RU2135119C1 - Method of preparation of orthopedic article from titanium alloy - Google Patents

Abstract

FIELD: orthopedic stomatology and maxillofacial orthopedics, and other medical and physiological fields of man vital activity. SUBSTANCE: in preparation for molding and molding of prosthesis or prosthesis member, for instance, base for removable denture, first blank of titanium alloy is hot-rolled to thickness of 3-15 mm and hardened from temperature of 950-1150 C. At temperature of 700-700 C, blank is deformed into sheet 0.5-2.5 mm thick which is placed on fireproof ceramic matrix. Then built-up from one side of sheet is pressure from 0.1 to 2 MPa, and from the other side, rarefaction is created from 0.7 to 7.0 Pa. Temperature is set from 750 to 1000 C. The invention provides for economically rational production of highly precise thin-walled bases from titanium alloys for comfortable removable dentures and other similar prostheses whose surface is precise copy of patient prosthetic field. EFFECT: higher efficiency.

Description

 The invention relates to medicine, in particular to orthopedic dentistry, maxillofacial orthopedics and other general medical and general physiological spheres of the human body.

 A known method of manufacturing removable dentures (bases), according to which the base is obtained by investment casting from a titanium alloy (Rogozhnikov G.I., Sochnev V.L., Olenev L.M. et al. Titanium bases for dentures, Perm, LLP Printing House Book 1994, p. 270).

 However, this method is very labor intensive in manufacturing, expensive special equipment and does not allow to obtain high-precision thin-walled bases of titanium alloys. The lack of accuracy in reproducing the microrelief of the palatal surface of the basis during casting leads to the need for additional mechanical processing (milling, grinding). In addition, the method does not allow to obtain an oral surface of the basis of a titanium alloy corresponding to the individual relief of the patient's palate. All these disadvantages lead to a decrease in the functional qualities of removable dentures in general.

 Closest to the technical solution is a method of manufacturing the bases of removable dentures, according to which the bases are obtained by pressing from titanium or a titanium alloy (Application N 62-32942, Japan, MKI 4 A 61 C 13/1, publ. 17.07.87).

 Meanwhile, it is known that titanium and its alloys are difficult to deform. This determines the use in this method of expensive tools made of special steels, which is problematic in the conditions of individual production, which is the manufacture of bases for dentures and other orthopedic products. In this way, it is also practically impossible to reproduce the relief of the mucous membrane of the patient’s oral cavity and other complex-profile thin-walled products with the necessary accuracy, on which the functional properties of the prostheses and the quality of treatment ultimately depend.

 The proposed method for manufacturing an orthopedic product from a titanium alloy, for example, a basis for a removable denture, is free from the above disadvantages, which is achieved by using workpieces from a titanium alloy sheet with a thickness of 0.5 - 2.5 mm, obtained by special modes, as well as by optimizing the molding technique.

 This method also provides high deformability of the titanium billet. Costly metal matrices have been replaced with significantly cheaper industrial refractory ceramics. Instead of complex and expensive punches, a small overpressure of an inert gas was used as a forming element.

 Achievable technical result - economically rational production of high-precision thin-walled bases of titanium alloys for comfortable removable dentures and other similar prostheses, the surface of which is an exact copy of the prosthetic field of the patient.

It is achieved by the fact that in the process of preparing the preform for forming, it is deformed by hot rolling to a thickness of 3-15 mm and hardening is carried out at a temperature of 950-1150 ^o C, and then, using the rolling, annealing and etching operations, a sheet with a thickness of 0.5 is obtained -2.5 mm, which is placed on a refractory ceramic matrix, which is placed on a pallet or in a cage of heat-resistant material and molded at a temperature of 750-1000 ^o C, while from one side of the sheet create a pressure of from 0.1 to 2.0 MPa , on the other hand, a vacuum from 0.7 to 7.0 Pa.

 The method is as follows.

