Avaliação in vitro da razão base/topo de dureza e da resistência de união push-out entre uma resina composta contendo diatomita e uma resina composta bulk-fill / In vitro evaluation of the base/top hardness ratio and push-out bond strength between a diatomite-containing composite resin and a bulk-fill composite resin

A escassez de dados científicos que validem os benefícios da diatomita para as propriedades físicas da resina composta Zirconfill® torna imperioso a realização de novos estudos, principalmente no tocante a utilização dessa resina contendo diatomita em restaurações semidiretas. Objetivo: Avaliar in vitro a polimerização e resistência de união entre uma resina composta contendo diatomita e de uma resina composta bulk-fill após 24 horas e após 06 meses de envelhecimento em água. Materiais e métodos: Foram utilizados 28 incisivos bovinos para produzir cavidades dentinárias cônicas (4,8 mm de diâmetro maior x 2,8 mm de diâmetro menor x 4 mm de espessura) e fator C de magnitude 3,1. Esses preparos cavitários (n=28) foram restaurados com as resinas compostas Filtek™ One Bulk-fill (BF) (3M ESPE) ou Zirconfill ® (ZF) (BM4), através da técnica semidireta, utilizando o sistema adesivo Single Bond Universal (3M ESPE) e o cimento resino dual Relyx™ Ultimate (3M ESPE). A análise da polimerização foi realizada através da razão base/topo (B/T) de dureza Vickers. E a resistência de união RU foi realizada através do teste de extrusão push-out em máquina de ensaio universal. As amostras foram armazenadas em água destilada a 37 ºC por 24 horas ou 06 meses, mas apenas a RU avaliou as amostras após 06 meses de envelhecimento. Os dados da B/T e da RU foram submetidos à análise de variância (ANOVA) a um e a dois critérios, respectivamente, com pós-teste de Tukey (p <0.05). Resultados: Não houve diferença estatisticamente significativa entre as resinas compostas na B/T. Para a RU, a resina composta ZF mostrou valores maiores do que a resina BF em ambos os tempos avaliados. Não houve diferença estatisticamente significativa de nenhuma resina na avaliação ao longo do tempo. Conclusão: A resina composta contendo diatomita mostrou-se promissora quando utilizada em restaurações semidiretas, visto que obteve resultados similar e até superior a resina composta bulk-fill (AU).

The scarcity of data validating scientific diatomite benefits for physical properties of Zirconfill® resin composite makes essential to develop new studies, especially regarding the use of this resin composite containing diatomite in semi-direct restorations. Aim: To evaluate in vitro the cure and bond strength between a resin composite containing diatomite and a bulk-fill resin composite after 24 hours and after 06 months of water storage. Materials and methods: Twenty-eight bovine incisors (n=28) were used to produce conical dentinal cavities (4,8 mm of larger diameter x 2,8 mm of smaller diameter x 4 mm of thickness) and C-factor of magnitude 3.1. These cavities were restored with Filtek™ One Bulk-Fill (BF) (3M ESPE) or Zirconfill® (ZF) (BM4) resin composites, through the semi-direct technique, using Scotchbond™ Universal (3M ESPE) adhesive system and Relyx™ Ultimate (3M ESPE) dual resin cement. The cure analysis was performed through bottom-to-top (B/T) ratio of vickers hardness, while bond strength (RU) was performed through the push-out test in a universal testing machine. The specimens were stored in distilled water at 37 ºC for 24 hours or 06 months, but only RU analyzed the specimens after 06 months aging. B/T and RU data were, respectively, submitted to one-way and two-way analysis of variance (ANOVA) with Tukey's post-test (p <0.05). Results: There was no statistically significant difference between the composite resins in B/T. For RU, the ZF composite resin showed higher values than the BF resin at both evaluated times. However, there was no statistically significant difference in resin composites over time. Conclusion: The resin composite containing diatomite showed promise when used in semi-direct restorations since it obtained similar or even superior results to bulk-fill resin composite (AU).

Do dual-cure bulk-fill resin composites reduce gaps and improve depth of cure

Abstract This in vitro study aimed to evaluate the gaps length and depth of cure of dual-cure bulk-fill resin composites inserted in box-shaped preparations. Box-shaped preparations (4 mm deep) were made in fifteen human third-molars and divided into three groups according to the resin composites (n=5): Dual-cure bulk-fill BulkEZ (BEZ); Dual-cure bulk-fill HyperFIL (HF); and Tetric Evoceram Bulk-fill (TETRIC), as control. Gaps length (%) was evaluated in tooth-restoration interface with micro-computed tomography (µCT). The restorations were sectioned, and the degree of conversion (DC) and Knoop microhardness were evaluated at five depths (0.3, 1, 2, 3, and 4 mm). Microhardness data were statistically evaluated using absolute values (KHN) and relative values (microhardness percentages in relation to top). Gaps length (%) increased in the following order: BEZ=TETRIC<HF. The microhardness percentages in relation to top significantly decreased from 2 mm for TETRIC and 3 mm for HF. BEZ had constant microhardness and DC at all depths, while HF and TETRIC presented a significant decrease on DC at 4 mm. Dual-cure bulk-fill composites did not reduce gaps compared to light-cure bulk-fill, but they can improve depth of cure of bulk-filled restorations.

Resumo O objetivo neste estudo in vitro foi mensurar as fendas e a profundidade de polimerização de compósitos resinosos bulk-fill duais inseridos em preparos em forma de caixa. Os preparos em forma de caixa (4 mm de profundidade) foram realizados em quinze terceiros molares e separados em 3 grupos, de acordo com o compósito resinoso (n = 5): Bulk-fill dual BulkEZ (BEZ); Bulk-fill dual HyperFIL (HF); Tetric Evoceram Bulk-fill (TETRIC). O comprimento das fendas (%) foi avaliado na interface dente-restauração por meio de micro-tomografia computadorizada (µCT). As restaurações foram seccionadas e o grau de conversão (GC) e microdureza Knoop foram avaliados em cinco profundidades (0,3, 1, 2, 3 e 4 mm). Os dados de microdureza foram avaliados estatisticamente por meio de valores absolutos e relativos (porcentagens de microdureza em relação ao topo). O comprimento das fendas (%) aumentou na seguinte ordem: BEZ = TETRIC <HF. O percentual de microdureza em relação ao topo diminuiu significativamente a partir de 2 mm para TETRIC e 3 mm para HF. BEZ apresentou percentuais de microdureza e de GC constantes em todas as profundidades, enquanto HF e TETRIC apresentaram decréscimo significativo no GC em 4 mm. Os compósitos resinosos bulk-fill duais não reduziram as fendas formadas quando comparados a um compósito bulk-fill fotopolimerizável; entretanto, os mesmos podem melhorar a profundidade de polimerização em restaurações de incremento único.

