Дисертації з теми "Ceramic metal bonding"

Orthodontic attachments must be able to bond to a wide range of tooth and prosthetic surfaces. Despite the high prevalence of fluorosis in many parts of South Africa (Louw A, Chikte U 1997), only limited information is available on the integrity of the bond between orthodontic brackets and fluorosed teeth. The objective of this study was to measure and compare Shear Bond Strengths (SBSs) of metal and ceramic orthodontic brackets on fluorosed and non-fluorosed teeth. One hundred and twenty (60 fluorosed and 60 non-fluorosed) extracted premolar teeth were divided into four groups A to D, consisting of 30 teeth in each group. BluGloo® was used as an orthodontic adhesive to bond brackets on the buccal surface of each tooth. The experimental groups consisted of Group A, in which Nu-Edge® metal brackets were used and Group B, in which InspireIce® ceramic brackets were bonded to fluorosed teeth. Group C and D consisted of Nu-Edge® metal brackets and InspireIce® ceramic respectively, bonded to non-fluorosed teeth. Bonding techniques were kept the same and standardised for all four groups. An Instron testing device was used to debond and measure the SBSs. SBSs were compared using ANOVA with posthoc analysis done using Dunnett’s C test for pairwise comparisons. Significance was set at P<0.05. The results showed that SBS of Group B>Group C>Group D>Group A. Ceramic brackets bonded to fluorosed teeth had the highest SBS with a mean of 15.78 (SD=9.07) Megapascals (MPa), while metal brackets bonded to fluorosed teeth produced the lowest SBS of 8.41 (SD=4.68) MPa. The SBSs of ceramic brackets bonded to fluorosed teeth was significantly higher than that of SBS of metal brackets bonded to fluorosed teeth, but not significantly different from SBSs obtained from either brackets bonded to non-flurosed teeth. The BluGloo adhesive if used to bond ceramic brackets to fluorosed teeth can produce adequate SBS for clinical use. The recommendation from this study is that ceramic brackets can be used efficiently to bond to fluorosed teeth. A follow up study should be carried out to assess the nature of enamel damage caused during debonding of flourosed teeth. This is a laboratory study and thus the clinical application should be interpreted with caution.
Dissertation (MChD)--University of Pretoria, 2014.
tm2015
Orthodontics
MChD
Unrestricted

Ces travaux de thèses ont pour objectif de présenter les résultats obtenus sur l'assemblage de deux couples de matériaux métal - céramiques par thermocompression : Inconel®625 / Alumine et TZM / Carbure de silicium. Elle se place dans la continuité des résultats obtenus sur des assemblages similaires, au sein du laboratoire IRCER, en étudiant la faisabilité de liaisons direct et de liaison après préoxydation de la partie métallique. Une partie est dédiée à la compréhension du mécanisme d’oxydation de l’inconel®625 en utilisant une thermobalance à insertion à chaud. A l’aide des cinétiques obtenues, le mécanisme d’oxydation est alors proposé et les conditions de préoxydation pour la partie d’assemblage suivante ont pu être déterminées. Ensuite au cours de ce manuscrit sont rapportés les procédés utilisés et les résultats obtenus après variations de paramètres tels que la température ou le temps de palier de traitement thermique sur les assemblages des deux couples. L'absence de formation d'une interphase pour le couple Inconel®625 / Alumine et la formation d'une interphase complexe pour le couple TZM / Carbure de silicium permette de proposer deux études différentes de liaison céramique- métal. Une partie est également consacrée à la caractérisation de la liaison obtenue, dans chaque cas, afin de déterminer sa tenue et expliquer ses propriétés à l'aide de la microscopie électronique à balayage mais aussi une simulation numérique pour le couple Inconel®625 / Alumine et des tests de tractions pour le couple TZM / Carbure de silicium
This work has for objective to present the results obtained for the ceramic-metal bonding by hot-pressing in two cases: Inconel®625 / Alumina and TZM / Silicon carbide. All the thesis take place according to the last results obtained for similar bonding, in the laboratory IRCER, by studying the feasibility of direct bonding and bonding after pre-oxidising the metal part. A part of this study is then dedicated to the oxidation behaviour of inconel®625 under CO2 using a thermobalance with a sample hot introduction. Using the oxidation kinetics obtained, the reaction mechanism is proposed and the conditions for the metal pre-oxidation determined.Then during the manuscript are presented the processes and the results obtained after variations of parameters such as temperature and the heat treatment time for the two couples of materials. The absence of inter-phase formation in the couple Inconel®625 / Alumina and the formation of a complex inter-phase in the couple TZM / Silicon carbide allow us to propose two studies with different metal-ceramic bonding.A last part is dedicated to the characterization and the understanding of the bonding obtained in each case. To explain the properties of the samples obtained we used scaning electron microscopy but also numerical simulation for the first couple Inconel®625 / Alumina and tensile test for the second couple TZM / Silicon carbide

