Effect of Nd:YAG Laser with/without Graphite Coating on Bonding of Lithium Disilicate Glass-Ceramic to Human Dentin.

This study evaluated the effect of different surface treatments on the tensile bond strength between lithium disilicate glass-ceramics, resin cement, and dentin. Fifty truncated cone-shape glass-ceramics were divided into five groups (n = 10): G1, control: 10% hydrofluoric acid (HF); G2, Nd:YAG laser + silane; G3, Sil + Nd:YAG laser; G4, graphite + Nd:YAG laser + Sil; and G5, graphite + Sil + Nd:YAG laser. Fifty human third-molars were cut to cylindrical shape and polished to standardize the bonding surfaces. The glass-ceramic specimens were bonded to dentin with a dual-cured resin cement and stored in distilled water for 24 h at 37ºC. Tensile testing was performed on a universal testing machine (10 Kgf load cell at 1 mm/min) until failure. The bond strength values (mean ± SD) in MPa were G1 (9.4 ± 2.3), G2 (9.7 ± 2.0), G3 (6.7 ± 1.9), G4 (4.6 ± 1.1), and G5 (1.2 ± 0.3). Nd:YAG laser and HF improve the bond strength between lithium disilicate glass-ceramics, resin cement, and dentin. The application of a graphite layer prior to Nd:YAG laser irradiation negatively affects this bonding and presented inferior results.

A randomized clinical trial of class II composite restorations using direct and semidirect techniques.

OBJECTIVE: This prospective study evaluated the clinical performance of large class II restorations made with different techniques over 24 months. MATERIALS AND METHODS: Thirty patients received two class II restorations (n = 60) using a nanohybrid composite and different restorative techniques (direct (DT), semidirect (SDT)), in a split-mouth randomized design. The same adhesive system was applied for all restorations. For DT, the restorative material was applied directly inside the tooth preparation. For SDT, a tooth preparation impression was obtained using alginate and a silicone flexible die was prepared. The restoration was made chairside on the model and additionally light cured. After that, it was cemented in preparation using resinous cement. All restorations were evaluated using the FDI criteria after 7 days, 6, 12, and 24 months postoperatively. RESULTS: After 24 months, 24 patients attended the recall and 48 restorations were evaluated. Fisher's statistical analysis (5%) showed no difference between the techniques. Nevertheless, Friedman's test showed significant differences for some criteria after 12 months of evaluation for both techniques. Postoperative sensitivity was reported in one DT restoration. Also, after 24 months, one SDT restoration presented marginal fracture, which was deemed unsatisfactory. CONCLUSIONS: After a 24-month follow-up, no significant difference between the tested techniques was detected. The restorations performed with both techniques produced clinically acceptable restorations. CLINICAL RELEVANCE: This study demonstrated the viability of applying two different operatory techniques (direct and semidirect) for class II resin composite restorations.

Influence of the addition of glass fibers reinforcements in the flexural strength of acrylic resin / Influência da adição de reforço de fibra de vidro na resistência flexural de resina acrílica

Objective: To evaluate the influence of glass fiber reinforcements used in nautical and sports products on the flexural strength of acrylic resin. Materials and methods: Thirty thermos activated acrylic resin bars (25 x 10.5 x 3.3 mm) were used. The samples were shared in 3 groups: bars with no glass fiber (control group, n = 10), bars reinforced with glass fiber and 0.18 mm thickness (group F1, n = 10) and bars reinforced with glass fiber and 0.80 mm thickness (group F2, n = 10). After 48 hours, samples were submitted to compression test in order to evaluate flexural strength. Obtained data were statistically analyzed with significance level of 5 %. Results: It was observed that the use of glass fiber effectively increased the flexural strength compared to the control group; the thickness of the glass fiber, however, did not present statistical differences. Conclusion: The use of fiber glass is a simple and cost-effective alternative to improve acrylic resin performance. (AU)

Objetivo: Avaliar a influência do reforço de fibra de vidro usada em produtos esportivos náuticos na resistência flexural da resina acrílica. Materiais e métodos: Trinta barras de resina acrílica termoativadas (25 x 10.5 x 3.3 mm) foram confeccionadas. As amostras foram divididas em 3 grupos: barras sem fibra de vidro (grupo controle, n = 10), barras com reforço de fibra de vidro com espessura de 0.18 mm (grupo F1, n = 10) e barras com reforço de fibra de vidro com espessura de 0.80 mm (grupo F2, n = 10). Após 48 horas, as amostras foram submetidas ao ensaio de compressão para avaliar a resistência flexural. Os dados obtidos foram analisados estatisticamente com nível de significância de 5%. Resultados: Foi observado que o uso de fibra de vidro aumentou efetivamente a resistência à compressão comparado com o grupo controle; a espessura da fibra de vidro, no entanto, não apresentou diferença estatisticamente significante. Conclusão: O uso de fibra de vidro é uma alternativa simples e de baixo custo para aprimorar a performance das resinas acrílicas. (AU)

The impact of at home and in-office bleaching agents on the color stability of bulk-fill composite resins / Impacto de agentes clareadores caseiros e de consultório na estabilidade de cor de resinas compostas bulk fill

