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Journal of Prosthetic Dentistry
Get PDFp. 264–268Statement of problem
Many studies have compared cement-retained and screw-retained implant prostheses. One disadvantage of cement-retained crowns is the lack of predictable retrievability, which can be overcome by creating a screw access channel on the occlusal surface.
Purpose
The purpose of this study was to evaluate the influence of a screw access channel on the retention of cement-retained implant prostheses.
Material and methods
Sixteen cast metal crowns were fabricated and divided into 2 groups of 8 specimens each: a control group (CG) comprising 8 cement-retained prostheses and an experimental group (EG) comprising 8 cement-retained prostheses with a screw access channel. Castings were cemented to abutments with RelyX U100, and the opening screw access channels of EG were filled with photopolymerized composite resin (Filtek Supreme XT). The tensile force required to separate the cemented castings from the abutments was measured after 24 hours of cementation with a universal load-testing machine (EMIC DL 2000). A significance level of 5% (α=.05) was considered statistically significant (Statistical analysis was performed by Kolmogorov-Smirnov non-parametric test and the Student t test).
Results
The mean force required to achieve the separation was 191 N for the control group (CG) and 161 N for the experimental group (EG). As shown by the nonparametric Kolmogorov-Smirnov test, the dependent variable followed a normal distribution (P=.923). The Student t test found no statistically significant difference (P=.353) between the groups.
Conclusions
Fabricating cement-retained implant prostheses with screw access does not compromise or reduce the retention of the crowns.Salvado
Comparação da adaptação marginal de peças protéticas confeccionadas no sistema CAD/CAM e no sistema termo-prensável: uma revisão de literatura
Get PDFTCC (graduação) - Universidade Federal de Santa Catarina. Centro de Ciências da Saúde. Odontologia.Com superioridade estética, alta resistência e longevidade, as restaurações livres de metal são hoje uma excelente escolha quando comparadas às restaurações com infraestrutura metálica. Além destes pré-requisitos citados, outro fator de fundamental importância é a adaptação marginal, que pode definir o sucesso ou insucesso de qualquer procedimento restaurador. O presente trabalho busca realizar uma revisão da literatura atual e coletar dados significativos a respeito da adaptação marginal de peças protéticas confeccionadas pela técnica de fresagem, denominada comumente de CAD/CAM, comparativamente a outros sistemas cerâmicos, visando sanar dúvidas e a fim de possibilitar a escolha da técnica mais adequada para as diferentes situações clínicas. Através dessa revisão de literatura, pode-se identificar um valor de limite para o que é considerável clinicamente aceitável em relação à adaptação marginal de peças protéticas (120 µm), onde observou-se que praticamente todos os estudos avaliando peças fabricadas através dos sistemas CAD/CAM e de cerâmica injetável apresentaram valores dentro desse padrão. Variações destes valores ocorrem conforme as diferentes marcas comerciais avaliadas pelas pesquisas, com a adaptação marginal apresentando-se maior ou menor, indicando a importância desse fator na hora de escolher o sistema a ser utilizado. Outros fatores, como a adaptação interna, também influenciam na durabilidade da peça, devendo ser também analisados na escolha do sistema. Assim, conclui-se que ambos os sistemas estão bem indicados para confecção de trabalhos protéticos, vistos que seus resultados não apresentam, de forma geral, diferenças significantes entre si que possam servir de contraindicação para qualquer um dos sistemas.With aesthetic superiority, high strength and longevity, metal-free restorations are an excellent choice when compared to restorations with metal infrastructure. Besides these mentioned prerequisites, another highly important factor is marginal adaptation, which can define the success or failure of any restorative procedure. This study aims to conduct a review of current literature and collect meaningful data about marginal adaptation of prosthetic pieces made by milling technique, commonly referred to as CAD / CAM, compared to other ceramic systems in order to answer questions and to enable the choosing the most appropriate technique for different clinical situations. Through this literature review, one can identify a limit value for what is clinically acceptable in relation to marginal fit of prosthetic pieces (120 µm), where it was observed