center x periphery) of the specimens inside the furnace (p =0.08), but the translucency was affected (periphery > center; p =0.009). Regarding to the number of feldspathic ceramic specimens, the biaxial flexural strength was affected (p =0.025), as well as the translucency (p <0.05). Conclusion: A higher quantity of feldspathic ceramic specimens for each firing cycle decreased its biaxial flexural strength and translucency. Also, specimens positioned at the center of the refractory became less translucent than those positioned at the periphery.

Translucency and masking ability of a translucent zirconia with different thicknesses over dark backgrounds / Translucidez e capacidade de mascaramento de uma zircônia translúcida com diferentes espessuras sobre substratos escuros

ABSTRACT Objectives: To evaluate the translucency, contrast ratio and masking ability of a translucent zirconia with different thicknesses. Methods: Disc shaped specimens (n= 3) with 10 mm (Ø) x 1.5 mm, 1 mm and 0.7 mm (thickness) were manufactured simulating all-ceramic simplified restorations. Substrate discs (n= 2; Ø: 10 mm; thickness: 2 mm) were simulated with composite resin shades: A2 (positive control) and C4; and metal alloys: silver (Ni-Cr) and golden (Cu-Al). Optical properties of the 9 translucent zirconia specimens placed on the 3 different substrates were analyzed by a spectrophotometer. The color variation (ΔE00) between each ceramic structure over the positive control substrate (A2) and over the dark backgrounds (C4, silvery, golden) were obtained as to their ceramic masking ability and subjected to non-parametric Kruskal Wallis test (5%). The translucency parameter (TP00) and contrast ratio (CR) of the different thicknesses of the ceramic discs were also collected and analyzed by one-way ANOVA and the Tukey test (5%). Results: The translucent zirconia showed greater opacity in the thickness of 1.5 mm, although it was not statistically different between 0.7 and 1.0 mm. All dark backgrounds significantly affected the final color of the simplified restoration in all evaluated thicknesses. However, the increase in ceramic thickness showed a decrease in ΔE00 values for all substrates. Conclusion: The translucent zirconia was not able to mask the dark substrates, independent of the evaluated thickness.

RESUMO Objetivos: Avaliar a translucidez, razão de contraste e capacidade de mascaramento de uma zircônia translúcida com diferentes espessuras. Métodos: Espécimes em forma de disco (n= 3) com 10 mm (Ø) x 1,5 mm, 1 mm e 0,7 mm (espessura) foram confeccionados simulando restaurações simplificadas em cerâmica pura. Discos de substrato (n= 2; Ø: 10 mm; espessura: 2 mm) foram simulados com as cores de resina composta: A2 (controle positivo) e C4; e ligas metálicas: prata (Ni-Cr) e ouro (Cu-Al). As propriedades ópticas dos 9 espécimes de zircônia translúcida posicionados nos 3 substratos diferentes foram analisadas por um espectrofotômetro. A variação de cor (ΔE00) entre cada espécime cerâmico sobre o substrato controle positivo (A2) e sobre os fundos escuros (C4, prateado, dourado) foi calculada quanto à capacidade de mascaramento da cerâmica e submetida ao teste não paramétrico de Kruskal Wallis (5%). O parâmetro de translucidez (TP00) e a razão de contraste (CR) das diferentes espessuras dos discos cerâmicos também foram coletados e analisados por ANOVA de uma via e teste de Tukey (5%). Resultados: A zircônia translúcida apresentou maior opacidade na espessura de 1,5 mm, embora não tenha sido estatisticamente diferente entre 0,7 e 1,0 mm. Todos os fundos escuros afetaram significativamente a cor final da restauração simplificada em todas as espessuras avaliadas. No entanto, o aumento da espessura da cerâmica mostrou uma diminuição nos valores de ΔE00 para todos os substratos. Conclusão: A zircônia translúcida não foi capaz de mascarar os substratos escuros, independente da espessura avaliada.

Optical Properties of a Glass Ceramic and an Indirect Resin Composite: Effects of Polishing and Staining / Propriedades Ópticas de uma Cerâmica Vítrea e uma Resina Composta Indireta: Efeitos do Polimento e Manchamento

Little information is available about the optical behavior of glass ceramics and indirect resin composites. This study aimed to evaluate if an indirect resin composite can present similar behavior of color stability and translucency to a glass ceramic after polishing and aging in staining beverage. Specimens of a dental ceramic (IPS e.max Ceram) and an indirect resin composite (SR Adoro) were made. Half the specimens of each material were polished with disc-shaped tips. Groups were divided according to aging media: distilled water or immersion in red wine for 20 min/day during 30 days. CIE L*a*b* coordinates were measured with a spectrophotometer at baseline and after 30 days of aging. Color change was calculated by CIEDE2000 and translucency was calculated by contrast ratio (CR). Statistical analysis were performed with ANOVA and Tukey tests. Aging in red wine caused perceptible color change in both materials. Polishing only increased color change of indirect composite when aged in red wine. Ceramic groups showed greater opacity than the composite in all measurements. The indirect composite remained more translucent and results showed that it is capable of presenting color stability similar to a ceramic. However, polishing seems to increase its color change. (AU)

