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Dissertations / Theses on the topic 'Dental materials Evaluation'
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1
Li, Jingjing. "Evaluation of different dental materials using a slugging fluidized bed." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0016/MQ58054.pdf.
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Shabanian-Borojeni, Mitra. "Wear studies of enamel and some restorative materials." Title page, contents and summary only, 2001. http://web4.library.adelaide.edu.au/theses/09PH/09phs5241.pdf.
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Includes bibliographical references (leaves [1-20]). A systematic analysis of wear involving the in vitro analysis of the wear of standard composite resin and glass ionomer cements restorations under controlled conditions; and, the qualitative and quantitative investigation of wear over a range of pH's and loads which might be encountered clinically in order to develop a "wear map" of the micromorphology of wearing teeth and restorations and a systematic modeling of wear rates.
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Sidhu, Sharanbir Kaur. "Resin-modified glass ionomer restorative materials : an evaluation involving microscopy." Thesis, King's College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.362847.
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Murphy, Matthew. "Evaluation of dental implant materials and interactions with calcium phosphate solutions." Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/evaluation-of-dental-implant-materials-and-interactions-with-calcium-phosphate-solutions(62aff83f-146d-4c79-85fd-0fb95c4d31e2).html.
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In this thesis, four experimental studies are reported. Two concern the surface structure of commercially relevant dental implant materials. Characterisation of four treated substrates supplied by Straumann AG was carried out. These include substrates equivalent to the commercially available SLA, SLActive and Roxolid implants. The materials vary in substrate alloy, commercially pure (grade 2) Ti and a TiZr alloy, and surface preparation treatments. All substrates are sandblasted and acid etched however post-etching one set are stored in air whilst the others are stored in saline. Within the work both substrate composition and surface treatment is shown to impact on the respective surface oxide thickness, crystallinity and morphology. The other two experimental studies concern calcium phosphate deposition from solution onto substrates. The first investigation is the deposition of calcium phosphate from a simulated body fluid onto implant-like substrates, shown to be structurally equivalent to the SLA and SLActive implant surfaces. The effect of surface modifications on calcium phosphate deposition is investigated; over the period investigated calcium phosphate did not deposit onto the SLA substrate, whilst deposition occurred within 3 days on the SLActive substrate. The role of Mg2+ ions in the simulated body fluid is also investigated, with increased [Mg2+] resulting in a longer induction period and modified crystallinity of the hydroxyapatite film formed. The final study is a model study of the initial calcium phosphate deposition on to substrates. TiO2 rutile (110) and Al2O3 corundum (0001) were prepared to be atomically flat and then exposed to a simple calcium phosphate solution. Changes in surface structure and surface chemistry over the first three hours of exposure were investigated. Deposition occurred rapidly on both substrates with a complete surface coverage after 3 hours.
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Lam, Wiley T. C. "In vitro evaluation of fluoride release and artificial caries formation with selected glass polyalkenoate cements." [Hong Kong] : Faculty of Dentistry, The University of Hong Kong, 1996. http://sunzi.lib.hku.hk/HKUTO/record/B3862817X.
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林德昭 and Wiley T. C. Lam. "In vitro evaluation of fluoride release and artificial caries formation with selected glass polyalkenoate cements." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B3862817X.
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Leung, Sau-kuen. "Clinical evaluation of compomers used as restorations in primary teeth." Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B2120360X.
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Hse, Mei-yin Kitty, and 許美賢. "Clinical evaluation of compomer, a polyacid-modified composite resin, in primary teeth: 1 year results." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B31954029.
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Hse, Mei-yin Kitty. "Clinical evaluation of compomer, a polyacid-modified composite resin, in primary teeth 1 year results /." Hong Kong : Faculty of Dentistry, The University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19902232.
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Leung, Sau-kuen, and 梁秀娟. "Clinical evaluation of compomers used as restorations in primaryteeth." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31954054.
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Ho, Fu-tak. "In vitro and in vivo evaluation of an improved glass-ionomer dental cement used for the atraumatic restorative treatment (ART) technique." Hong Kong : Faculty of Dentistry, The University of Hong Kong, 1996. http://sunzi.lib.hku.hk/HKUTO/record/B38628168.
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何富德 and Fu-tak Ho. "In vitro and in vivo evaluation of an improved glass-ionomer dental cement used for the atraumatic restorative treatment (ART) technique." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B38628168.
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Richey, Mark Daniel. "In-vitro evaluation of dye leakage of an MTA apical barrier at varying setting times." Morgantown, W. Va. : [West Virginia University Libraries], 2008. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5790.
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Thesis (M.S.)--West Virginia University, 2008.Title from document title page. Document formatted into pages; contains vii, 45 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 32-37).
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Loureiro, Flávia Helen Furtado. "Variações termicas ocorridas na fotoativação de composito em função da comparação de metodos de avaliação." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/290106.
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Orientador: Simonides ConsaniDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: O estudo avaliou o efeito de métodos de avaliação sobre as variações térmicas, em função de diferentes tipos de fotoativação do compósito Filtek Z250. Para o método de avaliação pelo dente foram utilizados 50 incisivos bovinos hígidos, nos quais foram feitos preparos cavitários (2x2x2mm) padronizados a 13mm da junção amelo-cementária. Os dentes foram separados aleatoriamente em 5 grupos (n=10), de acordo com o tipo de fotoativação: 1- luz halógena contínua (700 mW/cm2 por 20s); 2- luz halógena com dupla intensidade (inicial de 100 mW/cm2 por 5s obtida com espaçador, seguido de 700 mW/cm2 por 15s, totalizando 20s); 3- luz halógena intermitente (2s de ativação com 700 mW/cm2 seguido do mesmo tempo pela ausência de luz, totalizando 40s); 4- luz emitida por diodo (400 mW/cm2 por 20s); 5- luz emitida por arco de plasma de xenônio (1450 mW/cm2 por 10s). No método de avaliação pela matriz, a resina composta foi inserida num molde cúbico de silicone (2x2x2mm) apoiado numa base de resina acrílica para servir como guia do termopar. Um disco de dentina (1mm) foi colocado entre o termopar e a resina composta para simular a dentina remanescente do preparo cavitário do método de avaliação pelo dente. O protocolo experimental de fotoativação para o método de avaliação pela matriz foi similar ao método de avaliação pelo dente. As restaurações de ambos os métodos foram realizadas em ambiente controlado (37oC e 40±10% UR) e as temperaturas registradas com termômetro digital acoplado ao termopar tipo-K introduzido no canal radicular, de maneira que ficasse, no método dente, em contato com a dentina da câmara pulpar, correspondente à parede axial do preparo e no método matriz, em contato com o disco de dentina. Os dados foram submetidos à analise de variância e ao teste de Tukey em nível de 5% de probabilidade. A média da variação de temperatura registrada pela técnica da matriz (2.56oC) foi maior e com diferença estatisticamente significante quando comparada à média registrada na técnica do dente (1.17 oC), independente dos demais fatores. Houve diferença estatística significativa entre os fotoativadores quando comparados em cada método de avaliação e em todos os tipos de fotoativação quando os métodos de avaliação foram comparados entre si
Abstract: This study evaluated the effect of different methods of thermal evaluation using Filtek Z250 composite resin with different methods of photoativation. In the method of evaluation with tooth it was used 50 incisors where was prepared standardized cavities (2x2x2mm) 13 mm far from amelo-cementary junction. The teeth were randomly assigned into 5 groups (n=10), according to each light-curing method: 1- continue halogen light ( 700mW/cm2 per 20s); 2- halogen light with a soft-start mode (initial intensity of 100mW/cm2 per 5s obtained with a spacer and 700 mW/cm2 per 15s, totaling 20s); 3-intermittent halogen light (2s at 700 mW/cm2, followed by the same time of light absence, totaling 40s); 4- LED (400 mW/cm2 per 20s); PAC (1450 mW/cm2 per 10s). In the method of evaluation with matrix the resin composites were applied into a cubic elastomer mold (2x2x2mm). This mold was positioned under the acrylic resin base that guide the acess of thermocouple. Between the thermocouple and the composite, a 1.0mm dentine disc was positioned to simulated the remaining dentin of the method of evaluation with tooth. The same experimental protocol of photoativation was used for both methods. All experiments were carried out in a controlled environment (37 degree centigrates and 40±10% relative humidity). The variations of temperature(degree centigrates) were obtained using a digital thermometer attached to a type-k thermocouple, which was inserted into the root canal and in contact to the dentine of the pulp chamber (correspondent to the axial wall of the cavity) or in the matrix in contact with the dentine discs. The data were submitted to a two-way ANOVA and the means were compared by the Tukey's test (5%). The variation of temperature with the matrix technique (2.56 degrees centigrates) was higher and with significant different from the tooth technique (1.17 degrees centigrates), independent of the others factors. There was statistical difference among light cure units inside the same evaluation method and when the methods were compared.
