Composite resin reinforced with silk nanoparticles from Bombyx mori cocoon for dental applications.

The objective of this work was to evaluate the mechanical performance of Z350 resin composite modified with Bombyx mori cocoons silk nanoparticles for dental applications. Four experimental groups were analyzed G0% = Filtek Z350 resin composite (control); G1% = Filtek Z350 with 1% of silk nanoparticles; G3% = Filtek Z350 with 3% of silk nanoparticles; G5% = Filtek Z350 with 5% of silk nanoparticles. It was employed scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, 3-point flexural strength test, Knoop hardness test, and surface roughness. From 3-point flexural strength tests the control group presented the best results G0% = 113.33 MPa (±23.73). The higher flexural modulus was shown by groups G3% = 29.150 GPa (±5.191) and G5% = 34.101 GPa (±7.940), which are statistically similar. The Knoop microhardness test has shown statistical difference only among the G3% group between the top 80.78 (± 3.00) and bottom 68.80 (±3.62) and no difference between the groups. The roughness test presented no statistical difference between the groups. The incorporation of silk nanoparticles reduced the flexural strength of Z350 resin composite. The surface roughness and microhardness tests showed no changes in any of the groups studied.

Composite resin reinforced with silk nanoparticles from Bombyx mori cocoon for dental applications

Abstract The objective of this work was to evaluate the mechanical performance of Z350 resin composite modified with Bombyx mori cocoons silk nanoparticles for dental applications. Four experimental groups were analyzed G0% = Filtek Z350 resin composite (control); G1% = Filtek Z350 with 1% of silk nanoparticles; G3% = Filtek Z350 with 3% of silk nanoparticles; G5% = Filtek Z350 with 5% of silk nanoparticles. It was employed scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, 3-point flexural strength test, Knoop hardness test, and surface roughness. From 3-point flexural strength tests the control group presented the best results G0% = 113.33 MPa (±23.73). The higher flexural modulus was shown by groups G3% = 29.150 GPa (±5.191) and G5% = 34.101 GPa (±7.940), which are statistically similar. The Knoop microhardness test has shown statistical difference only among the G3% group between the top 80.78 (± 3.00) and bottom 68.80 (±3.62) and no difference between the groups. The roughness test presented no statistical difference between the groups. The incorporation of silk nanoparticles reduced the flexural strength of Z350 resin composite. The surface roughness and microhardness tests showed no changes in any of the groups studied.

Resumo O objetivo deste trabalho foi avaliar o desempenho mecânico da resina composta Z350 modificada com nanopartículas de seda Bombyx mori cocoons para aplicações odontológicas. Quatro grupos experimentais foram analisados: G0%) Resina Z350 apenas (grupo controle); G1%) Reforço com 1% de nanopartículas de seda; G3%) Reforço com 3% de nanopartículas de seda; e G5%) Reforço com 5% de nanopartículas de seda. Foi empregado microscopia eletrônica de varredura, espectroscopia de energia dispersiva de raios X, difração de raios X, teste de resistência à flexão de 3 pontos, teste de dureza Knoop e rugosidade superficial. Nos testes de resistência à flexão de 3 pontos o grupo controle apresentou melhores resultados G0% = 0.113 GPa (±0.024). O maior módulo de flexão foi demonstrado pelos grupos G3% = 29.151GPa (±5.191) e G5% = 34.102 GPa (±7.94), que são estatisticamente semelhantes. O teste de microdureza Knoop mostrou diferença estatística apenas entre o grupo G3% entre os 80.78 superiores (± 3.00) e os 68.80 inferiores (±3.62). Não há diferença entre os grupos. O teste de rugosidade não apresentou diferença estatística entre os grupos. A incorporação de nanopartículas de seda reduziu a resistência à flexão da resina composta Z350. Os testes de rugosidade superficial e microdureza não apresentaram alterações em nenhum dos grupos estudados.