Pouca informação comparando o comportamento óptico de cerâmicas vítreas e resinas compostas indiretas estão disponíveis na literatura. O objetivo deste estudo foi avaliar se uma resina composta indireta pode apresentar comportamento semelhante a uma cerâmica vítrea em relação à estabilidade de cor e translucidez após polimento e envelhecimento em meio altamente pigmentante. Espécimes de uma cerâmica vítrea (IPS e.max Ceram) e uma resina composta indireta (SR Adoro) foram preparados. Metade dos espécimes de cada material foram polidas com pontas de polimento. Os grupos foram divididos conforme o meio de armazenamento: água destilada ou vinho tinto por 20 min/dia durante 30 dias. As coordenadas CIEL*a*b* foram medidas com espectrofotômetro previamente e após os 30 dias de armazenamento. A alteração de cor foi calculada pela equação CIEDE2000 e a translucidez foi calculada por razão de contraste. A análise estatística foi realizada pelos testes ANOVA e teste de Tukey. O armazenamento em vinho levou a uma alteração de cor perceptível nos dois materiais. O polimento apenas causou alteração de cor na resina composta indireta quando imersa em vinho tinto. A resina composta indireta manteve-se mais translúcida e os resultados mostraram que esse material é capaz de apresentar estabilidade de cor semelhante à cerâmica. No entanto, o polimento parece aumentar sua alteração de cor. (AU)

Effect of bleaching on color stability and roughness of composite resins aged in staining beverage.

Composite resin properties can be affected by contact with gel during bleaching procedures; however, there is no consensus about the effect of this contact on resin susceptibility to color change. This study aimed to evaluate staining susceptibility and surface roughness changes in 2 composite resins (Filtek Z250 XT and Filtek Z350 XT) after application of bleaching peroxides and storage in different media. Forty-two disc-shaped specimens of each composite were made, polished, and divided into 3 groups according to treatment type (35% hydrogen peroxide, 16% carbamide peroxide, or deionized water as a control group). These groups were subdivided into 2 groups according to immersion media (n = 7): deionized water or red wine. Color and average roughness (Ra) measurements were taken 24 hours after specimen preparation (T0), immediately after bleaching procedures (T1), and immediately after aging (staining; T2). Statistical analyses were performed using 2-way analyses of variance for repeated measurements and the Tukey test (P < 0.05). Bleaching resulted in minimal color change (ΔE* < 1) in all groups. Filtek Z350 XT specimens presented greater mean values of color change. The Ra values did not increase significantly after bleaching procedures or aging (staining) in all groups. Thus, bleaching agents did not significantly change the color or roughness of the composite resins used in this study.

Deformation of implant abutments after framework connection using strain gauges.

When a cylinder is connected to an abutment it is expected that abutment and cylinder will be subjected to compression forces throughout their periphery because of the clamping force exerted by the screw. The deformation resultant of this compression should be measurable and uniform along the periphery of the abutment. Considering that multiple retainers connected to each other can affect the fit of a framework, as well as the use of different alloys, it is expected that the abutments will present different levels of deformation as a result of framework connection. The aim of this study was to evaluate the deformation of implant abutments after frameworks, cast either in cobalt-chromium (CoCr) or silver-palladium (AgPd) alloys, were connected. Samples (n  =  5) simulating a typical mandibular cantilevered implant-supported prosthesis framework were fabricated in cobalt-chromium and silver-palladium alloys and screwed onto standard abutments positioned on a master-cast containing 5 implant replicas. Two linear strain gauges were fixed on the mesial and distal aspects of each abutment to capture deformation as the retention screws were tightened. A combination of compressive and tensile forces was observed on the abutments for both CoCr and AgPd frameworks. There was no evidence of significant differences in median abutment deformation levels for 9 of the 10 abutment aspects. Visually well-fit frameworks do not necessarily transmit load uniformly to abutments. The use of CoCr alloy for implant-supported prostheses frameworks may be as clinically acceptable as AgPd alloy.

Ageing of silorane-based and methacrylate-based composite resins: effects on translucency.

OBJECTIVES: Verify if media and time of storage affect the translucency of a silorane-based composite (Filtek P90) compared to two methacrylate-based composites (Z350 and ROK), and compare two methods of translucency evaluation. METHODS: Specimens were divided into two groups (n=7) according to the storage media (deionized water or red wine). With a spectrophotometer (SP60) in reflectance mode, the CIE L*a*b* parameters and opacity percentage readings were conducted at baseline, 24h, 30 days, and 180 days. Data were analyzed using two-way repeated measures ANOVA and Tukey (p<0.05). Pearson correlation measured the relationship between translucency parameter and opacity percentage. RESULTS: When stored in water, P90 showed an increase, whereas Z350 decreased in translucency. ROK did not exhibit any tendency over time. When stored in wine, the translucency of all materials decreased. A negative relationship was found between translucency parameter and opacity percentage. When stored in water, the a* values for P90 decreased, whereas Z350 and ROK showed values increasing over time. When stored in wine, the L* parameter tended to decrease over time, an effect that was less intense for P90. Moreover, the b* parameter for P90 decreased, whereas methacrylate-based composites increased over time. CONCLUSIONS: P90 was more stable in red wine than the other materials and became more translucent in water whether metacrilate-based materials became more opaque. Both media as well as storage time affected the translucency of the materials tested. Translucency could be measured with both methods tested. CLINICAL SIGNIFICANCE: Silorane-based composites seemed to be more stable than methacrylate-based composites in red wine and became more translucent over time in water, which was different than methacrylate-based composites. More studies are needed to clarify silorane-based composites performance.

