Biomaterial Database

Experimental analysis of retention forces of different magnetic devices for bone-anchored auricular facial prostheses. 2008

A Voigt, and S Christ, and M Klein

Department of Oral and Maxillofacial Surgery, Plastic Surgery, Clinical Navigation and Robotics, Charité, University of Berlin, Germany. alexander.voigt@charite.de

The aim of this study was to determine which combination of differently designed magnetic abutments provides the best retention for an auricular prosthesis. The withdrawal forces of eight combinations of abutments were measured and results compared. There was a significantly higher withdrawal force in arrangements containing three magnets over only two. The highest withdrawal force was found in the combination of one telescopic magnet and two large spherical magnets (median: 7.69 N), whereas two telescopic magnets alone showed the lowest withdrawal force (3.41 N). The use of two conical magnets increased retention slightly, but the median retention force remained the same (3.41 N). The commonly used combination of two small spherical magnets and one telescopic magnet showed the lowest retention of combinations consisting of three magnets (4.94 N). There seems to be no difference in median withdrawal force if a conical magnet instead of a telescopic magnet is used. The withdrawal force at a 45 degrees angle was about 10% higher than the vertical force but the difference was not significant. The rupture force needed to tear the magnet completely out of the silicone was 240.6-519.7 N (mean 331.74 N) and therefore over 10 times higher than magnetic retention.

UI	MeSH Term	Description	Entries
D008280	Magnetics	The study of MAGNETIC PHENOMENA.	Magnetic
D011474	Prosthesis Design	The plan and delineation of prostheses in general or a specific prosthesis.	Design, Prosthesis,Designs, Prosthesis,Prosthesis Designs
D011475	Prosthesis Failure	Malfunction of implantation shunts, valves, etc., and prosthesis loosening, migration, and breaking.	Prosthesis Loosening,Prosthesis Durability,Prosthesis Migration,Prosthesis Survival,Durabilities, Prosthesis,Durability, Prosthesis,Failure, Prosthesis,Failures, Prosthesis,Loosening, Prosthesis,Loosenings, Prosthesis,Migration, Prosthesis,Migrations, Prosthesis,Prosthesis Durabilities,Prosthesis Failures,Prosthesis Loosenings,Prosthesis Migrations,Prosthesis Survivals,Survival, Prosthesis,Survivals, Prosthesis
D003035	Cobalt	A trace element that is a component of vitamin B12. It has the atomic symbol Co, atomic number 27, and atomic weight 58.93. It is used in nuclear weapons, alloys, and pigments. Deficiency in animals leads to anemia; its excess in humans can lead to erythrocytosis.	Cobalt-59,Cobalt 59
D004431	Ear, External	The outer part of the hearing system of the body. It includes the shell-like EAR AURICLE which collects sound, and the EXTERNAL EAR CANAL, the TYMPANIC MEMBRANE, and the EXTERNAL EAR CARTILAGES.	External Ear,Outer Ear,Ear, Outer,Ears, External,Ears, Outer,External Ears,Outer Ears
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D012493	Samarium	An element of the rare earth family of metals. It has the atomic symbol Sm, atomic number 62, and atomic weight 150.36. The oxide is used in the control rods of some nuclear reactors.
D012828	Silicones	A broad family of synthetic organosiloxane polymers containing a repeating silicon-oxygen backbone with organic side groups attached via carbon-silicon bonds. Depending on their structure, they are classified as liquids, gels, and elastomers. (From Merck Index, 12th ed)	Silicone
D013314	Stress, Mechanical	A purely physical condition which exists within any material because of strain or deformation by external forces or by non-uniform thermal expansion; expressed quantitatively in units of force per unit area.	Mechanical Stress,Mechanical Stresses,Stresses, Mechanical
D013499	Surface Properties	Characteristics or attributes of the outer boundaries of objects, including molecules.	Properties, Surface,Property, Surface,Surface Property