Objective: This study compared different composites for color stability after exposure to at home and in-office bleaching gels. Material and Methods: Composite resin specimens (6mm diameterx2mm thickness) were manufactured according to the following groups (n=20): RC- Conventional; BF-Bulk Fill; RF-Flow; BFF-Bulk-Fill Flow. The surfaces were stained with coffee solution for 36h. A spectrophotometer was used to record the initial color (L*a*b*). Half of the specimens from each group underwent bleaching with 35% hydrogen peroxide (in-office) in three 45-minute applications. New color measurements were performed after 7, 14 and 21 days. The other half of the specimens underwent bleaching with 22% carbamide peroxide (at home) in 14 1-hour applications. Further color measurements were performed after 7 and 14 days. For comparison between the color coordinates in different periods, ANOVA for repeated measures was applied (α=5%). The color variation (ΔE) was calculated for each group. Results: For in-office bleaching, there were no significant differences between the periods b* coordinate of the RF group, and for L* and b* coordinates of the BFF group. For at home bleaching the groups BF and BFF showed no differences for the L* coordinate. For the other coordinates, there was difference between the initial periods and after 14 days. The ΔE variation presented higher values for the at home bleaching groups. For both whiteners the bulk-fill resins presented the greatest color variations. Conclusions: Bulk Fill resins do not guarantee greater color stability than the other composite resins tested, including conventional flow resin. The conventional composite resin showed the lower ΔE. (AU)

Objetivo: Esse estudo comparou diferentes resinas compostas quanto a estabilidade de cor após exposição a géis clareadores de uso caseiro e de consultório. Material e Métodos: Espécimes de resina composta (6mm diâmetro x 2mm espessura) foram confeccionados de acordo com os seguintes grupos (n=20): RC- Convencional; BFBulk Fill; RF-Flow; BFF-Bulk-Fill Flow. As superfícies foram manchadas com solução de café por 36 horas. Um espectrofotômetro foi utilizado para mensurar a cor inicial (L*a*b*). Metade dos espécimes de cada grupo foi submetida ao clareamento com peróxido de hidrogênio 35% (clareamento de consultório) durante três aplicações de 45 minutos. Novas mensurações de cor foram realizadas após as aplicações de 7, 14 e 21 dias. A outra metade dos espécimes foi submetida ao clareamento com peróxido de carbamida 22% (clareamento caseiro) em 14 aplicações de 1 hora durante 14 dias. Novas mensurações de cor foram realizadas após 7 e 14 dias. Para comparação entre as coordenadas nos diferentes períodos foi aplicada a análise de variância ANOVA para medidas repetidas (α=5%). A variação de cor (ΔE) foi calculada para cada grupo. Resultados: Para o clareamento de consultório não houve diferenças significativas para a coordenada b* do grupo RF, e para L* e b* no grupo BFF. Para o clareamento caseiro os grupos BF e BFF não apresentaram diferenças para a coordenada L*. Para as outras coordenadas, houve diferenças entre os períodos inicial e após 14 dias. A variação de ΔE apresentou maiores valores para o grupo submetido ao clareamento caseiro. Para ambos clareadores a resina composta bulk fill apresentou as maiores variações de cor. Conclusões: As resinas compostas bulk fill não garantiram uma maior estabilidade de cor quando comparadas as resinas compostas tradicionais testadas, incluindo a resina flow. A resina composta convencional apresentou a menor variação de ΔE. (AU)

Effects of Contamination by Hemostatic Agents and Use of Cleaning Agent on Etch-and-Rinse Dentin Bond Strength.

The aim of this study was to evaluate the influence of contamination by hemostatic agents and rinsing with chlorhexidine on bond strength between dentin and resin composite. Ninety-six bovine teeth were sectioned to expose a flat dentin surface area. A standardized cavity with 2.0 mm in thickness, superficial diameter of 4.0 mm and bottom diameter of 3.0 mm was prepared with a diamond bur in each dentin specimen. The teeth were divided into four groups according to the hemostatic employed: G1: control; G2: use of ViscoStat, Ultradent; G3: Hemosthasegel, FGM; and G4: Hemostop, Dentsply. The groups were divided into two subgroups according to the cleaning protocol method (n=12): A: without any further cleaning; and B: cleaning with chlorhexidine at 0.2%. All cavities were filled using a dentin adhesive and a resin composite, following the manufacturer's instructions. After 24 h, the specimens were aged by thermal and mechanical cycling. The bond strength was determined by the push out bond test (MPa), Statistical analysis was performed using two-way ANOVA and Tukey test (p<0.05). Statistically significant differences were detected among all groups treated with hemostatic agents and the control group. The post-hoc test showed that cleaning the cavity with chlorhexidine significantly improves the bond strength between dentin and resin composite. Our results suggested that the use of chlorhexidine can reestablish the bond strength between dentin and resin composite when a hemostatic agent was applied.

