Efeito das técnicas de inserção e alisamento na estabilidade de cor e rugosidade superficial de resinas compostas

Introduction: Longevity and clinical success of dental restorations can be influenced by many factors during the restorative procedures. Objective: This study aimed to evaluate the influence of different placement techniques on color stability and surface roughness of two resin composites. Material and method: The groups of specimens (n=10) were divided according to resin composite (FiltekTM Z250 XT and FiltekTM Z350 XT) and placement technique: Mylar strip, spatula, dry brush, modeling liquid, and surface sealant. Color stability and surface roughness were accessed using a spectrophotometer (CIELab color space) and a rugosimeter (standard cutoff of 0.8 mm), respectively, after water storage. Subsequently, the specimens were immersed in coffee for 48 h and final color was measured. The data were analyzed using ANOVA and the Tukey’s post hoc test (α=5%) and the correlation between surface roughness (Ra) and color change (∆Eab) was assessed using the Pearson’s correlation coefficient. Result: The different placement techniques influenced Ra and ∆Eab on both resin composites. The groups treated with surface sealant showed greater difference in ∆Eab for both resin composites. The FiltekTM Z250 XT resin showed greater color stability compared with the FiltekTM Z350 XT resin regardless of the placement technique used. Ra of each placement technique was similar among the resin composites except for the FiltekTM Z350 XT modeling liquid group, which presented lower Ra values compared with those of FiltekTM Z250 XT. A correlation between Ra and staining was identified (p=0.268). Conclusion: Color stability and Ra are influenced by different placement techniques.Introdução: A longevidade e o sucesso clínico das restaurações dentárias podem ser influenciados por muitos fatores durante os procedimentos restauradores. Objetivo: Avaliar a influência da técnica de alisamento na estabilidade de cor e rugosidade superficial de duas resinas compostas. Material e método: Os grupos de amostras (n=10) foram divididos conforme a resina composta (FiltekTM Z250 XT e FiltekTM Z350 XT) e as técnicas empregadas: tira de poliéster, espátula, pincel seco, selante de superfície. A cor e a rugosidade da superfície foram avaliadas por espectrofotômetro (espaço de cor CIELab) e rugosímetro (corte padrão de 0,8 mm), respectivamente, após o armazenamento em água. Posteriormente, as amostras foram imersas em café por 48h e a cor final foi aferida. Os dados foram analisados usando teste ANOVA e Tukey post hoc (α = 5%) e a correlação entre rugosidade da superfície (Ra) e variação de cor (∆Eab) através do coeficiente de correlação de Pearson. Resultado: As técnicas de alisamento influenciaram a Ra e a ∆Eab em ambas as resinas compostas. Os grupos tratados com selante de superfície apresentaram maior diferença na ∆Eab. A resina FiltekTM Z250 XT apresentou maior estabilidade de cor comparada à FiltekTM Z350 XT, independentemente da técnica utilizada. A Ra das técnicas de alisamento foi semelhante entre os compósitos, exceto para o grupo do líquido modelador da FiltekTM Z350 XT, que apresentou os menores valores. Uma correlação entre Ra e manchamento (p = 0,268) foi identificada. Conclusão: A estabilidade da cor e a Ra são influenciadas pelas técnicas de alisamento utilizadas

Micromorphological Evaluation of Dentin Treated with Different Desensitizing Agents

Introduction: The purpose of a desensitizing agent is a permanent coating or filling of dentin surface. Morphological analysis in vitro of this treated surface is essential to understand the interaction between desensitizing agent and hypersensitive dentin. The aim was to evaluate the morphology of four dentin surface treated with desensitizing agents.Methods: This was an in vitro laboratory study, where fifteen specimens from extracted human premolars were obtained. The enamel was removed to expose the dentin surface, polished with silicon carbide abrasive papers and etched with 6% citric acid for 2 min. The specimens were randomly divided into 5 groups: G1 - without treatment (control) (C), G2 - fluoride varnish (FV), G3 - potassium oxalate (PO), G4 - 2-step self-etching adhesive system (AS), G5 - diode laser (DL). The specimens were cleaved in the lingualbuccal direction, prepared for analysis by Scanning Electron Microscope and the surface and interior of the dentinal tubules were observed at 1500× magnification.Results: In the control group, the dentin etching promoted smear layer removal and exposure of dentinal tubules. In the group of fluoride varnish, a film was observed on the surface, with plugs of varnish into tubules. In the group of oxalate, partial obliteration of the tubular entrances was observed. In the group of the adhesive system, the tubules were obstructed through the formation of hybrid layer and a physical barrier on the surface. In the group of the diode laser, dentin melting and solidification with partial occlusion of dentinal tubules were observed.Conclusions: All desensitizing agents evaluated demonstrated ability to modify the surface of dentin, with partial or total occlusion of dentinal tubules. Thus, it is suggested to do more clinical studies to verify the effectiveness of the findings