Mestrado
Mestre em Materiais Dentários
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Taylor, Nicholas Allen. "In-vitro evaluation of dye leakage of an MTA apical barrier after irrigation with 3% soldium hypochlorite, 2% chlorhexidine, MTAD, or 17% EDTA/3% sodium hypochlorite." Morgantown, W. Va. : [West Virginia University Libraries], 2007. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5240.
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Thesis (M.S.)--West Virginia University, 2007.Title from document title page. Document formatted into pages; contains vii, 40 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 30-34).
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Ahmed, Omnia Abdelmoneim Khidir. "An in-vitro evaluation of the efficacy of oral devices to remove dental biofilm from three prosthodontic materials." University of the Western Cape, 2019. http://hdl.handle.net/11394/6635.
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Magister Scientiae Dentium - MSc(Dent)Introduction: The evolution of Dentistry witnessed an increase in fixed prostheses as opposed to removable ones. Zirconia (ZrO2) and Lithium disilicate (LDS) are becoming the material of choice in implant or tooth retained prostheses. Polyetheretherketone (PEEK) is a recent alternative as it is lighter and causes less wear of opposing retained teeth. Biofilm formation is a permanent daily struggle for patients as it can be found in nearly all surfaces exposed to the natural environment. Therefore, the interest in a new device capable of removing or reducing oral biofilm from fixed prostheses is increasing. Aquaflosser (AQ) and Waterpik (WP) are examples of these oral irrigating devices that were introduced to the dental market recently. They can be effective in removing dental biofilm from different surfaces. Purpose of study: The purpose of this study is to evaluate biofilm formation on three fixed dental substructures and to evaluate the efficacy of two oral irrigating devices on biofilm removal from these three substructures.
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Lööf, Jesper. "Calcium-Aluminate as Biomaterial : Synthesis, Design and Evaluation." Doctoral thesis, Uppsala University, Department of Engineering Sciences, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-9173.
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In this thesis different aspects of calcium-aluminate (CA) as biomaterial are presented. Calcium aluminate is a chemically bonded ceramic with inherent properties making it suitable for use as biomaterial in some applications. In this thesis the emphasis is put on the basic chemical, physical and mechanical properties that may be achieved using the CA system as well as synthesis of the CA raw material. The basis for using CA in any application is the synthesis of the raw material. Different synthesis routes for producing CA are presented with focus on high temperature routes and the micro-structural and phase development during synthesis. As a base for further understanding of the CA properties a thorough outline of the reaction chemistry for CA is presented also including a description of how the reactions may be controlled and how formulations can be designed. The surface reactions of CA when subjected to simulated body fluid showed that CA is in vitro bioactive. An in vivo study in teeth also indicates that CA produces apatite at the tooth material interface. Dental materials are subjected to a harsh environment in the mouth with high mechanical forces, erosion and thermal changes. Also the demands on precise handling characteristics are high. For these reasons the in vitro evaluation of physical and mechanical properties are important. In this work several mechanical and physical properties of Ca-based formulations for dental applications has been tested using different methods. Some attention is also put on the specific characteristics of CA and the difficulties that arise when new material classes needs to be tested according to consensus standard methods. Finally studies on a CA-based formulation intended for Vertebroplasty is presented. The studies include basic mechanical properties as well as testing the material in an in vitro model utilising synthetic cancellous bone.
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Padovani, Gislaine Cristina 1979. "Evaluation of surface restorative materials submitted to degradation by biofilm, in situ = Avaliação da superfície de materiais restauradores submetidos à degradação por biofilme, in situ." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/288142.
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Orientadores: Mário Alexandre Coelho Sinhoreti, Regina Maria Puppin RontaniTese (Doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: Os objetivos desta tese composta por dois capítulos foram: Capítulo 1- avaliar as características estruturais e a viabilidade do biofilme, in situ, acumulado após 07 dias sobre diferentes materiais restauradores e Capítulo 2 - avaliar as características de superfície de diferentes materiais restauradores após 07 dias à biodegradação in situ. No capítulo 1 - quinze discos de cada material (IPS E.Max; Filtek Supreme; Vitremer; Ketac Molar Easymix; Amalgam GS-80) foram confeccionados em uma matriz metálica de 4,0mm X 1,5mm. O polimento foi realizado com o auxílio de discos Sof-Lex para os corpos-de-prova de Filtek Supreme, Vitremer e Ketac Molar Easymix; o Amalgam GS-80 foi polido com o kit de polimento para amálgama de prata e os corpos-de-prova de IPS E.Max foram jateados por óxido de alumínio, seguidos por ponta diamantada, taça de borracha e glazer. Para a realização da biodegradação in situ, foram selecionados quinze voluntários com idades entre 21-30 anos. Um dispositivo palatino, contendo 5 poços (um material restaurador por poço) foi confeccionado para cada voluntário. Após 07 dias de biodegradação imagens do biofilme utilizando o Microscópio de Varredura Confocal a Laser (CLSM) foram realizadas. A análise quantitativa foi realizada com o auxílio do software COMSTAT avaliando parâmetros como: área, biomassa, espessura média, espessura máxima e coeficiente de rugosidade. Na análise qualitativa, as imagens CLSM foram visualmente observadas e descritas como: viabilidade celular - predominância de verde e vermelho e arquitetura do biofilme - predominância e distribuição de espaços e canais no biofilme. Os dados foram analisados estatisticamente utilizando o teste de Kolmogorov-Smirnov e Kruskal-Wallis ao nível de 5% de significância. Os resultados demonstraram não haver diferença estatística entre os materiais avaliados e os parâmetros selecionados. Porém, Filtek Supreme e IPS E.Max apresentaram visualmente maior quantidade de células viáveis em comparação aos outros materiais restauradores. Assim, conclui-se que: na análise quantitativa não houve influência significativa do material restaurador sob as características morfológicas do biofilme. Entretanto, a análise qualitativa demonstrou aparentemente variações na viabilidade bacteriana frente aos diferentes materiais restauradores. No capítulo 2 - A metodologia empregada na confecção e preparo dos corpos-de-prova foi à mesma utilizada no capítulo 1, sendo os corpos-de-prova submetidos à leitura de dureza, rugosidade de superfície, análise de Microscopia Eletrônica de Varredura e análise de Energia Dispersiva de Raios-X antes e após a biodegradação. Os dados foram submetidos aos testes de Kolmogorov-Smirnov e Tukey-Kramer, nível de significância de 5%. Todos os materiais restauradores estéticos mostraram aumento significativo nos valores de rugosidade após biodegradação, confirmado pelas micrografias. Para a análise da dureza, Vitremer, Ketac Molar Easymix e Amalgam Gs-80 demonstraram aumento significativo nos valores após a biodegradação. A composição química inicial do Amálgama GS-80 e IPS E.Max não foi alterada pela ação do biofilme in situ, enquanto Filtek Supreme, Vitremer e Ketac Molar Easymix apresentaram alterações em seus espectros, com liberação de fluoreto para os materiais ionoméricos e adsorção de íons (Ca2+, Cl-) na superfície desses materiais. Pode-se concluir que os efeitos do biofilme sobre as propriedades de superfície são material-dependente
Abstract: The objectives of this Thesis, accomplished on two chapters, were: Chapter 1 - to evaluate the influence of different restorative materials on the morphology of biofilm, in situ, and Chapter 2 - to evaluate the influence of biofilm on the surface characteristics of different restoratives materials. Chapter 1- Fifteen discs of each material (IPS E.Max; Filtek Supreme; Vitremer; Ketac Molar Easymix; Amalgam GS-80) were prepared using a metallic mold of 4.0 mm X 1.5 mm. Polishing procedure was performed with sof-lex discs on composite resin, glass ionomer cement and cement-modified glass ionomer specimens; silver amalgam specimens were polished with a polishing kit for amalgam; ceramic specimens were polished with a aluminum oxide jet, followed by a diamond drill, rubber tip and glazer. To perform the in situ biodegradation, fifteen volunteers were selected (aged 21-30 years). A palatal device containing 5 wells (one restorative material per well) was prepared for each volunteer. After 07 days of biodegradation, a morphology analysis of the biofilm was performed using confocal laser scanning microscopy. The images generated by confocal microscopy were then converted into numerical data with the aid of the COMSTAT software, which evaluated parameters such as: area, biomass, average thickness, maximum thickness and roughness coefficient. Qualitative analysis was also performed to assess the architecture and bacterial viability. Data were submitted to Kolmogorov-Smirnov test and Kruskal-Wallis tests at 5% of significance. The results showed no statistical difference between the materials studied for the selected parameters, although the Filtek Supreme e IPS E.Max showed a higher amount of viable cells compared to other restorative materials. Thus, it was concluded that the quantitative analysis did not showed a significant influence of the restorative material on the structural characteristics of the biofilm. However, the qualitative analysis showed variations in bacterial viability on different restorative materials. In chapter 2 - The methodology employed in the manufacture and preparation of the specimens was the same used in Chapter 1. The specimens were submitted to the reading of hardness, roughness analysis, Scanning Electron Microscopy and Energy Dispersive X-Ray analysis before and after biodegradation. The data were subjected to the Kolmogorov-Smirnov and Tukey-Kramer test, at a significance level of 5%. All esthetic restorative materials showed a significant increase in roughness values after biodegradation. For the analysis of hardness, Vitremer, Ketac Molar Easymix and Amalgam Gs-80 demonstrated significant increase in the values after biodegradation. The initial chemical composition of the Amalgam GS-80 and IPS E.Max was not change by the action of biofilms in situ, while Filtek Supreme, Ketac Molar Easymix and Vitremer showed changes in their spectra, with fluoride release from glass ionomer materials and incorporation ions (Ca2+, Cl-) on the surface of some materials analyzed (Filtek Supreme, Ketac Molar Easymix and Vitremer).Under the conditions of this study, one can conclude that the effects of biofilm on the surface properties are material-dependent
Doutorado
Materiais Dentarios
Doutora em Materiais Dentários
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Cole, David J. "Evaluation of fit for 3D printed retainers as compared to thermoform retainers." VCU Scholars Compass, 2018. https://scholarscompass.vcu.edu/etd/5332.