Le secteur aéronautique connaît un important essor depuis les années 1960, avec pour conséquence l’augmentation majeure des températures de fonctionnement des turbines. L’utilisation de capteurs, au plus proche de la chambre de combustion, est nécessaire pour maîtriser les performances des turboréacteurs. Cela justifie le besoin industriel de développer des assemblages céramique-métal résistants à un environnement sévère (>1100°C sous air, vibrations, etc.)L’alumine est sélectionnée en raison de son caractère isolant à haute température. La principale difficulté réside dans le choix du substrat métallique, qui doit être à la fois : réfractaire, résistant à l’oxydation, pour un coût abordable. Le potentiel d’un carbure ternaire (de type phase MAX) est évalué en tant que substrat métallique. La composition des brasures est ajustée pour chaque système afin de garantir : une tenue en température, une excellente ductilité et une compatibilité métallurgique vis-à-vis du substrat métallique.Des brasures ternaires Au-Pd-Pt sont formulées et élaborées. Les contours de solidus et de liquidus de ce ternaire sont déterminés expérimentalement. Les mécanismes de diffusion, de dissolution ou encore de pénétration inter-granulaire, à l’interface métal/brasure, sont décrits afin d’apporter des améliorations aux systèmes développés. Au cours du brasage, la diffusion de l’aluminium des substrats alumino-formeurs vers la brasure est prédominante, malgré la mise en place d’une barrière de diffusion. Le recours à des substrats métalliques nobles s’avère incontournable.Les paramètres géométriques et chimiques de l’assemblage sont établis pour chaque nouveau système étudié sur la base des processus physico-chimiques survenant au cours du brasage et du vieillissement sous air. Les meilleurs assemblages développés présentent une excellente herméticité après brasage. Les essais de vieillissement en cyclage thermique, dans des conditions sévères, sollicitent fortement la liaison céramique-brasure jusqu’à la rupture interfaciale. Deux voies d’améliorations sont proposées pour assurer la durabilité de la liaison céramique-brasure au cours du cyclage thermique
Aerospace technology developments are blooming. Since the 1960’s the Turbine Entry Temperature for aero-engines gas turbines keeps rising to improve their efficiency. Sensors working close to the combustion chamber are required in order to master the turbine performances. This results in an industrial urge to develop ceramic-to-metal assemblies able to endure severe engine environment (>1100°C under air, vibrations, etc.)The choice of an alumina as the ceramic part ensures a good insulation at high temperature. The main issue remains the metallic material which must be refractory, resistant to oxidation and affordable. The application of a ternary carbide (phase MAX) is tested. The braze alloy composition is adjusted to each system so as to provide a good ductility, thermal stability and a metallurgical matching as regards dissolution and brittle compounds formation.Braze alloys based on the Au-Pd-Pt system are investigated. The aforesaid liquidus and solidus surfaces are defined from experimental measures. Diffusion, dissolution and inter-granular penetration at the metal/braze alloy interface are described to suggest improvements. Aluminum diffusion from alumina-forming materials towards the braze alloy is the dominant phenomenon during brazing, despite the use of a diffusion barrier. The use of noble materials for the metallic substrate is mandatory.Geometrical and chemical assembly parameters are defined for selected brazed system based on the physicochemical interactions occurring during brazing and aging under air. The best brazed assemblies present an excellent hermeticity after brazing. Thermal cycling aging in severe conditions is detrimental to ceramic-braze alloy bonding, leading to interfacial cracks. Two promising strategies are suggested to ensure a reliable ceramic-to-braze alloy bonding during thermal cycling

Thesis (Ph. D.)--University of Iowa, 2000.
Supervisor: Clark M. Stanford. Title-page, preliminaries, Certificate of approval, Table of contents and Project summary issued in paper (xii, 13 leaves ; 28 cm.). Includes bibliographical references. Also issued on CD-ROM (144 files, 33.7 megabytes).