Dureza de resinas compostas de diferentes cores, em profundidades distintas, fotoativadas por diferentes fotopolimerizadores / Hardness of composite resins of different colors, at distinc depths, photoactivated by different light-curing units

Objetivo: Avaliar a dureza de resinas compostas (RC) de cores diferentes em duas profundidades (topo e base), fotoativadas com diferentes fotopolimerizadores. Méto-do: Utilizaram-se duas RC de cores e opacidades diferentes (Filtek Supreme A1E®, Filtek Supreme A3D®) e quatro aparelhos fotopolimerizadores LED (Ultra Blue Is 600® - 450 mW/cm2; Optilight LD III® - 250 mW/cm2; Ultraled® - 250 mW/cm2; Radii® - 700 mW/cm2). Confeccionaram-se 24 matrizes de polímero de náilon (5 mm de diâmetro e 3 mm de espessura), nas quais as RC foram inseridas em dois incrementos de 1,5 mm cada, fotoativados por 20s cada. Submeteram-se os corpos-de-prova (cp) à análise de dureza Vickers no 'topo' e na 'base', com quatro medidas em cada superfície. A média de dureza de cada cp foi calculada e aplicaram-se análise de variância e Tukey. Resultados e conclusões: Observou-se que a dureza das RC variou conforme a cor do material e os aparelhos utilizados, com o Raddi e o Ultra Blue IS proporcionando os maiores valores. De forma geral, as RC apresentaram maior dureza no topo do que na base. Na base, a resina composta com maior translucidez apresentou maior dureza do que a resina composta opaca.

Effect of lipstick on composite resin color at different application times

OBJECTIVES: The aim of this study was to evaluate the influence of the contact of two lipsticks, one with common fixer and one with ultra fixer, on the color of a composite resin immediately, 30 min and 24 h after photoactivation. MATERIAL AND METHODS: Ninety specimens were prepared with a composite resin, Filtek-Z350. Specimens were polished and divided into 9 groups (n=10) according to time elapsed after photoactivation (A- immediately; B- 30 min; C- 24 h) and the contact with lipstick (UF- lipstick with ultra fixer; F- lipstick with common fixer). The control group was represented by specimens that did not have any contact with lipstick (C- without lipstick). Color measurements of the specimens were carried out using a spectrophotometer (Easyshade - CIE L* a* b* system). For UF and F groups, the baseline color of the specimens was measured immediately before pigmentation and the lipsticks were applied dry after 1 hour. The excess lipstick was removed with absorbent paper and final color checking was performed, including the control group. Differences between the final and baseline color measurements were calculated and data were analyzed statistically by the Kruskal-Wallis test at 5 percent. RESULTS: The means between the differences of color values were: AUF: 16.0; AF: 12.4; AC: 1.07; BUF: 9.51; BF: 8.3; BC: 0.91; CUF: 17.7; CF: 12.41; CC: 0.82. CONCLUSION: Groups where lipstick was applied showed greater staining than the control group at the three evaluation times. The lipstick with ultra fixer stained more than the lipstick with common fixer. Time elapsed between photoactivation and contact with lipstick had a similar influence on the groups that received lipstick application.

Effect of lipstick on composite resin color at different application times.

OBJECTIVES: The aim of this study was to evaluate the influence of the contact of two lipsticks, one with common fixer and one with ultra fixer, on the color of a composite resin immediately, 30 min and 24 h after photoactivation. MATERIAL AND METHODS: Ninety specimens were prepared with a composite resin, Filtek-Z350. Specimens were polished and divided into 9 groups (n=10) according to time elapsed after photoactivation (A- immediately; B- 30 min; C- 24 h) and the contact with lipstick (UF- lipstick with ultra fixer; F- lipstick with common fixer). The control group was represented by specimens that did not have any contact with lipstick (C- without lipstick). Color measurements of the specimens were carried out using a spectrophotometer (Easyshade - CIE L* a* b* system). For UF and F groups, the baseline color of the specimens was measured immediately before pigmentation and the lipsticks were applied dry after 1 hour. The excess lipstick was removed with absorbent paper and final color checking was performed, including the control group. Differences between the final and baseline color measurements were calculated and data were analyzed statistically by the Kruskal-Wallis test at 5%. RESULTS: The means between the differences of color values were: AUF: 16.0; AF: 12.4; AC: 1.07; BUF: 9.51; BF: 8.3; BC: 0.91; CUF: 17.7; CF: 12.41; CC: 0.82. CONCLUSION: Groups where lipstick was applied showed greater staining than the control group at the three evaluation times. The lipstick with ultra fixer stained more than the lipstick with common fixer. Time elapsed between photoactivation and contact with lipstick had a similar influence on the groups that received lipstick application.

