Estudo comparativo da rugosidade superficial entre compósitos à base de Ormocer e sistemas monoméricos tradicionais

The aim of this study was to evaluate the surface roughness of two Ormocer-based resin composites before and after mechanical toothbrushing. The study compared the brands Admira and Definite with composites based on conventional monomer systems (Bis-GMA, Bis-EMA, UEDMA e TEGDMA), Z250 and A110. Eight samples of each material with 4mm in diameter and 2mm in height were prepared using a metallic mold. After 24 hours they were polished and examined with a profilometer for measurement of the initial surface roughness (Ra, mm) before mechanical toothbrushing (30,000 cycles). After toothbrushing, the samples were taken to the profilometer once again to check the final surface roughness. The results were submitted to ANOVA and Tukey test (5%). The Admira composite presented a higher mean of surface roughness before toothbrushing (0.132mm), with a statistical difference from the composite A110 (0.082mm). Definite (0.110mm) and Z250 (0.105mm) composites showed no differences between themselves or among the other composites. No statistical differences were observed after toothbrushing between the composites Definite (0.178mm), Z250 (0.187mm), Admira (0.181mm), and A110 (0.193mm). All composites showed a statistically significant increase in the surface roughness after toothbrushing.O objetivo deste estudo foi avaliar a rugosidade superficial antes e após ensaio de escovação de dois compósitos a base de Ormocer e compará-los a compósitos a base de sistemas monoméricos tradicionais. O estudo comparou as marcas Admira e Definite com os compósitos baseados em sistemas de monoméricos tradicionais (Bis-GMA, Bis-EMA, UEDMA e TEGDMA): Z250 e A110. Oito amostras de cada material com 4 mm em diâmetro por 2 mm em altura foram confeccionadas em uma matriz metálica rosqueável. Depois de 24 horas, as amostras foram submetidas a polimento e análise da rugosidade superficial inicial (Ra, µm) através de um profilômetro antes do ensaio de escovação mecânica (30.000 ciclos). Após o ensaio de escovação as amostras foram levadas mais uma vez ao profilômetro para mensuração da rugosidade superficial final. Os resultados foram submetidos a ANOVA e ao teste de Tukey (5%). O compósito Admira apresentou a maior rugosidade superficial antes do ensaio de escovação mecânica (0,132 µm), média estatisticamente superior ao compósito A110 (0,082 µm). Os compósitos Definite (0,110 µm) e Z250 (0,105 µm) não apresentaram diferenças estatísticas entre si nem aos demais compósitos avaliados. Nenhuma diferença estatística foi observada após o ensaio de escovação entre os compósitos Definite (0,178 µm), Z250 (0,187 µm), Admira (0,181 µm), e A110 (0,193 µm). Todos os compósitos apresentaram aumento estatisticamente significante da rugosidade superficial após o ensaio de escovação mecânica

Efeito do uso de forradores resinosos sobre a microinfiltração de restaurações classe V em compósito odontológico

OBJETIVO: O objetivo desse estudo foi avaliar os efeitos da aplicação de um adesivo em diferentes espessuras ou em associação com um adesivo com carga ou com compósito de baixa viscosidade na microinfiltração marginal de restaurações com compósito odontológico. MÉTODOS: Quarenta incisivos bovinos foram selecionados e cavidades circulares (4mm de diâmetro X 2mm de profundidade) foram preparadas na região da junção cemento-esmalte. Os dentes foram então divididos em quatro grupos de acordo com o forramento utilizado: 1: (controle) aplicação do sistema de união Scotchbond Multi Uso (SBMU) - 1 camada de adesivo; 2: aplicação de 3 camadas do adesivo SBMU; 3: aplicação do SBMU, seguido pela aplicação de uma camada do adesivo Optibond FL; 4: aplicação do SBMU seguido pela aplicação de forramento com o compósito de baixa viscosidade Flow-it. Todas as cavidades foram restauradas com o compósito Z100. O teste de microinfiltração foi conduzido de acordo com a ISO (TR11405). Os dados foram analisados pelo teste de Kruskall-Wallis (p>;0,05). RESULTADOS: O grupo 4 apresentou redução significativa dos níveis de infiltração quando comparado ao grupo 1. Os grupos 2 e 3 apresentaram valores intermediários e não foram detectadas diferenças significativas quando estes grupos foram comparados aos grupos 1 e 4. CONCLUSÃO: O uso de forramento com compósito de baixa viscosidade pode reduzir os níveis de infiltração marginal, possibilitando melhora na qualidade das restaurações em compósito odontológico.PURPOSE: The aim of this study was to evaluate the effect of an adhesive applied in layers of different thickness or in association with a filled adhesive or with a low viscosity composite liner on the microleakage of composite restorations. METHODS: Forty bovine incisors were prepared with round cavities (4mm diameter X 2mm depth) on the cementoenamel junction. The teeth were assigned to four groups according to the liner used: 1 (control) - application of 1 layer of the Scotchbond Multi Purpose adhesive system (SBMP); 2 - application of 3 layers of SBMP; 3 - application of 1 layer of SBMP followed by application of one layer of Optibond FL adhesive; 4 - application of one layer of SBMP followed by application of flowable composite Flow-it. All cavities were restored using composite resin Z100. The microleakage test was conducted according to ISO (TR11405). Data were analyzed by Kruskall-Wallis test (a=0.05). RESULTS: Group 4 showed less leakage than Group 1. Groups 2 and 3 showed intermediate values and there were no statistical differences when they were compared to the values of Groups 1 and 4 CONCLUSION: The use of resin liners with flowable composites can reduce the microleakage of composite restorations