Effects of Contamination by Hemostatic Agents and Use of Cleaning Agent on Etch-and-Rinse Dentin Bond Strength

Abstract The aim of this study was to evaluate the influence of contamination by hemostatic agents and rinsing with chlorhexidine on bond strength between dentin and resin composite. Ninety-six bovine teeth were sectioned to expose a flat dentin surface area. A standardized cavity with 2.0 mm in thickness, superficial diameter of 4.0 mm and bottom diameter of 3.0 mm was prepared with a diamond bur in each dentin specimen. The teeth were divided into four groups according to the hemostatic employed: G1: control; G2: use of ViscoStat, Ultradent; G3: Hemosthasegel, FGM; and G4: Hemostop, Dentsply. The groups were divided into two subgroups according to the cleaning protocol method (n=12): A: without any further cleaning; and B: cleaning with chlorhexidine at 0.2%. All cavities were filled using a dentin adhesive and a resin composite, following the manufacturer's instructions. After 24 h, the specimens were aged by thermal and mechanical cycling. The bond strength was determined by the push out bond test (MPa), Statistical analysis was performed using two-way ANOVA and Tukey test (p<0.05). Statistically significant differences were detected among all groups treated with hemostatic agents and the control group. The post-hoc test showed that cleaning the cavity with chlorhexidine significantly improves the bond strength between dentin and resin composite. Our results suggested that the use of chlorhexidine can reestablish the bond strength between dentin and resin composite when a hemostatic agent was applied.

Resumo O objetivo desse estudo foi avaliar a influência da contaminação por agentes hemostáticos e da lavagem com clorexidina na resistência de união entre dentina e resina composta. 96 dentes bovinos foram seccionados para a exposição de uma área plana de dentina. Em cada bloco, uma cavidade cônica de 2 mm de espessura, diâmetro externo de 4 mm e diâmetro interno de 3 mm, foi confeccionado com uma ponta diamantada. Os dentes foram divididos em 4 grupos de acordo com o hemostático empregado, como descrito: G1- controle, G2- uso de ViscoStat - Ultradent, G3- uso de Hemosthasegel - FGM, G4- uso de Hemostop - Dentsply. Os grupos foram divididos em 2 subgrupos de acordo com o protocolo de limpeza utilizado (n=12): A - nenhum agente de limpeza; B - limpeza com clorexidina 0.2%. Todas as cavidades foram preenchidas utilizando adesivo dentinário e resina composta, seguindo as instruções dos fabricantes. Após 24 h, os espécimes foram submetidos a protocolo de envelhecimento em cicladora termomecânica. A resistência de união foi determinada pelo teste mecânico de push-out (MPa), as análises estatísticas foram realizadas utilizando ANOVA 2-fatores e teste de Tukey (p<0.05). Diferenças estatisticamente significativas foram detectadas entre todos os grupos tratados com agentes hemostáticos e o grupo controle. O teste post-hoc mostrou que a limpeza da cavidade com clorexidina aumenta significativamente a resistência de união entre dentina e resina composta. Os resultados sugerem que o uso da clorexidina pode restabelecer a resistência de união entre dentina e resina composta quando um agente hemostático é aplicado.

Efeitos de lasers de alta potência na superfície de cerâmicas vítreas de dissilicato de lítio e sua resistência de união à dentina humana / Effects of high power laser irradiation on lithium di-silicate glass ceramic surface and bond strength to human dentin

O objetivo desse estudo foi avaliar a eficiência da irradiação com lasers de alta potência e a influência da aplicação do silano previa ou posteriormente à irradiação com os lasers na resistência de união entre cerâmica vítrea de dissilicato de lítio, cimento resinoso e dentina humana. Foram confeccionados 50 espécimes tronco cônicos de cerâmica (n=10), divididos aleatoriamente em 5 grupos: 1- Controle Condicionamento com ácido hidrofluorídrico 10% por 1 min e aplicação do silano; 2- Er:YAG – irradiação com laser Er:YAG (200 mJ e 10 Hz), seguido do condicionamento com ácido hidrofluorídrico 10% por 1 min e aplicação do silano; 3- Silano + Er:YAG – Condicionamento com ácido hidrofluorídrico 10% por 1 min, aplicação do silano e irradiação com laser Er:YAG nos mesmo parâmetros do grupo anterior; 4- Nd:YAG – irradiação com laser Nd:YAG (120 mJ e 10 Hz), seguido de condicionamento com ácido hidrofluorídrico 10% por 1 min e aplicação do silano, 5- Silano + Nd:YAG -Condicionamento com ácido hidrofluorídrico 10% por 1 min, aplicação do silano e irradiação com laser Nd:YAG nos mesmo parâmetros do grupo anterior. Após os tratamentos os espécimes cerâmicos foram cimentados com cimento resinoso de presa dual à superfície de dentina de 50 molares humanos incluídos em resina acrílica ativada quimicamente. Após armazenamento por 24 h foi realizado o ensaio de tração em máquina de ensaios universais com célula de carga de 10 KgF e velocidade constante de 1mm/min. Os dados obtidos foram submetidos à ANOVA 2-fatores e teste de Dunnet (α=5%). A análise dos padrões de fratura foram analisadas em estereomicroscopio. Adicionalmente foram confeccionados 15 espécimes em cerâmica no formato cilíndrico, submetidos aos mesmo tratamentos dos grupos anteriores (n=3) e utilizados para análise do ângulo de contato e análise em microscópio eletrônico de varredura. O teste de Dunnet mostrou diferenças significativas entre o grupo controle (9,42 ± 2,27 MPa) e os grupos Er (19,25 ± 3,7 MPa) e ...

