DE2134925C3 - Titanium alloy bone implant - Google Patents

Description

Τι

Alloy (weight percent)
ΤΓΠ5ΖΓ j Ti35Zr [TlSOZr | T565Zr

Tl 85Zr

Zr

Strength data of the
hot rolled and
annealed metal

Omax in kg / mm ¹

din ·;

modulus of elasticity
in kg / mm ^s

Melting point in 'C ...

corrosion

Tissue compatibility

55
40

10600
1720

70
31

95
23

100
21

11300

650 1 610

Alloy like pure metals
Alloy like pure metals

95
25th

1690

70
29

11000
1860

The low modulus of elasticity is biomechanical Goals are of great importance; In addition to sufficient strength, implants must have one of the Function of the bone have adapted rigidity, and the consistently low modulus of elasticity also enables less stiff implants to be made with the same strength.

The minimum of the melting point at around 50 % Zr facilitates the casting of the material, and it has also been found that alloys with 25 to 75% Zr are very "fluid" and fill casting molds very well.

The corrosion behavior and tissue compatibility the alloys are just as excellent as those of the pure metals. The bone is also full vital, one can even occasionally speak of an actual stimulation of bone formation.

On the other hand, it was found that the machining shape of the alloy remains comparable to that of titanium. Surface treatments can also be carried out in the same way, with oxides, nitrides or carbides being carried out by means of heat treatment (gas, salts, etc.) or anodic oxidation
Technically pure titanium contains up to 3% die

Elements Fe, O ₁ , Ni, etc. as impurities or

strength-increasing additives. Such additives can

be contained in the alloys according to the invention.

Implants of the Bone surgery, such as plates, screws, bone

nails, etc., produce, namely as a casting, by forging or by machining. for the dental prosthesis uses the casting process. Casting methods can be used for dental surgery implants or forging and machining

be applied; such an implant is driven, for example, into the bone of the jaw, where it is grows together, or screwed to this and covered with tissue except for protruding stumps, whereby prostheses are then attached to these. The GE-

Forged alloy has the advantage that it is completely homogeneous, and the grain size, which for the elongation can be important, can be adjusted by the deformation process and annealing

Claims (2)

These numbers on corrosion were electrochemical ** Claims: measured in vivo on rabbits. The metal was in %, Implanted muscle. After the attempt of 1, bone implant, which is known for 3 to 9 weeks, the sign attached to the metal that it was histologically examined from a titanium-zirconium tissue. It was found in all the alloy of 25 to 75 '/ _a zirconium, balance titanium cases a tissue encapsulation of the metal by at most 3% binder and production-related encryption, which is a typical foreign body reaction,
impurities and strength sidewalk emden additives Similar tests for titanium and zirconium were besteht- corrosion currents of 10 ^"I0 A / cm * or less, corresponds 2. Bone implant according to claim 1, characterized io speaking an attack of less 0.005 μ ^ αη ^ ά. characterized that the alloy consists of 50% titanium. The histology showed no encapsulation, only a fine and 50% zirconium with the production-related loose connective tissue in the manner of a filling reaction, impurities. and the fabric attached to the metal was too vascularized, i.e. of full vitality,
is titanium and zirconium are soft metals (see e.g. A.D. McQuillan and M. K. McQuillan: Titanium, Metallurgy of the Raser Metals, Volume 4, Butterworths Scientific Publications, London 1956; G. L. M i 11 e r: "Zirconium", Metallurgy of the For surgical implants, stainless steel ao Raser Metals, VoI. 2, Butterworths Scientific PuWi- (Standards: USA ASTM F 55, ASTM F 56; GB Brit. Cations, London 1957). The strength requirements of standard 3531-1962), cobalt alloys for implants, materials for dental prosthetics composition O, 4% C, O, 3% Si, O, 5% Mn, 3O, 8% Cr, they meet in the cast or annealed Condition 5.1% Mo, 0.7% Fe and the rest Co (norms: USA not. Also, the casting processes are not easy because of the high ASTM F 54; British Standard 3531-1962), titanium as melting point and reactivity.
(Standards: USA ASTM F 67-66; British Standard A Ti-Zr alloy is known as a master alloy 3531-1962 / 1967) and a Ti 6 AI 4 V alloy (standard binary alloys of Ti and Zr do not find any for clinical tests in the USA: ASTM 1968). Application, although the following properties are known The cobalt-chromium-molybdenum alloys of the above are: mentioned composition and alloys of the 30 melting point of the alloy 50Ti 50Zr (weight composition 0.1% C, 1.1% Si, 0.7% Mn, 28.3% percent) is 1610 ° C, i.e. about 100 lower than Cr, 24.4 ό Ni and the rest Co are also lower than Zr for dental Ti and about 25OC. She points higher medical implants used. Strengths than the pure metals and good ductility These implants are surgically opened subperiosteally. Jaw anchored and covered with tissue. At her- 35 The bone implant according to the present They carry prostheses with protruding pins. Because of invention that is useful for both surgical and dental Inadequate tolerance, there is a lack of long-term success. Ab- purposes can be used is now recognizable Reactions and inflammations show that it consists of a Ti-Zr alloy, which often. In the case of contact with metals, the percentage by weight is usually 25 to 75%, preferably 50% also observed gum recession. 40 Zr, remainder titanium and a maximum of 3% manufacturing Kobelt-chromium-molybdenum-, nickel-chromium- and certain impurities and strength-increasing Gold alloys are cast alloys. Receivables contains additions. to such materials for implants and prosthetics From the German Auslegeschrift 1294029 is are: Low melting point, good flow behavior, a titanium alloy made from 10 to 50% zirconium, up to Sufficient mechanical strength, hardness and not 45 to 10% iron, the remainder titanium, known to be ductile, solid low ductility, tissue friendliness. and is very resistant to corrosion. From the constant In living tissue all metals corrode more wedge such alloys against acids results or less strong, and even if it is not visible there is no direct indication of the suitability of such Attack occurs a reaction of the tissue: With the materials as bone implants, because here others Corrosion turns the metal into hydroxides and oxides so face points and more complex processes play a role transferred, which play in the electrolyte of the tissue fluid. In particular, the slightest corrosion dissociate and speed ^ demanded in the area of the tissue cells, with less the cereals local reaction, specific to each metal, plays a role as such, but that the solve. Certain metals inhibit cell growth until corrosion products that occur are non-toxic to the toxic reaction, others are neutral. 55 are. When choosing the material for the im- The following is known of the cast alloys: Plantate to ensure that no metal is in the Gold alloys have a melting point between bodies that can be seen as a foreign body with latent 900 and 100O ⁰ C, have a Vickers hardness ^ compatibility turns out to be,
of about 200 Kp / m *. an elongation limit of The following table gives measured properties 2Ό / _o and show a corrosion 6o in body fluid which, with regard to the application as an implant current of about 10- 'A / cm *, is important,
grip of about 10ug / cm * d _The strengths of the alloys let through The above-mentioned cobalt alloys have cold working, ^{increasing by about 30 kg / mm 1} , a melting temperature of 1300 to 1400 ^° C., without the elongation dropping to less than 15%, have a Vickers hardness of about 250, an elongation _{limit 6 S.} The high strengths make binary Ti-Zr ^of »/ ο and cause a corrosion current of alloys with 25 to 75% Zr, ideally suited for about lü_ A / cm corresponding to an attack by implants, namely as forged or about 0.1 μβ / ςΐη · α. cast metal.