Syfte: Syftet med föreliggande in-vitro studie är att undersöka olika kompositbaserade reparationssystem och dess bindningsstyrka till porslin för metallkeramiska konstruktioner. Material och metod: Metallstavar tillverkades via CAD/CAM i CoCr (5.0x5.0x15.0mm) kortsidan förbehandlades genom sandblästring (aluminumoxid, 250 µm), ångblästring, oxidation, sandblästring och ångblästring. Fältspatporslin applicerades enligt följande: opak, dentin, emalj, till höjden av 1.2 ± 0.2 mm. Porslinsytorna slipades med sandpapper, 600-, 800-, 1200-kornstorlek kiselkarbid. Fem grupper (n=15) gav totalt 75 provkroppar. På vardera provkropp applicerades adhesiv samt kompositmaterial enligt fabrikanternas anvisningar (Kuraray, Kulzer, Voco, Ivoclar) inklusive kontrollgrupp som etsades med fluorvätesyra (Ultradent). Samtliga provkroppar termocyklades (5000 cykler, mellan 5°C och 55°C) före/efter applicering av kompositmaterial. Skjuvkraftstest utfördes på alla provkroppar med belastningshastighet 0.5 mm/min. Frakturanalys utfördes där brottytorna delades in i adhesiv-, kohesiv- eller mixfraktur. Resultaten analyserades med one-way ANOVA, Tukey´s test med signifikansnivån α=0.05. Resultat: Fluorvätesyra påvisade en signifikant högre bindningsstyrka 11.32 ± 4.28  MPa i jämförelse med övriga grupper (p<0.01). Övriga gruppers medelvärde var mellan 2.61 ± 1.36 till 3.96 ± 2.85 MPa. Det fanns ingen signifikant skillnad mellan de övriga grupperna. Samtliga grupper fick adhesiva frakturer, men Voco-gruppen uppvisade även mixfrakturer.  Slutsats: Samtliga reparationssystem visar på låg bindningsstyrka och baserat på resultaten kan det inte rekommenderas. Förbehandling av porslinsyta med fluorvätesyra i kombination med silan resulterar i högst bindningsstyrka till komposit. Värdet är trots allt lågt för en god långtidsprognos, men det enda som kan rekommenderas. Det faktum att fluorvätesyra har giftiga egenskaper vore det lämpligt att fortsätta utvecklingen av reparationssystem för att hitta ett lämpligt alternativ.
Purpose: The purpose of this study is to investigate different repair systems and their bond strength to porcelain for metal-ceramic constructions. Material and method: Metal were manufactured by CAD / CAM in CoCr (5.0x5.0x15.0mm), was pretreated with sandblasting (alumina, 250 µm), steam blasting, oxidation, sandblasting and steam blasting. Feldspar porcelain was applied according to the following steps: opaque, dentin, enamel, selfglaze to a final porcelain height of 1.2 ± 0.2 mm. The porcelain surfaces were groud with silicon carbide sandpaper, 600-, 800-, 1200-grain size. Five groups (n = 15) in a total of 75 specimens. Adhesives and composite materials were applied to each group according to the instructions of the various manufacturers  (Kuraray, Kulzer, Voco, Ivoclar, Ultradent, Etching with hydrofluoric acid). All specimens were thermocycled (5000 cycles) in two water baths between 5 ° C and 55 ° C before and after application of composite material. Shear bond strength test was performed on all specimens with a load speed of 0.5 mm / min and the bond strength was reported in MPa. Fracture analysis was performed where the fracture surfaces were divided into adhesive, cohesive or mixed fracture. The results were analyzed with one-way ANOVA, Tukey´s test with significance level α= 0.05. Result: The result clearly showed that hydrofluoric acid had a significantly higher bond strength of 11.32 ± 4.28 MPa compared to the other groups (p <0.01). The mean value of the other groups was between 2.61 ± 1.36 to 3.96 ± 2.85 MPa, with  no significant difference between the groups. All groups had adhesive fractures, but the Voco-group also showed mixed fractures. Conclusion: The study concludes that all repair systems have a low bond strength and based on the results can’t be recommended. Pretreatment of the porcelain surface with hydrofluoric acid in combination with silan results in the highest bond strength to composite, the bond strength is still too low for long-term use, but the only one that can be recommended. However hydrofluoric acid is highly toxic which require further research in the field in order to develop reparation systems with suitable properties.