The aim of this study was to evaluate the efficiency of irradiation with high-power lasers and the influence of silane application before or after irradiation with lasers on the bond strength between lithium disilicate glass-ceramic, resin cement and human dentin. Fiftytruncated-cones ceramic specimens (n=10) were randomly divided into 5 groups: Control- etching with hydrofluoric acid 10% for 1 min and application of silane; 2- Er -Er:YAG laser irradiation (200 mJ and 10 Hz), followed by etching with hydrofluoric acid 10% for 1 min and application of silane; 3- Sil + Er - etching with hydrofluoric acid 10%for 1 min, silane application and irradiation with Er: YAG laser in the same parameters as the previous group; 4- Nd:YAG laser - irradiation with Nd: YAG laser (120 mJ and 10 Hz), followed by etching with hydrofluoric acid 10% for 1 min and application of thesilane, 5- Sil + Nd- Etching with hydrofluoric acid 10% for 1 min, silane application and irradiation with Nd: YAG laser on the same parameters as the previous group. After treatment, the ceramic specimens were cemented with dual cure resin cement to the dentin of 50 human molars included in acrylic resin. After storage for 24 h it wassubmitted to tensile test in a universal testing machine with 10 kgf load cell andconstant speed of 1 mm/min. Data were submitted to ANOVA 2-way and Dunnet test (α = 5%). The analysis of fracture patterns were analyzed in stereomicroscope. In addition were made 15 ceramic specimens in cylindrical shape, subjected to the sametreatment of the above groups (n = 3) and used for analysis of the contact angle analysis and scanning electron microscope. The Dunnet test showed significant differences between Control group (9.42 ± 2.27 MPa) and Er group (19.25 ± 3.7 MPa) and Sil + Er (14.11 ± 4.11 MPa). ANOVA 2-way (p <5%) for Laser Type (p <0.0001) and Technical of Silanization (p = 0.0002) showed significant differences for bothfactors, but not for their interaction. ...

Efeitos de lasers de alta potência na superfície de cerâmicas vítreas de dissilicato de lítio e sua resistência de união à dentina humana / Effects of high power laser irradiation on lithium di-silicate glass ceramic surface and bond strength to human dentin

O objetivo desse estudo foi avaliar a eficiência da irradiação com lasers de alta potência e a influência da aplicação do silano previa ou posteriormente à irradiação com os lasers na resistência de união entre cerâmica vítrea de dissilicato de lítio, cimento resinoso e dentina humana. Foram confeccionados 50 espécimes tronco cônicos de cerâmica (n=10), divididos aleatoriamente em 5 grupos: 1- Controle Condicionamento com ácido hidrofluorídrico 10% por 1 min e aplicação do silano; 2- Er:YAG – irradiação com laser Er:YAG (200 mJ e 10 Hz), seguido do condicionamento com ácido hidrofluorídrico 10% por 1 min e aplicação do silano; 3- Silano + Er:YAG – Condicionamento com ácido hidrofluorídrico 10% por 1 min, aplicação do silano e irradiação com laser Er:YAG nos mesmo parâmetros do grupo anterior; 4- Nd:YAG – irradiação com laser Nd:YAG (120 mJ e 10 Hz), seguido de condicionamento com ácido hidrofluorídrico 10% por 1 min e aplicação do silano, 5- Silano + Nd:YAG -Condicionamento com ácido hidrofluorídrico 10% por 1 min, aplicação do silano e irradiação com laser Nd:YAG nos mesmo parâmetros do grupo anterior. Após os tratamentos os espécimes cerâmicos foram cimentados com cimento resinoso de presa dual à superfície de dentina de 50 molares humanos incluídos em resina acrílica ativada quimicamente. Após armazenamento por 24 h foi realizado o ensaio de tração em máquina de ensaios universais com célula de carga de 10 KgF e velocidade constante de 1mm/min. Os dados obtidos foram submetidos à ANOVA 2-fatores e teste de Dunnet (α=5%). A análise dos padrões de fratura foram analisadas em estereomicroscopio. Adicionalmente foram confeccionados 15 espécimes em cerâmica no formato cilíndrico, submetidos aos mesmo tratamentos dos grupos anteriores (n=3) e utilizados para análise do ângulo de contato e análise em microscópio eletrônico de varredura. O teste de Dunnet mostrou diferenças significativas entre o grupo controle (9,42 ± 2,27 MPa) e os grupos Er (19,25 ± 3,7 MPa)...