Enhancing glass ionomer cement features by using the calcium phosphate nanocomposite

Abstract This study showed the synthesis of Glass ionomer cements (GIC) modified with calcium phosphate nanoparticles (nCaP). The nCaP/GIC were submitted to mechanical compression and diametral tensile tests. The biocomposite were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). Cytotoxicity and cell viability tests were performed on the human bone marrow mesenchymal stem cells using a 3-(4,5-dimethylthiazol-2yl)2,5-diphenyl- tetrazolium-bromide assay and LIVE/DEAD assays. Statistically significant differences were observed for mechanical properties (Kruskal-Wallis, p<0.001), nCaP/GIC showed higher resistance to compression and diametral traction. The SEM analyses revealed a uniform distribution nCaP in the ionomer matrix. The EDX and XRD results indicated that hydroxyapatite and calcium β-triphosphate phases. The FTIR spectra revealed the asymmetric band of ν3PO43- between 1100-1030cm-1 and the vibration band associated with ν1PO43- in 963cm-1 associated with nCaP. The nCaP/GIC presented response to adequate cell viability and non-cytotoxic behavior. Therefore, the new nCaP/GIC composite showed great mechanical properties, non-cytotoxic behavior, and adequate response to cell viability with promising dental applications.

Resumo Este estudo apresenta a síntese de cimentos de ionômero de vidro (GIC) modificados com nanopartículas de fosfato de cálcio (nCaP). Os nCaP / GIC foram submetidos a ensaios mecânicos de compressão e tração diametral. Os biocompósitos foram caracterizados por microscopia eletrônica de varredura (MEV), espectroscopia de energia dispersiva de raios-X (EDX), difração de raios-X (XRD) e espectroscopia de infravermelho com transformada de Fourier (FTIR). Os testes de citotoxicidade e viabilidade celular foram realizados em células-tronco mesenquimais da medula óssea humana usando um ensaio de 3- (4,5-dimetiltiazol-2-il) 2,5-difeniltetrazólio-brometo e ensaios LIVE / DEAD. Diferenças estatisticamente significativas foram observadas para as propriedades mecânicas (Kruskal-Wallis, p <0,001), nCaP / GIC apresentou maior resistência à compressão e tração diametral. As análises de SEM revelaram uma distribuição uniforme de nCaP na matriz do ionômero. Os resultados de EDX e DRX indicaram fases de hidroxiapatita e β-trifosfato de cálcio. Os espectros de FTIR revelaram a banda assimétrica de ν3PO4 3- entre 1100-1030cm-1 e a banda de vibração associada a ν1PO4 3- em 963cm-1 associada a nCaP. O nCaP / GIC apresentou resposta adequada à viabilidade celular e comportamento não citotóxico. Portanto, o novo compósito nCaP / GIC apresentou ótimas propriedades mecânicas, comportamento não citotóxico e resposta adequada à viabilidade celular com promissoras aplicações odontológicas.

Biomechanics of internal connection in mandibular implant-supported prosthesis under effect of loadings and number of implants: A 3D finite element analysis.

INTRODUCTION: The success of bone-implant prostheses depends on several factors, among them an adequate distribution and passive adaptation of occlusal loading. OBJECTIVE: this study evaluated the stress distribution in mandibular implant-supported prosthesis with internal connection morse taper interface, under effect of number of implants (4 or 5) and loadings (bilateral 100 N, bilateral 300 N). MATERIALS AND METHODS: the virtual models were subjected to analysis by 3D finite element method, across four experimental conditions. RESULTS: The stress values were evenly distributed to the peri-implant bone and implants in all simulated conditions. Stress values did not increase in the same proportion as the increase in the applied load (from 100 to 300 N). The stress value was 1.1 times higher on the implants and nearly doubled (1.5-2 times) on the peri-implant bone. CONCLUSION: For mandibular implant-supported prosthesis, the morse taper interface is strongly recommended, with similar mechanical demand for four and five implants in both loading conditions. Five implants offered no additional benefit over four implants. The commercial pure titanium frameworks presented stress values close to the yield strength of the metal, especially at the intersection with the cantilever.

