Avaliação da microdureza e da rugosidade de compósitos resinosos de uso direto e indireto / Assessing microhardness and roughness of composite resins of direct and indirect use

Objetivo: avaliar rugosidade superficial por meio de perfilometria de contato mecânico bem como a resistência à microdureza Knoop em resinas fotoativadas de forma convencional ou com sistemas de polimerização adicional. Materiais e método: 82 corpos de prova foram distribuídos nos seguintes grupos: SI: Solidex®, Z1D: Z100®, Z35D: Z350®, OD: Opallis®, Z1I: Z100®, Z35I: Z350® e OI: Opallis®. Os incrementos de resina foram fotopolimerizados por 40 segundos cada. O grupo contendo a resina de uso indireto Solidex® (SI) e os grupos Z1I, Z35I e OI contendo resinas de uso direto avaliadas como uso indireto tiveram fotopolimerização por 40 segundos mais 7 minutos adicionais com EDG-LUX. As amostras foram armazenadas em água destilada a 37 °C por 24 horas. Em seguida foi realizado o ensaio de rugosidade e posteriormente o de microdureza superficial. As médias coletadas foram analisadas pelo teste não paramétrico de Kruskal-Wallis e o de comparação múltipla de Dunn. Resultados: a resina indicada para uso direto Z100® obteve os maiores valores de microdureza, independente da presença de fotoativação adicional. Já a resina indicada para uso indireto Solidex, obteve os menores valores de microdureza. Os valores de rugosidade não apresentaram diferenças estatísticas entre os materiais analisados. Conclusão: resinas de uso direto com polimerização adicional podem ser bem utilizadas na forma indireta.

Avaliação da resistência de união entre dentina e pinos de fibra de vidro utilizando três diferentes técnicas de cimentação / Evaluation of the bond strength between the dentin and fiberglass posts using three different cementing techniques

O sucesso clínico da cimentação de pinos intrarradiculares está diretamente relacionado à correta aplicação e à escolha dos agentes cimentantes. Objetivo: avaliar a resistência de união ao teste de push-out entre dentina e pinos de fibra de vidro, utilizando três diferentes técnicas de cimentação. Materiais e método: foram cimentados trinta pinos de fibra de vidro em incisivos bovinos, divididos nos seguintes grupos: Grupo I ? Single Bond 2 + RelyX ARC, Grupo II ? Scotchbond Multipurpose Plus + RelyX ARC, e Grupo III ? RelyX U100. O teste de push-out foi realizado e os resultados foram submetidos à análise de variância. Resultados: o teste de análise de variância, ANOVA, não mostrou diferenças significativas entre os grupos (p<0,05). Conclusão: após análise dos resultados, pode-se concluir que o sucesso clínico da cimentação de pinos intrarradiculares, com materiais resinosos, deve-se, predominantemente, à retenção por atrito e não apenas à ligação adesiva propriamente dita.

Marginal adaptation of class V composite restorations submitted to thermal and mechanical cycling.

OBJECTIVE: This study evaluated the effect of the margin location and an adhesive system on the marginal adaptation of composite restorations. MATERIAL AND METHODS: Class V cavities were prepared in bovine teeth with the gingival margin on the dentin and the incisal margin on the enamel. The cavities were restored with a micro-hybrid composite resin using an etch-and-rinse [Single Bond 2 (SB)] or a self-etching adhesive [Clearfil SE Bond (CL)]. After finishing and polishing the restorations, epoxy replicas were prepared. The marginal adaptation was analyzed using scanning electronic microscopy (SEM, 500 x magnification). The higher gap width in each margin was recorded (T0). After the first evaluation, the samples were submitted to thermal cycling (2,000 cycles of 5°C±2°C followed by 55°C±2°C - T1) and mechanical cycling (100,000 cycles of 50 kN and 2 Hz - T2). Replicas of samples were rebuilt after each cycling and analyzed under SEM. The data were submitted to Mann-Whitney, Wilcoxon and Friedman testing (α=0.05). RESULTS: The SB presented higher gaps in the dentin than the enamel, while there was no difference between the substrate for the CL. In the dentin, the CL showed better marginal sealing than the SB. The opposite occurred in the enamel. There were no significant differences between the baseline, thermal and mechanical cycling for any experimental condition. CONCLUSIONS: The outcomes of the present study showed that the adhesive system and margin location have an important effect on the marginal adaptation of composite restorations.