Post-cure heat treatments influence on mechanical and optical properties of resin composites

Abstract This study evaluated the effect of post-cure heat treatment (PCHT) on the Knoop microhardness (KHN), degree of conversion (DC), color changes, and contrast ratio (CR) of four resin composites (RCs): Z100 (3M ESPE), Z350 XT (3M ESPE), Estelite Omega (Tokuyama) and Empress Direct (Ivoclar Vivadent). Specimens (12 × 1 mm) were prepared for each material (n = 10 / group). After curing, samples were subjected to PCHT for 10 min at 100°C or 170°C. Control group was maintained at room temperature (24°C) for the same time. The DC was analyzed by FT-NIR immediately and 24 h after the PCHT (n = 3 / group). KHN was analyzed 24 h after PCHT (n = 10 / group). According to CIEDE2000 (∆E00), color measurements were obtained immediately after curing, five minutes after PCHT, and after seven days of storage in water, coffee, and red wine. Data were analyzed by One and Two-Way ANOVA (p < 0.05). Z100, Z350, and Estelite Omega showed increases in KHN with increased temperature (p < 0.05). PCHT at 100°C and 170°C led to a higher DC of all RCs (p < 0.05). Initially, the PCHT lead to increased ∆E00 values (p < 0.05), which was decreased after immersion in coffee and wine (p < 0.05). Considering the effect of PCHT and staining solutions, lower color changes were observed in the thermally treated specimens (p < 0.05). Taken collectively, the results suggest the PCHT as an economical and practical alternative to enhance direct RC's properties in direct-indirect and indirect restorations.

Resumo Este estudo avaliou o efeito do tratamento térmico pós-cura (PCHT) na microdureza Knoop (KHN), grau de conversão (DC), mudanças de cor e razão de contraste (CR) de quatro compósitos resinosos (RCs): Z100 (3M ESPE ), Z350 XT (3M ESPE), Estelite Omega (Tokuyama) e Empress Direct (Ivoclar Vivadent). Corpos de prova (12 × 1 mm) foram preparadas para cada material (n = 10 / grupo). Após a cura, as amostras foram submetidas ao PCHT por 10 min a 100 ou 170° C. O grupo controle foi mantido à temperatura ambiente (24° C) pelo mesmo tempo. O DC foi analisada por FT-NIR imediatamente e 24 h após a PCHT (n = 3 / grupo). KHN foi analisado 24 h após PCHT (n = 10 / grupo). De acordo com o CIEDE2000 (∆E00), as medidas de cor foram obtidas imediatamente após a cura, cinco minutos após a PCHT e após sete dias de armazenamento em água, café e vinho tinto. Os dados foram analisados por ANOVA de um e dois fatores (P < 0,05). Z100, Z350 XT e Estelite Omega mostraram aumentos no KHN com o aumento da temperatura (P < 0,05). PCHT a 100 ° C e 170 ° C levou a uma maior DC de todos os RCs (P < 0,05). Inicialmente, o PCHT levou ao aumento dos valores de ∆E00 (P < 0,05), que diminuiu após a imersão em café e vinho (P < 0,05). Considerando o efeito de PCHT e soluções de coloração, menores mudanças de cor foram observadas nas amostras tratadas termicamente (P < 0,05). Os resultados sugerem o PCHT como uma alternativa econômica e prática para aumentar as propriedades diretas de compósitos resinosos em restaurações diretas-indiretas e indiretas.

CHX stabilizes the resin/demineralized dentin interface

Abstract The aim of this study was to evaluate the effect of 2% chlorhexidine digluconate (CHX) on microtensile bond strength (µTBS) between an adhesive system and under 3 dentin conditions. For that, this study evaluated the adhesive interface at initial, after 6 months and 1 year of storage. Forty-eight human third molars were prepared and randomly divided into 3 groups, according to dentin substrates: sound dentin (Sd), caries-infected dentin (Ci) and caries-affected dentin (Ca). The groups were subdivided into two according to the dentin pre-treatment: application of 2% CHX or without pre-treatment (control). The dentin surfaces were etched with 35% phosphoric acid gel and bonded with Adper Single Bond 2 (3M ESPE) adhesive system according to manufacturer's instructions. Subsequently, the specimens were stored in deionized water at 37°C for 24h, 6 months and 1 year. Two additional teeth were used to analyze the bonding interfaces by SEM. Data was submitted to three-way ANOVA in a split plot design and Tukey's test (α = 0.05). The results showed that Ci decreased µTBS values when compared to Ca and Sd, regardless storages time or treatment. Stored samples for 6 months and 1 year decreased the µTBS for the control group, but no difference was found between storages time for the CHX group. As a conclusion, the 2% CHX application after etching showed improved dentin bond strength in the storage time, regardless of the substrates evaluated.

Resumo O objetivo deste estudo foi avaliar o efeito do digluconato de clorexidina 2% (CHX) na resistência de união à microtração (µTBS) entre um sistema adesivo e sob 3 condições de dentina. Para tanto, este estudo avaliou a interface adesiva no início, após 6 meses e 1 ano de armazenamento. Quarenta e oito terceiros molares humanos foram preparados e divididos aleatoriamente em 3 grupos, de acordo com os substratos dentinários: dentina hígida (Dh), dentina infectada por cárie (Di) e dentina afetada por cárie (Da). Os grupos foram subdivididos em dois de acordo com o pré-tratamento: aplicação de CHX 2% ou sem pré-tratamento (controle). As superfícies da dentina foram condicionadas com gel de ácido fosfórico a 35%, em seguida, utilizou-se o sistema adesivo Adper Single Bond 2 (3M ESPE) de acordo com as instruções do fabricante. Posteriormente, os corpos-de-prova foram armazenados em água deionizada a 37°C por 24h, 6 meses e 1 ano. Dois dentes adicionais foram usados ​​para analisar as interfaces de união no MEV. Os dados foram submetidos a ANOVA três fatores em esquema de parcela subdividida e ao teste de Tukey (α = 0,05). Os resultados mostram que a Di diminuiu os valores de µTBS quando comparado as Da e Dh, independente do tempo de armazenamento ou tratamento. Amostras armazenadas por 6 meses e 1 ano diminuíram a µTBS para o grupo de controle, mas nenhuma diferença foi encontrada entre o tempo de armazenamento para o grupo CHX. A aplicação de CHX 2% após o condicionamento apresentou melhora na resistência de união à dentina no tempo de armazenamento, independente dos substratos avaliados.

