Resumo Introdução Recentemente, vêm surgindo no mercado alguns alginatos de armazenamento prolongado. Não há, no entanto, um consenso na literatura a respeito da estabilidade dimensional destes materiais durante este armazenamento Objetivo Avaliar, por meio de método prático experimental, a estabilidade dimensional de um alginato de armazenamento tardio. Material e método O material de moldagem utilizado foi o alginato Hydrogum 5 (Zhermack). Uma matriz metálica cilíndrica foi utilizada para a realização das moldagens, com 38 mm de diâmetro externo, 30 mm de diâmetro interno e cuja superfície superior apresenta três linhas paralelas entre si com 25 mm de comprimento e 20, 50 e 75 µm de largura. Após o tempo de geleificação do material de moldagem, 16 moldes foram colocados em um umidificador e essas amostras foram fotografadas utilizando-se uma câmera digital (Canon EOS Rebel 3Ti, Canon) associada a um software para análise das imagens obtidas (ImageJ 1.52a, U.S. National Institutes of Health; DI). A calibragem da régua foi 10 cm e, posteriormente, três linhas foram medidas três vezes, para se obter uma média dos comprimentos das linhas. As amostras foram fotografadas nos seguintes intervalos: imediatamente, 24, 48, 72, 96 e 120 horas. Resultado Os dados mostraram diferenças estatisticamente significantes para o fator tempo quando comparada a leitura imediata com os demais períodos de tempo de leitura (p<0,001) e quando comparada a leitura após 24 h de armazenagem com os demais períodos de tempo (p<0,001). Não houve diferença estatística (p>0,05) quando os tempos de armazenamento de 48 h, 72 h, 96 h e 120 h foram comparados entre si. Todos os valores encontravam-se dentro dos valores preconizados pela ISO 21563:2013. Conclusão Os moldes dos alginatos testados podem ser armazenados por até cinco dias em 100% de umidade relativa.
This article presents a clinical case involving the integrated application of CAD/CAM and DSD. DSD – Digital Smile Design – assists in obtaining a treatment plan adjusted to the patient’s facial features, achieving the best aesthetic potential. The integration between DSD and CAD/CAM allows for greater fidelity in respect to the original plan. A patient received a rehabilitation with veneers milled out of leucite-reinforced feldspathic ceramics, using the CAD/CAM system and a DSD-obtained digital wax-up. This workf low simplifies design and fabrication, providing greater accuracy and predictability to the rehabilitation process. The digital planning and development of the mockup also makes clinical conditions more predictable. Making ceramic veneers using the CAD/CAM technique requires judicious adhesive cementation, and also an accurate practical and theoretical knowledge on the part of the professional.
Resin matrix ceramics consist in a polymeric matrix with predominantly inorganic refractory compounds which may include porcelain, glass, ceramics, and glass ceramics, and are divided into three subgroups: Nanoceramics, Vitroceramics, and Zirconia-silica. The aim of this study was to compare, through a literature review, the mechanical and biological properties of resin matrix ceramics, with glass matrix ceramics and polycrystalline ceramics. After reviewing 44 articles found in the US National Library of Medicine (PubMed) database (studies published in English, human clinical studies, in vitro or in vivo studies) that evaluated some properties of this material, such as elasticity modulus, wear resistance, adhesiveness, stain resistance and hardness, this article concluded that, although they belong to the same group, resin matrix ceramics are different from each other due to their microstructures. Moreover, when compared to other ceramic groups, it showed some superior properties, such as flexural strength, fatigue strength and internal adaptation.
Objective: this study aims to evaluate, through a literature review, the adhesiveness of zirconia and lithium disilicate after different surface treatments and to establish a protocol to be followed in the clinic. Material and Methods: the methodology was developed from the electronic search in the database National Library of Medicine (PUBMED), using the terms "zirconia surface treatment bond strength" and "lithium disilicate surface treatment", including only clinical studies in humans, in-vitro or in-vivo, and literature reviews. All articles were published in the last 16 years and written in the English language. Results: after selecting the scientific articles following the inclusion and exclusion criteria, 26 studies remained for the literature review. Conclusion: after the review, it was concluded that cementation protocols for lithium disilicate and zirconia are different due to their different microstructures. Lithium disilicate should be conditioned with 4.5% hydrofluoric acid followed by phosphoric acid smearing, silane (hot air drying), and universal adhesive application. On the other hand, zirconia restorations should be sandblasted with silica-coated aluminum oxide followed by silanization or blasting with aluminum oxide, associated with zirconium primer application.
Introduction: The discovery of titanium osseointegrated implants enabled the development of screw or cement-retained dental prostheses. However, each retention method involves different aspects. Objective: this study aims at reviewing the literature of in vitro and in vivo studies of the last 7 years on the mechanical, biological, aesthetic and occlusal properties and the cost of screw and cementretained prostheses to identify what can promote greater longevity and economy by considering the patient's clinical framework. Data sources: Our method was based on the collection of scientific articles published in English from 2012 to 2018 in the PubMed database. Summary of the findings: we noted that in some clinical cases, a retention method was more appropriate than the other, as seen in the access to the posterior region or the palatal face of the crowns, the position/ angulation of implants in the anterior region, the patient's health and economic conditions. Both protheses can suffer or not from mechanical and biological complications. Reversibility can also be associated to cement-retained protheses. There are alternatives to screwed prosthetics to achieve satisfactory aesthetics in the anterior region despite being more expensive. Ideal occlusion tends to be more easily achieved by cemented prosthesis as it avoids prosthetics screws and the formation of crown holes, despite the contributions of correct planning followed by the analysis of static and in motion occlusions. Conclusion: each retention method has its advantages and disadvantages. Therefore,the best method is the one that best fits the characteristics and needs of each patient.
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