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ABSTRACT
EVALUATION OF FIT FOR 3D PRINTED RETAINERS AS COMPARED TO THERMOFORM RETAINERS
By David Cole, D.M.D.
A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Dentistry at Virginia Commonwealth University
Thesis Directors: Eser Tüfekçi, D.D.S., M.S., Ph.D., M.S.H.A.
Professor, Department of Orthodontics
Sompop Bencharit, D.D.S., M.S., Ph.D.
Associate Professor and Director of Digital Dentistry, Department of General Practice
Introduction: Despite recent advances in three-dimensional (3D) printing, little information is available on 3D printed retainers
Methods: Three reference models were used to fabricate traditional vacuum formed, commercially-available vacuum formed, and 3D printed retainers. For each model, three retainers were made using the three methods (a total of 27 retainers). To determine the trueness, the distances between the intaglio surface of the retainers and the occlusal surface of the reference models were measured using an engineering software. A small difference was indicative of a good fit.
Results: Average differences of the traditional vacuum formed retainers ranged from 0.10 to 0.20mm. The commercially-available and 3D printed retainers had a range of 0.10 to 0.30mm and 0.10 to 0.40mm, respectively.
Conclusions: The traditional vacuum formed retainers showed the least amount of deviation from the original reference models while the 3D printed retainers showed the greatest deviation.
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Silva, Emmanuel João Nogueira Leal da 1985. "Evaluation of cytotoxicity and physicochemical properties of calcium silicate-based endodontic sealer - MTA Fillapex = Avaliação das propriedades físico-químicas e biológicas de um cimento endodôntico a base de silicato de cálcio ¿ MTA Fillapex." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/289746.
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Orientador: Alexandre Augusto ZaiaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: O cimento endodôntico obturador MTA Fillapex® foi criado numa tentativa de aliar as propriedades físico-químicas e a capacidade seladora dos cimentos resinosos às excelentes propriedades biológicas do agregado trióxido mineral (MTA). Entretanto, ainda existe uma escassez de trabalhos na literatura avaliando as suas características físico-químicas e biológicas. Dessa forma, os objetivos deste estudo foram: 1) avaliar propriedades físico-químicas (radiopacidade, escoamento e pH) e biológicas (citotoxicidade) do cimento endodôntico MTA Fillapex e comparar com o cimento AH Plus, 2) realizar um acompanhamento em longo prazo do efeito citotóxico em fibroblastos 3T3 de diferentes cimentos endodônticos contemporâneos, e 3) avaliarem a partir de um ensaio multiparamétrico em longo prazo os efeitos citotóxicos do MTA Fillapex e do AH Plus em uma cultura primária de osteoblastos humanos. Os resultados do estudo mostraram que embora o AH Plus tenha apresentado radiopacidade estatisticamente maior que o MTA Fillapex (P<0.05), ambos os cimentos obtiveram os valores mínimos exigidos pela ISO 6876/2001. O MTA Fillapex apresentou um pH alcalino em todos os períodos experimentais, enquanto o AH Plus demonstrou um pH ligeiramente neutro, com diferenças estatisticamente significantes entre os cimentos (P<0.05). Com relação ao escoamento, ambos os cimentos apresentaram os valores mínimos exigidos pela ISO 6876/2001, no entanto o AH Plus apresentou valor estatisticamente mais baixo do que o do MTA Fillapex (P<0.05). Com relação à citotoxicidade, em todos os períodos testados o MTA Fillapex foi mais citotóxico do que o AH Plus (P<0.05). Quando comparado com diversos cimentos endodônticos, novamente o MTA Fillapex apresentou os maiores valores de citotoxicidade (P<0.05), permanecendo moderadamente citotóxico mesmo após 5 semanas de sua manipulação. Quando testados em um ensaio multiparamétrico utilizando culturas de osteoblastos humanos, ambos os cimentos foram citotóxicos sem apresentar nenhuma diferença significativa quando testados imediatamente após a manipulação (P>0.05). No entanto, uma semana após sua manipulação o AH Plus se tornou não citotóxico em todos os parâmetros avaliados. Por outro lado, o MTA Fillapex permaneceu citotóxico durante todo o período experimental, mostrando diferenças estatisticamente significantes quando comparados com o AH Plus (P<0.05). Dentro da metodologia empregada e de acordo com os resultados apresentados, pode-se concluir que embora o MTA Fillapex tenha apresentado propriedades físico-químicas adequadas para a utilização na terapia endodôntica, o mesmo apresentou-se altamente citotóxico nas diversas condições testadas
Abstract: The endodontic sealer MTA Fillapex® was developed in an attempt to combine the physicochemical properties and sealing capacity of resin-based cements to the excellent biological properties of mineral trioxide aggregate (MTA). However, little information exists regarding MTA Fillapex physicochemical properties. Thus, the aims of the present study were: 1) evaluate the physicochemical (radiopacity, flow and pH) and biological (cytotoxicity) properties of MTA Fillapex and compare it with AH Plus, 2) investigate MTA Fillapex effects on the cytotoxicity during a period of 5 weeks in 3T3 fibroblasts and compare with 7 different endodontic sealers, and 3) verify, through a multiparametric in vitro assay, the long term cytotoxic effects in human osteoblasts of the MTA Fillapex and compare it with AH Plus. The results of the study showed that although AH Plus presented higher radiopacity than MTA Fillapex (P<0.05), both sealers showed ISO 6876/2001 minimum required values. MTA Fillapex presented alkaline pH in all experimental times, while AH Plus demonstrated slightly neutral pH (P<0.05). Both sealers showed ISO 6876/2001 required values for flow, however AH Plus flow was significantly lower than that of MTA Fillapex (P<0.05). In all tested periods, MTA Fillapex was more cytotoxic than AH Plus (P < .05). When compared to 7 different endodontic sealers, MTA Fillapex was associated with significantly less cell viability (P<0.05) even after 5 weeks of manipulation. When tested in a muliparametric assay using human osteoblasts, no significant difference was found among the materials when fresh mixed (p>0.05). After one week AH Plus become noncytotoxic, on all three parameters evaluated. Conversely, MTA Fillapex remained cytotoxic over the entire experimental period, showing significantly differences when compared to AH Plus (P<0.05). Within the employed methodology and according to the results can be concluded that although MTA Fillapex showed suitable physicochemical properties for use in endodontic therapy, it appeared highly cytotoxic in the different tested conditions
Doutorado
Endodontia
Doutor em Clínica Odontológica
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Abouelleil, Sayed Hazem. "Dental composite properties evaluation : from experimental approaches to the prerequisite of a chewing bench." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSE1054/document.