Rehabilitación estética mínimamente invasiva en diente anterior afectado por hipoplasia de esmalte: Reporte de caso clínico / Minimally Invasive Restoration in Anterior Teeth Affected by Enamel Hypoplasia: Clinical Case Report

RESUMEN La preservación de tejido dental sano contribuye a la práctica de una Odontología conservadora, permitiendo la aplicación de los principios biológicos y mecánicos de una forma más predecible. Las preparaciones cavitarias mínimamente invasivas son el complemento de la correcta selección de materiales adhesivos y de resina compuesta. La correcta aplicación de un protocolo adhesivo nos proporcionará resultados estéticos imperceptibles y un longevo desempeño clínico.

ABSTRACT The preservation of healthy dental structures contributes to the practice of a conservative dentistry. This concept involves the implementation of biological and mechanical principles in a more predictable manner. Minimally invasive cavity preparations are the complement to the selection of adhesive and composite resin materials. The correct application of an adhesive protocol will provide imperceptible aesthetic restorations and adequate clinical performance.

Color Stability of Bulk-Fill Resin Composites after Immersion in Different Media / 대한소아치과학회지

The aim of this study was to evaluate the color stability of bulk-fill and conventional resin composites with respect to different storage media and thickness of composites.Filtek™ Z250 and Filtek™ Z350XT were evaluated as conventional resin composites. Filtek™ Bulk-fill Posterior Restorative and Tetric® N-Ceram Bulk Fill were evaluated as bulk-fill resin composites.CIE L*a*b* values of baseline were measured after 24 hours of storage in distilled water, and each resin composite group was divided into three subgroups and stored in distilled water, red wine, and coffee media respectively. Again after 1, 7 and 28 days of immersion, color changes (ΔE*) were calculated using the CIE L*a*b* values.The greatest ΔE* was observed in red wine for all resin composites, and the mean color changes were ranked in the increasing order of distilled water, coffee, red wine. Filtek™ Z350XT exhibited the greatest color change in all media, followed by Filtek™ Bulk-fill Posterior Restorative. Filtek™ Z250 and Tetric® N-Ceram Bulk Fill followed with similar mean color change values. According to the 2 different thicknesses of 2 mm and 4 mm of bulk-fill resin composites, there was no thickness-related difference on color changes.

Shrinkage stress and elastic modulus assessment of bulk-fill composites

Abstract Bulk-fill composites were introduced in dentistry to accelerate clinical procedures while providing adequate outcomes. Concerns regarding the use of bigger composite increments rely on the polymerization shrinkage and shrinkage stress, which may generate gaps on the adhesive interface and result in a reduced success rate. Objective: To evaluate the polymerization shrinkage stress of different bulk-fill resin composites and their elastic modulus. Materials and Methods: Fourteen specimens were made for each of the nine different resin composites (seven with 12 mm3 and seven with 24 mm3): Surefill SDR flow (SDR), X-tra Base (XB), Filtek Bulk Fill Flowable (FBF), Filtek Z350XT Flow (Z3F); Tetric Evo Ceram Bulk Fill (TBF), X-tra Fil (XF), Filtek Bulk Fill (FBP), Admira Xtra Fusion (ADM) and Filtek Z350 XT (Z3XT). Linear shrinkage stress was evaluated for 300 s with the aid of a linear shrinkage device adapted to a Universal Testing Machine. For each composite group, seven additional specimens (2x2x25 mm) were made and Young's modulus was evaluated with a 3-point bending device adapted in a Universal Testing Machine with 0.5 mm/min crosshead speed and 50 KgF loading cell. Results: For 12 mm3 specimens, three-way ANOVA showed that only SDR and TBF generated lower stress after 20 s. Considering 300 s, TBF, SDR, and XF generated the lowest stress, followed by ADM, FBP, XB, and FBF, which were similar to Z3XT. Z3F generated the highest stress values for all time points. Considering 24 mm3 specimens after 20 s, all bulk fill composites generated lower stress than Z3XT, except XB. After 300 s, SDR, FBP, and ADM generated the lowest stress, followed by TBF and XF. For elastic modulus, one-way ANOVA showed that FBF, SDR, Z3F, and ADM presented the lowest values, followed by XB and TBF. FBP, Z3XT, and XF presented the highest elastic modulus among the evaluated composites. Conclusions: Bulk-fill resin composites presented equal to lower shrinkage stress generation when compared to conventional composites, especially when bigger increments were evaluated. Bulk-fill composites showed a wide range of elastic modulus values, but usually similar to "regular" composites.

Influence of α-Si3N4 and SP1SiO2 fusing conditions and filler ratios in properities of dental resin composites / 吉林大学学报(医学版)

Objective: To detect the optimal fusing temperature, the fusing time and the best filler ratio of α-Si3N4 and SP1SiO2, and to clarify their influence in the properities of dental resin composites. Methods: The α-Si3N4 crystalline were mixed with SP1SiO2 particle at the ratio of5:l (Wt%), and then were sintered under 500°C, 650°C, 800°C, 950°C and 1 100°C at a rise rate of 250 · h-1 and maintained for 10 min, 30 min and 3 h, respectively (used as α-Si3N4-SP1SiO2 groups). SP1SiO2 particle, α-Si3N4 crystalline, mixed and non-fused α-Si3N4 and SP1SiO2 (mixed) groups were set up, and two commercially available resin composites were selected and used as control groups. And they were fully mixed with the resin matrix in 60% (Wt%) after the treatment of cyclohexane solution to make the samples. The flexural strength of specimen was tested and the morphology of section under SEM was analyzed. Then α-Si3N4 was mixed with SP1SiO2 in a ratio of 2; 1. It was fused under the optimal fusing conditions. After the treatment of cyclohexane solution, it was mixed and polymerized with the resin matrix in the proportions of 20%, 40%, 60%, 70% and 75% (Wt%), and two kinds of commercially available resin composites were selected and used as control groups. The flexural strength of specimens was tested and the morphology of section under SEM was analyzed. Results: The maximum flexural strength value in α-Si3N1-SP1SiO2 groups was at 800°C and 30 min (P>0. 05); the flexural strength value was significantly higher than those in SP1SiO2 group, α-Si3N1 crystalline group, mixed group and two control groups (P<0. 05), and the morphology of section SEM was consistent with the mechanical properties. The flexural strengths of resin composites were increased gradually with the increasing of filler ratios of α-Si3N4 and SP1SiO2 fusion from 20% to 60% (P<0. 05); the flexural strength values of resin composites with the proportion of 60%-70% were not increased significantly, the flexural strength values of resin composites with the proportion of 70%-75% were decreased, and the flexural strength values of the resin composites with the proportion of 60% and 70% were significantly higher than those of resin composites with the proportions of 20%, 40%, 75% and control groups; the morphology of section under SEM was consistent with the mechanical properties. Conclusion: The optimum fusing condition for α-Si3N4 and SP1SiO2 is 800°C for 30 min, and the best filler ratio of α-Si3N4 and SP1SiO2 is 70%.