碩士
中山醫學大學
口腔材料科學研究所
102
Computer-aided design and computer-aided manufacturing (CAD/CAM) all-ceramic crowns have become popular dental prosthesis in recent years. However many patients still need to rely on porcelain fused to metal (PFM) crown restoration due to their clinical conditions. There has been a new technique called Press-on-Metal (POM) that has gradually become widely accepted in the market. The production process of POM differs from the traditional PFM. Apart from being more time-saving in the fabrication process, POM also offers another treatment option to both the dentist and technician in clinical practice. Nevertheless whether the bonding strength of porcelain to metal win POM is similar to the traditional PFM and whether POM restorations can withstand temperature changes in the mouth are still yet to be investigated. The purpose of this study was to compare the traditional feldspathic ceramic, and die-cast key leucite ceramic and three different metals knot strength. According to ISO9693 (1999) standard, making rectangular resin pattern 60, test pieces were cast metal (gold alloy, palladium and cobalt-chromium alloy), respectively, then the respective test pieces sticking tiles metal (PFM cum control group), and a hot ceramic plate (POM group), followed by three-point bending test. Three-point bending tests were further performed after 20,000 thermal cycles. The results showed that the control group of gold alloys and ceramics had the highest bond strength (Au-F) 50.19 MPa (p<0.05), followed by palladium alloys and nickel-chromium alloys; while the POM group palladium alloy (Pd-P) had the lowest bond strength 36.91MPa (p>0.05). Experimental results show that 20,000 times before and after thermal cycling, the PFM Group of different metal-ceramic specimen bond strength was significantly lower (p<0.05), while no significant difference POM group (p>0.05), hot and cold cycles on the bond strength of the specimen has a significant impact. Looking at all the tests results, the conclusion is that although the bond strength using POM method of making the test piece is not superior to PFM, but the bond strength POM method of specimen in line with ISO9693 standards, so the dentists and dental technicians and patients economic considerations, POM law will be one of the clinical method of prosthetic treatment options.

碩士
中山醫學院
口腔醫學研究所
86
Titanium and its alloys have been widely used in dentistry because of their excellent biocompatibility and corrosion resistance. In addition, its low specific gravity, high strength, low thermal conductivity have made this metal as an alternative metal used for dental prostheses. The purpose of this study was to evaluate the effect of metal thickness of cp titanium on the flexural bond strength of ceramic to cp titanium. In cast specimens of cp titanium Grade II (Group I) and Grade III (Group II), wax patterns of different thickness (subgroup: 0.3, 0.5, 0.7 and lmm) were made and in Ni-Cr-Be alloy (Group III) cast specimens, those of different thickness (subgroup: 0.3 and 0.5mm) were prepared. Fifteen specimens were made in each thickness of metal. The fired square-shaped porcelain layer covered a central portion of one side of a metal surface for a total thickness of 1.0mm ceramic thickness achieved. Titanium specimens/Tibond ceramic (Dentsply DeTrey GmbH, Greieich) and Ni-Cr-Be alloy specimens/Will-Cream ceramic (Williams, Ivoclar North America Inc, USA) combinations were used. The specimens were subjected to Three-point bending test, and the load of bond failure was recorded. The surface of each debonded specimens were examined and photographed to determine the mode of bond failure. A two-way ANOVA followed by a Scheff's analysis was to analyze the data. There was no statistically significant difference of flexural bond strength between Ti II and Ti III specimens (P>0.05). The metal thickness of cp titanium, either Grade II or Grade III, do effect the flexural bonding strength of c.p. titaniumceramic(P<0.05). There were no statistically significant difference (P>0.05) of the metal-ceramic flexural bonding strength among Ti II, III (10.mm) and Ti II, III(0.7mm) specimens,but Ti II, III(1.0 and 0.7mm) were significantly stronger than Ti II, III (0.3mm) specimens (P>0.05). The flexural bonding strength of Ni-Cr-Be (0.5mm) specimens were stronger than Ti Grade II, III (0.7mm) specimens but there was no statistically significant difference (P>0.05). The study of the interfaces between ceramic and alloys was done by scanning electron microscopy (SEM) and energy dispersive X-ray spectrometer (EDS). It is observed that the anchor points were found in the Ni-Cr-Be alloy-ceramic interface, and the both fracture types, i. e., cohesive and adhesive type, were coexistent in its fracture surface. Compared to the Ni-Cr-Be alloy, the fracture of c. p. titanium-ceramic interface after bending test revealed that the fracture is adhesive type dominantly. It was concluded that metal thickness of cp titanium, either Grade II or Grade III, will effect the flexural bond strength of cp titanium, either Grade III, will effect the flexural bond strength of cp titanium-ceramic and the minimum of metal thickness was recommended as 0.5mm to be used on cp titanium-ceramic system.