Enhancing glass ionomer cement features by using the calcium phosphate nanocomposite.

This study showed the synthesis of Glass ionomer cements (GIC) modified with calcium phosphate nanoparticles (nCaP). The nCaP/GIC were submitted to mechanical compression and diametral tensile tests. The biocomposite were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). Cytotoxicity and cell viability tests were performed on the human bone marrow mesenchymal stem cells using a 3-(4,5-dimethylthiazol-2yl)2,5-diphenyl- tetrazolium-bromide assay and LIVE/DEAD assays. Statistically significant differences were observed for mechanical properties (Kruskal-Wallis, p<0.001), nCaP/GIC showed higher resistance to compression and diametral traction. The SEM analyses revealed a uniform distribution nCaP in the ionomer matrix. The EDX and XRD results indicated that hydroxyapatite and calcium ß-triphosphate phases. The FTIR spectra revealed the asymmetric band of ν3PO43- between 1100-1030cm-1 and the vibration band associated with ν1PO43- in 963cm-1 associated with nCaP. The nCaP/GIC presented response to adequate cell viability and non-cytotoxic behavior. Therefore, the new nCaP/GIC composite showed great mechanical properties, non-cytotoxic behavior, and adequate response to cell viability with promising dental applications.

Ellagic acid on the quality of the adhesive interface of class I composite resin restorations after aging

To evaluate the effect of ellagic acid on the inhibition of matrix metalloproteinase by analyzing the quality of the adhesive interface with bond strength measures in periods of 24 hours and six months of storage. Method: 40 healthy human third molars were prepared with class I cavities (5x4x3mm). The teeth were divided into four experimental groups: Group 1- without application of ellagic acid and storage time of 24 hours; Group 2- with ellagic acid/24 hours; G3- without ellagic acid/six months; Group 4- with ellagic acid/six months. Then, the cavities were restored with Single Bond Universal adhesive and Z350 composite resin, with and without the previous application of ellagic acid. Subsequently, hourglass-shaped specimens were obtained and subjected to the bond strength (BS) test (n = 10) in a universal testing machine. The bond test was performed after 24 hours and six months of storage. For the standard evaluation (n = 3) the samples were infiltrated with silver nitrate and placed in a developing solution for analysis in a Scanning Electron Microscope (SEM). The data obtained were analyzed with the Kruskal-Wallis non-parametric test, showing a statistically significant difference. Results: The highest bond strength values were found for the 24-hour groups followed by the groups with six months of storage. For nano-infiltration, groups G1 and G2 showed lower infiltration than groups G3 and G4. Conclusion: The previous application of ellagic acid did not affect the BS of the adhesive interface of the adhesive system analyzed, regardless of storage time.

Influence of the volume of restorative material on the concentration of stresses in the restorative interface.

BACKGROUND: To evaluate the microtensile strength in the adhesive interface depending on the volume of the composite resin used to restore class I cavities. MATERIAL AND METHODS: Forty-eight human third molars received a standardized class I cavity preparation and they were separated into six experimental groups: G1 - single-bottle adhesive system; G2 - bonding system with load; G3 - single-bottle adhesive associated with low-viscosity composite resin; G4 - loaded adhesive associated with low-viscosity composite; G5 - resin-modified glass ionomer associated with single-bottle adhesive; and G6 - resin-modified glass ionomer associated with loaded adhesive. All cavities were restored with a universal restorative composite. After completing the restorations, the samples were stored for seven days in a stove (37°C) and the microtensile bond strength was evaluated by producing slices and applying axial loading in an Instron universal testing machine at a speed of 0.5 mm/min. The thickness of the intermediate layer formed on the cavity floor to verify the relationship between the volume of restorative composite and the concentration of stresses in the buccal wall. With the data obtained in the microtensile strength test, an Analysis of Variance (ANOVA) was performed entirely at random. RESULTS: Duncan's test showed that group 4 (Filtek Flow/Optibond Solo Plus) obtained the highest mean of microtensile strength with no statistically significant difference to groups 3 (Filtek Flow/Single Bond), 5 (Vitremer/Single Bond), and 6 (Vitremer/Optibond Solo Plus). It also showed a statistically significant difference to groups 2 (Optibond Solo Plus) and 1 (Single Bond), with no statistical difference between the other groups studied. CONCLUSIONS: The highest mean of microtensile strength was obtained when the volume of the restorative material decreased through the interposition between the material and the adhesive system of a base with low elasticity modulus. Key words:Adhesion, microtensile, composite resin.