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La littérature scientifique révèle que les résultats in vitro sur les matériaux dentaires ont une faible corrélation avec le comportement clinique. Les tests standardisés aux normes fournissent des informations précieuses et pertinentes sur les propriétés des matériaux dentaires, et permettent aussi de comparer les résultats de différents instituts. Cependant, le développement de nouveaux matériaux à partir de nouvelles formulations chimiques nécessite une amélioration des méthodes d'évaluation. Ce travail de recherche est réalisé dans le but d'approfondir les connaissances sur les méthodes d'évaluation des matériaux dentaires avant insertion dans la cavité buccale. Une grande importance a été donnée au choix des matériaux à tester ; nous nous sommes basés sur les dernières tendances actuelles et les derniers développements de composition de matériaux dentaires. La même importance a été donnée à des méthodes et des techniques d'essai au laboratoire ; leur corrélation avec les résultats cliniques a été mise en évidence. Les modifications apportées à la méthodologie de ces tests ont exploré davantage les aspects cachés des différentes interactions de paramètres. La caractérisation et l'évaluation des matériaux dentaires nécessitaient une meilleure compréhension de l'interaction entre les différentes propriétés pour expliquer le vieillissement des matériaux. Notre travail a consisté à combiner de nombreuses études pour répondre à ce sujet. Les études ont porté sur les propriétés mécaniques et physiques, le composite fibré et Bulk, les matériaux CAM CAD, les adhésifs dentaires, le choc thermique et le cyclage thermique, le bisphénol A. L'objectif final était de développer un simulateur oral qui permettrait la reproduction de différents paramètres chimiques, physiques et mécaniques de l'environnement buccal, permettant ainsi de combler l'écart entre les tests in vitro et in vivo de matériaux dentairesScientific literature reveals that in vitro results are poorly correlated to materials clinical behavior. ISO standardized testing provides valuable information about the dental materials properties, and enables result comparison between different institutes. Conversely, new materials chemistry and formulations requires improved methodology and testing methods. Throughout our studies included in this work, the main objective was to reach a more global knowledge of the way dental materials are evaluated before being inserted into the oral cavity. A great deal of emphasis was given to the choice of materials to be tested, and that it would represent the current trends in dental practice and the latest developments in material composition. Equal highlight was given to the choice of testing methodology and laboratory testing techniques and their correlation to the clinical outcome. The modifications made to the methodology of these tests explored further the concealed aspects of different parameter interactions. Dental materials characterization and assessment required more understanding about the interaction between different properties to explain material aging; our work was to combine numerous studies to answer this topic. The studies included mechanical and physical properties, bulk and fiber composite, CAD CAM block materials, dental resin adhesive, thermal shock and thermal cycling, Bisphenol A. The final objective was to develop an oral simulator that would enable the reproduction of different chemical, physical and mechanical parameters of the oral environment, thus permitting to bridge the gap between in vitro and in vivo testing of dental materials
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Rodrigues, Raquel Viana 1988. "Avaliação por meio da tomografia de coerência óptica do esmalte bovino restaurado por diferentes materiais frente ao desafio cariogênico = Evaluation of bovine enamel restored with different materials submitted to cariogenic challenge using optical coherence tomography." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/288859.
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Orientadores: Fernanda Miori Pascon, Regina Maria Puppin-RontaniDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba
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Resumo: O objetivo neste estudo in vitro foi analisar o esmalte bovino restaurado com diferentes materiais após o desafio cariogênico por meio da Tomografia de Coerência Óptica (OCT). Vinte e quatro incisivos bovinos foram selecionados, planificados e lixados para remoção do esmalte superficial, resultando em uma espessura de esmalte de 1 mm. Cavidades (1,5 x 0,5 mm) foram preparadas na superfície vestibular dos dentes, usando máquina padronizadora de preparos com ponta diamantada (#3131). Em seguida, os dentes foram distribuídos aleatoriamente em 3 grupos de acordo com o material restaurador (n=8): Cimento de Ionômero de Vidro Convencional - KetacTM Molar Easymix (3M ESPE); Cimento de Ionômero de Vidro Modificado por Resina - VitremerTM (3M ESPE); e Resina Composta - FiltekTM Z350 (3M ESPE). Os procedimentos restauradores foram realizados de acordo com as recomendações do fabricante e pelo mesmo operador. Após 24 horas foi realizado o acabamento e polimento com ponta diamantada (#3139) e discos Sof-LexTM (3M ESPE) de granulação média à extra-fina. As análises foram realizadas antes e após do desafio cariogênico utilizando o sistema de OCT (OCP930SR Thorlabs Inc.). Foram obtidas nove imagens de cada espécime, as quais foram analisadas por software (LabView 8) para se obter o coeficiente de atenuação óptico total em duas diferentes distâncias da área restaurada: 0-200?m e 200-400?m, a partir da margem da restauração. Todos os espécimes foram submetidos à ciclagem de pH, para simular o desafio cariogênico. Para isso, os espécimes foram imersos em solução desmineralizadora durante 6 horas e solução remineralizadora por 18 horas durante cinco dias, e dois dias adicionais em solução remineralizadora. Os dados foram submetidos à Análise de Variância e teste t pareado (p<0,05). Os dados da concordância intra-examinador foram analisados e a mesma foi considerada excelente (0,97). Não foi observada diferença entre os materiais em relação ao desafio cariogênico e áreas de análise (p>0,05). Considerando os tempos, antes e após o desafio cariogênico para cada material, nenhuma diferença significativa foi encontrada para KetacTM Molar Easymix em 0-200?m (p=0, 0932) e em 200-400?m (p=0, 0986). No entanto, observou-se diferença estatisticamente significativa para VitremerTM (p=0,0246) e FiltekTM Z350 (p=0,0360) para ambas as áreas 0-200?m (p=0,0071) e 200-400?m (p=0,0014), sendo que houve aumento no coeficiente de atenuação óptico depois da ciclagem, indicando perda mineral. Nas condições do presente estudo, concluiu-se que: 1) alterações no esmalte bovino foram detectadas quanto este foi restaurado com materiais resinosos, uma vez que foi observado aumento no coeficiente de atenuação óptico, o que sugere a perda de mineral do esmalte após desafio cariogênico; 2) KetacTM Molar Easymix não apresentou diferença entre antes e após o desafio cariogênico indicando efeito protetor ao esmalte ao redor das restaurações quando esse material foi utilizado in vitro; 3) não foi observada diferença entre os materiais antes e após o desafio cariogênico
Abstract: The aim of this in vitro study was to evaluate by Optical Coherence Tomography (OCT) analysis the bovine enamel restored with different materials submitted to cariogenic challenge. Twenty-four bovine incisors were selected, grounded and flattened to remove the first enamel surface and enamel thickness was measured in 1 mm. Cavities (1.5 x 0.5 mm) were prepared in the buccal surface of each tooth using a diamond bur (#3131) using a standard cavity preparation device. After that, teeth were randomly divided into 3 groups according to restorative material (n=8): Conventional Glass Ionomer Cement - KetacTM Molar Easymix (3M ESPE); Resin-Modified Glass Ionomer - VitremerTM (3M ESPE), and Resin Composite - FiltekTM Z350 (3M ESPE). All restorative procedures were performed according to the manufacturer's recommendations and by the same operator. After 24 hours it was performed finishing and polishing with diamond bur (#3139) and Sof-LexTM (3M ESPE) granulation medium to extra-fine. Analyzes were performed before and after the cariogenic challenge using OCT system (OCP930SR Thorlabs Inc.). Nine images were obtained from each specimen, which were analyzed by software (LabView 8) to obtain the total optical attenuation coefficient at two different distances from the restored area: 0-200?m or 200-400?m from the restoration margin. All specimens were submitted to pH-cycling to simulate the cariogenic challenge. For this, specimens were immersed in demineralizing solution for 6 hours and remineralizing solution for 18 hours for five days and two days in remineralizing solution. Data were submitted to ANOVA and paired t-test (p<0.05). Data from intra-examiner agreement were analyzed and was considered excellent (0.97). It was not observed difference among materials regarding the cariogenic challenge and areas of analysis (p>0.05). Considering before and after cariogenic challenge for each material, no significant difference was found for KetacTM Molar Easymix at 0-200?m (p=0.0932) and at 200-400?m (p=0.0986). However, statistically significant difference for VitremerTM (p=0.0246) and FiltekTM Z350 (p=0.0360) for both areas 0-200?m (p=0.0071) and 200-400?m (p=0.0014) was observed because of the increasing in optical attenuation coefficient after pH cycling, showing mineral loss. Within the conditions of the present study, it could be concluded that: 1) changes in bovine enamel were detected for resin-based materials since it was observed increase in optical attenuation coefficient, suggesting enamel mineral loss after cariogenic challenge; 2) Glass Ionomer Cement (KetacTM Molar Easymix) showed no difference between before and after cariogenic challenge indicating protective effects in enamel around the restoration; 3) no difference was found between the materials before or after the cariogenic challenge
Mestrado
Materiais Dentarios
Mestra em Materiais Dentários
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Naasan, Mohamad A. "Evaluation of glass ionomer cement restorations : a confocal microscopical study." Thesis, King's College London (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299073.