Introduction : La force d’adhésion à l'interface métal-céramique avec les résines auto-polymérisantes destinées au collage indirect des boîtiers orthodontiques n'a pas été évaluée à ce jour et un protocole clinique basé sur la littérature scientifique est inexistant. Objectifs : 1) Comparer la force de cisaillement maximale entre des boîtiers métalliques et des surfaces en porcelaine préparées selon différentes méthodes; 2) Suggérer un protocole clinique efficace et prévisible. Matériel et méthodes : Quatre-vingt-dix disques en leucite (6 groupes; n = 15/groupe) ont été préparés selon 6 combinaisons de traitements de surface : mécaniques (+ / - fraisage pour créer les rugosités) et chimiques (acide fluorhydrique, apprêt, silane). Des bases en résine composite Transbond XT (3M Unitek, Monrovia, California) faites sur mesure ont été collées avec le système de résine adhésive auto-polymérisante Sondhi A + B Rapid Set (3M Unitek, Monrovia, California). Les échantillons ont été préservés (H2O/24hrs), thermocyclés (500 cycles) et testés en cisaillement (Instron, Norwood, Massachusetts). Des mesures d’Index d’adhésif résiduel (IAR) ont été compilées. Des tests ANOVAs ont été réalisés sur les rangs étant donné que les données suivaient une distribution anormale et ont été ajustés selon Tukey. Un Kruskall-Wallis, U-Mann Whitney par comparaison pairée et une analyse de Weibull ont aussi été réalisés. Résultats : Les médianes des groupes varient entre 17.0 MPa (- fraisage + acide fluorhydrique) à 26.7 MPa (- fraisage + acide fluorhydrique + silane). Le fraisage en surface ne semble pas affecter l’adhésion. La combinaison chimique (- fraisage + silane + apprêt) a démontré des forces de cisaillement significativement plus élevées que le traitement avec (- fraisage + acide fluorhydrique), p<0,05, tout en possédant des forces similaires au protocole typiquement suggéré à l’acide fluorhydrique suivi d’une application de silane, l’équivalence de (- fraisage + acide fluorhydrique + silane). Les mesures d’IAR sont significativement plus basses dans le groupe (- fraisage + acide fluorhydrique) en comparaison avec celles des 5 autres groupes, avec p<0,05. Malheureusement, ces 5 groupes ont des taux de fracture élévés de 80 à 100% suite à la décimentation des boîtiers. Conclusion : Toutes les combinaisons de traitement de surface testées offrent une force d’adhésion cliniquement suffisante pour accomplir les mouvements dentaires en orthodontie. Une application de silane suivie d’un apprêt est forte intéressante, car elle est simple à appliquer cliniquement tout en permettant une excellente adhésion. Il faut cependant avertir les patients qu’il y a un risque de fracture des restorations en céramique lorsque vient le moment d’enlever les broches. Si la priorité est de diminuer le risque d’endommager la porcelaine, un mordançage seul à l’acide hydrofluorique sera suffisant.
Background : Bond strength at the metal-ceramic interface of auto-polymerizing resins used in orthodontic indirect bonding has not yet been evaluated and a literature-based clinical protocol is lacking. Goals : 1) To compare shear bond strength (SBS) between metal brackets and differently treated porcelain surfaces; 2) To suggest efficient and predictable chairside approaches. Materials and methods : Ninety leucite discs (6 groups; n=15/group) were prepared following 6 combinations of mechanical (+/- bur roughening) and chemical (hydrofluoric acid, primer, silane) treatments. Metal brackets with custom composite resin Transbond XT (3M Unitek, Monrovia, California) bases were bonded with the adhesive resin system Sondhi A+B Rapid Set (3M Unitek, Monrovia, California). Samples were stored (H2O/24hrs), thermocycled (500 cycles) and tested (Instron, Norwood, Massachusetts). Maximum SBS and adhesive remnant index (ARI) scores were collected for each sample. ANOVAs were performed on ranks since data was not normally distributed, and then adjusted with the post-hoc Tukey method. A Kruskall-Wallis, a Mann Whitney U pairwise comparison and a Weibull analysis were also performed. Results : SBS medians of groups ranged from 17.0 MPa (- bur + hydrofluoric acid) to 26.7MPa (- bur + hydrofluoric acid + silane). Bur roughening did not affect bond strength. The chemical preparation of (- bur + primer + silane) showed statistically significant higher SBS than (- bur + hydrofluoric acid) preparation (p<0,05), while having similar SBS to the popular recommended protocol (- bur + hydrofluoric acid + silane). ARI scores were statistically significant lower in group (- bur + hydrofluoric acid) with p<0,05, while all other 5 groups were not different from each other. Percentage of porcelain damage in these 5 groups were very high at 80-100%. Conclusion : All the tested surface preparations combinations provided clinically adequate adhesion for orthodontic tooth movement. A silane and primer combination for porcelain surface preparation is clinically attractive as it is safe and simple and provides great adhesion for orthodontic tooth movement. It is wise to warn patients that there is a risk of porcelain fractures when debonding brackets. If one prefers to avoid porcelain fracture at all cost, one may treat porcelain with hydrofluoric acid only.