The aim of this study was to evaluate the efficiency of irradiation with high-power lasers and the influence of silane application before or after irradiation with lasers on the bond strength between lithium disilicate glass-ceramic, resin cement and human dentin. Fiftytruncated-cones ceramic specimens (n=10) were randomly divided into 5 groups: Control- etching with hydrofluoric acid 10% for 1 min and application of silane; 2- Er -Er:YAG laser irradiation (200 mJ and 10 Hz), followed by etching with hydrofluoric acid 10% for 1 min and application of silane; 3- Sil + Er - etching with hydrofluoric acid 10%for 1 min, silane application and irradiation with Er: YAG laser in the same parameters as the previous group; 4- Nd:YAG laser - irradiation with Nd: YAG laser (120 mJ and 10 Hz), followed by etching with hydrofluoric acid 10% for 1 min and application of thesilane, 5- Sil + Nd- Etching with hydrofluoric acid 10% for 1 min, silane application and irradiation with Nd: YAG laser on the same parameters as the previous group. After treatment, the ceramic specimens were cemented with dual cure resin cement to the dentin of 50 human molars included in acrylic resin. After storage for 24 h it wassubmitted to tensile test in a universal testing machine with 10 kgf load cell andconstant speed of 1 mm/min. Data were submitted to ANOVA 2-way and Dunnet test (α = 5%). The analysis of fracture patterns were analyzed in stereomicroscope. In addition were made 15 ceramic specimens in cylindrical shape, subjected to the sametreatment of the above groups (n = 3) and used for analysis of the contact angle analysis and scanning electron microscope. The Dunnet test showed significant differences between Control group (9.42 ± 2.27 MPa) and Er group (19.25 ± 3.7 MPa) and Sil + Er (14.11 ± 4.11 MPa). ANOVA 2-way (p <5%) for Laser Type (p <0.0001) and Technical of Silanization (p = 0.0002) showed significant differences for bothfactors, but not for their interactio...

Removable partial or complete dentures exposed to beverages and mouthwashes: evaluation of microhardness and roughness / Próteses parciais e totais removíveis expostas a bebidas e enxaguatórios bucais: avaliação da microdureza e rugosidade

Purpose: To evaluate microhardness and roughness of denture base polymethylmethacrylate resinn exposed to acid beverages and mouthwashes. Material and method: Rectangular samples (n=80) were prepared from poly (methyl methacrylate) (PMMA). They were divided into 8 groups and had the initial microhardness and Knoop roughness measured. Samples of each group were immersed for 10 min into a test solution (coffee, lemon juice, chlorhexidine gluconate, red wine, cola-based soft drink, vinegar or antiseptic with and without alcohol) and after stored in artificial saliva for 23 h and 50 min, completing a period of 24 h. This procedure was performed for 14 consecutive days and after this period the microhardness and surface roughness measurements were made again. Data were statistically analyzed using ANOVA non parametric, Kruskal-Walis and the Dunn´s test for microhardness and the t-Student and ANOVA for roughness. Result: For microhardness there were found statistically significant differences among the chlorhexidine gluconate solution, antiseptic without alcohol and cola-based soft drink. For roughness was observed that the mean values between the initial period and after immersion in the test products differed statistically in all groups, without difference among groups. Conclusion: The microhardness of poly(methyl methacrylate) was affected by continue exposition to chlorhexidine gluconate, antiseptic without alcohol and cola-based soft drink. The roughness of poly(methyl methacrylate) is negatively influenced by the exposure to all tested products. It may be concluded that both, microhardness and roughness, were affected by the treatments.

Objetivo: Avaliar a rugosidade e microdureza de uma resina acrílica utilizada para base de prótese quando submetidas a diferentes bebidas e enxaguatórios bucais. Material e método: Oitenta amostras retangulares foram confeccionadas com polimetilmetacrilato, e separados em 8 grupos. As amostras foram avaliadas quanto à microdureza e rugosidade (Knoop) superficiais e imersas por 10 minutos em um dos seguintes produtos: café, suco artificial de limão, gluconato de clorexidina, vinho tinto, refrigerante a base de cola, vinagre e antissépticos com e sem álcool. Após a imersão nas soluções, as amostras foram acondicionados em saliva artificial por 23 horas e 50 minutos, completando o período de 24 horas. Esse procedimento ocorreu por 14 dias consecutivos e após esse período outras mensurações de microdureza e rugosidade foram realizadas. Os dados obtidos foram analisados estatisticamente pela ANOVA não paramétrico, Kruskal-Walis e teste de Dunn para a microdureza e ANOVA e t-student (alfa=5%) para rugosidade. Resultado: Para microdureza foram encontradas diferenças significativas entre os grupos onde houve imersão em clorexidina, antisséptico sem álcool e refrigerante de coca-cola. Para a rugosidade foi observado que a media entre os valores antes e após a imersão nos produtos diferiu estatisticamente em todos os grupos, porém sem diferença entre eles. Conclusão: A microdureza do polimetilmetacrilato foi afetada pela exposição ao gluconato de clorexidina, antisseptico sem álcool e refrigerante à base de coca-cola. A rugosidade da superfície do polimetilmetacrilato foi afetada por todos os produtos estudados.