Microabrasion effect on enamel susceptibility to penetration of hydrogen peroxide: an experimental and computational study.

To evaluate in vitro transenamel/transdentinal of penetration of H2O2 after microabrasive. Computational models were performed to verify peroxide penetration and evaluate if geometric modifications could affect in vitro results. Enamel/dentin blocks from bovine incisors were prepared and randomly divided into groups (n = 15) according with abrasive (35% phosphoric acid and pumice or 6.6% hydrochloric acid and silica) and bleaching agents (16% carbamide peroxide and 35% H2O2). From artificial pulp chambers, the H2O2 concentration was measured and SEM was used for surface morphology. Numerical models were performed (Abaqus® v6.12) modifying slightly enamel/dentin thickness based on experimental data. All groups presented H2O2 penetration, although no significant difference was noted between the control and experimental groups (p > 0.05). The numerical analysis demonstrated the role of dental tissue thickness in the H2O2 penetration. Microabrasion is recommended as its association with bleaching procedures and small modifications in thicknesses of enamel/dentin can cause substantial changes in HP penetration. Such diffusion aspect is clinically relevant for the bleaching procedures since very thin enamel could present more peroxide propagation through dental tissues.

Comparative Analysis of Shear Bond Strength of Steel and Ceramic Orthodontic Brackets Bonded with Six Different Orthodontic Adhesives / Análisis Comparativo de la Resistencia al Corte de Brackets de Ortodoncia de Acero y Cerámica Unidos con Seis Adhesivos de Ortodoncia Diferentes

ABSTRACT: Orthodontic accessories bonding in tooth enamel has been a critical step since the introduction of direct bonding techniques due to the importance of bracket stability. The aim of this study was to evaluate adhesion strength of different adhesive systems used for bracket bonding on dental surface. The present in vitro study was made from the analysis of shear strength of steel and ceramic brackets bonding with six different types of orthodontic adhesives. The brackets were bonded to 120 human extracted first premolar teeth with Orthocem®, Orthocem® + Ambar Universal® primer, Orthobond Plus®, Biofix®, Transbond XT®, Ortholink VLC®. Shear strength tests were performed on a universal testing machine EZ-Test-Shimadzu® and the data were analyzed using ANOVA test with Post-Hoc Bonferroni and 95 % statistical significance (p <0.05). Transbond XT® and Ortholink VLC® resin values showed greater shear resistance for steel brackets bonding and Transbond XT® and Orthobond Plus® adhesives showed better adhesion results for ceramic brackets bonding.

RESUMEN: La unión de accesorios de ortodoncia en el esmalte dental ha sido un paso crítico desde la introducción de las técnicas de unión directa debido a la importancia de la estabilidad del soporte. El objetivo de este estudio fue evaluar la fuerza de adhesión de diferentes sistemas adhesivos utilizados para la unión de brackets en la superficie dental. El presente estudio in vitro se realizó a partir del análisis de la resistencia al corte de brackets de acero y de cerámica unidos con seis tipos diferentes de adhesivos de ortodoncia. Los brackets se unieron a 120 primeros premolares extraídos con los adhesivos Orthocem®, Orthocem® + Ambar Universal® primer, Orthobond Plus®, Biofix®, Transbond XT®, Ortholink VLC®. Las pruebas de resistencia al corte se realizaron en una máquina de prueba universal EZ-Test-Shimadzu® y los datos se analizaron usando la prueba ANOVA con Bonferroni Post-Hoc y 95 % de significación estadística (p <0,05). Los valores de resina Transbond XT® y Ortholink VLC® mostraron una mayor resistencia al corte para la unión de brackets de acero y los adhesivos Transbond XT® y Orthobond Plus® mostraron mejores resultados de adhesión para la unión de brackets cerámicos.