Avaliação do efeito de enxaguatórios bucais na rugosidade superficial de resinas acrílicas quimicamente ativadas / Evaluation of oral mouth rinses in superficial roughness of self-curing acrylic resin

O objetivo neste trabalho foi avaliar o efeito de dois enxaguatórios bucais (Periogard [PER] (Colgate-Palmolive Ind. Com. Ltda – São Paulo, SP, Brasil) e Listerine [LIS] (Johnson & Johnson Healthcare Products – Skillman-NJ,EUA)) na rugosidade de superficie de duas resinas acrílicas polimerizáveis quimicamente (Duralay [DUR] (Reliance Dental – Worth, IL, EUA] e Dencrilay [DEN] (Dencril Caieiras, SP, Brasil)), tendo como grupo controle o soro fisiológico [SOR], totalizando 6 grupos (n=8). Para a confecção dos corpos-de-prova (CP) foram utilizadas 48 matrizes de poliacetal com um orifício central cilíndrico de 5 mm de diâmetro por 5 mm de profundidade. A resina acrílica foi manipulada e inserida no orifício com seringa plástica, com a matriz posicionada sobre uma lâmina de vidro. Outra lâmina foi pressionada sobre a matriz e esse conjunto foi colocado numa panela de pressão durante a polimerização. As faces correspondentes aos diâmetros dos cp foram regularizadas com lixa d’água 220 e as faces que apresentaram menos irregularidades receberam o acabamento com as demais lixas (320, 400, 600, 1200) sob refrigeração com água, em uma politriz. Após 24 horas de armazenagem em água foram realizadas as leituras iniciais num rugosímetro na escala Ra. Os CP foram imersos nas soluções para bochecho durante 10 minutos por dia, por 10 dias. Entre os intervalos de imersão nas soluções para bochechos as resinas ficaram armazenados em soro fisiológico. Nesse período, o grupo controle ficou todo o tempo armazenado em soro fisiológico. Em seguida, os CP foram submetidos à leitura final de rugosidade (Ra), pelo mesmo avaliador. Os resultados iniciais foram: DUR+LIS=0,20; UR+PER=0,21; DUR+SOR=0,25; DEN+LIS=0,33;DEN+SOR=0,33; DEN+PER=0,36; e finais: DUR+PER=0,28; DUR+LIS=0,28; DEN+SOR=0,31; DUR+SOR=0,34;DEN+PER=0,43; DEN+LIS=0,43. A análise de variância e o teste de Tukey (5%)...

The aim of this study was to evaluate the effect of two oral mouth rinses (Periogard [PER] Periogard [PER] (Colgate- Palmolive Ind. Com. Ltda – São Paulo, SP, Brazil) and Listerine [LIS] (Johnson & Johnson Healthcare Products – Skillman, NJ, USA)) in superficial roughness of two self-curing acrylic resins (Duralay [DUR] (Reliance Dental – Worth, IL, USA] and Dencrilay [DEN] (Dencril Caieiras, SP, Brazil)). Physiologic solution [SOR] was used in control group. The research has a total of 06 groups (n=08). For the confection of the testing samples, 48 molds were made of poliacetal with a cylindrical central hole with 5 mm of diameter and 5 mm of thickness. Therefore, with the mold positioned on a glass blade, acrylic resin was manipulated and inserted in the hole with a plastic syringe. With another blade, a compression force was realized against the mold and these things together were put in a pressure pot with water during the polymerization. Testing sample’s faces were planned with sandpapers granulation 220 and the less irregularface was polished with others sandpapers (320, 400, 600, 1200) under refrigeration in a politrix. After 24 hours in water, initial reading was recorded with a roughness meter with Ra scale. The resin samples were immersed in the mouth rinses during 10 min/day for 10 days. Resins were stored in physiologic solution, between immersion intervals in mouth rinses.Control groups were all the time stored in physiologic solution...

Effect of cantilever length and framework alloy on the stress distribution of mandibular-cantilevered implant-supported prostheses.

OBJECTIVES: The purpose of this in vitro study was to analyze the stress distribution on components of a mandibular-cantilevered implant-supported prosthesis with frameworks cast in cobalt-chromium (Co-Cr) or palladium-silver (Pd-Ag) alloys, according to the cantilever length. MATERIAL AND METHODS: Frameworks were fabricated on (Co-Cr) and (Pd-Ag) alloys and screwed into standard abutments positioned on a master-cast containing five implant replicas. Two linear strain gauges were fixed on the mesial and distal aspects of each abutment to capture deformation. A vertical static load of 100 N was applied to the cantilever arm at the distances of 10, 15, and 20 mm from the center of the distal abutment and the absolute values of specific deformation were recorded. RESULTS: Different patterns of abutment deformation were observed according to the framework alloy. The Co-Cr alloy framework resulted in higher levels of abutment deformation than the silver-palladium alloy framework. Abutment deformation was higher with longer cantilever extensions. CONCLUSION: Physical properties of the alloys used for framework interfere with abutment deformations patterns. Excessively long cantilever extensions must be avoided.