Marginal adaptation of class V composite restorations submitted to thermal and mechanical cycling

Objective: This study evaluated the effect of the margin location and an adhesive system on the marginal adaptation of composite restorations. Material and Methods: Class V cavities were prepared in bovine teeth with the gingival margin on the dentin and the incisal margin on the enamel. The cavities were restored with a micro-hybrid composite resin using an etch-and-rinse [Single Bond 2 (SB)] or a self-etching adhesive [Clearfil SE Bond (CL)]. After finishing and polishing the restorations, epoxy replicas were prepared. The marginal adaptation was analyzed using scanning electronic microscopy (SEM, 500 x magnification). The higher gap width in each margin was recorded (T0). After the first evaluation, the samples were submitted to thermal cycling (2,000 cycles of 5°C±2°C followed by 55°C±2°C – T1) and mechanical cycling (100,000 cycles of 50 kN and 2 Hz – T2). Replicas of samples were rebuilt after each cycling and analyzed under SEM. The data were submitted to Mann-Whitney, Wilcoxon and Friedman testing (á=0.05). Results: The SB presented higher gaps in the dentin than the enamel, while there was no difference between the substrate for the CL. In the dentin, the CL showed better marginal sealing than the SB. The opposite occurred in the enamel. There were no significant differences between the baseline, thermal and mechanical cycling for any experimental condition. Conclusions: The outcomes of the present study showed that the adhesive system and margin location have an important effect on the marginal adaptation of composite restorations.

Effect of curing unit and adhesive system on marginal adaptation of composite restorations.

This study sought to evaluate how a curing unit and adhesive system affected the marginal adaptation of resin composite restorations. Class V cavities were prepared in bovine teeth with a gingival margin in dentin and an incisal margin in enamel. The cavities were restored with a micro-hybrid resin composite using one of four adhesives: Single Bond 2, Prime & Bond NT, Clearfil SE Bond, Xeno IV. The light-activations were performed using a quartz-tungsten-halogen (QTH) lamp or a second-generation light-emitting diode (LED). Restorations were finished and polished and epoxy replicas were prepared. Marginal adaptation was analyzed by using scanning electronic microscopy (magnification 500X). The widest gaps in each margin were recorded, and data were submitted to Kruskal-Wallis, Mann-Whitney, and Wilcoxon tests (α = 0.05). Differences between the adhesives were observed only when the dentin margins were evaluated: Clearfil SE Bond demonstrated better marginal adaptation than Prime & Bond NT or Single Bond 2 (which demonstrated the widest gaps in the dentin margin). The type of curing unit only affected the results for Xeno IV when the enamel margin was analyzed; the LED lamp promoted smaller gaps than the QTH lamp.

Avaliação de métodos para mensuração da adaptação marginal e espessura de linha de cimentação em restaurações indiretas / Evaluation of methods for measurement of marginal adaptation and cement thickness on indirect restorations

Objetivos: Comparar métodos utilizados na mensuração da adaptação marginal e espessura de linha de cimentação em restaurações indiretas do tipo inlay. Materiais e método: Foram confeccionados preparos cavitários para inlay em 24 terceiros molares humanos, assim como restaurações inlays em resina composta. Metade das amostras foi utilizada para avaliar, sem a cimentação da restauração, a adaptação marginal, ao passo que as demais foram cimentadas e a espessura da linha de cimentação foi mensurada. Foram feitas avaliações nas regiões cervical, interproximal e oclusal, utilizando-se três metodologias: lupa estereoscópica, microscopia óptica e microscopia eletrônica de varredura, sendo que com esta última avaliou-se apenas a região oclusal. Resultados: Para avaliação da adaptação marginal, não houve diferença entre a lupa estereoscópica e microscopia óptica. Quando foi mensurada a linha de cimentação, a lupa apresentou menor valor na região interproximal. A microscopia eletrônica de varredura apresentou os menores valores. Conclusões: Para medir adaptação de peças em um preparo pode-se utilizar tanto lupa estereoscópica quanto microscopia óptica. Para avaliar a linha de cimentação o melhor método é MEV.