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CARDOSO, Gina Maria Coelho de Souza. "Avaliação das características fisico-químicas de géis de fluor de uso odontológico profissional." Universidade Federal de Campina Grande, 2014. http://dspace.sti.ufcg.edu.br:8080/jspui/handle/riufcg/342.
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O uso clínico de géis de flúor para aplicação tópica por profissionais está indicado para prevenção e tratamento de cárie e erosão dental devido à capacidade de interação com o processo de desmineralização-remineralização da matriz mineral do dente. O objetivo geral deste trabalho foi avaliar géis com flúor para remineralização dentária de uso tópico profissional quanto às características físico-químicas especificadas nos registros concedidos pela ANVISA. Foi verificada a existência de quinze (15) registros válidos na ANVISA, referentes a dezesseis (16) produtos de gel com flúor de uso tópico odontológico. Quanto a estes produtos, são oito (8) géis de flúor neutro e oito (8) géis de flúor acidulado. Todos os produtos possuem em sua composição fluoreto de sódio e o polímero mais utilizado para formação do gel é hidroxietil celulose, conforme declarado nos processos de registro na ANVISA. Em 60% dos processos de registro válidos há informação sobre o pH dos produtos. Com o levantamento realizado em março de 2014 nas dentais do Distrito Federal (DF), verificou-se a comercialização de dois produtos de um mesmo fabricante, sendo um gel de flúor neutro e um gel de flúor acidulado. Para a caracterização físico-química, foram adquiridos nove frascos de 200 mL de gel de flúor comercializados no DF: três de gel de flúor acidulado dentro da validade, três de gel flúor acidulado fora da validade e três de gel de flúor neutro. Estes produtos foram avaliados pelas seguintes técnicas: Microscopia eletrônica de varredura (MEV), Espectroscopia de energia dispersiva de raios X (EDS), espectroscopia na região de infravermelho com transformada de Fourier (FTIR), calorimetria exploratória diferencial (DSC), análise termogravimétrica (TGA) e avaliação do potencial hidrogeniônico (pH). Os elementos químicos identificados na análise por EDS estão condizentes com a composição química dos produtos declarados pelo fabricante à ANVISA. Os resultados de FTIR não demonstraram alterações significativas entre as amostras avaliadas. Foram verificados resultados diferentes entre as amostras, nos ensaios de TGA e DSC, isto provavelmente está relacionado com a desidratação das amostras e a formação de aglomerados. Os produtos avaliados a 25°C apresentaram resultados satisfatórios quanto ao pH. Mais pesquisas sobre a caracterização físico-química para o gel de flúor tópico de uso profissional odontológico são necessárias para embasar o desenvolvimento de normas técnicas específicas.
Clinical use of fluoride gels for topical application by professionals is indicated for prevention and treatment of dental caries and dental erosion due to the ability to interact with the process of demineralization - remineralization of tooth mineral matrix. The general objective of this work was to evaluate the physicochemical characteristics of topical gels for professional dental remineralization specified in the records granted by ANVISA. There were fifteen (15) valid records, relating to sixteen (16) products of fluoride gel use dental topic has been verified. As for these products, there were eight (8) neutral fluoride gels and eight (8) acidulated fluoride gels. All products contain in their composition sodium fluoride and the most used polymer for gel formation is hydroxyethyl cellulose. All acidulated fluoride gels have in their composition 1.23 % fluorine ions and all neutral fluoride gels contain 2 % NaF in its composition, as stated in the registration process at ANVISA. In 60 % of valid registration process there was information about the pH of the product. In the survey conducted in March 2014 in dental stores at Federal District (DF), it was observed the marketing of two products from the same manufacturer, being one neutral fluoride gel and one gel of acidulated fluoride. For physicochemical characterization, nine bottles of 200 ml of fluoride gel were acquired in DF: three of acidulated fluoride gel within the validity, three of acidulated fluoride gel out of date and three of neutral fluoride gel. These products were evaluated by the following techniques: Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectrometry (EDS), Fourier Transform Infrared Spectrometer (FTIR), Differential Scanning Calorimetry (DSC), Thermogravimetry (TG) and evaluation of the hydrogen potential (pH). The chemical elements identified by EDS analysis, in regions without clusters and with clusters of dehydrated samples, are consistent with the chemical composition of the products declared by the manufacturer to ANVISA. The FTIR outcomes showed no significant changes among analyzed samples. Different results among samples were observed during DSC and TGA tests, this is probably related to dehydration of the samples and the formation of agglomerates. More studies about the physicochemical characteristics of topical gels for professional dental remineralization are needed to support the development of specific technical standards.
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Le, Roux Andre Rayne. "Design and evaluation of alumina/feldspar resin infiltrated dental composite materials." Thesis, 2008. http://hdl.handle.net/10321/430.
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Submitted in fulfilment of the degree of Doctor of Dental Material Science in the
Department of Dental Services,
Faculty of Health Sciences,
Durban University of Technology,
Durban, South Africa, 2008.Introduction: Incorporating a feldspar chemical bond between alumina filler particles is expected to increase the wear resistant and flexural strength properties, while reducing flexibility of dental composites. Aims and Objectives: An investigation was carried out to evaluate the influence of the feldspar chemical bonding between alumina filler particles on wear, flexural strength and flexibility of experimental alumina/feldspar dental composites. It was hypothesized that wear resistance and flexural strength would be significantly increased with increased feldspar mass, while flexibility was expected to decrease. Methods: Alumina was chemically sintered and bonded with 30%, 40%, 50% and 60% feldspar mass, silanized and infiltrated with UDMA resin to prepare the dental restorative composite material specimens. Results and conclusions: Significantly higher wear resistant characteristics resulted with increased feldspar mass (p<0.5). Improvements in flexural strength characteristics as the feldspar mass was increased was not statistically different (p>0.5). Flexibility characteristics as the feldspar mass was increased was not statistically different (p>0.5). The alumina/feldspar specimens showed lower flexibility (mm displacement) than SR ADORO (p<0.05). Feldspar chemical bonding between the alumina particles may improve on the wear resistance and Flexibility of alumina/feldspar composites when compared to SR ADORO. This study evaluated the influence of a chemical feldspar bond between alumina filler particles.
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Chong, Voon Joe. "PREPARATION AND EVALUATION OF NOVEL ANTIBACTERIAL DENTAL RESIN COMPOSITES." Thesis, 2013. http://hdl.handle.net/1805/3353.