Comparación de la resistencia compresiva de resinas convencionales vs resinas tipo Bulk fill

Objetivo: El propósito de este estudio fue comparar la resistencia compresiva de 2 resinas tipo Bulk fill y 2 resinas convencionales. Materiales y métodos: 136 muestras cilíndricas (2mm y 4mm), divididos en 8 grupos (n=17); G1 SonicFill™ (4x2mm), G2 SonicFill™ (4x4mm), G3 Tetric® N-Ceram Bulk Fill (4x2mm), G4 Tetric® N-Ceram Bulk Fill (4x4mm), G5 Filtek™ Z250 XT (4X2mm), G6 Filtek™ Z250 XT (4x4mm), G7 Te-Econom Plus® (4x2mm) y G8 Te-Econom Plus® (4x4mm). La resistencia compresiva fue evaluada con la máquina Instron® a una velocidad de desplazamiento fijo de 1,0mm/min. Los test de ANOVA, Kruskall Wallis, t Student y U de Mann Whitney fueron empleados para el análisis estadístico. Resultados: para las resinas Bulk Fill, Tetric® N-Ceram Bulk Fill (310,06- 4x2mm, 303,87-4x4mm) mostró mayor resistencia compresiva que SonicFill™. Para las resinas convencionales, Filtek™ Z250 XT (295,9-4x2mm, 289,7-4x4mm) obtuvo mayor resistencia compresiva que Te-Econom Plus®. A la comparación de todos los grupos, Tetric® N-Ceram Bulk Fill presentó los valores compresivos más altos en ambos espesores 4x2mm(0,122) y 4x4mm(0,333), con diferencias estadísticas significativas (p<0,001*-4x2mm, p=0,004- 4x4mm). Conclusión: Tetric® N-Ceram Bulk Fill puede ser una buena opción para restauraciones posteriores, ya que su propiedad mecánica de resistencia compresiva es superior en relación con las otras evaluadas.

Objective: The aim of this study was compare the compressive strength of 2 Bulk fill resin composites and 2 conventional resin composites. Materials and methods: one hundred and thirty six cylindrical samples (2mm and 4mm), divided in 8 groups (n = 17); G1 SonicFill™ (4x2mm), G2 SonicFill™ (4x4mm), G3 Tetric® N-Ceram Bulk Fill (4x2mm), G4 Tetric® N-Ceram Bulk Fill (4x4mm), G5 Filtek™ Z250 XT (4x2mm), G6 Filtek™ Z250 XT (4x4mm), G7 Te-Econom Plus® (4x2mm) and G8 Te-Econom Plus® (4x4mm). Specimens were evaluated to compressive stress test using Instron® machine at crosshead speed of 1.0 mm/min. One way Anova, Kruskall Wallis, Student's t and U Mann Whitney tests were employed for statistical analyses. Results: For Bulk resin composites, Tetric® N-Ceram Bulk Fill (310.06-4x2mm, 303.87-4x4mm) showed higher compressive strength than SonicFill™. For conventional resin composites, Filtek™ Z250 XT (295.9-4x2mm, 289.7-4x4mm) showed higher compressive strength than Te-Econom Plus®. For comparison,Tetric® N-Ceram Bulk Fill was higher compressive strength in both thickness 4x2mm (p=0.122) and 4x4mm (p=0.333) and it was statistically significant (<0.001*- 4x2mm, 0.004-4x4mm) among them. Conclusion: Tetric® N-Ceram Bulk Fill offers a good mechanical property like a compressive strength which is better in comparison to the others resin composites evaluated in this study.

Translucency,opalescence and fluorescence properties of six light-cured resin composites / 实用口腔医学杂志

Objective:To evaluate the translucency,opalescence and fluorescence reflection of 6 light-cured resin composites. Methods:Disks of 6 resin composites including Filtek Supreme XT-YT(XT),Filtek Supreme XT-A3B(3M),Clearfil Majesty-A3 (MJ),Gradia Direct-A3(GC),Venus-A3(VE)and Charisma Diamond-A3(CA)were prepared in the diameter of 9 mm with the thickness 2.0 mm.PR-650 spectral scanning colorimeter was used to measure and caculate translucency parameters(TP),opal-escence parameter(OP)and fluorescence reflection(FL)and to draw the fluorescence reflection curves.Results:Except XT and MJ,TP value of other resin composites were in the range of natural tooth.Only OP value of XT was in the range of natural tooth en-amel.FL value of XT was close to that of natural tooth dentin.Fluorescent peak wavelength of GC,MJ,VE and CA were in the range of natural tooth,but fluorescent peak height was higher than that of natual tooth.TP was positively correlated with OP(r =0.85,P <0.05).There was no statistic correlation between TP and FL,between OP and FL.Conclusion:The 6 resin composites can simulate optical property of natual tooth,but the opalescence of resin composites is defective.

Effect of Brushing Time and Dentifrice Abrasiveness on Color Change and Surface Roughness of Resin Composites

Abstract: Dentifrice abrasiveness and brushing time may increase color change (∆E) and surface roughness (∆Ra) of resin composites. This study aimed to evaluate the effect of mechanical brushing time of dentifrices with different abrasiveness on ∆E and ∆Ra of nanofilled (Z350, 3M ESPE) and nanohybrid (Tetric N-Ceram, Ivoclar Vivadent) resin composites. Sixteen specimens (12 mm diameter x 2 mm thick) were fabricated using a white Teflon matrix of each resin composite and a ceramic (IPS e.max Ceram, Ivoclar Vivadent), used as control. After initial color readouts on white backgrounds (Spectrophotometer PCB 6807, Byk Gardner), with D65 standard illuminant, and surface roughness (Rugosimeter Surfcorder SE 1700, Kosalab) with cut-off=0.8 mm and speed=0.25 mm/s, specimens were assigned (n=8) according to the abrasiveness of the dentifrices: RDA* 68 (Colgate) and RDA* 180 (Colgate Total Plus Whitening). Specimens were submitted to mechanical brushing (58,400 cycles) and after every 14,600 cycles (1 year of brushing by a healthy individual), new color and surface roughness readouts were taken. Color stability was calculated by CIEDE2000. Data were analyzed by 3-way repeated measures ANOVA and Bonferroni test (p<0.05), and demonstrated that the dentifrice abrasiveness (p=0.02) and brushing time (p<0.0001) affected the ∆E of nanofilled resin composite. There was no difference on surface roughness of materials (p=0.6752) or brushing time (p=0.7997). In conclusion, the longer the brushing time and dentifrice abrasiveness, the greater the color change of the nanofilled resin composite. The surface roughness was not influenced by dentifrice abrasiveness.