Simplified ethanol wet-bonding technique: an alternative strategy for resin-dentin bonding in root canals.

The objective of this study was to evaluate the effect of the simplified ethanol wet-bonding technique on luting of posts to intraradicular dentin. The effect was assessed by push-out bond strength testing and confocal laser scanning microscopic analysis. Thirty endodontically treated roots were distributed into 3 groups (n = 10): water wet-bonding; stepwise ethanol wet-bonding; and simplified ethanol wet-bonding. After cementation of the posts, the roots were sectioned. Specimens were stored for 24 hours or 1 year before they were stressed to failure. Specimens from each group were processed for microscopic analysis. Data were analyzed using a 2-way analysis of variance and the Tukey test (α = 0.05). Statistically significant differences in push-out bond strength values were observed between the technique groups (P < 0.001) and between the storage periods (P = 0.009). The bond strength results in the group bonded using the simplified ethanol wet-dehydration approach did not differ from those in the group bonded using the stepwise ethanol technique at either storage time interval (P > 0.05). From 24 hours to 1 year, there was a similar decrease in bond strength for specimens prepared with the simplified and stepwise techniques. The microscopic results confirmed that ethanol wet-bonding technique improved the quality of the interface. The simplified ethanol wet-dehydration protocol achieved bond strengths and stability over time that were similar to those obtained with the stepwise ethanol technique and may be considered an alternative strategy to accomplish resin cement-root dentin bonding.

Evaluation of Finishing/Polishing Techniques on Low-Shrink Posterior Restorative After Mechanical Cycling / Avaliação de Técnicas de Acabamento/Polimento em Restaurações Posteriores de Baixa Contração Após Ciclagem Mecânica

The aim of this study was to evaluate the surface roughness of a silorane and methacrylate-based composite resins subjected to different finishing/polishing techniques. Twelve disk specimens were prepared from each composite resin: P90®, Z350® and Charisma, divided into 12 groups according to the finishing/polishing technique: no finishing/polishing (control); finishing with 1112 FF diamond burs; finishing with 1112 FF diamond burs associated to Enhance/Pogo; finishing with 1112 FF diamond burs associated to Enhance/Pogo/Polishing/Poli I and II pastes/Fotogloss. After initial readouts of surface roughness, the specimens were subjected to mechanical cycling (1.200.000 cycles) and immediately subjected to final roughness readouts. Surface roughness means was statistically analyzed by ANOVA and Tukey-Kramer test (α=0.05). SEM images were realized after finishing/polishing and after mechanical cycling. The P90 composite showed surface roughness values similar to other investigated composites. However, significant difference was observed in finishing/polishing techniques. The diamond burs group showed the highest surface roughness differing from the other composite resins (α < 0.05). Enance/Pogo showed the lowest results, which presented no difference compared to the polishing paste group (α > 0.05). The low-shrink posterior restorative showed similar surface roughness when compared to dimethacrylate composite resins and suitable to posterior restorations. (AU).

O objetivo deste estudo foi avaliar a rugosidade superficial de resinas compostas à base silorano e metacrilato submetidas a diferentes técnicas de acabamento/polimento. Foram preparadas 12 amostras de disco de cada resina composta: P90®, Z350® e Carisma, divididas em 12 grupos de acordo com a técnica de acabamento / polimento: sem acabamento / polimento (controle); acabamento com ponta diamantada 1112 FF; acabamento com ponta diamantada 1112 FF associada a Enhance / Pogo; acabamento com ponta diamantada 1112 FF associada a Enhance / Pogo / Polishing / Pastas Poli I e II / Fotogloss. Após as leituras iniciais da rugosidade da superfície, os espécimes foram submetidos a ciclos mecânicos (1.200.000 ciclos) e submetidos imediatamente a leituras de rugosidade final. As medias de rugosidade superfícial foram analisadas estatisticamente por ANOVA e teste de Tukey-Kramer (α = 0,05). As imagens de MEV foram realizadas após o acabamento / polimento e após a ciclagem mecânica. O compósito P90 mostrou valores de rugosidade superficial semelhantes a outros compósitos investigados. Tough, mostrou diferença significativa nas técnicas de acabamento / polimento. O grupo de pontas damantadas apresentou maior rugosidade superficial que diferiu das outras resinas compostas (α <0,05). Enance / Pogo mostrou os menores resultados, que não apresentaram diferença em relação ao grupo de pasta de polimento (α> 0,05). O material restaurador posterior de baixa contração apresentou rugosidade superficial semelhante quando comparado as resinas compostas de dimetacrilato e são restaurações adequadas para região posterior. (AU).