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Indiana University-Purdue University Indianapolis (IUPUI)Both quaternary ammonium bromide (QAB) and furanone derivatives were synthesized, characterized and formulated into dental resin composites for improved antibacterial properties. Compressive strength (CS) and S. mutans viability were used to evaluate the mechanical strength and antibacterial activity of the restoratives. The effects of chain length, loading, saliva and aging on CS and S. mutans viability were investigated. Chapter 2 describes how we studied and evaluated the formulated antibacterial resin composites by incorporating the synthesized QAB-containing oligomers into the formulation. The results show that all the QAB-modified resin composites showed significant antibacterial activity and mechanical strength reduction. Increasing chain length and loading significantly enhanced the antibacterial activity but dramatically reduced the CS as well. The 30-day aging study showed that the incorporation of the QAB accelerated the degradation of the composite, suggesting that the QAB may not be well suitable for development of antibacterial dental resin composites or at least the QAB loading should be well controlled. Chapter 3 describes how we studied and evaluated the formulated antibacterial resin composite by incorporating the synthesized furanone derivative into the formulation. The results show that the modified resin composites showed a significant antibacterial activity without substantially decreasing the mechanical strengths. With 5 to 30% addition of the furanone derivative, the composite kept its original CS unchanged but showed a significant antibacterial activity with a 16-68% reduction in the S. mutans viability. Further, the antibacterial function of the new composite was found not to be affected by human saliva. The aging study indicates that the composite may have a long-lasting antibacterial function. In summary, we have developed a novel QAB- and furanone-containing antibacterial system for dental restoratives. Both QAB- and furanone-modified resin composites have demonstrated significant antibacterial activities. The QAS-modified experimental resin composite may not be well suitable for development of antibacterial dental resin composites due to its accelerated degradation in water unless the QAB loading is well controlled. The furanone-modified resin composite shows nearly no reduction in mechanical strength after incorporation of the antibacterial furanone derivative. It appears that the furanone-modified resin composite is a clinically attractive dental restorative that can be potentially used for long-lasting restorations due to its high mechanical strength and permanent antibacterial function.
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Boldaji, Abdollah. "Clinical evaluation of facet materials in fixed prosthodontics." Doctoral thesis, 2006. http://www.nusl.cz/ntk/nusl-268908.
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MUDr. BOLDAJI, Abdollah The author in his PhD thesis deals with the assessment of long-term stability of commonly used bevel crown. The work deals with the changes in color, shape, surface integrity, marginal adaptation and the state of the surrounding tissues to determine the ideal facet material.
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Richards, Philip S. "Light-cured periodontal dressing a clinical evaluation : a thesis submitted in partial fulfillment ... periodontics ... /." 1988. http://books.google.com/books?id=n0Y_AAAAMAAJ.
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Shabanian-Borojeni, Mitra. "Wear studies of enamel and some restorative materials / Mitra Shabanian-Borojeni." Thesis, 2001. http://hdl.handle.net/2440/19796.
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Includes bibliographical references (leaves [1-20]).xxi, 168, [20] leaves : ill. (some col.) ; 30 cm.
A systematic analysis of wear involving the in vitro analysis of the wear of standard composite resin and glass ionomer cements restorations under controlled conditions; and, the qualitative and quantitative investigation of wear over a range of pH's and loads which might be encountered clinically in order to develop a "wear map" of the micromorphology of wearing teeth and restorations and a systematic modeling of wear rates.
Thesis (Ph.D.)--University of Adelaide, Dept. of Dentistry, 2001
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Somers, Grant Brandon. "An evaluation of the colours of base metal alloy oxide layers, and its effects on the shade of base metal alloy metal-ceramic restorations." Thesis, 1997. http://hdl.handle.net/10321/1979.
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Dissertation submitted in compliance with the requirements for the Master's Degree in Technology: Dental Technology, Technikon Natal, 1997.Globally, difficulties are being experienced by the dental world to match manufactured prosthetic restorations with natural tooth colour. The primary objective of this study was therefore to evaluate the colour of five different metalceramic base metal alloy oxide layers, and the effects of each oxide layer on the shade of the porcelain applied to its surface. The increase in the cost of gold alloys in the dental industry has influenced manufacturers to provide alloys which are cost effective and have adequate mechanical properties for the manufacture of metal ceramic restorations. Five base metal alloys used in the fabrication of metal-ceramic restorations were selected. The selection of the base metal alloys was based on popularity in the industry, availability and cost. The following five base metal alloys were selected for the investigation: Wiron 99 (nickel-chrome) Ceradium V (nickel-chrome-beryllium) Remanium CD (nickel-chrome) \x95 Wirobond (cobalt-chrome) Heranium (nickel-chrome) Bond-on-4 (low noble content alloy {control group; which was gilded}) II Thirty specimens for each alloy group (180 in all) were cast, using the lost wax technique. Three ceramic layers (notably the opaque, dentine and a glaze layer) were applied to the 20mm in diameter surface of each specimen. .\xB7t Finally both sample groups were tested against a custom shade guide the colour being compared specifically with the Vita A 1 shade. The reason for the inclusion of the shade guide was that, clinically, most shade selections are made by comparing the patient's tooth shade with a manufactured shade guide. A wide selection of shades are available to the ceramist. A certain school of thought that recommends that the metal surfaces of semi-precious metals be gilded with a gold gilding paste before the application of ceramics. in order to block out the dark oxide colour and enhance the colour of the ceramic to a more aesthetic and warmer colour. Therefore, prior to the opaque firing of the control group (Bond-on-4), a gilding layer of Spectra Seal Paste was applied to the surface of each specimen. Following each application of ceramic, the appropriate firing cycles were used to fire the ceramic. The following factors affected the selection of the shade of ceramic used in this study: the shade which is most influenced by the dark oxide layer the more popular shades of ceramic ( the A class of shades). It was established, through a review of the literature (Crispen, 1991), that the most objective form of testing colour at the time of the study, was the use of a reflectance spectrophotometer. This form of testing had been proved to be cost effective and was consequently used in this investigation. III Thesurve
M
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Chao, Tzu-Hsuan, and 趙子萱. "Fiber Types Used in Dental Filling Composite Materials: Preparation Technique and Property Evaluation." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/86539256387914988461.
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碩士中臺科技大學
醫學工程暨材料研究所
101
Dental filling composite material is used a common material for the treatment of damaged teeth. This study uses Intermediate Restorative Material (IRM®) as matrix and polylactic acid (PLA) and low melting point polylactic acid (LMPLA) fiber as reinforcing material to make the IRM®/LMPLA/PLA composite filling material. According to a previous study of this laboratory, the zinc-oxide powder and eugenol solvent are mixed with a ratio of 3:1, and then added with different wt% of LMPLA/PLA fiber or non-woven. The setting time, compressive strength, solubility and leakage of resulting composite filling materials are evaluated.
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Waddell, John Neil. "The evaluation of the applicability of using gold plating to enhance the predictability and strength of base metal post ceramic gold solder joints when using a flux that does not discolour the porcelain." Thesis, 1993. http://hdl.handle.net/10321/2160.
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Dissertation submitted in compliance with the requirements for the Master's Diploma in Technology: Dental Technology, Technikon Natal, 1993.The unpredictability of solder joints in dental base metal alloys constitute a major problem. This study aimed to establish whether gold plating the joint surfaces of a metal ceramic base metal alloy prior to postceramic soldering would enhance the predictability of the soldering method and joint strength. 150 standardised test specimens were prepared from 3 Oegussa dental alloys, viz Resistal P (Nier), Oegulor M (AUPt) and Realor (PdAU). The Resistal P specimens were subjected to 6 porcelain firing cycles and solder joint surfaces of 40 specimens gold plated prior to soldering, using gold plating equipment and solutions found in the jewellery industry. suitable fluxes were used and all soldering was done in a porcelain furnace. First the soldering method was validated by soldering 20 oegulor M specimens and determining the tensile strength of the 10 joints in an Instron testing machine. The data were then compared with the ISO minimum standards. The soldering method proved sound and a control was thus established. secondly, using 3 alloy combinations without gold plating, 30 solder joints were made and their tensile strengths determined. This established the level of predictability and strength and parameters for comparison. Thirdly, the above procedure was repeated, but the Resistal P specimen joint surfaces were gold plated prior to investing for soldering. The levels of predictability and strength were then compared with the parameters set. The fracture sites of broken joints were examined and photographed using a metallurgical microscope. The data were analysed using 4 statistical tests. The Oegulor M control group solder joints were the strongest and the Resistal P joints the weakest. The success rates for the non-plated joints were; oegulor M to oegulor M = 100%, Resistal P to oegulor M = 90%, Resistal P to Realor = 80% and Resistal P to Resistal P = 60%. The success rates for the gold plated joints were; Resistal P to oegulor M = 60%, Resistal P to Realor = 40% and Resistal P to Resistal P = 80%. This study found, under the circumstances of testing, that gold plating of the base metal alloy prior to investing for postceramic soldering did not enhance the strength, solderability and predictability of the solder joints to an extent that a flux that does not discolour porcelain can be used.