Resistance to degradation of restorations on sound and affected dentin of primary teeth submitted to mechanical and carious challenges

Este estudo objetivou investigar a resistência à degradação de restaurações de cimento de ionômero de vidro modificado por resina (CIVMR) e adesivo/resina composta sobre dentina sadia e afetada por cárie de dentes decíduos submetidas a desafio cariogênico e ciclagem mecânica, por meio de teste de microtração e nanoinfiltração. Cavidades oclusais tipo Classe I foram preparadas em 60 molares decíduos esfoliados. Metade dos dentes foi submetida ao processo de indução de cárie artificial, por meio de ciclagem de pH. Os dentes foram aleatoriamente restaurados com um dos dois materiais: um CIVRM (Vitremer®) e um sistema adesivo de condicionamento total (Adper Single Bond 2®) seguido de resina composta (Filtek Z100®). Após 24 horas de armazenagem em água a 37°C, as amostras dos grupos controle seguiram para os procedimentos de teste, enquanto as demais foram re-divididas e submetidas a dois métodos de desafio: desafio cariogênico (ciclagem de pH) e ciclagem mecânica (50.000 ciclos, 90 N, 3 Hz). Para os testes, os dentes foram seccionados em fatias seriadas de aproximadamente 1mm de espessura, das quais uma foi separada para o teste de nanoinfiltração e as demais foram seccionadas no sentido perpendicular de forma a obter espécimes em formato de palito com 1 mm2 de área, que foram fixados a uma máquina de ensaios universal e submetidos ao teste de microtração. Os valores nominais de resistência de união foram registrados em MPa e analisados por meio de ANOVA e testes de comparações múltiplas de Games-Howel (=0,05). As fatias designadas para o teste de nanoinfiltração foram impermeabilizadas com esmalte exceto nas interfaces e imersos em nitrato de prata amoniacal por 24 horas para evidenciação dos espaços nanométricos e sinais de degradação nas interfaces. Após a imersão em solução reveladora, essas fatias foram preparadas e observadas em MEV, utilizando modo de elétrons retroespalhados. A nanoinfiltração nas interfaces foi mensurada com o programa Leica QWin, registradas em m2 e analisadas por meio de ANOVA e teste de comparações múltiplas de Tukey-Kramer. A resistência de união do Vitremer não foi comprometida pela condição da dentina (sadia ou afetada). Contrariamente, o adesivo Single Bond 2® apresentou valores de resistência adesiva significativamente menores quando aderido à dentina afetada por cárie. A ciclagem mecânica não influenciou a resistência de união para ambos os materiais, enquanto o desafio cariogênico resultou em um decréscimo significativo na resistência adesiva do Adper Single Bond 2®, mas não para as restaurações de Vitremer®. O padrão de falha misto foi predominante em todos os grupos. Em relação à nanoinfiltração, o Vitremer® não apresentou diferença no padrão de infiltração em função do substrato sadio ou cariado. Em contrapartida, o adesivo Adper Single Bond 2® apresentou maiores áreas de infiltração de prata nas interfaces com dentina cariada em comparação à dentina sadia. Os desafios cariogênico e mecânico, por sua vez, não influenciaram a infiltração de prata para nenhum dos materiais e substratos. Em conclusão, o substrato cariado e o desafio cariogênico negativamente afetam o comportamento das restaurações de adesivo/resina composta, mas não afetam para as restaurações de CIVRM.This study aimed to investigate the resistance to degradation of resin modified glass ionomer cement (RMGIC) and adhesive/composite restorations on sound and caries-affected dentin of primary teeth subjected to carious challenge and load-cycling, by means of microtensile test and nanoleakage. Occlusal class I cavities were prepared on sixty sound exfoliated second primary molars. Half teeth were submitted to pH-cycling to induce artificial caries lesion. Teeth were randomly restored with one of the two materials: (1) a RMGIC (Vitremer®) and a (2) a total-etch adhesive system (Adper Single Bond 2®) followed by composite resin (Filtek Z100®). After storage in distilled water 37°C for 24 hours, sample from control groups followed to test procedures while the other ones were re-divided and submitted to two different aging methods: carious challenge (pH-cycling) and load-cycling (50 000 cycles, 90N, 3Hz). For testing, teeth were sectioned into about 1mm slabs, from which, one was separated for nanoleakage testing and the others were perpendicularly sectioned into 1mm2 beams that were tested to failure in tension in a universal testing machine. Data on microtensile bond strengths were registered in MPa and analyzed by ANOVA and Games-Howell multiple-comparisons tests (=0.05). Slabs meant for nanoleakage testing were coated with nail varnish except for the bonded interfaces, and immersed in ammoniacal AgNO3 for 24 hours in order to disclose nanometer-sized spaces and degradation signs within interfaces. After immersion in photodeveloping solution, bonded sections were prepared and observed under SEM using the backscattered electron mode. Nanoleakage patterns at interfaces were measured using Leica QWin, registered in m2 and analyzed by ANOVA and Tukey-Kramers multiple-comparisons tests. Vitremer bond strength was not affected by dentin condition (sound or affected). Conversely, Adper Single Bond 2® showed significantly lower bond strength values when bonded to caries-affected dentin. Load-cycling did not influence bond strength for both materials. While carious challenge resulted in a significant decrease in microtensile bond strengths of Adper Single Bond 2®, but did not for Vitremer restorations. The mixed failure pattern was predominant in all groups. Concerning nanoleakage, Vitremer® did not show difference in leakage pattern between sound and caries-affected dentins. In contrast, the adhesive Adper Single Bond 2®, presented greater leakage areas at affected dentin interfaces than sound ones. The cariogenic and mechanical challenges did not influence silver penetration for none of the materials and substrates. In conclusion, the caries-affected substrate and the cariogenic challenge negatively affected the behavior of the adhesive/composite restorations, but did not affect for RMGIC restorations