Resistência flexural de resinas compostas imersas em diferentes líquidos / Flexural strength of composite resins immersed in liquids different

O estudo teve como objetivo avaliar a resistência flexural de duas resinas compostas (Filtek Z350 eOpallis) quando submersas em diferentes líquidos (Listerine®, Coca-Cola® e água destilada). Foram confeccionados60 corpos-de-prova (cp), 10 cp para cada grupo. Para confecção dos cp as resinas compostasforam inseridas numa matriz metálica desmontável com a parte interna de 10 mm X 1 mm X 2 mm. As resinascompostas foram cobertas em ambos os lados com tira de poliéster e lâmina de vidro com a finalidadede deixar uma superfície plana. Os cp foram fotoativados com o LED OPTLIGHT LD MAX (±300 mW/cm2)por 40 segundos e imersos em cada um dos meios à 37ºC por 24 horas. Os cp foram medidos com paquímetrodigital e submetidos ao teste de flexão em três pontos na máquina de ensaios EMIC a 1mm/min. Osdados foram submetidos à Analise de Variância e ao teste de Tukey (5%) e os resultados foram (MPa): Z350:água- 74,6; Coca-Cola- 101,3; Listerine®- 72,4 / Opallis: água- 43,5; Coca-Cola®- 80,4; Listerine®- 48,1.A resina composta Z350 apresentou maior resistência flexural em todos os meios estudados. Não houvediferença de resistência flexural das resinas compostas entre os meios água e Listerine®. As duas resinascompostas tiveram maiores valores de resistência flexural quando submersas em Coca-Cola®.

The study evaluated the flexural strength of two composite resins (Filtek Z350 e Opallis) stored at37oC for 24 hours in different liquids (Listerine®, Coca- Cola® and distilled water). Sixty specimens weremade, 10 for each group. The specimens were obtained by means of a rectangular stainless steel matrix witha cavity of 10mm x 1mm x 2mm. Specimens were light cured in all extension for 40 seconds using LED OPTLIGHTLD MAX (±300mW/cm2). After polymerization the specimens were stored in the liquids for 24 hours.After this period the three points flexural strength test was carried out, with a crosshead speed of 1mm/min.Data were submitted to ANOVA and Tukey (5%) and the results (MPa) were: Z350: distilled water- 74.6;Coca-Cola- 101.3; Listerine®- 72.4 / Opallis: distilled water - 43.5; Coca-Cola®- 80.4; Listerine®- 48.1. Thecomposite resin Filtek Z350 demonstrated higher flexural strength in all liquids. No differences were foundin composite resins between distilled water and Listerine®. Both resins presented higher flexural strengthvalues when immersed in Coca-Cola®.

Influência de colutórios bucais na dureza de resinas compostas / Influence of mouthrinses on the hardness of composite resin materials

O objetivo deste trabalho foi avaliar o efeito de colutórios bucais na dureza de três resinas compostas (Filtek Supreme® A2B – nanoparticulada [SUP], Filtek Z250® A2 – híbrida [Z25], Filtek Flow® A2 – híbrida de consistência fluida [FLO]). Três colutórios foram selecionados (Listerine® [LIS], PerioGard® [PER] e Cepacol® [CEP]) e a água destilada [AD] foi utilizada como solução de controle. Setenta e duas matrizes de um polímero de náilon, com 3 mm de diâmetro e 3 mm de espessura, foramconfeccionadas. As resinas foram inseridas nas matrizes em dois incrementos, os quais foram fotoativados por 20s cada. Os corpos-de-prova (cps) foram aplainados em lixas d’água e armazenados em água destilada por 24h. Cada tipo de resina composta foi dividido em quatro grupos (n = 6) de acordo com as soluções estudadas, as quais foram utilizadas sob o seguinte regime: três imersões por dia de 10min cada, durante trinta dias.Durante o período do estudo, os cps foram individualmente armazenados em água destilada. Cinco leiturasde dureza foram realizadas em cada cp e a média do número de dureza Knoop (KHN) dessas leituras foi utilizadapara a realização da análise estatística. Os resultados e desvios-padrão (DP) foram: SUP + LIS = 63,3(5,2) Bb; SUP + PER = 70,0(3,6)Ab; SUP + CEP = 67,8(3,6)ABb; SUP + AD = 64,3(3,8)Bb; Z25 + LIS = (2,4)88,4Aa; Z25 + PER = 77,1(5,4)Ba; Z25 + CEP = 83,8(3,9)Aa; Z25 + AD = 83,7(4,1)Aa; FLO + LIS = 44,3(4,1)Ac; FLO + PER = 46,5(1,6)Ac; FLO + CEP = 48,7(2,0)Ac; FLO + AD = 44,2(0,8)Ac. Após a análise de variância e o teste de Tukey (5 por cento), observou-se diferença estatística significativa entre a dureza Knoop das resinas testadas, sendoZ25 > SUP > FLO. Conclui-se que as resinas compostas comportaram-se de maneira diferente para cada tipo desolução utilizada

Effect of abutment's height and framework alloy on the load distribution of mandibular cantilevered implant-supported prosthesis.