Color stability of artificial teeth after exposure to acid and staining agents / Estabilidade de cor de dentes artificiais após a exposição a agentes ácidos e corantes

Alterações na cor dos dentes artificiais ocorrem principalmente devido à ingestão de bebidas e uso de produtos de limpeza e desinfecção de próteses. Soluções mais agressivas de limpeza devem ser identificadas e o paciente deve ser informado, a fim de evitar ou reduzir a frequência de seu uso, para maior longevidade de próteses. O objetivo deste estudo foi avaliar as alterações na cor de dentes artificiais antes e após imersão em bebidas e soluções desinfetantes. Material e Métodos: noventa e seis dentes artificiais de resina foram aleatoriamente divididos em 8 grupos. Cada grupo foi imerso por 10 min em uma solução de teste (café, suco de limão, gluconato de clorexidina, vinho tinto, refrigerantes à base de cola, vinagre ou antisséptico com e sem álcool) e, em seguida, os espécimes foram armazenados em saliva artificial durante 23 horas e 50 min, perfazendo um período de 24 h. Este procedimento foi realizado durante 14 dias consecutivos e depois desse período a segunda medição de cor foi feita. Os dados obtidos com o espectrofotômetro usando o CIEL * a * b * foram analisados através de ANOVA não paramétrico, Kruskal-Walis e o teste de Dunn. Resultados: Foram verificadas diferenças na variação de cor para cada grupo experimental após o desafio. As diferenças estatisticamente significativas foram encontradas entre os grupos de café, vinho tinto e suco de limão. Conclusão: Todas as substâncias mudaram a cor dos dentes artificiais; café foi a substância que causou mais descoloração dos dentes artificiais, alterando a cor e luminosidade; os antissépticos bucais com e sem álcool promoveram clareamento dos dentes artificiais...

Changes in color of artificial teeth mainly occur due to ingestion of beverages and use of products for cleaning and disinfection. More aggressive solutions must be identified and the patient provided with explanations in order to avoid or reduce the frequency of their use, to higher longevity of dentures. The purpose of this study was to evaluate changes in color of artificial teeth before and after immersion in beverages and disinfectants. Material and Methods: 96 artificial resin teeth were randomly divided into 8 groups. Each group was immersed for 10 min into a test solution (coffee, lemon juice, chlorhexidine gluconate, red wine, cola-based soft drink, vinegar or antiseptic with and without alcohol) and then the specimens were stored in artificial saliva for 23 h and 50 min, completing a period of 24 h. This procedure was performed for 14 consecutive days and after this period the second color measurement was made. Data obtained with the spectrophotometer using the CIEL*a*b* system were statistically analyzed using ANOVA non parametric, Kruskal-Walis and the Dunn test. Results: There were found differences in color variation for each experimental group after the challenge. Statistically significant differences were found among coffee, red wine and lemon juice groups. Conclusion: All substances changed the color of artificial teeth; coffee was the substance that caused most staining of artificial teeth, altering color and luminosity; the oral antiseptics with and without alcohol promoted whitening of the artificial teeth...

Avaliação de diferentes tratamentos de superfície na resistência de união de cerâmica de di-silicato de lítio / Evaluation of different surface treatments on the shear bond strength of lithium dissilicate ceramic

O objetivo deste estudo foi avaliar o efeito de diferentes tratamentos de superfície na resistência de união entre a cerâmica de di-silicato de lítio IPSe.max Press (Ivoclar Vivadent, Liechtenstein) e o cimento resinoso Variolink II (Ivoclar Vivadent, Liechtenstein) quando submetidos a teste de tração. Para isso 330 bases tronco-cônicas de cerâmica de di-silicato de lítio foram aleatoriamente divididas em 11 grupos de acordo com o tratamento a ser realizado: C - grupo controle; J - Jateamento com óxido de alumínio (50 μm); JAr - Jateamento com óxido de alumínio (30 μm) e secagem do silano com ar quente; GEr -Revestimento da superfície com grafite e tratamento com laser Er:YAG(200 mJ de intensidade de energia e 10 Hz defrequência); GErAr – Revestimento da superfície com grafite, tratamento com laser Er:YAG (200 mJ de intensidade de energia e 10 Hz de frequência) e secagem do silano com ar quente; Er - Tratamento com laser Er:YAG (200 mJ de intensidade de energia e 10 Hz de freqüência); ErAr -Tratamento com laser Er:YAG (200 mJ de intensidade de energia e 10 Hzde frequência) e secagem do silano com ar quente; GNd – revestimento da superfície com grafite e tratamento com laser Nd:YAG (120 mJ de intensidade de energia e 15 Hz de frequência); GNdAr – Revestimento da superfície com grafite, tratamento com laser Nd:YAG (120 mJ de intensidade de energia e 15 Hz de frequência) e secagem do silano com arquente; Nd – Tratamento com laser Nd:YAG (120 mJ de intensidade de energia e 15 Hz de frequência); NdAr – Tratamento com laser Nd:YAG (120mJ de intensidade de energia e 15 Hz de frequência) e secagem do silano com ar quente. O cimento resinoso que uniu os espécimes foi fotoativado por 40 segundos utilizando o aparelho LED (Radii cal-SDI). Então, foi realizada a ciclagem termomecânica com carga de 60N, 1.000 ciclos termicos e 24000 mecânicos e o ensaio mecânico de tração na máquina de ensaios universal EMIC. Os dados obtidos foram submetidos aos ...

