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Biomedical subjects

K Böning

Publications and source records attributed to K Böning.

14 recordsLinked to original sources
PubMed2004

Dentocase - open-source education management system in dentistry.

Since 2001, an interdisciplinary project on multimedia education in medicine has been sponsored by the Federal Ministry of Education and Research at the Charité. One part of the project is on dentistry. In the light of the results of a survey of dental students, an Internet-based education management system was created using open-source back-end systems. It supports four didactic levels for editing documentation of patient treatments. Each level corresponds to the learning abilities of the students. The patient documentation is organized to simulate the working methods of a physician or dentist. The system was tested for the first time by students in the summer semester of 2003 and has been used since the winter semester of 2003 as part of the curriculum.

Computer-Assisted Instruction↗
PubMed1999

Six-year follow-up of titanium and high-gold porcelain-fused-to-metal fixed partial dentures.

In a randomized clinical study 47 titanium and gold-alloy fixed partial dentures (FPDs) were placed during a 1-year period. In the titanium group (n = 22) all metal substructures were made of unalloyed titanium. The titanium substructures were fabricated by copy milling, spark erosion and laser welding (Procera, Nobelpharma). Ceramic veneering was carried out with Duceratin titanium ceramics (Ducera, Germany). In the control group (n = 25) the high-gold alloy Degudent U (Degussa, Germany) and Vita VMK 68 ceramics (Vita, Germany) were used. The longest observation time was 6 years. Only one FPD had to be removed due to metal-ceramic failure (titanium group). The clinical performance of all 125 porcelain-fused-to-metal (PFM) veneers with respect to the longevity of the metal-ceramic compound was described by Kaplan-Meyer survivor analyses. Relating survival to a completely intact ceramic veneer, the 5-year survivor rate was 84% for titanium and 98% for the high-gold alloy. PFM titanium restorations exhibited a significantly increased risk of metal-ceramic failure. However, concerning defects requiring removal, no significant differences in titanium versus high-gold alloy occurred. There were no significant differences in the survival distributions between crowns and pontics within the two groups.

Adult↗
PubMed1994

Clinical performance of machined titanium restorations.

In 37 patients 88 titanium restorations were placed during a 1-year period 1990-91. The 69 crowns and 19 fixed partial dentures comprised 147 prosthodontic units. All restorations were fabricated by duplication milling and electrical discharge machining of pure titanium (Procera Technology, Nobelpharma, Gothenburg, Sweden). Based on the results of clinical follow-up, Kaplan-Meier survivor functions were calculated. The survivor rate of 40 metal crowns and pontics was 100%. In 107 porcelain-fused-to-metal units the 3-year survivor rate concerning removal was 95%. When relating the survival to an intact ceramic veneer, the 3-year survivor rate of porcelain-fused-to-metal units was 84%. The quality of the restorations evaluated by the rating system of the California Dental Association was found to be satisfactory in the vast majority of cases. It can be concluded that machined titanium restorations are suitable for clinical use, although not all problems, especially in the field of metal-ceramics have yet been completely solved.

Crowns↗
PubMed1991

[Is titanium an alternative for base metal alloys?].

Because of the excellent biocompatibility titanium can be considered as an ideal material for prosthetic reconstructions. Especially for base metal alloys titanium is an alternative due to the low cost. Processing still causes problems. In this paper a vacuum pressure casting system and a combination of milling and spark erosion are described and investigated. Both techniques are suitable to manufacture prosthetic restorations with a high accuracy of fit. Problems in dental castings lie in the occurrence of a superficial reaction zone of about 40-100 microns width. No final conclusions concerning the metal-ceramic compound can be drawn at the moment for lack of undisputable results in different mechanical bonding tests. Due to the remaining difficulties the future importance of titanium in prosthetic dentistry cannot be prognosticated.

Dental Alloys↗
PubMed1991

[Castability and accuracy of fit of a titanium casting system].

The titanium casting system Cyclarc (Morita) was examined for its suitability for the fabrication of dense, fitting restorations. The investment material Titavest CB exhibited no setting expansion. Instead, thermal expansion, highly dependent on the liquid/power ratio and the temperature during preheating, was observed. The castability of unalloyed titanium is fully acceptable for the fabrication of prosthetic restorations. Single crowns showed a high accuracy of fit, if an optimal liquid/power ratio was used for investment.

Crowns↗
PubMed1991

[Ceramo-metallic bond of cast titanium].

The ceramo-metallic bond strength of cast titanium was tested according to DIN draft 13927. While the specimens failed in the bending tests, they clearly passed the 3-point bending test after removal of the surface reaction layer prior to firing. Light microscopy and SEM showed a satisfactory wetting of the titanium surface by the ceramic material. The result of X-ray analyses suggest that titanium particles are retained in the ceramic material when this layer is broken off its metallic substructure.

Dental Bonding↗
PubMed1991

[Fixed tooth replacement of milled/spark eroded titanium].

In a clinical study the accuracy of fit of 82 crowns manufactured with the Procera-system (duplication milling/spark erosion) was investigated. The average marginal space width was 71 microns. Roughness of eroded surfaces was found to be similar to that of coarsely ground metal. Below the eroded areas a zone of increased hardness with a width of approximately 20 microns was demonstrated.

Crowns↗
PubMed1990

Palladium alloys in prosthodontics: selected aspects.

The high costs of gold and platinum have caused other alloys to be considered in the construction of prosthetic appliances. This paper reports on the grain structure, corrosion resistance and microstructure of palladium alloys. Also discussed are the properties of these alloys and how these affect their technical manipulation.

Chemical Phenomena↗
PubMed1990

[Quantitative analysis of the corrosion rates of palladium alloys by isolated polarization].

The corrosion resistance of three palladium alloys and one conventional high noble alloy were examined by isolated polarization. Using this method, isolated plots of the cathodic and anodic reaction can be recorded. The corrosion current is given as the anodic and cathodic plots intercept. The current densities of the palladium alloys were approximately ten times higher than of the high noble alloy. All results were dependent on the acidity of the electrolyte.

Corrosion↗
PubMed1989

[Corrosion testing of palladium alloys with the aid of anodic potentiodynamic polarization].

The corrosion resistance of five palladium alloys has been tested by means of anodic potentiodynamic polarization before and after different heat treatment procedures. The results show a marked reduction in the corrosion resistance of the Pd Ag, Pd Cu and Pd Au materials as against high gold alloys. Within the group of the Pd alloys the Pd Au materials showed the highest resistance to corrosion. Correlations with the thermal pretreatment procedure applied could not be demonstrated.

Corrosion↗