Effect Of Resin Liners On The Microleakage Of Class V Dental Composite Restorations.

The aim of this study was to evaluate the effect of an adhesive applied in layers of different thickness or in association with a filled adhesive or with a low viscosity composite liner on the microleakage of composite restorations. Forty bovine incisors were prepared with round cavities (4mm diameter X 2mm depth) on the cementoenamel junction. The teeth were assigned to four groups according to the liner used: 1 (control) - application of 1 layer of the Scotchbond Multi Purpose adhesive system (SBMP); 2 - application of 3 layers of SBMP; 3 - application of 1 layer of SBMP followed by application of one layer of Optibond FL adhesive; 4 - application of one layer of SBMP followed by application of flowable composite Flow-it. All cavities were restored using composite resin Z100. The microleakage test was conducted according to ISO (TR11405). Data were analyzed by Kruskall-Wallis test (a=0.05). Group 4 showed less leakage than Group 1. Groups 2 and 3 showed intermediate values and there were no statistical differences when they were compared to the values of Groups 1 and 4 The use of resin liners with flowable composites can reduce the microleakage of composite restorations.1256-6

Effect of Camphorquinone Concentration in Physical-Mechanical Properties of Experimental Flowable Resin Composites

The aim of this study was to evaluate the effect of camphorquinone concentration in physical-mechanical properties of experimental flowable composites in order to find the concentration that results in maximum conversion, balanced mechanical strength, and minimum shrinkage stress. Model composites based on BISGMA/TEGDMA with 70% wt filler loading were prepared containing different concentrations of camphorquinone (CQ) on resin matrix (0.25%, 0.50%, 1%, 1.50%, and 2% by weight). Degree of conversion was determined by FTIR. Surface hardness was assessed before and after 24 h ethanol storage and softening rate was determined. Depth of cure was determined by Knoop hardness evaluation at different depths. Color was assessed by reflectance spectrophotometer, employing the CIE-Lab system. Flexural strength and elastic modulus were determined by a three-point bending test. Shrinkage stress was determined in a Universal Testing Machine in a high compliance system. Data were submitted to ANOVA and Tukey's test (alpha = 0.05). The increase in CQ concentration caused a significant increase on flexural strength and luminosity of composites. Surface hardness was not affected by the concentration of CQ. Composite containing 0.25% wt CQ showed lower elastic modulus and shrinkage stress when compared to others. Depth of cure was 3 mm for composite containing 1% CQ and 2 mm for the other tested composites. Degree of conversion was inversely correlated with softening rate and directly correlated with elastic modulus and shrinkage stress. In conclusion, CQ concentration affects polymerization characteristics and mechanical strength of composites. The concentration of CQ in flowable composite for optimized polymerization and properties was 1% wt of the resin matrix, which allows adequate balance among degree of conversion, depth of cure, mechanical properties, and color characteristics of these materials.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Univ Fed Sao Paulo, Inst Ciencias Ambientais Quim & Farmaceut, Diadema, SP, BrazilUniv Anhanguera Sao Paulo UNIAN, Sao Paulo, SP, BrazilCSIC, ICTP, Madrid, SpainUniv Metropolitana Santos UNIMES, Santos, SP, BrazilUniv Mogi das Cruzes, NPT, Mogi das Cruzes, SP, BrazilUniv Fed Sao Paulo, Inst Ciencias Ambientais Quim & Farmaceut, Diadema, SP, BrazilFAPESP: 2015/16569-8Web of Scienc

Efeito da contaminação salivar e do tempo de recondicionamento ácido na resistência da união ao cisalhamento de um selante de fóssulas e fissuras