The aim of this study was to evaluate the bond strength afforded by different surface treatments on IPS e.max Press ceramic united to Variolink II (both Ivoclar-Vivadent, Liechtenstein), when subjected to tensile test. 330 ceramic bases were divided into 11 groups in accordance with the surface treatment performed: C - control group J - aluminum oxide sandblast, JAr aluminum oxide sandblast and silane hot air dry, GEr - surface coating withgraphite and treatment with Er: YAG laser (200 mJ of energy intensity and frequency 10 Hz), GErAr - surface coating with graphite, treatment with Er:YAG laser (200 mJ of energy intensity and 10 Hz frequency) and silane hotair dry; Er - treatment with Er: YAG laser (200 mJ of energy intensity and frequency 10 Hz) ErAr - treatment with Er: YAG laser (200 mJ intensity energy and 10 Hz frequency) and silane hot air dry; GNd - coating the surface with graphite and treatment with Nd: YAG laser (120 mJ of energy and intensity of frequency 15 Hz); GNdAr - coating the surface with graphite, treatment with Nd: YAG laser (120 mJ of energy intensity and 15 Hz frequency) and silane hot air dry; Nd - treatment with Nd: YAG laser (120mJ of energy intensity and frequency 15 Hz); NdAr - treatment with Nd: YAGlaser (120 mJ of energy and intensity of frequency 15 Hz) and silane hot airdry. The resin cement that unite the specimens was cured for 40 second susing the LED cure equipment (Radii-cal SDI). Then they were termomechanical cycled (60N, 1,000 thermical cycles and 24000 mechanical) and were submitted to the tensile test in a universal testing machine EMIC-2000. Data were tested for Dunnet ( α = 5 % ) and 3 ANOVAWay . The Er group showed higher tensile strength greater than the controlgroup and the other groups, while the NdG group presented results of bond strength lower than the control group and the other surface treatments. The other groups did not differ statistically from the control group. It was..

Evaluation of visual perception towards color selection of teeth from different populations by employing color scale, white light and different background contrasts / Avaliação da percepção visual na seleção de cor dos dentes em diferentes populações, empregando escala de cor, luz branca e contraste simultâneo de fundos

Objective: To evaluate the visual perception of dentistry professors, technicians and undergraduates on tooth color selection through varying the background contrast and tooth translucency. Material & Methods: Fifteen artificial teeth of different colors and translucencies were used and divided into three groups and placed onto cardboards in the following colors: white, red and black. Blindly, the observers (professors (n = 30), technicians (n = 30) and undergraduates (n = 30), selected the artificial tooth color that they judged compatible with VITA scale, when positioned onto the three background colors, at constant illumination through white artificial light. The obtained data were statistically analyzed by Kruskal-Wallis test. Results: There were no statistically significant differences among the studied populations in tooth color selection, regardless of the background colors, with all observers exhibiting a high number of errors. There were statistically significant differences in the number of matching answers among the studied teeth, with those exhibiting different translucencies showing the highest error rate (D1= 2 right answers; D4 = 0 right answers). Conclusion: Professional expertise was not decisive in tooth color selection; the number of matching answers of the three populations varied according to the background used; the most translucent teeth with different resin layers exhibited the smallest number of matching answers and the observers’ visual acuity differed and it should be effectively trained to achieve success in tooth color selection of prostheses and restorations

Objetivo: Avaliar a percepção visual na seleção de cor de dentes por professores de odontologia, técnicos de laboratório e alunos da graduação com contraste simultâneo de fundo. Material e Métodos: Foram utilizados 15 dentes de estoque de diferentes cores e translucidez, divididos em três grupos e posicionados em fundos de papel cartão nas cores: branco, vermelho e preto. Os observadores professores (n = 30), técnicos de laboratório (n = 30) e alunos (n = 30), selecionavam a cor dos dentes de estoque de diferentes cores, posicionados nas três cores de fundo, sempre com iluminação de luz artificial branca e comparavam com dentes da escala de cores. Após obtenção dos dados estes foram analisados pelo teste estatístico de Kruskal- Wallis. Resultados: os resultados mostraram que não existem diferenças estatisticamente significantes entre as populações estudadas, quando da seleção da cor dos dentes, independentemente das cores dos fundos e que o número de acertos foi muito pequeno, necessitando de melhor aprimoramento dos profissionais e alunos de graduação. Conclusão: Não houve diferença nos valores de acerto dos professores, alunos e técnicos de laboratório; a distribuição de acertos nos três diferentes fundos foi semelhante para os observadores; a porcentagem de erros entre os observadores foi muito elevada; a maior parte dos acertos diferiu conforme o dente avaliado, devido à maior translucidez e camadas de resina existentes e há necessidade de maior treinamento dos profissionais de odontologia para seleção das cores dos dentes.

Dentinal Hypersensitivity: pre-hybridization as an alternative treatment / Hipersensibilidade dentinária: pré-hibridização como um tratamento alternativo

A hipersensibilidade dentinária pode ocorrer quando há exposição da dentina após preparos dentários para restaurações indiretas. Para evitar ou minimizar desconfortos pós-operatórios, os adesivos dentinários têm sido utilizados para proteger a dentina exposta. Esta técnica é denominada pré-hibridização. Apesar da utilização clínica, ainda existem controvérsias sobre a eficácia, o material e o protocolo mais adequado para realizá-la. Objetivo: Esta revisão tem como objetivo discutir os conceitos que envolvem a pré-hibridização, baseando-se nos artigos mais relevantes publicados (2002 até a data atual), indexados nas bases de dados da SciELO, MEDLINE e Pubmed. Método: Para a pesquisa foram utilizadas as seguintes palavras-chave: pré-hibridização, hipersensibilidade dental e variáveis (ex.: pré-hibridização dentinária, hipersensibilidade dentinária, tratamento de hipersensibilidade). Foram selecionadas as referências do tipo revisão e artigos de pesquisa originais. Foram feitos esforços para identificar estudos sobre tratamentos clínicos comparativos, controlados e estudos de meta-análise sobre a hipersensibilidade e a pré-hibridização dentinária. Resultado: Baseado na revisão realizada é possível destacar os adesivos autocondicionantes como a primeira escolha para os procedimentos de pré-hibridização. Conclusão: Porém, a literatura ainda não apresenta um protocolo consolidado e as pesquisas clínicas que estudam a eficiência desta técnica são limitadas.