Resumo: A abrasividade do dentifrício e o tempo de escovação podem aumentar a alteração de cor (∆E) e rugosidade de superfície (∆Ra) das resinas compostas. Este estudo teve como objetivo avaliar o efeito do tempo de escovação mecânica com dentifrícios de diferentes abrasividades, sobre o ∆E e a ∆Ra das resinas compostas (nanoparticulada, Z350, 3M ESPE e nanohíbrida, Tetric N-Ceram, Ivoclar Vivadent). Dezesseis amostras (12 mm de diâmetro x 2 mm de espessura) foram obtidas utilizando uma matriz de teflon branca, de cada resina composta e uma cerâmica (IPS e.max Ceram, Ivoclar Vivadent), considerada como controle. Após as leituras iniciais de cor sobre fundo branco (Espectrofotômetro PCB 6807, Byk Gardner), com iluminante padrão D65, e de rugosidade de superfície (Rugosímetro Surfcorder SE 1700, Kosalab), com cut-off=0,8 mm e velocidade=0,25 mm/s, as amostras foram separadas (n=8) de acordo com a abrasividade dos dentifrícios: RDA* 68 (Colgate) e RDA* 180 (Colgate Total Plus Whitening). Amostras foram submetidas a escovação mecânica (58.400 ciclos), sendo que a cada 14.600 ciclos (1 ano de escovação por um indivíduo saudável), novas leituras de cor e rugosidade de superfície foram realizadas. A estabilidade de cor foi calculada segundo CIEDE2000. Os dados foram analisados (3-way ANOVA medidas repetidas, teste de Bonferroni, p<0,05), e demonstrou-se que a abrasividade dos dentifrícios (p=0,02) e o tempo de escovação (p<0,0001) afetaram o ∆E da resina composta nanoparticulada. A rugosidade de superfície não foi influenciada pela abrasividade dos dentifrícios (p=0,6752) ou tempo de escovação (p=0,7997). Concluiu-se que quanto maior o tempo de escovação mecânica e a abrasividade do dentifrício, maior a alteração de cor da resina composta nanoparticulada. A rugosidade de superfície não foi influenciada pela abrasividade do dentifrício.

Curing depth of a silorane-based resin composite

Introduction: The silorane-based resin appears aiming to minimize the effects of polymerization shrinkage, but other properties must be studied. Objective: To evaluate the polymerization depth of two composites with different organic matrix. Material and methods: 80 cylindrical specimens were prepared using a metallic matrix, with three layers (top, middle and bottom), 1 mm high and 5 mm in diameter. The specimens were divided into eight groups (n = 10) according to the composite resins: Filtek P90 (3M/ESPE); Filtek Z250 (3M/ESPE), light-cured with a LED device with different irradiance and times (600mW/cm2 x 40s, 1000mW/cm2 x 40s, 1000mW/cm2 x 20s; 1400mW/cm2 x 20s). The irradiance was controlled by placing plastic rings coupled to the device's tip. Immediately after polymerization, the specimens' layers were separated and five Knoop microhardness readings (initial hardness) were performed on each one of the four layers (0, 1, 2, and 3 mm). After 7 day storage in water at 37ºC, new readings were performed (final microhardness). The data were analyzed by four-way ANOVA (resin, energy density, depth and time) and Tukey test (α = 0.05). Results: The microhardness decreased with the depth increasing both in the initial and 7 day readings. The hardness increased with the highest power densities. The resin P90 had lower hardness values. Conclusion: The silorane-based resin showed Knoop microhardness values significant smaller than those of methacrylate-based resin in almost all evaluated parameters. However, both presented similar behaviors in relation to the curing depth.

Degradation of Resin Composites in a Simulated Deep Cavity

The aim of this study was to analyze the sorption and solubility of a nanofilled (Filtek Z350) and a midifilled (Filtek P60) resin composite in oral environment-like substances, in a simulated deep cavity. A cylindrical cavity prepared in a bovine incisor root was incrementally filled with resin composites. The obtained resin composite cylinders were cut perpendicularly to the axis to obtain 1-mm-thick discs that were divided into fifteen groups (n=5) according to depth (1, 2, 3, 4 and 5 mm) and immersion media (distilled water - DW, artificial saliva - AS and lactic acid - LA). The sorption and solubility were calculated based on ISO 4049:2000. Additionally, the degree of conversion (DC%) was calculated by FT-IR spectroscopy. Data were analyzed using multifactor analysis of variance (MANOVA) followed by Tukey's HSD post-hoc test and linear regression analysis (a=0.05). The DC% was higher for the midifilled resin composite and was negatively influenced by cavity depth (p<0.05). The nanofilled resin composite presented higher sorption and solubility than did the midifilled (p<0.05). The immersion media influenced the sorption and the solubility as follows: LA>AS>DW, (p<0.05). Both phenomena were influenced by cavity depth, with the sorption and solubility increasing from 1 to 5 mm (p<0.05). The degradation of resin composite restorations may be greater in the deepest regions of class II restorations when the composite is exposed to organic acids present in the oral biofilm (lactic acid).