Impact of malocclusion on oral health-related quality of life among schoolchildren.

The aim of the present study was to evaluate the prevalence and impact of malocclusion on oral health-related quality of life (OHRQoL) among schoolchildren aged 8 to 10 years and their parents in Diamantina, a town in the southeast of Brazil. A cross-sectional study was conducted with a sample of 390 randomly selected children who were subjected to a clinical oral examination. The Dental Aesthetic Index was used to diagnose malocclusion and the need for orthodontic treatment. The Child Perceptions Questionnaire (CPQ (8-10)) was used to evaluate the impact of malocclusion on OHRQoL. The children's parents answered the Brazilian Economic Criterion Questionnaire for the socioeconomic classification. Data analysis involved the nonparametric Kruskal-Wallis test and Spearman's correlation coefficients. The variables were grouped into a hierarchy of categories ranging from distal to proximal determinants. Poisson regression analysis with robust variance was performed at each level to correlate the total CPQ (8-10) score with the independent variables. The prevalence of malocclusion was 78.7%. Crossbite remained significantly associated with a negative impact on OHRQoL (PR = 1.28; 95%CI:1.17-1.39; p < 0.001). The prevalence of malocclusion was high in the sample investigated and exerted a negative impact on OHRQoL.

Evaluation of degree of conversion and the effect of thermal aging on the color stability of resin cements and flowable composite.

PURPOSE: The aim of this in vitro study was to evaluate the color stability and degree of conversion (DC) of dual-cure and light-cure cements and flowable composites after thermal aging. MATERIALS AND METHODS: A total of 50 human incisors were prepared and divided into six groups (n = 10). Veneers were fabricated using IPS Empress Direct composite resin were bonded with three types of luting agents: Light-cured, conventional dual, and flowable composite according to the manufacturer's instructions. The groups were as follows: Filtek Z350XT Flow/Single Bond 2, RelyX ARC/Single Bond 2, RelyX Veneer/Single Bond 2, Tetric N-Flow/Tetric N-Bond, and Variolink II/Tetric N-Bond. Commission Internationale de l'Éclairage L*, a* and b* color coordinates were measured 24 h after cementation procedure with a color spectrophotometer and reevaluated after 10,000 thermal cycles. To evaluate the DC 50 specimens (n = 10) of each resin material were obtained and Fourier transform infrared spectroscopy was used to evaluate the absorption spectra. Statistical analysis was performed with one-way ANOVA and Tukey's test (α = 0.05). RESULTS: No statistically significant differences in ΔE* occurred after aging. The greatest change in lightness occurred in the Variolink II resin cement. Changes in red-green hue were very small for the same cement and largest in the Tetric N-Flow flowable resin composite, while the greatest change in blue-yellow hue was a yellowing of the RelyX ARC luting cement. RelyX ARC exhibited the highest DC, and there were no statistically significant differences in DC among the other cements. CONCLUSIONS: Resin-based luting agent might affect the final of ceramic veneer restorations. The thermal aging affected the final color of the evaluated materials, and these were regarded as clinically unacceptable (ΔE >3.3).