Dentinal hypersensitivity may occur after the dentine exposure because of indirect restoration preparations. Either to avoid or decrease postoperative discomfort, dentinal adhesives have been used to protect the exposed dentine. This technique is called pre-hybridization. Notwithstanding, despite of the clinical use, there still exist controversies on its efficacy and the most adequate material and protocol to execute it. Objective:This review study aimed to discuss the concepts involving the pre-hybridization based on the most important papers published from 2002 to date, indexed at the following databases: SciELO, MEDLINE and Pubmed. Methods: The following keywords were applied in the searching: pre-hybridization, tooth hypersensitivity and their possibilities (e.g.: dentinal pre-hybridization, dentinal hypersensitivity, hypersensitivity treatment). Only review and original research studies were selected. Efforts to identify comparative, controlled clinical studies as well as meta-analysis studies on hypersensitivity and dentinal pre-hybridization were made. Results: Based on the review conducted, it was possible to highlight that the self-conditioning adhesives have been the first choice for pre-hybridization procedures. Conclusion: However, the literature still lacks on determining a consolidated protocol and the clinical effectiveness of this procedure.

Biocompatibility of a chlorhexidine local delivery systemin a subcutaneous mouse model

Objective: This study aimed evaluating histologically and histomorphometrically the response of the conjunctivetissue face to the implant of chlorhexidine chips in the subcutaneous tissues of rats. Study Design: In this research35 male rats Wistar were used to analyze the biocompatibility and the degradation process of chlorhexidine chip.In each animal, it was made 2 incisions for subcutaneous implantation of chlorhexidine chip (test group) and apolytetrafluorethylene membrane (control group). The morphological changes in subcutaneous implantations wereassessed after 1, 3, 5, 7, 10, 14, 21 days. The data were submitted to Friedman nonparametric test to analyze thecomparisons among observation periods and to allow the comparison among groups. Results: Differences werefound in the analysis of the inflammatory response when comparing the tested materials (p values ≤ 0.05). In testgroup was observed hemorrhage, edema and intense inflammatory infiltrate predominantly neutrophilic aroundmaterial. From 3-day and subsequent periods was verified granulation tissue externally at this infiltrate. From10-day on was observed crescent area of degradation of chlorhexidine chip, associated with neutrophilic and macrophagicinfiltrate, that maintained until 21-day. In the control group, moderate inflammatory infiltrate was observedinitially, predominantly polymorphonuclear, edema and granulation tissue 3-day period. The inflammatoryinfiltrate was gradually replaced for granulation tissue, culminating in a fibrous capsule. Giant multinucleate cellssituated at contact interface with the coating was examined since 3-day and persisted until 21-day. Conclusion:The chlorhexidine chip induces an intense acute inflammatory response at subcutaneous tissue of rats. Therefore,at conditions of this study was not biocompatible (AU)

Biocompatibility of a chlorhexidine local delivery system in a subcutaneous mouse model.

OBJECTIVE: This study aimed evaluating histologically and histomorphometrically the response of the conjunctive tissue face to the implant of chlorhexidine chips in the subcutaneous tissues of rats. STUDY DESIGN: In this research 35 male rats Wistar were used to analyze the biocompatibility and the degradation process of chlorhexidine chip. In each animal, it was made 2 incisions for subcutaneous implantation of chlorhexidine chip (test group) and a polytetrafluorethylene membrane (control group). The morphological changes in subcutaneous implantations were assessed after 1, 3, 5, 7, 10, 14, 21 days. The data were submitted to Friedman nonparametric test to analyze the comparisons among observation periods and to allow the comparison among groups. RESULTS: Differences were found in the analysis of the inflammatory response when comparing the tested materials (p values ≤ 0.05). In test group was observed hemorrhage, edema and intense inflammatory infiltrate predominantly neutrophilic around material. From 3-day and subsequent periods was verified granulation tissue externally at this infiltrate. From 10-day on was observed crescent area of degradation of chlorhexidine chip, associated with neutrophilic and macrophagic infiltrate, that maintained until 21-day. In the control group, moderate inflammatory infiltrate was observed initially, predominantly polymorphonuclear, edema and granulation tissue 3-day period. The inflammatory infiltrate was gradually replaced for granulation tissue, culminating in a fibrous capsule. Giant multinucleate cells situated at contact interface with the coating was examined since 3-day and persisted until 21-day. CONCLUSION: The chlorhexidine chip induces an intense acute inflammatory response at subcutaneous tissue of rats. Therefore, at conditions of this study was not biocompatible.