OBJECTIVES: In cantilevered implant-supported complete prosthesis, the abutments' different heights represent different lever arms to which the abutments are subjected resulting in deformation of the components, which in turn transmit the load to the adjacent bone. The purpose of this in vitro study was to quantitatively assess the deformation of abutments of different heights in mandibular cantilevered implant-supported complete prosthesis. MATERIAL AND METHODS: A circular steel master cast with five perforations containing implant replicas (Theta 3.75 mm) was used. Two groups were formed according to the types of alloy of the framework (CoCr or PdAg). Three frameworks were made for each group to be tested with 4, 5.5 and 7 mm abutments. A 100 N load was applied at a point 15 mm distal to the center of the terminal implant. Readings of the deformations generated on the mesial and distal aspects of the abutments were obtained with the use of strain gauges. RESULTS: Deformation caused by tension and compression was observed in all specimens with the terminal abutment taking most of the load. An increase in deformation was observed in the terminal abutment as the height was increased. The use of an alloy of higher elastic modulus (CoCr) also caused the abutment deformation to increase. CONCLUSION: Abutment's height and framework alloy influence the deformation of abutments of mandibular cantilevered implant-supported prosthesis.

Compressive strength of glass ionomer cements used for atraumatic restorative treatment / Resistência à compressão de cimentos de ionômero de vidro utilizados no tratamento restaurador atraumático

Purpose: This study evaluated the compressive strength of five glass ionomer cements (Ketac Molar, Fuji IX, Magic Glass, Vidrion R, and Vitro Molar) as a function of storage period (1 hour and 24 hours). Methods: Sixteen specimens of each material were fabricated according to ISO/DP #7489 Specification using a 6x12 mm (diameter and height) matrix. After setting, specimens were stored in distilled water at 37 ºC. Eight specimens per cement were subjected to the compressive strength test in a universal testing machine after 1 hour, and the other eight specimens were tested after 24 hours. Data were analyzed by ANOVA and Tukey's test (α=5%). Results: The compressive strength mean values (kgf) after 1 and 24 hours were: Ketac Molar: 218.75 and 297.88; Fuji IX: 335.75 and 350.88; Magic Glass: 61.50 and 140.13; Vidrion R: 142.38 and 230.88; and Vitro Molar: 183.38 and 297.50. After 1 hour Fuji IX had the highest compressive strength. All materials but Fuji IX showed higher compressive strength in 24 hours than in 1 hour. After 24 hours, no significant differences were found among Fuji IX, Ketac Molar, and Vitro Molar. Magic Glass had the lowest compressive strength in both storage periods. Conclusion: Fuji IX showed the best results after 1 hour. After 24-hour storage, Fuji IX, Ketac Molar, and Vitro Molar had similar performance.

Objetivo: Este estudo avaliou a resistência à compressão de 5 cimentos de ionômero de vidro (Ketac Molar, Fuji IX, Vitro Molar, Magic Glass e Vidrion R), em dois tempos de armazenagem (1 h e 24 h). Metodologia: Foram confeccionados 16 corpos-de-prova (CP) para cada material (n=8), seguindo as especificações da ISO/DP 7489. Os materiais foram manipulados e inseridos numa matriz desmontável (6 mm de diâmetro e 12 mm de altura). Após a presa os CP foram armazenados em água destilada a 37 ºC. Metade dos CP de cada material foi submetida a ensaio de compressão após 1 h e a outra metade foi testada após 24 h. Os resultados foram analisados por ANOVA e teste de Tukey (α=5%). Resultados: Os valores médios de resistência à compressão (kgf) após 1 h e 24 h foram: Ketac Molar: 218,75 e 297,88; Fuji IX:335,75 e 350,88; Magic Glass:61,50 e 140,13; Vidrion R:142,38 e 230,88, e Vitro Molar:183,38 e 297,50. Em 1 h o Fuji IX apresentou a maior resistência à compressão. Com exceção do Fuji IX, todos os ionômeros apresentaram maior resistência em 24h do que em 1 h. Em 24 h não houve diferença entre Fuji IX, Ketac Molar e Vitro Molar. O cimento Magic Glass apresentou os menores valores nos 2 tempos. Conclusão: O cimento Fuji IX apresentou os melhores resultados após 1 h. Após 24 h de armazenamento, Fuji IX, Ketac Molar e Vitro Molar tiveram desempenho similar.

Compressive strength of glass ionomer cements using different specimen dimensions.

