Alloys or metallic compositions – Cobalt base – Chromium containing
Patent
1982-11-01
1984-07-10
Rutledge,, L.
Alloys or metallic compositions
Cobalt base
Chromium containing
420442, 420443, 433207, C22C 1905, C22C 1907
Patent
active
044592620
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The invention relates to an alloy based on cobalt or nickel, especially for the preparation of dental prostheses which are corrosion- and wear-resistant, can be formed in the cold state, polishable, true in colorfast and weldable.
STATE OF THE ART
Dental prostheses are known to be made in two different forms, those that are firmly attached to the available teeth, and those that are removably loosely inserted.
The firmly attached prostheses have been prepared in dentistry for several decades by a process involving one or more steps.
Dental technicians completed the crowns from pre-manufactured sockets made from corrosion-resistant steel according to the so called "pulling" method.
Bridges are prepared through soldering the crowns that are brought onto the supporting teeth in the above manner, with bridge bodies cast by separate modeling.
This technology incurs numerous problems and possibilities or error in the setting up and preparation of the width and the length of the crowns as well as in the soldering together of the crowns, and also in the soldering together of the crowns and the bridge bodies. The fit is, therefore, not always perfect and this affects the useful life of the supporting teeth. At the solder joints the bridge tends to become rigid and develop intercrystalline stress corrosion which leads to premature breaking. Furthermore, the preparation of a test crown is required which substantially increases the time required for the preparation of dental prosthetics, represents additional work for the dentist, and doubles the burden on the patient.
In the interest of better patient care recently the so called "single piece casting process" was developed for preparing crown- and bridge prostheses. In this case the entire prosthesis is prepared from a single casting cast from a single model.
In this case there are fewer possibilities of error, the edge closure of the crowns is more complete and since there is no need for separate trial bodies the prosthesis is completed more quickly, and the entire process requires less time from the dentist and the patient.
The number of dental prostheses prepared according to the "single piece casting process" shows a worldwide increasing tendency. In Hungary e.g. in the year 1979, compared to 1971, about hundred times as many dental prostheses were prepared according to the "single piece casting process". This corresponds still only to 37% of the total number of prostheses made in 1979, because the usefullness of the "single piece casting process" is limited due to strict requirements on the useful alloys as well as to the high price and availability problems occasioned thereby.
In the preparation of dental prostheses in accordance with the "single piece casting process" the alloy that is used should not only have sufficient strength, and resistance against wear and corrosion, but should also possess other properties, such as good casting ability, good ductility for accurate adjustment, polishability, colorfastness and elasticity. It should also assure a corresponding mechanical adhesion of plastic covering layers required for aesthetic reasons. The general strength requirements of suitable alloys are:
These requirements are satisfied from among the available metal alloys used in dental technology, only by the noble metal alloys (gold-, silver-, platinum-, palladium alloys). These generally have the following characteristics:
The cobalt-chromium alloys, such as Vitallium, that are mostly used for making bridge members, have the following properties:
These alloys have only limited castability, because they are rigid and are too hard. Due to these latter properties small cross section prostheses made from these materials are very fragile and tend to splinter and tend to damage the adjacent healthy teeth during use. Therefore, they are not suitable for the preparation of dental prostheses cast from a single piece. Alloys for the preparation of removable dental fixtures have similar strength requirements and they have to have even better cas
REFERENCES:
patent: 4053308 (1977-10-01), Tesk et al.
patent: 4255190 (1981-03-01), Prosen
Fogtechnikai Vallalat
Katona Gabriel P.
McDowell Robert L.
Rutledge, L.
LandOfFree
Alloys based on cobalt or nickel, especially for preparing denta does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Alloys based on cobalt or nickel, especially for preparing denta, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Alloys based on cobalt or nickel, especially for preparing denta will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1575978