Avaliação do potencial cariogênico de medicamentos pediátricos

O objetivo desta pesquisa foi avaliar o potencial cariogênico de seis medicamentos pediátricos através da verificação dos edulcorantes presentes na fórmula, do potencial de causar xerostomia e da frequência de ingestão, pesquisados na bula dos medicamentos. Foi também verificado o pH endógeno das medicações através do pHmetro Quimis, modelo Q 400-A. As medicações selecionadas para avaliação foram àquelas mais citadas em pesquisa prévia realizada nas Clínicas de Odontopediatria da UFSM. Foi verificado que a maior parte das medicações avaliadas continham sacarose em sua composição e o pH endógeno de todos os medicamentos foi ácido, sendo inferior ao pH crítico para desmineralização do esmalte em 2/3 deles. O único medicamento encontrado com potencial de causar xerostomia foi o Claritin

Evaluation of the methodologies used in clinical trials and effectiveness of chemo-mechanical caries removal with CarisolvTM Avaliação das metodologias utilizadas nos ensaios clínicos e efetividade da remoção químico-mecânica de tecido cariado com Carisolv®

This investigation aims to discuss the methodologies applied in clinical trials published about CarisolvTM, in order to assess the best scientific evidence concerning chemo-mechanical caries removal. Papers concerning the use of CarisolvTM were sought using a search strategy. The titles and abstracts of all the reports identified through the search were analyzed by a single reviewer. The inclusion criterion involved: clinical trials having CarisolvTM in one of the study groups. Then, those that fulfilled the inclusion criterion underwent methodology assessment and data extraction. Only 12 papers met the inclusion criterion. It was observed that none of these studies complied with all the evaluated research methodological principles required in order to have power of evidence generation. CarisolvTM proved to be effective in caries removal. Appointment mean time was greater, but the perceived time was shorter than that using conventional techniques due to patients' perception of more comfort and a reduction of anesthesia needs. There were no adverse effect in long-term assessments. In studies with microbiological evaluation of the remaining dentine, it was observed that both the conventional and chemo-mechanical methods produced statistically significant reduction on counts of viable microorganisms.Esta investigação objetiva discutir as metodologias aplicadas em ensaios clínicos publicados sobre Carisolv®, para verificar a melhor evidência científica concernente à remoção químico-mecânica de tecido cariado. Artigos referentes ao uso de Carisolv® foram procurados utilizando-se uma estratégia de busca. Os títulos e resumos de todos os estudos identificados pela procura foram analisados por um único revisor. O critério de inclusão envolveu: ensaios clínicos contendo o sistema Carisolv® em um dos grupos de estudo. Os estudos que preencheram o critério de inclusão foram submetidos à avaliação de metodologia e extração de dados. Somente 12 artigos preencheram o critério para inclusão. Foi verificado que nenhum desses estudos obedeceu a todos os princípios metodológicos considerados necessários para que uma pesquisa tenha poder de geração de evidências. O Carisolv® demonstrou ser eficaz na remoção de tecido cariado. O tempo de consulta foi maior, mas o tempo percebido foi inferior em comparação ao tempo das técnicas convencionais devido à percepção dos pacientes de mais conforto e de redução da necessidade de anestesia. Não houve efeito adverso em avaliações a longo prazo. Em estudos com avaliação microbiológica da dentina remanescente foi verificado que ambos os métodos convencional e químico-mecânico produziram redução significativa na contagem de microrganismos viáveis