Effect of cavity preparation design on the fracture resistance of directly and indirectly restored premolar

Aim: The aim of this study was to evaluate the fracture resistance of human premolars with extensive cavity preparations of the inlay and onlay types, for performing direct and indirect composite resin restorations. Methods: Eight-four premolars were divided into 7 groups (n=12): G1=intact teeth; G2=inlay/Filtek Z-250 direct; G3=inlay/ Filtek Z-250 light polymerized indirectly; G4=inlay/ Solidex; G5=onlay/ Filtek Z-250 direct; G6=onlay/ Filtek Z-250 light polymerized indirectly; G7=onlay/ Solidex. Indirect Filtek Z- 250 restorations were light activated using the EDG-lux oven. All samples were submitted to axial compression load in a Universal Testing Machine until fracture. The data were submitted to the one-way ANOVA and Tukey’s test (a=0.05). Results: The results (N) were: G6-1938a, G5-1570ab, G7-1285b, G1-1215b, G4-1174b, G3-1146b and G2-1112b. The onlay cavities restored indirectly with Filtek Z-250 presented significantly higher fracture resistance (G6) than the other groups, except for onlay restorations made directly with Filtek Z-250 (G5), which, in turn, did not differ significantly from the other groups. However, the onlay restorations made with Filtek Z-250 led to more catastrophic failure modes. Conclusions: 1. Adhesive inlay restorations, irrespective of the type of composite resin and light-activation technique used, restored the fracture resistance of intact teeth.

Kinetics of conversion of two dual-cured adhesive systems.

The aim of this study was to evaluate the kinetics of conversion of Scotchbond Multi-purpose Plus (3M ESPE, St Paul, MN) and Prime&Bond NT (Dentsply De Trey, Konstanz, Germany) used in light-cured, self-cured, or dual-cured versions. The adhesive systems were used in the light-cured version (without the use of chemical initiator) or mixed with its respective chemical initiator either with light activation (dual-cured) or not (self-cured). The degree of conversion (DC) was monitored as a function of time during 5 minutes with a Fourier transform infrared spectrometer equipped with an attenuated total reflectance device. Light-cured and dual-cured modes of Scotchbond Multi-purpose Plus presented the highest DC at 5 minutes. The addition of the self-cure activator (dual-cured mode) to Prime&Bond NT reduced the DC. For the self-cured versions, only the Scotchbond Multi-purpose Plus presented any polymerization reaction at 5 minutes. For the two bonding systems tested, it appears that light curing of the adhesive is important in order to reach a high DC in the first moments after the bonding procedure.

Effect of the adhesive application mode and fiber post translucency on the push-out bond strength to dentin.

This study evaluated the effect of the adhesive application mode and fiber post translucency on the push-out bond strength to dentin. Bovine roots were endodontically treated, and 10 roots were used for each adhesive application mode: PB (Prime&Bond 2.1), PB + SC (Self-cure activator), PB + SBM (Scotchbond Multi-purpose adhesive system), BB (Brush&Bond), BB + CAT (chemical catalyst), and BB + SBM. The translucent Light-Post and Aestheti-Post were cemented. The roots/cemented posts were transversally sectioned to originate three thirds (cervical, middle, and apical). The push-out test was performed, and the failure mode of fractured specimens was analyzed. There was no difference between the fiber posts. For PB and BB, the use of hydrophobic adhesive resin SBM increased post bond strength. The use of SC and CAT catalyst did not affect the push-out bond strength values. The apical third presented the lowest bond strengths.

Diametral tensile strength of composite resins submitted to different activation techniques.

The aim of this study was to evaluate the diametral tensile strength (DTS) of composite resins submitted to different curing techniques. Four composite resins were tested in this study: Targis (Ivoclar), Solidex (Shofu), Charisma (Heraeus-Kulzer) and Filtek Z250 (3M Espe). Sixty-four cylindrical specimens were prepared and divided into eight groups according to each polymerization technique (n = 8). The indirect composite resins (Targis and Solidex) were polymerized with their respective curing systems (Targis Power and EDG-lux); Charisma and Filtek Z250 were light-cured with conventional polymerization (halogen light) and additionally, with post-curing systems. Specimens were stored in artificial saliva at 37 degrees C for one week. DTS tests were performed in a Universal Testing Machine (0.5 mm/min). The data were statistically analyzed by ANOVA and Duncan tests. The results were (MPa): Z250/EDG-lux: 69.04 feminine; Z250/Targis Power: 68.57 feminine; Z250/conventional polymerization: 60.75b; Charisma/Targis Power: 52.34c; Charisma/conventional polymerization: 49.17c; Charisma/EDG-lux: 47.98c; Solidex: 36.62d; Targis: 32.86d. The results reveal that the post-cured Z250 composite resin showed the highest DTS means. Charisma composite presented no significant differences when activation techniques were compared. Direct composite resins presented higher DTS values than indirect resins.