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Wu, Hung-Chun, and 吳宏駿. "Evaluation of Machinability and Properties of Novel Glass－Ceramic Materials for Dental All-Ceramic Crowns." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/91517216139135857460.
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碩士大葉大學
機械工程研究所碩士班
96
Dental ceramic applied to oral technology has been two hundred years of history. All-ceramic crowns in the production technology and components also increasingly progress. A glass-ceramic crown as the main ingredients in commercial products occupy an important position. The reason is that glass-ceramic glass can be controlled through the crystallization of the extent of the production of polycrystalline. Also can change the composition and the elements required of glass by the nature of glass-ceramic. Calcium-mica is known as one of fluorophlogopite type mica. The feature of the calcium-mica are the great glass stability of the melt and machinability. The experimental use of calcium mica and glass system which by Wu et al. research and development components for the proportion of mixed glass-ceramic. Expect to be able to produce a machinability of all-ceramic crowns. Experimental steps include differential thermal analysis, XRD crystalline phase analysis, SEM analysis of micro-structure and mechanical properties. The results are calcium-mica and apatite generated at 882℃ at the same time, but the crystallization of calcium-mica is more obvious. Sintering temperature is higher, calcium-mica and apatite crystal are higher. Added calcium-mica ratio reached 70%, glass-ceramic will be natural fragmentation in the air.The mechanical tests include micro-hardness test and machinability test. In micro-hardness experimental results, added calcium-mica in glass, will increase the glass-ceramic hardness after sintering. The machinability test assessment using cutting speed and cutting edge integrity to comprehensive assess. All of the specimens compared with commercial dental materials IPS e.max CAD and cercon base 12. The best machinability specimen is 50G50C of 950℃ for the heat treatment.
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AlRasheed, Rawan S. "In vitro evaluation of polymerization energy for bulk fill composites." Thesis, 2016. http://hdl.handle.net/1805/10275.
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Indiana University-Purdue University Indianapolis (IUPUI)Recently, the concept of “bulk-fill” resin-based composites (RBCs) has been re-emphasized, with claimed improvements in depth of cure (DOC) with similar mechanical properties and comparable adaptation to walls and margins relative to conventional composite. More research is needed to carefully examine the properties of these new materials. The objective of this study was to measure the light energy, microhardness (VHN), and elastic modulus across the depth of one conventional and three bulk-fill RBCs. Materials and Methods: Three commercially available bulk-fill RBCs (Tetric EvoCeram Bulk Fill [TE], SonicFill [SF], X-tra fill[XF]) and one conventional RBC (Premise [PR]) were evaluated (n = 10). DOC (using Vickers’s microhardness), elastic modulus (using atomic force microscopy), and the mean irradiance and total light energy transmitted through different thicknesses of RBC were measured by a spectrometer. The effects of group, location, and curing depth on VHN were analyzed using mixed-model ANOVA. Elastic modulus and light energy comparisons were made using two-way ANOVA, with a significance level of 5 percent. Results: There was a significant difference in the depths for the mean irradiance and total energy between different depths in all materials. All materials achieved the manufacturers’ claimed DOC. XF had the highest DOC with 7 mm and a light energy of 0.56± 0.02 J/cm2 at 7 mm. PR had the lowest DOC with 3 mm and a light energy of 0.84 ±0.12 J/cm2 at 3 mm. The elastic modulus showed significant variation in depth profiles that were different than the DOC. Significance: The manufacturers’ claims for bulk-fill DOC were achieved using a microhardness method. However, this method failed to detect the quality of the polymerization. Assessment of the elastic modulus using AFM is a promising method for greater understanding of the polymerization.
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Jain, Vishal V. "Evaluation of Second Generation Indirect Composite Resins." Thesis, 2008. http://hdl.handle.net/1805/1702.
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Indiana University-Purdue University Indianapolis (IUPUI)Indirect composites were introduced so that the composites can be cured extraorally to improve the degree of conversion and other material properties. These materials are indicated as long term full coverage dental restorative materials. However the mechanical and physical properties of new Second Generation Indirect Composites for this particular application have not been fully evaluated. The purpose of the study was to compare the appropriateness of the four commercially available laboratory composite resins for application as long term full coverage restorative materials. Water solubility and sorption levels, staining resistance, gloss, surface roughness, wear due to tooth brush abrasion, two-body and three-body wear, fracture toughness and radiopacity of four indirect composite restorative materials; Radica (Dentsply), Sculpture Plus (Pentron), Belleglass-NG (Kerr) and Gradia Indirect (GC America) were determined. The results showed that the four composites differed significantly from each other. Bell eglass-NG and Gradia Indirect showed negative water solubility. All the four groups demonstrated less color stability when exposed to coffee slurry for 3 weeks. Significant decrease in gloss and volume occurred when the omposites were exposed to simulated tooth-brush abrasion. Sculpture Plus v demonstrated lowest abrasion and attrition wear resistance among the four indirect composites. Radica had the highest fracture toughness and radiopacity of all the composites with values close to or less then dentin. In conclusion, different indirect composite systems possessed different mechanical and physical advantages when compared to each other. In general, Belleglass-NG demonstrated superior advantages due to its higher abrasion and attrition wear resistance and stain resistance. This was followed by Radica,Gradia Indirect and Sculpture Plus.
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Sun, Ming. "A laboratory evaluation of detail reproduction, contact angle, and tear strength of three elastomeric impression materials." Thesis, 2011. http://hdl.handle.net/1805/2802.
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Indiana University-Purdue University Indianapolis (IUPUI)Fabrications of desirable fixed or removable dental prostheses depend upon accurate casts or dies. Recently, the most frequently used impression materials have been polyether (PE) and polyvinyl siloxane (PVS). However, both have their limitations: PVS is inherently hydrophobic, and PE is rigid. In order to take advantage of the desirable qualities of both PVS and PE impression materials, a new generation of impression material is being developed called vinyl polyether silicone (VPES, GC). The purpose of the present study was to compare the properties of hydrophilic PVS, PE, and VPES in regard to surface detail reproduction, contact angle, and tear strength. The hypotheses to be tested were: 1) VPES will show a significant superiority insurface detail reproduction compared with PVS and PE impression materials; 2) VPES will show a significant superiority in wettability compared with PVS and PE impression materials; 3) VPES will show a significant superiority in tear strength compared with PVS and PE impression materials. In order to test the surface detail reproduction, impressions were made of stainless steel dies with a parallel series of 15 different width lines on the surface and tested under dry and moist conditions. The wettability was assessed by contact angles of saturated CaSO4 aqueous solution drops on flat impression surfaces. A trouser tear test was employed to test the tear strength. The trouser-shaped specimens were prepared and tested in the Instron Universal Testing Machine. The data were analyzed by one-way ANOVA and Pearson‘s Chi square, (p < 0.05). All the materials showed better detail reproduction under the dry conditions than the moist conditions. There were no differences between the three materials in detail reproduction when impressing under either moist conditions or dry conditions. All the materials showed good wettability in the contact angle test. PVS rendered a contact angle as low as 34.19º. The contact angle of VPES was 44.84º, which was lower than 54.76º for PE. In the tear strength test, PE showed nearly two time higher tear strength than the other two impression materials. VPES showed slightly lower tear strength than PVS. The tear strength of the three materials tested in increasing order was VPES, PVS, PE. VPES showed comparable detail reproduction to PVS and PE and better wettability than PE, but showed the lowest tear strength compared with PE and PVS.
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Wasson, Waletha. "Evaluation criteria for the color appearance match of esthetic restorative materials with the human dentition an empirical analysis and its application to dental education : a thesis submitted in partial fulfillment ... for the degree of Master of Science in Restorative Dentistry ... /." 2001. http://catalog.hathitrust.org/api/volumes/oclc/68962579.html.
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Huang, Sung-En 1980. "Effect of HA-coating and HF etching on experemental zirconia implant evaluation using in vivo rabbit model." Thesis, 2010. http://hdl.handle.net/1805/2366.