The purpose of this study was to evaluate the compressive strength of two glass ionomer cements, a conventional one (Vitro Fil - DFL) and a resin-modified material (Vitro Fil LC - DFL), using two test specimen dimensions: One with 6 mm in height and 4 mm in diameter and the other with 12 mm in height and 6 mm in diameter, according to the ISO 7489:1986 specification and the ANSI/ADA Specification No. 66 for Dental Glass Ionomer Cement, respectively. Ten specimens were fabricated with each material and for each size, in a total of 40 specimens. They were stored in distilled water for 24 hours and then subjected to a compressive strength test in a universal testing machine (EMIC), at a crosshead speed of 0.5 mm/min. The data were statistically analyzed using the Kruskal-Wallis test (5%). Mean compressive strength values (MPa) were: 54.00 +/- 6.6 and 105.10 +/- 17.3 for the 12 mm x 6 mm sample using Vitro Fil and Vitro Fil LC, respectively, and 46.00 +/- 3.8 and 91.10 +/- 8.2 for the 6 mm x 4 mm sample using Vitro Fil and Vitro Fil LC, respectively. The resin-modified glass ionomer cement obtained the best results, irrespective of specimen dimensions. For both glass ionomer materials, the 12 mm x 6 mm matrix led to higher compressive strength results than the 6 mm x 4 mm matrix. A higher variability in results was observed when the glass ionomer cements were used in the larger matrices.

Microtensile bond strength of photoactivated and autopolymerized adhesive systems to root dentin using translucent and opaque fiber-reinforced composite posts.

STATEMENT OF PROBLEM: The use of fiber-reinforced composite resin posts in endodontically treated teeth has increased. However, selecting an adhesive system that provides reliable and long-lasting bonding to root canal dentin remains difficult. PURPOSE: This study evaluated the microtensile bond strength of 2 adhesive systems to root dentin and 2 different fiber-reinforced composite resin posts. MATERIAL AND METHODS: Forty single-rooted teeth were instrumented, and root canals were prepared for translucent (Light Post [LP]) or opaque (Aestheti Post [AP]) quartz fiber-reinforced composite resin posts. Two adhesive systems were used: Scotchbond Multi-Purpose Plus (SBMP) (autopolymerized) as a control group, and Single Bond (SB) (photoactivated). Teeth were assigned to 4 groups (n=10): SBMP+LP, SBMP+AP, SB+LP, SB+AP. After post cementation, roots were perpendicularly sectioned into 1-mm-thick slices, which were trimmed to obtain dumbbell-shaped specimens. The specimens were divided into 3 regions: cervical (C), middle (M), and apical (A). To determine the bond strength, the bonding area of each specimen was calculated, and specimens were attached to a device to test microtensile strength at a crosshead speed of 1 mm/min. Data were analyzed using 3-way analysis of variance and the Tukey test (alpha=.05). Fractured specimens were examined under a x 25 stereomicroscope to determine the mode of fracture. RESULTS: There were significant differences only among root dentin regions (P<.001). The cervical third (9.16 +/- 1.18 MPa) presented higher mean bond strength values, especially for SBMP. Middle and apical regions demonstrated lower values (7.08 +/- 0.92 and 7.31 +/- 0.60 MPa, respectively). Adhesive and post main factors did not demonstrate significance. Also, no interaction was significant. No cohesive fractures within resin cement, fiber-reinforced composite resin post, or root dentin were identified. CONCLUSIONS: Both adhesive systems tested demonstrated reliable bonding when used with translucent and opaque fiber-reinforced composite posts.

Compressive strength of glass ionomer cements using different specimen dimensions

The purpose of this study was to evaluate the compressive strength of two glass ionomer cements, a conventional one (Vitro Fil® - DFL) and a resin-modified material (Vitro Fil LC® - DFL), using two test specimen dimensions: One with 6 mm in height and 4 mm in diameter and the other with 12 mm in height and 6 mm in diameter, according to the ISO 7489:1986 specification and the ANSI/ADA Specification No. 66 for Dental Glass Ionomer Cement, respectively. Ten specimens were fabricated with each material and for each size, in a total of 40 specimens. They were stored in distilled water for 24 hours and then subjected to a compressive strength test in a universal testing machine (EMIC), at a crosshead speed of 0.5 mm/min. The data were statistically analyzed using the Kruskal-Wallis test (5 percent). Mean compressive strength values (MPa) were: 54.00 ± 6.6 and 105.10 ± 17.3 for the 12 mm x 6 mm sample using Vitro Fil and Vitro Fil LC, respectively, and 46.00 ± 3.8 and 91.10 ± 8.2 for the 6 mm x 4 mm sample using Vitro Fil and Vitro Fil LC, respectively. The resin-modified glass ionomer cement obtained the best results, irrespective of specimen dimensions. For both glass ionomer materials, the 12 mm x 6 mm matrix led to higher compressive strength results than the 6 mm x 4 mm matrix. A higher variability in results was observed when the glass ionomer cements were used in the larger matrices.

