TY - JOUR A1 - Reich, Sven A1 - Hornberger, Helga T1 - The effect of multicolored machinable ceramics on the esthetics of all-ceramic crowns JF - Journal of Prosthetic Dentistry N2 - Statement of problems: Computer-aided design/computer-assisted machining systems offer the possibility of fabricating restorations from one machinable ceramic block. Whether multishaded blocks improve esthetic results and are a viable alternative to individually stained ceramics has not been fully determined. Purpose: The aim of this investigation was to examine the effect of multishaded blocks on the esthetic appearance of all-ceramic CEREC crowns and compare these crowns with single-shade and stained restorations. Material and methods: Ten subjects were included in this study. For each subject, 6 different crowns were milled with the use of a CEREC machine. One crown was milled from each of the following machinable ceramic materials: CEREC Vitablocs Mark II in classic colors; Vitablocs Mark II in 3D-Master colors; Vitablocs Mark II in either classic or 3D-Master colors, with additional staining; Megadenta Bloxx multishaded; Mark II experimental multilayer; and an experimental multilayer leucite ceramic. Three independent examiners assessed the esthetic appearance of crowns fabricated to match each subject's anterior tooth shade. A scale of 1 to 6 was used to score the shade match and esthetic adaptation of each crown, with 1 representing excellent characteristics and 3.5 serving as the threshold for clinical acceptability. The examiners' scores were averaged, and the mean values were analyzed with the Wilcoxon signed rank test (P=40 MPa as measured according to ISO 6 872; said second material is an organic material which at least partly fills the pores of said porous matrix; and said composite material has a modulus of elasticity, E, of >=25 GPa as measured according to ISO 10 477. Y1 - 2001 UR - https://depatisnet.dpma.de/DepatisNet/depatisnet?action=bibdat&docid=US020090001623A1 ER - TY - PAT A1 - Muerrle, Ulrich A1 - Hornberger, Helga T1 - Method of making a ceramic restoration N2 - Production of a dental reconstruction comprises: (a) forming a mold (12) from a model (10); (b) using (12) to make an isotropically heat-expandable replica from a ceramic precursor (14); (c) oxidizing (14) to produce an enlarged ceramic replica; (d) forming a silicone mold from this replica; (e) using (d) to make a second ceramic replica; and (f) sintering the second replica with volume reduction to form a replica identical to (10). T2 - Verfahren zur Herstellung einer Zahnrestauration aus Keramik Y1 - 2003 UR - https://depatisnet.dpma.de/DepatisNet/depatisnet?action=bibdat&docid=EP000001346702A1 ER - TY - JOUR A1 - Hornberger, Helga A1 - Marquis, Peter M. A1 - Franks, J. T1 - The impact of diamond-like coatings on the strength of dental ceramics JF - Journal of Dental Research Y1 - 1995 VL - 74 SP - 522 ER - TY - JOUR A1 - Hornberger, Helga A1 - Marquis, Peter M. T1 - Mechanical properties and microstructure of In-Ceram BT - a ceramic-glass composite for dental crowns JF - Glastechnische Berichte - Glass Science and Technology Y1 - 1995 VL - 68 IS - 6 SP - 188 EP - 194 ER - TY - JOUR A1 - Kloiber, Jessica A1 - Anetsberger, Viktoria A1 - Schultheiß, Ulrich A1 - Hornberger, Helga T1 - High quality surfaces of magnesium alloy AZ31 by adjusting appropriate electropolishing parameters JF - Electrochimica Acta Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-79298 N1 - Corresponding author der OTH Regensburg: Jessica Kloiber VL - 513 PB - Elsevier ER - TY - JOUR A1 - Kloiber, Jessica A1 - Schultheiß, Ulrich A1 - Hornberger, Helga T1 - Impact of heat treatment on the surface quality of electropolished WE43 alloy JF - Materials Letters N2 - In this study, the Mg alloy WE43 was solution annealed and precipitation hardened prior to electropolishing to evaluate the effects of different microstructures on the electropolishing result. While coarsely distributed precipitates led to surfaces showing wavy structures and dents after electropolishing, a uniform microstructure resulted in an even finish of the surface. The homogenization and refinement of the microstructure by heat treatment is a method to ensure improved electropolished surfaces of Mg materials Y1 - 2025 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-83512 SN - 0167-577X N1 - Corresponding author der OTH Regensburg: Jessica Kloiber VL - 397 PB - Elsevier BV ER - TY - JOUR A1 - Manaranche, Claire A1 - Hornberger, Helga T1 - A proposal for the classification of precious dental alloys according to their resistance