that virtually all studies evaluating pieces fabricated using CAD systems / CAM and press ceramic showed values within this limit. Variations of these values occur according to the different brands evaluated by this research, with the marginal adaptation presenting higher or lower gaps, indicating the importance of this factor when choosing the system to be used. Other factors, such as internal adaptation, also influence the durability of the piece, and should too be analyzed in selecting the system. Thus, it is concluded that these systems are well suited for making prosthetic work, seen that their results do not show, in general, significant differences that could contraindicated them
Magnetic retention in Prosthetic Dentistry
No full textMagnets are a popular method of attaching removable prostheses to either retained roots or osseointegrated implants. This paper reviews the development of magnets in dentistry and describes the different types of magnetic attachments that are available. The clinical applications of magnets in prosthetic dentistry are illustrated and future technological advancements indicated. Whilst different magnetic materials that mirrored the developing technology have been used, the main drawback to their use is the potential of corrosion of the magnetic material in the mouth. However, newly emerging technologies may provide a solution to this problem, allowing the continued use of magnets in prosthetic dentistry
Avaliação clínica da influência da iluminação na seleção visual da cor
Get PDFDissertação (mestrado) - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde. Programa de Pós-Graduação em OdontologiaObjetivo: O propósito deste trabalho foi avaliar a influência da iluminação na seleção visual da cor. Metodologia: Sessenta alunos do curso de Graduação em Odontologia da Universidade Federal de Santa Catarina, com uma idade média de 23 anos, selecionaram pelo método visual, a cor do incisivo central superior direito de uma paciente, utilizando duas escalas de cor VITA Classical (VC) e VITA Linearguide 3D Master (V3D) (VITA Zahnfabrik, Alemanha), com e sem o auxilio de uma fonte de iluminação padrão de 6.500K. Resultados: Para controle, a cor foi obtida por seleção instrumental com espectrofotômetro. Na análise estatística, foi aplicado o Teste de proporções entre os grupos testados, Grupo 1 com luz ambiente e Grupo 2 com iluminação padronizada, sendo que as diferenças estatísticas foram observadas diferenças estatísticas entre VC (luz ambiente) (3,3%) e V3D (luz ambiente) (6,6%) (p= 0,5536); VC (luz padronizada D65) (50%) e V3D (luz padronizada D65) (63,3%) (p= 0,2974); VC (luz ambiente) (3,3%) e VC (luz padronizada D65) (50%) (p<0.0001); V3D (luz ambiente) (6,6%) e V3D (luz padronizada D65) (63,3%) (p<0.0001). Mediante o teste Mann-Whitney, foram comparados os escores de acertos dos dois grupos, para as seleções visuais com e sem iluminação padronizada. Conclusão: Independente da escala de cor, a utilização de uma fonte de iluminação padronizada de 6.500K aumenta a probabilidade de acerto na seleção da cor na clínica odontológica.Purpose: The purpose of this study was to analyze the influence of illumination on the visual shade selection of tooth color. Methods: Sixty undergraduate students of the Universidade Federal de Santa Catarina school of dentistry, with a mean age of 23 years, selected by the visual method, the color of a maxillary right central incisor of one patient, using two types of shade guides, VITA Classical (VC) and VITA Linearguide 3D-Master (V3D) (VITA Zahnfabrik, Germany) with and without the use of a standard artificial daylight source 6500K. Results: The results were compared with prior spectrophotometric data. Statistical analysis was applied to test of proportions between the groups, and statistical differences were found between: VC (ambient light) (3,3%) and V3D (ambient light) (6,6%) (p= 0,5536); VC (standard daylight D65) (50%) and V3D (standard daylight D65) (63,3%) (p= 0,2974); VC (ambient light) (3,3%) and VC (standard daylight D65) (50%) (p<0.0001); V3D (ambient light) (6,6%) and V3D (standard daylight D65) (63,3%) (p<0.0001); By the Mann-Whitney test, were compared the scores of correct answers of the two groups for the visual shade selections with and without the use of the standard illuminant D65. Conclusions: Regardless of the shade guide, the use of a standardized light source 6.500K increases the probability of correct color selection in the dental clinic
Prosthetic Dentistry on the Internet