Este estudo teve como objetivo avaliar a resistência à compressão de dois cimentos de ionômero de vidro, um convencional (Vitro Fil® - DFL) e outro modificado por resina (Vitro Fil LC® - DFL), utilizando-se dois tamanhos de amostras: uma com 6 mm de altura e 4 mm de diâmetro e outra com 12 mm de altura e 6 mm de diâmetro, seguindo-se a especificação 7489:1986 da ISO e a especificação n. 66 da ANSI/ADA para Cimento Dental de Ionômero de Vidro, respectivamente. Foram confeccionados 10 corpos-de-prova (CP) de cada material para cada tamanho de amostra, totalizando 40 CP. Estes CP foram armazenados em água destilada e ensaiados 24 horas após a manipulação do material, sob uma carga de compressão em uma Máquina de Ensaio Universal (EMIC) a uma velocidade de 0,5 mm/min. Foi realizada a análise estatística para comparação dos resultados utilizando-se o teste Kruskal-Wallis (5 por cento). As médias dos testes de resistência à compressão (MPa) foram: 54,00 ± 6,6 e 105,10 ± 17,3 para a amostra de 12 mm x 6 mm utilizando-se Vitro Fil e Vitro Fil LC, respectivamente, e 46,00 ± 3,8 e 91,10 ± 8,2 para a amostra de 6 mm x 4 mm utilizando-se Vitro Fil e Vitro Fil LC, respectivamente. O cimento de ionômero de vidro modificado por resina obteve melhores resultados independentemente do tamanho do corpo-de-prova. Para ambos os cimentos de ionômero de vidro, a matriz de 12 mm x 6 mm apresentou maiores valores de resistência que a matriz de 6 mm x 4 mm. Uma maior variabilidade nos resultados pôde ser observada quando os cimentos ionoméricos foram utilizados nas matrizes maiores.

Estudo comparativo da efetividade de selamento marginal de dois sistemas adesivos aplicados após a utilização de um material provisório a base de óxido de zinco e eugenol / Comparative study of marginal sealing effectiveness of two adhesive systems applied after using a zinc-oxide eugenol-based provisional material

O objetivo deste trabalho foi avaliar a influência de restaurações temporárias de óxido de de zinco eugenol (OZE) na microinfiltração marginal de restaurações de resina composta em esmalte e cemento-dentina, utilizando dois sistemas adesivos. Foram realizadas duas cavidades classe V padronizadas (3 X 3 X 2 mm) em quarenta molares humanos extraídos. Os dentes foram divididos em dois grupos: teste e controle. As cavidades do grupo-teste receberam restaurações provisórias com OZE e foram armazenadas por cinco dias em ambiente com umidade de 100 por cento. Os dentes do grupo de controle foram armazenadas nas mesmas condições do grupo-teste sem o OZE. O material foi removido com cureta e para cada dente dos grupos-teste e de controle uma das cavidades foi restaurada empregando-se um adesivo com condicionamento ácido total (Single Bond) e, na outra, um adesivo com primer autocondicionante (Cleartil SE Bond). A resina composta Filtek foi utilizada para restaurar as cavidades. Posteriormente à termociclagem, os dentes foram corados com azul de metileno (0,5 por cento)por 2h. Após lavados e secos, os espécimes foram cortados longitudinalmente e avaliados em lupa (40X), sendo os dados analisados estatisticamente pelo teste de Kruskal-Wallis. Em cemento-dentina observou-se que o OZE influenciou apenas o adesivo com primer autcondicionante e o Single Bond apresentou menor microinfiltração que o Clearfil tanto nos grupos com quanto naqueles sem OZE. Em esamlte não houve diferença estatísitica entre os grupos com e sem OZE quando utilizado o Clearfil. Este mostrou menor índice de microinfiltração em esmalte quando comparado ao Single Bond no grupo sem OZE e não houve diferença significativa em relação ao grupo com OZE.

Microtensile bond strength of light- and self-cured adhesive systems to intraradicular dentin using a translucent fiber post.

This study evaluated the bond strength of a light- and self-cured adhesive system to different intraradicular dentin areas (cervical, middle and apical thirds). Twenty single-rooted teeth were instrumented and their roots were prepared to receive a #2 translucent fiber post (Light Post). The root canals were irrigated with 0.5% sodium hypochlorite for one minute, rinsed with water and dried using paper tips. The teeth were divided into two groups (n=10): Single Bond [SB] (light-cured) and Scotchbond Multi-Purpose Plus [SBMP] (self-cured). To avoid polymerization of the materials through the root lateral walls, the teeth were placed in a silicone mold and the adhesives applied with a thin microbrush according to manufacturer's instructions. The resin cement, Rely X ARC, was inserted into the root canals using Lentulo burs. The post was then placed and the light-curing procedure was carried out for 40 seconds (+/-500 mW/cm2). The roots were kept in a 100% relative moisture environment for 24 hours and stored in distilled water for an additional 24 hours. Each root was perpendicularly sectioned into 1-mm thick sections, resulting in approximately four slices per region. Dumbbell-shaped slices were obtained by trimming the proximal surfaces of each slice using a diamond bur until it touched the post. The bonded area was calculated, slices were attached to a special device and submitted to microtensile testing at 1 mm/minute crosshead speed. Data were analyzed using ANOVA and Tukey's test. The mean bond strength values (MPa) were: SBMP: cervical=10.8a, middle=7.9b%, apical=7.1bc; SB: cervical=8.1b, middle=6.0c, apical=6.9b. Significant differences were found between adhesive systems only for the cervical third. The cervical region showed higher mean bond strength values than the middle and apical regions (p<0.0001).