O propósito deste estudo foi avaliar o efeito do tempo de contaminação salivar (TCS) e de recondicionamento ácido (TRA) na resistência da união ao cisalhamento (RC) do selante Fluroshield. Foram selecionados 45 terceiros molares. Os dentes foram seccionados no sentido mésio-distal e suas superfícies foram lixadas até a obtenção de uma área plana em esmalte. Em seguida, as amostras foram distribuídas aleatoriamente em 9 grupos (n=10), em função do TCS e TRA (segundos), respectivamente: G1 - controle; G2 - 30 e 0; G3 - 60 e 0; G4 - 30 e 2; G5 - 30 e 5; G6 - 30 e 15; G7 - 60 e 2; G8 - 60 e 5; G9 - 60 e 15. Em seguida, foi realizada a aplicação do selante de acordo com as instruções do fabricante. Os corpos-de-prova obtidos foram armazenados em água destilada a 37ºC por 72 horas, e então submetidos ao ensaio de cisalhamento à velocidade de 0,5mm/min. Os resultados foram submetidos à análise de variância (ANOVA), e indicaram que não houve diferença estatística significativa (p>;0,05) entre todos os grupos. Observou-se que: 1 - quanto maior o TCS, menores os valores de RC (MPa); 2- quanto maior o TRA, maior o valor de RC (MPa). Pôde-se concluir que houve uma tendência para o menor TCS (30s) e os maiores TRA (5 e 15s) em retornar aos valores de RC do grupo controle.The aim of this study was to evaluate the effect of saliva contamination (SCT) and re-etching time (RET) on the shear bond strength (SBS) of the Fluroshield sealant. Forty-five extracted third molars were sectioned and flattened until reach an enamel surface area. Then, all samples were etched for 30 sec with 35% phosphoric acid and then they were distributed into 9 groups (n=10) according to SCT and RET (seconds), respectively: G1- control (no SCT and no RET); G2- 30s and 0s; G3- 60s and 0s; G4-30s and 2s; G5- 30s and 5s; G6- 30s and 15s; G7-60s and 2s; G8- 60s and 5s; G9- 60s and 15s. The sealant was applied according to the manufacturer's instructions. The samples were stored in distilled water at 37ºC for 72h and subjected to the SBS test. The results indicated that there was no statistically significant difference between the groups (p>;0.05). However, it could be noticed that: 1- the longer the SCT, the lower the SBS values; 2 - the longer the RET, the higher the SBS values. It could be concluded that there was a tendency to the shortest SCT (30s) associated to the longest RET (5 and 15s) to reach similar SBS values for the control group

Mechanical properties of composites as functions of the syringe storage temperature and energy dose

Objective: To investigate the mechanical properties of different classifications of composites indicated for posterior application as functions of the storage condition and of the energy dose. Material and Methods: Specimens (8x2x2 mm) were obtained according to the factors: I) Composites (3M ESPE): Filtek P60, Filtek Z350XT, and Filtek Silorane; II) Syringe storage conditions: room temperature, aged, oven, refrigerator, and freezer; and III) Energy dose: 24 J/cm2 and 48 J/cm2. After photoactivation, the specimens were stored at 37ºC for 24 h. After storage, a three-point bending test was carried out in a universal testing machine at 0.5 mm/min. Flexural strength (S) and flexural modulus (E) were calculated. Data were analyzed by three-way ANOVA and Tukey's test (α=0.05). Results: Different storage conditions significantly affected the silorane composite for S; conversely, no effects were noted in terms of E. The accelerated aging protocol significantly increased the S of Filtek P60 and Filtek Silorane, whereas storage in the oven significantly decreased the S for all of the composites tested. Filtek P60 was the only composite not affected by the lower storage temperatures tested for S, whereas for the silorane this parameter was impacted at the same conditions. The factor "dose" was not statistically significant. Conclusions: The syringe storage at different temperature conditions proved to influence mostly the flexural strength, a clinically important characteristic considering the posterior indication of the materials tested. The silorane composite should not be stored at lower temperatures

Influence of chemical degradation and abrasion on surface properties of nanorestorative materials