Influence of enamel acid-etching on mechanical properties and nanoleakage of resin composite after aging

The aim of this study was to evaluate how acid-etching of the cavosurface enamel in Class I resin composite restorations influences the bond strength to the pulpal wall and the restoration, Knoop microhardness and nanoleakage after thermomechanical aging. For this research 76 fresh human molars were selected and restored with Silorane or Clearfil SEBond/Z350XT composite divided in 4 groups (Silorane system restored with or without enamel cavosurface acid-etching and Clearfil SEBond/Z350XT with or without enamel cavosurface acid-etching). To induce artificial aging, samples were subjected to thermomechanical cycling through 200,000 and thermal cycling between 5 and 55 °C with 30 second filling and 15-second drainage steps. Microhardness and microtensile bond strength were evaluated in 32 teeth (n=8) each and nanoleakage evaluation was performed in 12 teeth (n=3). Samples restored by Clearfil SEBond/Z350 XT without cavosurface acid-etching showed significantly lower microtensile bond strength results. The resin composite Z350XT presented higher values of Knoop microhardness. It was observed little or no infiltration for Silorane groups and moderate infiltration for Clearfil SE Bond groups. Acid-etching of the cavosurface enamel during restoration procedure with Clearfil Se Bond resulted in a stronger bond after thermomechanical cycling. Silorane groups showed less infiltration than Clearfil SE Bond groups (AU)

Active application of primer acid on acid-treated enamel: Influence on the bond effectiveness of self-etch adhesives systems.

AIM: Evaluate the composite-to-enamel bond after passive or active application of self-etching primer systems on polished or pre-etched enamel with phosphoric acid. MATERIALS AND METHODS: Two self-etch adhesives systems (SEAS) were used: Clearfil SE Bond and Easy Bond. Third human molars were divided into 8 groups (N = 10). The crown of each tooth was sectioned into halves and the mesial/distal surfaces were used. The adhesives were actively or passively applied on enamel with or without prior phosphoric-acid etching. Resin composite cylinders were built after adhesive application. After stored in relative humidity for 24 hr/37°C the specimens were subjected to microshear test in universal testing a machine at a crosshead speed of 0.5 mm/minute. The results were analyzed with three-way ANOVA and the Tukey test. The enamel-etching pattern was evaluated under SEM. RESULTS: The 2-step SEAS system presented significantly higher adhesive bond strength means (47.37 MPa) than the 1-step (36.87 MPa). A poor enamel- etching pattern was observed in active mode showing irregular and short resin tags, however there was not compromised the bond strength. CONCLUSION: Active or passive application produced similar values of bond strength to enamel regardless of enamel pretreatment and type of SEAS.

Reconhecimento e avaliação da ansiedade em indivíduos com paralisia cerebral durante consultas odontológicas / Recognition and evaluation of anxiety in individuals with cerebral palsy during dental appointments

Objetivo: o objetivo deste estudo foi verificar a correlação entre a avaliação da ansiedade realizada por meio de medidas fisiológicas e pela observação do comportamento de pacientes com paralisia cerebral realizado pelo dentista durante a primeira consulta odontológica. Métodos: quarenta pacientes com idade variando de 7 a 26 anos, com paralisia cerebral foram submetidos a exames odontológicos. A pressão arterial e a frequência cardíaca foram aferidas no início e no final da primeira consulta odontológica. O dentista avaliou o comportamento antes e após o exame clínico dentário através da observação do comportamento do paciente (inquietação / agitação / tiques nervosos, palidez, transpiração excessiva, resistência e mudança aparente na frequência respiratória). Foi utilizado o teste de correlação de Spearman para determinar a correlação entre as medidas fisiológicas e a classificação comportamental da ansiedade feita pelo cirurgião dentista a um nível de significância de 95%. Resultados: os sinais comportamentais mais frequentes foram inquietação / agitação / tiques nervosos (50,0%) e resistência (27,5%). Foi encontrada uma correlação positiva significativa entre os dois métodos de avaliação de ansiedade utilizados (p <0,05). Os pacientes considerados ansiosos pelo dentista apresentaram medidas fisiológicas mais elevadas do que aqueles considerados calmos (p <0,05). Conclusão: a observação contínua do comportamento de pacientes com paralisia cerebral durante o exame odontológico é uma ferramenta valiosa para o reconhecimento e avaliação da ansiedade por parte da equipe odontológica. Estudos adicionais são necessários para validar um código de expressões faciais e corporais ou reações de ansiedade em pacientes com paralisia cerebral.(AU)

