ABSTRACT
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.
ABSTRACT
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.
ABSTRACT
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.
Subject(s)
Matrix Metalloproteinases , Dental Cements , Ellagic AcidABSTRACT
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)
Subject(s)
Humans , Adhesives , Composite Resins , Dental Cavity Preparation , Silorane Resins , Tensile StrengthABSTRACT
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)
Subject(s)
Humans , Male , Female , Behavior Observation Techniques , Cerebral Palsy , Dental Anxiety , Disabled Persons , Monitoring, Physiologic , Arterial Pressure , Diagnosis, Oral , Heart Rate , Signs and SymptomsABSTRACT
O contorno cosmético é uma técnica operatória que requer do profissional amplo conhecimento de estética e reflexão da luz, pois implica desgaste irreversível da estrutura dental sadia. Este artigo relata um caso clínico de contorno cosmético que ilustra as possibilidades de remodelação estética do sorriso guiadas por princípios de ilusão de óptica, na qual foi possível, mediante a realização de desgastes em esmalte, obter resultados satisfatórios com previsibilidade.
Cosmetic recontouring is a technique that demands comprehensive skills and knowledge about esthetics light dynamics by the professional, since irreversible reduction of tooth sound structure is required. This paper is a case report of the cosmetic contouring showing the possibilities of esthetic recontouring of the smile following principles of optical illusion, from which it was possible through enamel reduction to achieve satisfactory, predictable results.