Diametral tensile strength of composite resins submitted to different activation techniques / Resistência à tração diametral de compósitos resinosos submetidos a diferentes técnicas de ativação

The aim of this study was to evaluate the diametral tensile strength (DTS) of composite resins submitted to different curing techniques. Four composite resins were tested in this study: Targis (Ivoclar), Solidex (Shofu), Charisma (Heraeus-Kulzer) and Filtek Z250 (3M Espe). Sixty-four cylindrical specimens were prepared and divided into eight groups according to each polymerization technique (n = 8). The indirect composite resins (Targis and Solidex) were polymerized with their respective curing systems (Targis Power and EDG-lux); Charisma and Filtek Z250 were light-cured with conventional polymerization (halogen light) and additionally, with post-curing systems. Specimens were stored in artificial saliva at 37°C for one week. DTS tests were performed in a Universal Testing Machine (0.5 mm/min). The data were statistically analyzed by ANOVA and Duncan tests. The results were (MPa): Z250/EDG-lux: 69.04ª; Z250/Targis Power: 68.57ª; Z250/conventional polymerization: 60.75b; Charisma/Targis Power: 52.34c; Charisma/conventional polymerization: 49.17c; Charisma/EDG-lux: 47.98c; Solidex: 36.62d; Targis: 32.86d. The results reveal that the post-cured Z250 composite resin showed the highest DTS means. Charisma composite presented no significant differences when activation techniques were compared. Direct composite resins presented higher DTS values than indirect resins.

O objetivo do trabalho foi avaliar a resistência à tração diametral (DTS) de compósitos submetidos a diferentes técnicas de polimerização. Foram testados quatro compósitos neste estudo: Targis (Ivoclar), Solidex (Shofu), Charisma (Heraeus-Kulzer) e Filtek Z250 (3M Espe). Foram confeccionados 64 corpos-de-prova cilíndricos, que foram divididos em 8 grupos de acordo com a técnica de polimerização (n = 8). Os compósitos indiretos (Targis e Solidex) foram polimerizados com seus respectivos sistemas de ativação (Targis Power e EDG-lux); Charisma e Filtek Z250 foram fotoativados com polimerização convencional (luz halógena) e, adicionalmente, com sistemas de polimerização adicional. Os corpos-de-prova foram armazenados em saliva artificial a 37°C por uma semana. Ensaio de DTS foi realizado em Máquina Universal de Ensaios Instron (0,5 mm/min). Os dados foram analisados estatisticamente pelos testes ANOVA e Duncan. Os resultados foram (MPa): Z250/EDG-lux: 69,04ª; Z250/Targis Power: 68,57ª; Z250/polimerização convencional: 60,75b; Charisma/Targis Power: 52,34c; Charisma/polimerização convencional: 49,17c; Charisma/EDG-lux: 47,98c; Solidex: 36,62d; Targis: 32,86d. Os resultados indicaram que o compósito Z250 polimerizado adicionalmente mostrou os maiores valores de DTS. O compósito Charisma não apresentou diferenças significativas quando foram comparadas diferentes técnicas de polimerização. Compósitos diretos apresentaram maiores valores de DTS que os compósitos indiretos.

Postoperative sensitivity in Class I composite resin restorations in vivo.

PURPOSE: This study evaluated the postoperative sensitivity of posterior Class I composite resin restorations, restored with a self-etching or a total-etch one-bottle adhesive system. MATERIALS AND METHODS: One hundred four restorations were replaced by one clinician in 52 patients. Each patient received two restorations. After cavity preparations were completed under rubber-dam isolation, they were restored using Clearfil SE Bond or Single Bond and a resin-based restorative material (Filtek Z250). Sensitivity was evaluated at 0 and 7 days and 6 months using cold stimuli, and recorded using a visual analogue scale. If sensitivity was experienced on day 7, patients were also contacted on days 14 and 30 to assess the degree of sensitivity. The scores were analyzed as nonparametric data by means of the Friedman and Wilcoxon tests. RESULTS: No statistically significant differences in sensitivity were found between the two adhesives systems at days 0 and 7 or at 6 months. No spontaneous postoperative sensitivity was reported. CONCLUSIONS: The adhesives systems used in this study showed no differences in postoperative sensitivity, and did not show spontaneous sensitivity after 6 months.