Aim: The present study aimed to verify the correlation between the evaluation of anxiety performed through physiological measures and the observation of the behavior of patients with cerebral palsy performed by the dentist during the first dental visit. Methods: Forty patients with cerebral palsy, varying from seven to 26 years of age, were submitted to dental examinations. The blood pressure and heart rate were measured at the beginning and end of the first dental appointment. The dentist evaluated the behavior before and after the dental exam by observing the patient's behavior (restlessness / agitation / nervous tics, pallor, excessive perspiration, resistance, and apparent change in breathing rate). The Spearman correlation test was used to determine the correlation between the physiological measures and the behavioral classification of anxiety made by the dentist at a significance level of 95%. Results: The most frequent behavioral signs were restlessness / agitation / nervous tics (50.0%), and resistance (27.5%). Through the Kruskal-Wallis test and Spearman's correlation, a significant positive correlation was found between the two anxiety assessment methods used in this study (p<0.05). The patients considered anxious by the dentist presented higher physiological measurements than did those considered calm (p<0.05). Conclusion: It can therefore be concluded that the continuous observation of the behavior of patients with cerebral palsy during the dental examination is a valuable tool for the recognition and evaluation of anxiety on the part of the dental team. Further studies are warranted to validate a code of facial and body expressions or anxiety reactions in patients with cerebral palsy.(AU)

Nanoleakage of fiber posts luted with different adhesive strategies and the effect of chlorhexidine on the interface of dentin and self-adhesive cements.

The aim of this in vitro study was to evaluate the nanoleakage of fiber posts luted using different adhesive strategies and to investigate the effect of 2% chlorhexidine (CHX) on nanoleakage at the resin-dentin interfaces of self-adhesive cements. The self-adhesive and etch-and-rinse adhesive groups tested demonstrated similar results with regard to nanoleakage. Pretreatment with CHX promoted an adequate seal at the resin-dentin interface for self-adhesive cements.

Minimally invasive cosmetic dentistry: smile reconstruction using direct resin bonding.

Discrepancies in tooth size and shape can interfere with smile harmony. Composite resin can be used to improve the esthetics of the smile at a low cost while offering good clinical performance. This article presents an approach for restoring and correcting functional, anatomic, and esthetic discrepancies with minimal intervention, using composites and a direct adhesive technique. This conservative restorative procedure provided the patient with maximum personal esthetic satisfaction.

Influence of photo-curing distance on bond strength and nanoleakage of self-etching adhesive bonds to enamel and dentin.

OBJECTIVES: To assess the influence of light-curing unit tip distance on the microtensile bond strength (µTBS) and nanoleakage of self-etching adhesives to enamel and dentin. MATERIALS AND METHODS: Flat buccal surfaces were prepared on 198 bovine incisors. The teeth were randomly assigned into nine groups for µTBS (n = 8) and nanoleakage (n = 3) testing according to the adhesive system (Clearfil Protect Bond, Clearfil Tri-S Bond or One Up Bond F Plus) and distance from the light-curing tip (0, 3 or 6 mm). The bonded samples were tested in tension (0.5 mm/min) and nanoleakage was analyzed using SEM. RESULTS: Clearfil Protect Bond exhibited the highest tensile strength on both enamel and dentin. Leakage was higher in samples exposed at a distance of 6 mm on enamel and 0 mm on dentin. One Up Bond F Plus experienced the greatest amount of nanoleakage on both substrates. CONCLUSIONS: Light-curing unit distance did not influence the µTBS of the adhesives, but nanoleakage increased on enamel samples when photoactivation occurred at a distance of 6 mm.