At the first stage, according to the optimal conditions, a sheet of titanium alloy is prepared with a thickness of 0.5-2.5 mm with specified properties guaranteeing the receipt (reproduction) of an accurate surface print with all the features and details of the micro- and macrorelief at the subsequent stages of the process according to models made of refractory ceramics. For this, the initial hot-rolled billet with a thickness of 3-15 mm from a titanium alloy is preheated in a furnace to a temperature of 950-1150 ^o C and cooled in cold water.

Then this preform is deformed at a temperature of 700-800 ^o C to the desired thickness, after which it is cleaned of scale in a solution of sulfuric and hydrofluoric acids, heated in a vacuum oven (to prevent oxidation) and then cut into measuring billets.

At the second stage, models are made of refractory ceramics by casting using gypsum impressions. Then these models are placed on a pallet or in a metal cage of heat-resistant alloy, which has special cutouts, the size and shape of which allows you to place an impression of the oral surface of any patient or another model in it. The number of simultaneously molded parts can vary from 1 to N and depends on the size of the stamp and economic feasibility. Then, on top of the ceramic models, a sheet of titanium alloy with a thickness of 0.5-2.5 mm is applied, a pallet or holder with a sheet is heated to a temperature of 750-1000 ^o C, then a vacuum (vacuum) of 0.7 - 7.0 Pa is created under the sheet, and from above create an inert gas pressure, for example, argon, from 0.1 to 2.0 MPa, after a 15-40-minute exposure, the model is cooled to room temperature. Bases or other products of the required profile are cut along the contour, for example, with a laser beam, grind the edge on the abrasive wheel, remove the scale in the sandblasting apparatus, and if necessary, electro-polish the surface.

 The manufacture of the basis for a removable denture was tested in the clinic of orthopedic dentistry of the Moscow Medical Dental Institute. Semashko. The results allow us to conclude that the use of titanium bases for removable dentures is highly effective.

 In practice, a method of manufacturing a basis for a removable denture and other products can be implemented, for example, as follows.

 A sheet of titanium alloy is clamped between the flanges of the two halves of the mold, in the lower half-mold there are models on a pallet or in a holder, the shape and relief of which must be reproduced from titanium alloy. The alignment of the half-forms, their mixing and dilution, the creation of a clamping force along the sheet edge between the half-forms is carried out by the press system. After clamping the sheet, the half-molds form an airtight chamber divided by the sheet into two parts, each of which has a channel of communication with the gas system and can be independently evacuated or filled with an inert gas under some pressure.

 Sealed molds are placed in a furnace in which they are heated to a predetermined temperature. Upon reaching the required temperature, an inert gas, for example argon, pressure differential is created between the upper and lower chambers, so that the sheet bends towards the evacuated half-mold and is “blown” into the ceramic matrix (model) located in it, making its relief easier. During this period, time and pressure are maintained according to a specific program selected for each specific part. At the end of this program, the furnace is removed from the tool to accelerate its cooling, the tightness of the half-molds is maintained by the press to a temperature that excludes oxidation of the extracted part. After that, the pressure in both half-molds is equalized to normal and the workpiece is removed from the mold, the bases or other parts are cut out and subjected to final mechanical and electrochemical processing.

Claims (1)

A method of manufacturing an orthopedic product from a titanium alloy, for example, a basis for a removable denture, which consists in the fact that the titanium alloy preform is prepared for molding and then molded, characterized in that during preparation of the preform for molding, it is deformed by hot rolling to a thickness of 3- 15 mm and hardening is carried out from a temperature of 950-1150 ^o C, and then, using the operations of rolling, annealing and etching, a sheet of thickness 0.5-2.5 mm is obtained, which is placed on a refractory ceramic matrix, the matrix is placed on a pallet or in about yme heat-resistant material and is molded at 750-1000 ^o C, wherein the one side of the sheet, a pressure of from 0.1 to 2.0 MPa, on the other hand - the vacuum is from 0.7 to 7.0 Pa.