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Indiana University-Purdue University Indianapolis (IUPUI)The objective of this study was to evaluate the in vivo performance of the hydroxyapatite (HA) coating and hydrofluoric acid (HF) etching zirconia (ZrO) implants and to compare the result with titanium (Ti) implants treated in a similar manner. A total of four different implant types were tested in this study. Threaded zirconia implants with HA coating (Test 1) and zirconia implants with HF-treated surfaces (Test 2) were used to compare to the same size of titanium implants treated in identical fashion (control 1 and control 2). All implants measured about 3.5 mm at the thread diameter and 7.0 mm in total length. Each rabbit received two zirconia and two titanium implants treated in the same manner (either HA-coated or HF-etched). The samples were implanted into the rabbit tibias and retrieved at 6 weeks. Upon retrieval, 24 specimens (6 samples for each group) were fixed and dehydrated. The samples were then embedded undecalcified in PMMA for histomorphometry to quantify the bone-to-implant contact (BIC). Another 24 samples were kept in 0.9% saline and were evaluated using removal torque (RT) analysis to assess the strength of the implant-to-bone interface. The histomorphometric examination demonstrated direct bone-to-implant contact for all four groups. HA particle separation from the implants surface was seen in a majority of the HA-coated samples. No signs of inflammation or foreign body reaction were found during examination. Due to the HA particle smear contamination in the ZrO-HA group, no data was collected in this group. The mean BIC at the first three threads of the Ti-HA, Ti-HF and ZrO-HF were 57.78±18.22%, 46.41±14.55% and 47.41±14.05%, respectively. No statistically significant difference was found pair-wise among these three groups. When comparing the BIC data with the machined-surface implants, a statistically significant difference was found between the Ti-HA versus Ti implant group and the Ti-HF versus Ti implant group. The mean bone area (BA) at the first three threads for Ti-HA, Ti-HF and ZrO-HF showed statistically significant difference (p<0.05) between the ZrO-HF and Ti-HA groups, favoring the ZrO-HF group. The value of the peak removal force could only be collected from the Ti-HA group during the removal torque test. The mean RT value for the Ti-HA group was 24.39±2.58 Ncm. When comparing the RT result with our pilot study using machined-surface implants, the Ti-HA group showed statistically significant (p<0.05) higher values than the machined-surface Ti implants. The result of this study proves the in vivo biocompatibility of all four implant types tested. In the three measurable implant groups, the histomorphologic analysis showed comparable osseointegration properties in this animal model.
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Rayes, Steven K. "An evaluation of pupectomies utilizing Vitapex root canal filling material in primary anteriors and molars a retrospective study : a thesis submitted in partial fulfillment ... for the degree of Master of Science in the Department of Orthodontic and Pediatric Dentistry ... /." 2003. http://catalog.hathitrust.org/api/volumes/oclc/68962686.html.
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Whatley, Jenny J. (Jenny Johnson) 1982. "An in-vitro evaluation on the biocompatibility of resilon by the microbiota of the infected root canal utilizing an agar disc diffusion assay." Thesis, 2012. http://hdl.handle.net/1805/3093.
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Indiana University-Purdue University Indianapolis (IUPUI)Resilon is a resin-based obturation material that claims to create a monoblock through bonding of RealSeal sealer to the dentin walls and to the core material. Resilon is comprised of a biodegradable polymer, polycaprolactone, and inorganic fillers. Resilon has been shown to undergo enzymatic hydrolysis by bacterial enzymes such as lipase. This study aims to demonstrate if bacteria found within the infected root canal system are capable of degrading Resilon utilizing an agar disc hydrolysis method. A 0.1-percent Resilon emulsion and a gutta-percha emulsion were prepared with Tryptic Soy Agar in plates. Several bacterial species were inoculated in eight spots each on the Resilon and gutta-percha agar plates and the plates were observed for the formation of hydrolytic halos surrounding bacteria signifying their ability to degrade the material. The bacterial enzyme Lipase PS served as a positive control. P. intermedia, P. aeruginosa, P. assacharoylitica, S. epidermidis and S. aureus all demonstrated hydrolytic halos, clear zones, at each of the eight inoculation locations (100%, 95%CI 63%-100%) on the Resilon plates. The halos were similar to those seen in the positive lipase control. No halos were seen with E. faecalis, F. nucleatum, S. mutans, S. sanguis, or P. gingivalis at any of the eight inoculation spots (0%, 95%CI 0%-37%) on the Resilon plates. No hydrolytic halos were seen around any bacterial colonies or the Lipase PS on the gutta-percha plates. The results of this study indicate that bacteria found in endodontic infections can hydrolize Resilon dispersed into an emulsion. The potential exists for Resilon degradation after its use as an obturation material in infected root canal systems. Given that root canal therapy does not render a canal void of microorganisms, it is prudent to obturate the root canal system with a material that cannot be degraded by bacteria and their enzymes.
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Tsai, Pei-hua, and 蔡佩樺. "Preparation and Evaluation of Chitosan/CaSO4/platelet Rich Plasma Microspheres as Dental Implant Material." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/93381570916861294361.
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碩士義守大學
生物醫學工程學系碩士班
95
Periodontal disease and bone cancer might cause severe alveolus bone loss. One common used therapy to treat this disease is so-called debridement. After that, a bone conductive material is put into defect of alveolus bone to improve the regeneration of bony tissues. Thus, the purpose of the thesis is to prepare chitosan/CaSO4 microspheres, by using a high voltage electrostatic system, to act as dental implant (filling) materials. Besides, platelet gel that enriched growth factors are also used an ingredient to prepare chitosan/CaSO4/PRP microspheres which probably can serve as growth factors slow release carrier (after activated with thrombin). The preliminary results revealed that the chitosan/CaSO4/PRP microspheres are in the range of 322.2 ± 40.8μm ~ 471.6 ± 57.9μm in diameter. The in-trapped growth factors are able to sustained release at 24-hour period test. Three groups of microspheres, chitosan/CaSO4 microspheres (Group A) , chitosan/CaSO4 microspheres mixed with thrombin (Group B), chitosan/CaSO4/PRP microspheres mixed with thrombin (Group C) are prepared and the efficacy of these microspheres in bone regeneration are evaluated in pig oral model. The animal implantation study will be observed by HE stain and Trichrome stain.
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Trindade, Carlos Otavio Cançado. "Fit evaluation of a castable ceramic material in intracoronal restorations a thesis submitted in partial fulfillment ... restorative dentistry, operative ... /." 1988. http://books.google.com/books?id=GHo9AAAAMAAJ.
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Yanishen, I. V., O. V. Sidorova, and V. Horiushko. "Providing the clinical and technological quality the supporting dental gypsum᾽s material: comparative evaluation the physical and mechanical properties." Thesis, 2015. http://repo.knmu.edu.ua/handle/123456789/12385.
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Lin, Wen Hung, and 林文鴻. "Evaluation on the Physical and Chemical Properties and the Biocompatibility of the Dental Metallic Material Implanted in an Acid Etching Surface." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/63974831494383950353.
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碩士國立中興大學
生命科學院碩士在職專班
92
Abstract The object of this research is titanium, a metal material of synthetic implant, and this research evaluates respectively the three categories of (1) the nature of the material, (2) the material and cell culture, and (3) the material and organ culture. Having been etched, the surface layer of titanium has mm-sized beehive-like coarse holes, the roughness of which can be as big as 2.28μm, which is bigger than the holes commonly seen on the etching surface. We can find in the analysis on the component parts of the surface layer that the layer is more oxidized in TA than in TM. In cell adhesion and growth, we find that it is non-poisonous and bio-compatible. Through the SEM observation we find that the cell morphology is smoother in TA than in TM and there are more filopodia attached; therefore, the mechanical interlocking between the implant surface and osseous tissues can be expected to be enhanced. In organ culture, the frontal head bone of the newborn mouse is cultured with TM and TA, and we observed the growth and calcification of the defected bone tissue on the rims of the holes. Through the contra-photomicroscope, we observed that TA and TM are osteoconductive and that the bone cells attached themselves to the rim of the material from the rims of the holes. Furthermore, through the SEM observation and quantitative analysis, we found that, the organ having been cultured for five weeks, there were more and thicker cells on the bottom, side and surface of the TA than on those of TM, and the calcification of TA is more obvious than that of TM. To sum up, TA is an ideal implant material. Key words：titanium, dental implant, osteoprogenitor cells, osseointegration, biocompatibility