O objetivo deste estudo foi analisar a absorção e a solubilidade de uma resina composta nanopartículada (Filtek Z350) e de uma híbrida (Filtek P60) em substâncias simuladoras do ambiente oral em um modelo de cavidade profunda. Uma cavidade cilíndrica, construída em uma raiz de um incisivo bovino, foi preenchida incrementalmente com as resinas compostas. Os cilindros obtidos foram seccionados perpendicularmente ao eixo para obtenção de discos com 1 mm de espessura, que foram divididos em 15 grupos (n=5) de acordo com a profundidade (1, 2, 3, 4 e 5 mm) e o meio de imersão (água destilada - AD, saliva artificial - SA e ácido lático - AL). A absorção e a solubilidade foram calculadas com base na norma ISO 4049:2000(E). Adicionalmente, o grau de conversão (GC%) foi calculado através de espectroscopia FT-IR. Os dados obtidos foram analisados usando análise de variância multifatorial, teste de Tukey HSD e análise de regressão linear (a=0,05). A resina composta híbrida apresentou o maior grau de conversão, sendo este influenciado pela profundidade da cavidade (p<0,05). A resina composta nanopartículada apresentou maiores valores de absorção e solubilidade (p<0,05). O meio de imersão influenciou a absorção e a solubilidade: AL>SA>AD (p<0,05). Ambos os fenômenos foram influenciados pela profundidade da cavidade, com os valores aumentando de 1 para 5 mm (p<0,05). A degradação de restaurações de resinas compostas pode ser maior em regiões profundas de restaurações classe II e quando o material é exposto à ácidos orgânicos produzidos pelo biofilme oral (ácido lático).

Beyond the discourse of amalgam vs composite resin restorations / Além do discurso de restaurações de amálgama x resina composta

OBJECTIVE: To diagnose the prevalence of amalgam and resin composite restorations performed by professionals in public service and university students in a municipality in the Northeast of the State of Paraná. METHODS: Ten basic health units were randomly selected, at which 500 clinical record charts of patients of both sexes aged from 18 to 50 years were consulted. To analyze the prevalence of restorations performed by students, a questionnaire was applied to 4th and 5th year students, containing questions relative to the number of restorations and type of material using in intramural clinical activities. RESULTS: In the basic health units, 66% of restorations were performed with amalgam, and 34% with resin composite. At the dental school, 4th year students responded that when they were in the 3rd year, out of a total of 367 restorations, 21.5% were performed with amalgam and 78.5% with resin composite. For the 5th year group of students, the percentage of teeth restored with amalgam was 14.3%, 12.0% and10.2%, when they were in the 3rd, 4the and 5th years of the course, respectively. The results obtained revealed that the indication of the restoration material differed in the two scenarios. CONCLUSION: In the basic health units, the majority of restorations were performed with amalgam, whereas at the dental school there was higher prevalence of resin composite restorations. One must reflect whether professional education has adequately developed the necessary competencies for decision making and meeting the needs of this population. .

OBJETIVO: Diagnosticar a prevalência de restaurações de amálgama e resina composta realizadas por profissionais no serviço público e estudantes universitários de um município do noroeste do estado do Paraná. MÉTODOS: Foram selecionadas aleatoriamente dez unidades básicas de saúde, das quais foram consultados 500 prontuários de pacientes com 18 a 50 anos, de ambos os sexos. Para analisar a prevalência das restaurações realizadas pelos estudantes, aplicou-se um questionário aos estudantes do quarto e quinto ano contendo perguntas relativas ao número de restaurações e tipo de material utilizado nas atividades clínicas intramuros. RESULTADOS: Nas unidades básicas de saúde, 66% das restaurações foram feitas com amálgama e 34% com resina composta. Na escola, os estudantes do quarto ano responderam que quando estavam no terceiro ano, de um total de 367 restaurações, 21,5% foram feitas com amálgama e 78,5% com resina. Para o grupo de estudantes do quinto ano, a porcentagem de dentes restaurados com amálgama foi de 14,3%, 12,0% e 10,2%, respectivamente, para quando estavam no 3º, 4º e 5º ano do curso. Os resultados obtidos revelaram que a indicação do material restaurador nos dois cenários é divergente. CONCLUSÃO: Nas unidades básicas de saúde a maioria das restaurações realizadas foi de amálgama enquanto na escola, a maior prevalência foi de resina composta. Deve-se refletir se a formação profissional tem desenvolvido adequadamente as competências necessárias para a tomada de decisão e o atendimento às necessidades da população. .

Staining susceptibility of methacrylate and silorane-based materials: influence of resin type and storage time

Introduction: The color stability of composite resins is a fundamental factor in their clinical behavior. Objective: To evaluate the color stability of composite resins of different colors exposed to a cola-based soft drink after different storage periods. Additionally, three methacrylate-based materials and one silorane-based material were evaluated. Material and methods: Specimens of three methacrylate-based materials (Opallis EA3, DA3 and T-Neutral; Filtek Supreme XT A3E, A3D and CT; 4 Seasons A3 Enamel, A3 Dentin and High Value) and one silorane-based material (Filtek P90 A3) were prepared, light-cured for 40 s, and manually polished with Sof-Lex discs. Samples were stored for 1 h, 24 h or 7 days. The color was evaluated by CIE-Lab system before and after immersion for 10 min in a cola-based soft drink. Color variation (ΔE) was calculated from individual values of L*, a* and b*, being considered imperceptible when < 1, clinically acceptable when ≤ 3.3, and clinically inacceptable when higher than 3.3. Data were evaluated by two-way Anova and Dunnett's T3 tests (α = 0.05). Results: There were differences among the resins (p < 0.001), with an interaction effect being also observed (p < 0.001). Storage time was not significant (p = 0.246). P90 showed a ΔE smaller than one unit at all studied times. Supreme XT CT and 4 Seasons High Value showed higher ΔE, but not above the critical value of 3.3. The only material that showed ΔE higher than 3.3 was Opallis DA3 after 1 h of storage. Conclusion: The silorane-based composite resin showed smaller ΔE at the times studied.

Influência da composição da matriz orgânica, conteúdo inorgânico e tratamento térmico sobre diferentes propriedades de compósitos experimentais / Influence of composition of the organic matrix, filler content and thermic treatment on different properties of experimental composites

Objetivo: Analisar a influência da matriz orgânica, do conteúdo inorgânico e do tratamento térmico (TT) sobre diferentes propriedades de compósitos experimentais, tais como o grau de conversão (GC), tenacidade à fratura (KIC), resistência à flexão (RF) e módulo de elasticidade (ME). Métodos: Para o experimento foram analisadas seis formulações de compósitos experimentais com proporções molares de Bis-GMA:TEGDMA de 5:5 e 7:3, a carga utilizada foi o vidro de bário, nas concentrações de 30, 50 e 70% em peso, e os fotoiniciadores a amina e canforoquinona. O GC foi analisado através da espectroscopia no infra-vermelho (FTIR) (n=5). A KlC foi avaliada pelo método single-edge notched beam (SENB). As imagens das superfícies de fratura foram capturadas por um estereomicroscópio e a KlC calculada (n=10). A análise da RF e ME foi realizada através do teste dos três pontos (n=10). Para todos os fatores de variação estudados, metade dos espécimes imediatamente após à confecção receberam TT em estufa convencional, a 170º C por 10 minutos e a outra metade não. Após 24 horas, as amostras foram destinadas de acordo com os ensaios realizados...