Get PDFSince the late sixties when the ARPANET- first computer network was developed, Internet has had a great impact on the way of thinking, buying, teaching, learning and everyday life, including dentistry. The beginning of internet in science and research, has proved to be irreplaceable way of communication between researchers all over the word. Currently (April 2002) one of the most popular search engines on the net (Google) indexed about 2 billion web pages, 35 million of non HTML documents and 700 million Usenet messages, which makes the Internet the greatest information service ever. The purpose of this study was to investigate which part of the web space is taken by prosthetic dentistry and the importance which it gains on the Internet. The method used was standard Internet search engine keyword queries preformed using six web search engines: Google, Lycos, Infoseek, AltaVista, Northern Light, HotBotand Excite. Research results suggest that there is currently (May 2002) about 30 thousand pages (0.0015% of searched web space) which contain terms: prosthetic dentistry or prosthodontics and about one thousand web pictures connected to these terms. Content analysis suggests that quality and real informative value of the majority of those pages is low. To conclude-informative space on the Internet concerning
prosthetic dentistry is still in development and the need for confirmation and authorized information is obvious
Magnets in prosthetic dentistry
No full textMagnetic retention is a popular method of attaching removable prostheses to either retained roots or osseointegrated implants. This review chronicles the development of magnets in dentistry and summarizes future research in their use. The literature was researched by using the Science Citation Index and Compendex Web from 1981 to 2000. Articles published before 1981 were hand researched from citations in other publications. Articles that discussed the use of magnets in relation to prosthetic dentistry were selected
Análise de falhas mecânicas em próteses fixas realizadas na clínica III do curso de Odontologia da UFSC – Um estudo piloto
Get PDFTCC (graduação) - Universidade Federal de Santa Catarina. Centro de Ciências da Saúde. Odontologia.Estudos sobre a incidência de falhas em Próteses Fixas realizadas em Cursos de Graduação em Odontologia são escassos no Brasil. Esse trabalho avaliou a incidência das falhas mecânicas em Próteses Fixas (PF) realizadas pelos alunos na Clínica III (ODT7016) do Curso de Graduação em Odontologia da UFSC. Pacientes atendidos na universidade que tiveram suas próteses confeccionadas entre 2010 e 2014 foram submetidos à avaliação clínico-radiográfica e ao exame periodontal. Buscou-se também informações relevantes nos prontuários dos pacientes armazenados no Serviço de Triagem. Vinte pacientes atenderam aos critérios de elegibilidade, totalizando 60 PF (26 coroas unitárias, 25 retentores intrarradiculares e 9 próteses parciais fixas). As falhas protéticas mais prevalentes foram: impacção alimentar por falha no contato proximal (37,1%), incompatibilidade de cor e de forma (17,1%), desadaptação marginal (11,4%), desgaste do material de revestimento (8,3%) e contato prematuro (5,7%). Conclui-se que a taxa de sucesso dos tratamentos com próteses fixas realizadas nesta universidade foi de 35%. Com isso, sugere-se um maior rigor no planejamento e execução dos tratamentos, desde o preenchimento do prontuário à inserção dos pacientes no programa de manutenção e controle das próteses após o término de seu tratamento para obter-se maior longevidade e previsibilidade das PF
Marginal fit changes during porcelain firing cycles
No full textThe marginal fit changes that occur during the porcelain firing cycles of palladiumcopperand nickel-chromium copings both with shoulder and chamfer finish lines were investigated with scanning electron microscopy. Three copings from each alloy test group were used as nonporcelainized controls. Comparisons of the firing cycles revealed a greater change during the degassing stage, and the opaque firing caused a decrease in marginal gap. There was a small increase in gap size after firing body porcelain. The marginal fit change for the palladium-copper copings (19.39 μm) during degassing was significantly greater than that for the nickelchromium copings (8.65 μm). However, no significant differences were found when the effects of margin design and porcelain proximity to fit of metal-ceramic crowns were compared. © 1995 The Editorial Council of The Journal of Prosthetic Dentistry
Selected Applications for Current Polymers in Prosthetic Dentistry - State of the Art
No full text
Background:
Polymers have wide applications in medicine, including dentistry, i.e.
in prosthetic dentistry.