to corrosion based on the iso 10271 standard JF - European Cells and Materials N2 - A lot of dental alloys are available on the market. Among these alloys, there are the conventional alloys, the so called casting alloys used without ceramics, the bonding alloys used with high fusing ceramics and the universal alloys used without or with low fusing ceramics. It is im portant to know the physical and mechanical properties of these materials but also their biocompatibility and their resistance to corrosion. Dental alloys are generally placed in the mouth for many years, they must not induce adverse biological reactions such as gingival swelling and erythema, mucosal pain and lichenoid reactions. Although these troubles are often caused not by the materials itself (1, 2), they can be induced by the metallic ions released during their corrosion. In order to decrease the risks to the health, it is necessary to study the corrosion of the dental alloys. Currently, the ISO 10271 Standard (3), describes 3 different corrosion tests: a static immersion test (chemical corrosion), an electrochemic al test and a tarnish test. However, there are no indications yet about the possible interpretation of test results. In this paper, we propose a method to compare and classify the dental alloys in relation to their chemical and electrochemical corrosion results. METHODS: The material tested are pure metals such as gold, palladium, silver, copper and zinc as well as dental alloys which are commercially sold (see Table 1). 54 different materials have been tested. A minimum of four samples of each material were tested by electrochemic al corrosio n and a minimum of three in chemical test. The samples were cast and prepared as indicated by the manufacturer and by the ISO 10271. For the electrochemical test, the samples are in the form of disks 11 mm in diameter. They are tested with a potentiostat/galvanostat Voltalab Model 21. For the chemical test, the samples are rectangular with the dimensions 35X10X1.7 mm. The solution used and the operating conditions are described in the ISO 10271. The concentration of metallic ions released is measured by Induced Coupled Plasma Y1 - 2003 UR - https://www.researchgate.net/publication/242728857_A_proposal_for_the_classification_of_precious_dental_alloys_according_to_their_resistance_to_corrosion_based_on_the_ISO_10271_standard VL - 5 IS - SUPPL. 1 SP - 34 EP - 36 PB - Univ. of Wales CY - Aberystwyth, Wales ER - TY - JOUR A1 - Schultheiß, Ulrich A1 - Hornberger, Helga T1 - Comparison of etchants for corrosion-resistant stainless steels in medical engineering JF - Practical Metallography N2 - Corrosion-resistant stainless steels are widely used in medical engineering. Today, additive manufacturing techniques are also used for this purpose, in particular for implant steels. Additively processed materials sometimes react differently to etching than conventionally processed ones. The use of etchants for contrasting the microstructure must therefore be adapted. Chemical etching using V2A etchant, Murakami, and anhydrous Kalling solutions, as well as electrochemical etching using nitric acid, sodium hydroxide, and oxalic acid were performed. Etched samples made of conventionally processed X2CrNi-Mo17-12-2 were compared to samples manufactured using selective laser melting and sintering, and the optimal contrast was developed in each case. It can be shown that the different etchants reveal different microstructural constituents and that etchants must therefore be selected as a function of the application. N2 - Korrosionsbeständige Edelstähle werden vielfältig in der Medizintechnik eingesetzt. Dabei werden insbesondere bei Implantat-Stählen heute auch additive Fertigungstechniken angewandt. Additiv verarbeitete Materialien reagieren teilweise anders beim Ätzen als konventionell verarbeitete, weshalb der Einsatz von Ätzmitteln zur Gefüge-Kontrastierung adaptiert werden muss. Es wurde sowohl chemisch mit V2A-Beize, Murakami- und wasserfreier Kalling-Lösung geätzt, als auch elektrochemisch mit Salpetersäure, Natronlauge und Oxalsäure. Geätzte Proben aus konventionell verarbeitetem X2CrNiMo17-12-2 wurden mit Proben verglichen, die mittels selektivem Laserschmelzen und -sintern hergestellt wurden, und die jeweils optimale Kontrastierung entwickelt. Es kann gezeigt werden, dass die unterschiedlichen Ätzmittel verschiedene Gefügebestandteile hervorheben und somit je nach Anwendungsfall das jeweilige Ätzmittel ausgewählt werden muss. Y1 - 2024 U6 - https://doi.org/10.1515/pm-2024-0094 VL - 62 IS - 1 SP - 19 EP - 30 PB - de Gruyter ER -