Objective: To analyze the influence of organic matrix, the inorganic content and thermic treatment (TT) on different properties of experimental composites, such as the degree of conversion (DC), fracture toughness (KIC), flexural strength (FS) and elastic modulus (EM). Methods: This experiment analyzed six formulations of experimental composites with 5:5 and 7:3 molar proportions of Bis-GMA: TEGDMA. The load used was barium glass at concentrations of 30, 50 and 70% by weight and the photoinitiators, camphorquinone and amine. GC was analyzed by infrared spectroscopy (FTIR) (n=5). The KIC was evaluated by a "single-edge notched beam" (SENB). The images of the fracture surfaces were captured by a stereomicroscope and KIC calculated (n=10). The analysis FS and EM were performed by testing three points (n=10). For all the variation factors studied, half of the specimens immediately after the preparation received TT in conventional oven at 170º C for 10 minutes and the other half not. After 24 hours, the samples were designed according to the tests. Data were analyzed using ANOVA/Tukey the degree of conversion, fracture toughness and flexural strength, and Kruskal-Wallis test for the elastic modulus (=5%). Results: Analysis of GC (%) statistical significance was observed for the three variation factors analyzed individually (monomer, filler and TT), as well as for the interaction monomer x TT (p <0.001). For KIC and FS, significant changes were observed only in the three variation factors (monomer, filler and TT) analyzed individually (p<0.001). For EM, the individual factors (monomer, filler and TT) TT x filler interaction showed statistical significance (p <0.001), as well as the monomer x filler interaction (p = 0.001). Conclusions: The organic matrix and inorganic content of experimental composites influenced the GC, KIC, FS and EM, and the TT caused improvements in the properties studied.

Avaliação da influência da aplicação de um selante de superfície no comportamento clínico de restaurações de resina composta classe I / Evaluation of the influence of a surface sealant in the clinical behavior of composite resin class I restorations

A aplicação de selantes de superfície, através da penetração nas irregularidades superficiais e na interface dente/restauração, é realizada ao final do procedimento restaurador e pode minimizar algumas limitações, prolongando a longevidade clínica das restaurações de resina composta. Este estudo clinico randomizado se propôs a avaliar o efeito da aplicação de um selante de superfície no comportamento clínico de restaurações posteriores de resina composta do tipo classe I. Vinte e sete pares de dentes molares ou pré-molares, superiores ou inferiores, que apresentavam lesões de cárie (classe I) ou restaurações de amálgama ou resina composta (classe I) insatisfatórias, que necessitavam de substituição completa, foram aleatorizados e preparados e restaurados com a resina composta Esthet-X. Sobre a superfície da resina de apenas um dente de cada par foi aplicado o selante de superfície Lasting Touch utilizando o modelo experimental de boca dividida. A avaliação única foi realizada empregando-se o método direto USHPS modificado, nos tempos: baseline, 6 meses, 12 meses, por dois operadores. Radiografias interproximais e réplicas das faces oclusais foram obtidas por meio da moldagem com silicona de adição e vazadas com resina epóxica para avaliação qualitativa com Microscópio Eletrônico de Varredura. Os dados foram submetidos ao teste de Mc Nemar (p<0,05). Para a integridade marginal, após 6 meses de avaliação, apenas 1 (4%) restauração do grupo com selante de superfície recebeu o escore Bravo. Aos 12 meses, a integridade marginal apresentou 1 (4%) do grupo sem selante e 2 (7%) restaurações com selante com escore Bravo. Os resultado apresentados nos períodos de avaliação não apresentaram diferenças estatisticamente significantes (p=1,0, para todas as condições. Não houve diferença no desempenho clínico de restaurações de resina composta com e sem selante de superfície, sendo aceitáveis após 12 meses de avaliação. As observações em MEV demonstraram...

The finishing, polishing and surface sealant application, by superficial irregular penetration and between restoration interface, are applied at the end of the restoration and decrease these limitations, and extend the clinical longevity of composite resin restorations. This clinical randomized controled study however aimed to evaluate the effect of the surface sealant application in the clinical behavior of composite posterior resin class I restorations. Twenty seven pairs of upper or lower molars or premolars with carious lesions (class I), and unsatisfactory amalgam or composite resin restorations, which needed total replacement, were randomized and prepared and restored with Esthet X composite resin. The composite resin surface of one tooth from each pair was covered with Lasting Touch surface sealant (Split Mouth Design). The clinical evaluation was made by using the modified direct method USPHS, at the following times: baseline, 6 months and 12 months, by two different operators. Bitewing radiographs and replicas of the occlusal surfaces were obtained by using a silicone impression material poured with epoxy resin for the qualitative evaluation with Scanning Electron Microscopy. The data was analyzed with the McNemar test (p <0.05). Results showed that for the marginal integrity, after 6-month evaluation, only 1 (4%) sealed restoration had a Bravo rating. At the end of 12 months, the marginal integrity showed 1 (4%) sealed restoration and 2 (7%) non sealed Bravo restorations. Results at all evaluations periods did not show statistical significant differences (p=1.0) for all conditions. There was no difference in the clinical performance of the composite resin restorations (Esthet X) with or without the surface sealant (Lasting Touch), demonstrated good behavior after 12 months. Based on SEM examinations, the surface sealant application promoted a regular and smooth surface, for all the evaluation times. In a 12 months evaluations period, the surface...