Aim: The aim of this in vitro study was to investigate the synergistic effect of chemical degradation (erosion) and three-body abrasion (mechanical degradation) on the surface roughness (Ra) and hardness (KHN) of two nanorestorative materials and two conventional materials. Methods: Discshaped specimens (5 mm in diameter, 2 mm thick) of Filtek Z350™ and TPH Spectrum™ composites and Ketac Nano™ and Vitremer™ light-curing glass ionomer cements, nanomaterials and conventional materials were prepared according to the manufacturer's instructions. After 24 h, polishing procedures were performed and initial measurements of Ra and KHN were taken in all specimens. The specimens were divided into 12 groups (n = 10) according to material and storage media: artificial saliva, orange juice, and Coca-Cola®. After 30 days of storage, the specimens were submitted to mechanical degradation and re-evaluated for Ra and KHN. Data were tested for significant differences by repeated-measure three-way ANOVA and Tukey's tests (p<0.05). Results: Erosion and abrasion wear significantly decreased hardness of all materials. Only Filtek Z350 roughness, however, was not affected by erosion and abrasion. All materials showed a significant increase in surface roughness after erosion and abrasion, except for Filtek Z350. After chemical and mechanical degradation, the KHN of all samples had decreased significantly. After mechanical degradation, the acidic drinks (Coca-Cola® and orange juice) were more aggressive than artificial saliva to all materials. Conclusions: A synergistic effect was observed by the increase in roughness for all materials, except for Filtek Z350; hardness values decrease for all materials, regardless of whether they were nanofilled or not. The RMGICs were more susceptible to degradation than the composites, considering both hardness and roughness surface parameters142100105sem informaçã

Influence of environmental conditions on properties of ionomeric and resin sealant materials

OBJECTIVES: The aim of this study was to determine the effect of environmental conditions on the degradation of ionomeric and resin sealant materials. MATERIAL AND METHODS: FluroShield, Vitremer, and Ketac Molar disc-shaped specimens (n=18/material) were prepared, polished, subjected to initial hardness and roughness readings. Six discs of each material were randomly assigned to one of three different storage solutions: 0.3% citric acid (CA), demineralization solution (DE), and remineralization solution (RE). The specimens were individually immersed in 3 mL of the test solutions, which were daily changed. After 15 days of storage, new surface roughness and hardness readings were done. Fluoride release in the solutions was measured within 15 days. Data were analyzed by ANOVA and Tukey's and Contrast tests (&#945;=0.05). RESULTS: The storage in CA increased the roughness of Vitremer and Ketac Molar. A significant reduction in hardness was observed for all materials after storage in all solutions. For all materials, the greatest amounts of fluoride release occurred during the 1st day. FluroShield presented the same patterns of fluoride release in all solutions. Ketac Molar and Vitremer released the highest amounts of fluoride in the CA solution. CONCLUSIONS: Ionomeric materials are more susceptible to degradation than resin-based materials under acidic conditions. Acidic conditions lead to a higher fluoride release from ionomeric materials

Influence of the incorporation of triclosan methacrylate on the physical properties and antibacterial activity of resin composite

The incorporation of antimicrobials in the composites as an attempt to reduce bacterial adhesion without jeopardizing mechanical properties is a challenge for Dentistry. Objective: To evaluate the bacterial adhesion and physical properties of a composite containing the methacrylate triclosan- derivative monomer (TM). Methodology: TM was synthesized and added to an experimental composite. Samples were divided into two groups: Control and TM (13.4 wt%). Antibacterial Activity: Three specimens of each material were prepared and placed on bacterial suspensions of Streptococcus mutans for 1, 5 and 10 days. After these periods the counting of the colonies (log10) was performed. Assays was performed in triplicate. Physical Properties: Three-body Abrasion (TBA): Ten specimens of each material were prepared and stored at 37°C/24 h. The surface roughness (Ra) and hardness (KHN) were analyzed. Next, the specimens were submitted to abrasive wear (30,000 cycles) and re-evaluated for Ra and KHN; Sorption/solubility (SS): cylindrical specimens (n=10) were prepared and weighted. The specimens were immersed in deionized water for 7 days at 37°C and then their weight was verified again. SS were calculated using accepted formulas; Diametral tensile strength (DTS): specimens (n=10) underwent test performed in an Instron universal testing machine at a crosshead speed of 1 mm/min. Data were submitted to appropriate statistical tests according to data distribution and assay (p&lt;0.05). Results: Bacterial Adhesion: TM showed a significant reduction on biofilm accumulation in the evaluated periods: 1 day (1.537±0.146); 5 days (2.183±0.138) and 10 days (4.469±0.155) when compared with Control: 1 day (4.954±0.249); 5 days (5.498±0.257) and 10 days (6.306±0.287). Physical Properties: For TBA, SS and DTS no significant difference was found between groups Control and TM. The incorporation of methacrylate triclosan-based monomer in the experimental composite reduce bacterial adhesion of S. mutans and did not affect important polymer properties.&nbsp