Aim:
The following paper is aimed at demonstrating the applications of selected modern
polymers in prosthetic dentistry based on the reported literature.
Material and Methods:
The study was conducted using the PubMed, SCOPUS and CINAHL
databases in relation to documents published during 1999–2017. The following keywords were
used: polymers with prosthetic dentistry, impression materials, denture base materials, bite
registration materials, denture soft liners, occlusal splint materials and 3D printing. Original
papers and reviews which were significant from the modern clinical viewpoint and practical
validity in relation to the possibility of using polymeric materials in prosthetic dentistry were
presented.
Results:
Denture base materials were the most commonly modified polymers. Modifications
mainly concerned antimicrobial properties and reinforcement of the material structure by introducing
additional fibers. Antimicrobial modifications were also common in case of relining
materials.
Conclusion:
Polymeric materials have widely been used in prosthetic dentistry. Modifications
of their composition allow achieving new, beneficial properties that affect the quality of patients’
life. Progress in science allows for a more methodologically-advanced research on the
synthesis of new polymeric materials and incorporation of new substances into already known
polymeric materials, that will require systematization and appropriate classification.
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Estudo da resistência de união entre a resina composta e a resina acrílica submetida a diferentes tratamentos de superfície
Get PDFTCC (graduação) - Universidade Federal de Santa Catarina. Centro de Ciências da Saúde. Odontologia.O presente estudo tem como objetivo principal avaliar a resistência de união entre a resina composta e a resina acrílica submetida a diferentes tratamentos de superfície. Os corpos de prova, produzidos em resina acrílica unida à resina composta, foram divididos em cinco grupos. Nos primeiros dois grupos, denominados controle, sendo compostos por duas partes de resina acrílica, foram realizados tratamento de superfície através do condicionamento com monômero por 3 segundos (C3) e 180 segundos (C180). No terceiro (E3) a superfície foi condicionada com monômero por três segundos, aplicado adesivo que foi ativado antes de receber a resina composta (E3). No quarto grupo (E60) condicionamos com monômero por 60 segundos e adesivo (E60). E a quinta superfície foi condicionada com monômero por 180 segundos, aplicação de silano e adesivo (E180). Após o corte em palitos, os espécimes foram individualmente fixados a um dispositivo próprio para o teste em uma Máquina de Ensaio Universal (Instron). Os testes foram realizados com velocidade constante de 0,5 mm/min até o momento em que houve a ruptura das amostras. Os valores de resistência à microtração foram mensurados em N, e transformados em MPa. Entre os grupos estudados, o grupo E180 apresentou os melhores resultados (32,9 MPa).The present study evaluated the bond strength between a composite resin and a self cured acrylic resin that received different surface treatments. The specimens, made of composite bonded to an acrylic resin and acrylic resin only, were divided in 5 groups. In two of the control groups, surface treatment was conditioning with MMA for 3 (C3) and 180 (C180) seconds respectively, in the third group the surface was conditioned with MMA for 3 seconds (E3), adhesive was applied and cured prior to the composite application, on the fourth group the MMA conditioning was for 60 seconds and adhesive (E60) and the fifth group had the surface conditioned with MMA for 180 seconds, silane application and adhesive (E180). After making the sticks, the specimens were individually put in a proper device for micro tensile testing in an Instron Universal Testing Machine. The tests were run under constant speed of 0.5mm/min until peak break. The bond strength values were measured in N and transformed in MPa, dividing the strength. Among the studied groups, group E180 had the best results (32,9 MPa)
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