Avaliação da influência da aplicação de um selante de superfície no comportamento clínico de restaurações de resina composta classe I / Evaluation of the influence of a surface sealant in the clinical behavior of composite resin class I restorations

A aplicação de selantes de superfície, através da penetração nas irregularidades superficiais e na interface dente/restauração, é realizada ao final do procedimento restaurador e pode minimizar algumas limitações, prolongando a longevidade clínica das restaurações de resina composta. Este estudo clinico randomizado se propôs a avaliar o efeito da aplicação de um selante de superfície no comportamento clínico de restaurações posteriores de resina composta do tipo classe I. Vinte e sete pares de dentes molares ou pré-molares, superiores ou inferiores, que apresentavam lesões de cárie (classe I) ou restaurações de amálgama ou resina composta (classe I) insatisfatórias, que necessitavam de substituição completa, foram aleatorizados e preparados e restaurados com a resina composta Esthet-X. Sobre a superfície da resina de apenas um dente de cada par foi aplicado o selante de superfície Lasting Touch utilizando o modelo experimental de boca dividida. A avaliação única foi realizada empregando-se o método direto USHPS modificado, nos tempos: baseline, 6 meses, 12 meses, por dois operadores. Radiografias interproximais e réplicas das faces oclusais foram obtidas por meio da moldagem com silicona de adição e vazadas com resina epóxica para avaliação qualitativa com Microscópio Eletrônico de Varredura. Os dados foram submetidos ao teste de Mc Nemar (p<0,05). Para a integridade marginal, após 6 meses de avaliação, apenas 1 (4%) restauração do grupo com selante de superfície recebeu o escore Bravo. Aos 12 meses, a integridade marginal apresentou 1 (4%) do grupo sem selante e 2 (7%) restaurações com selante com escore Bravo. Os resultado apresentados nos períodos de avaliação não apresentaram diferenças estatisticamente significantes (p=1,0, para todas as condições. Não houve diferença no desempenho clínico de restaurações de resina composta com e sem selante de superfície, sendo aceitáveis após 12 meses de avaliação. As observações em MEV demonstraram...

The finishing, polishing and surface sealant application, by superficial irregular penetration and between restoration interface, are applied at the end of the restoration and decrease these limitations, and extend the clinical longevity of composite resin restorations. This clinical randomized controled study however aimed to evaluate the effect of the surface sealant application in the clinical behavior of composite posterior resin class I restorations. Twenty seven pairs of upper or lower molars or premolars with carious lesions (class I), and unsatisfactory amalgam or composite resin restorations, which needed total replacement, were randomized and prepared and restored with Esthet X composite resin. The composite resin surface of one tooth from each pair was covered with Lasting Touch surface sealant (Split Mouth Design). The clinical evaluation was made by using the modified direct method USPHS, at the following times: baseline, 6 months and 12 months, by two different operators. Bitewing radiographs and replicas of the occlusal surfaces were obtained by using a silicone impression material poured with epoxy resin for the qualitative evaluation with Scanning Electron Microscopy. The data was analyzed with the McNemar test (p <0.05). Results showed that for the marginal integrity, after 6-month evaluation, only 1 (4%) sealed restoration had a Bravo rating. At the end of 12 months, the marginal integrity showed 1 (4%) sealed restoration and 2 (7%) non sealed Bravo restorations. Results at all evaluations periods did not show statistical significant differences (p=1.0) for all conditions. There was no difference in the clinical performance of the composite resin restorations (Esthet X) with or without the surface sealant (Lasting Touch), demonstrated good behavior after 12 months. Based on SEM examinations, the surface sealant application promoted a regular and smooth surface, for all the evaluation times. In a 12 months evaluations period, the surface...

Difference in the color stability of direct and indirect resin composites

Indirect resin composites are generally regarded to have better color stability than direct resin composites since they possess higher conversion degree. OBJECTIVE: The present study aimed at comparing the changes in color (ΔE) and color coordinates (ΔL, Δa and Δb) of one direct (Estelite Sigma: 16 shades) and 2 indirect resin composites (BelleGlass NG: 16 shades; Sinfony: 26 shades) after thermocycling. MATERIAL AND METHODS: Resins were packed into a mold and light cured; post-curing was performed on indirect resins. Changes in color and color coordinates of 1-mm-thick specimens were determined after 5,000 cycles of thermocycling on a spectrophotometer. RESULTS: ΔE values were in the range of 0.3 to 1.2 units for direct resins, and 0.3 to 1.5 units for indirect resins, which were clinically acceptable (ΔE<3.3). Based on t-test, ΔE values were not signifcantly different by the type of resins (p>0.05), while ΔL, Δa and Δb values were signifcantly different by the type of resins (p<0.05). For indirect resins, ΔE values were infuenced by the brand, shade group and shade designation based on three-way ANOVA (p<0.05). CONCLUSION: Direct and indirect resin composites showed similar color stability after 5,000 cycles of thermocycling; however, their changes in the color coordinates were different.

Efecto de diferentes técnicas de pulido y refrigeración en la rugosidad superficial de una resina nanohíbrida / Effect of different techniques of cooling and polishing the surface roughness of a composite resin nanohíbrida

El objetivo de este trabajo in vitro fue evaluar la rugosidad superficial de una resina compuesta nanohíbrida (Tetric N Ceram®) utilizando 3 técnicas de acabado superficial, con y sin refrigeración. Materiales y método: Fueron confeccionados 60 especimenes (n=10), obtenidos por medio de una matríz metálica (10 x 2 mm). Los especímenes fueron almacenados durante 24 horas en agua destilada a temperatura ambiente, siendo posteriormente divididos en 6 grupos: G1- astropol + refrigeración, G2-astrobrush + refrigeración, G3- astropol + astrobrush + refrigeración, G4-astropol sin refrigeración, G5-astrobrush sin refrigeración, G6- astropol + astrobrush sin refrigeración. La lectura de la rugosidad superficial (Ra) fue realizada 24 horas luego de los respectivos tratamientos por medio de un rugosímetro marca Mitutoyo, tipo SJ - 201P (Japón). Resultados: Los datos fueron sometidos al test de ANOVA (p?0,05) y demostraron que no existe diferencias estadísticamente significantes entre las diferentes técnicas de pulido y refrigeración. Conclusión: La técnica de pulido y refrigeración no interfiere en la rugosidad superficial, por tanto se debe tener en consideración las demás propiedades físicas de las resinas compuestas y el aspecto biológico del diente

The study evaluated in vitro the surface roughness in a nanohibrid composite resin (Tetric N Ceram®) polished with the use three polishing techniques with and without refrigeration. Materials and Methods: Sixty discs (n=10), was made with aid of a metal matrix measuring 10 x 2 mm. The specimens were stored in artificial saliva in an oven at 37oC (±1 oC), for 24 hours. After this time the specimens were submitted to action of astropol + refrigeration (G1), astrobrush + refrigeration (G2), astropol + astrobrush + refrigeration(G3), astropol whithout refrigeration (G4), astrobrush whithout refrigeration (G5), astropol + astrobrush whithout refrigeration (G6). The surface roughness (Ra) of the specimens was avaliated after 24 hours using profilometer (Mitutoyo SJ - 201P - Japon). Results: the data were submitted to Analysis of Variance ANOVA (p?0,05) and were no statistically significant differences detected for each technique. Conclusion: The effect polishing techniques and refrigeration not interferance in the surface roughness, but needed consideration of others properties