Evaluation of the surface roughness of a nanofilled composite resin submitted to different smoothing and finishing techniques

Abstract Introduction: Controlling the surface smoothness characteristics of the composite resin when performing a direct restorative technique is one of the factors involved in achieving restorative success. Objective: The purpose of this study was to evaluate the surface roughness of a nanofilled composite resin submitted to different smoothing and finishing techniques. Material and method: Fifty test specimens were made with the Z350 XT composite resin (3M ESPE) and then divided into five study groups according to the smoothing and finishing method applied, as follows: G1 (control), polyester strip; G2, composite spatula; G3, brush cleaned with absolute alcohol and dried; G4, brush cleaned with absolute alcohol, dried and moistened with Single Bond (3M ESPE); and G5, brush cleaned with absolute alcohol, dried and moistened with Natural Glaze surface sealant (DFL). After fabrication, the specimens were stored for 24 h in deionized water. The surface roughness of the specimens was measured using a profilometer. Surface roughness means were compared by analysis of variance followed by Tukey’s test at a level of significance of 5%. Result: The lowest surface roughness was observed in G1 (control group) and the highest, in G3. G5 had lower surface roughness values compared to the other test groups, and presented values similar to those of the control group. Conclusion: The smoothing and finishing techniques influenced the surface roughness of the composite resin. Application of the surface sealant by the copolymerization technique resulted in lower roughness values. The use of a clean, dry brush promoted roughness values beyond the acceptable limit, and is therefore liable to compromise the performance of composite resin restorations

Evaluation of the surface roughness of a nanofilled composite resin submitted to different smoothing and finishing techniques

Abstract Introduction: Controlling the surface smoothness characteristics of the composite resin when performing a direct restorative technique is one of the factors involved in achieving restorative success. Objective: The purpose of this study was to evaluate the surface roughness of a nanofilled composite resin submitted to different smoothing and finishing techniques. Material and method: Fifty test specimens were made with the Z350 XT composite resin (3M ESPE) and then divided into five study groups according to the smoothing and finishing method applied, as follows: G1 (control), polyester strip; G2, composite spatula; G3, brush cleaned with absolute alcohol and dried; G4, brush cleaned with absolute alcohol, dried and moistened with Single Bond (3M ESPE); and G5, brush cleaned with absolute alcohol, dried and moistened with Natural Glaze surface sealant (DFL). After fabrication, the specimens were stored for 24 h in deionized water. The surface roughness of the specimens was measured using a profilometer. Surface roughness means were compared by analysis of variance followed by Tukey’s test at a level of significance of 5%. Result: The lowest surface roughness was observed in G1 (control group) and the highest, in G3. G5 had lower surface roughness values compared to the other test groups, and presented values similar to those of the control group. Conclusion: The smoothing and finishing techniques influenced the surface roughness of the composite resin. Application of the surface sealant by the copolymerization technique resulted in lower roughness values. The use of a clean, dry brush promoted roughness values beyond the acceptable limit, and is therefore liable to compromise the performance of composite resin restorations

Artificial methods of dentine caries induction: A hardness and morphological comparative study

Objective: To assess the ability of two chemical and a microbiological methods to produce dentine caries lesions resembling naturally developed dentine caries lesions.Design: Forty sound second primary molars were divided into four experimental groups according to the method to produce artificial caries lesions: (1) sound (negative control); (2) acidified gel; (3) pH-cycling; and (4) microbiological, all for 14 days. Ten second primary molars presenting natural dentine caries lesions comprised the (5) positive control group. After the artificial caries induction, all samples were longitudinally sectioned and polished in order to obtain Knoop microhardness values from 10 to 500 mu m depth from the bottom of the cavities. Morphological analysis of the surfaces was carried out by SEM. Hardness data were compared among the five experimental groups using One-Way ANOVA and post hoc SNK's test.Results: The hardness values of chemically created caries-like lesions did not differ from that of natural caries lesions on shallower depths. The results indicated that chemical caries induction methods promote a superficial demineralization and that pH-cycling is more effective than acidified gel. The former, produced a thicker layer of demineralization, with similar hardness values than natural lesions. Despite the microbiological method provided an excessive softness of the primary dentine, this method presented morphology more comparable to natural lesions.Conclusions: pH-cycling is more appropriated to simulate a substrate that resembles affected caries dentine layer, after caries removal. The microbiological method seems more indicated to simulate a dentine caries lesion with an infected layer, previously to caries removal. (C) 2009 Elsevier Ltd. All rights reserved.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq