RU2551628C1 - Method for making metal-ceramic dentures - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: metal frame is made of valve metals. It is cleaned and processed. A ceramic layer min. 50 mcm thick is formed on the metal frame by micro-arch oxydation in a water electrolyte solution of aluminium sulphate; the frame is then glazed, and the denture is thermally processed in vacuum at temperatures not exceeding allotropic transformation temperatures in the metal frame, but no more than 830°C, for a hold up time of min 15 minutes. A temperature rise rate shall not exceed 15°C/min, whereas a cool down rate is no more than 7°C/min, while the ceramic layer relates to total coating thickness as 0.6 - 0.8.

EFFECT: by producing the metal-ceramic structures having the desired physical properties and high strength characteristics, the method enables producing the dentures at lower labour intensity, high quality, reliability and aesthetic characteristics.

20 dwg, 10 tbl, 1 ex

Description

The invention relates to medicine, namely to orthopedic dentistry in the manufacture of cermet dentures.

A known method of producing ceramic coatings on the surface of dentures and implants, including coating by plasma spraying, characterized in that the ceramic coatings are multilayer, and first apply a porous layer of metal identical to the base metal, then apply layers of a mechanical mixture of metal and ceramics, gradually increasing the ceramic content from 20 to 90% from layer to layer, the ceramic layer is sprayed last, and the total thickness of the plasma-sprayed coating is 90-200 μm [1].

The closest in technical essence is a method of manufacturing cermet dentures, including the manufacture of a metal base, cleaning, processing, applying a ceramic coating [2].

The objective of the invention is to reduce the complexity of manufacturing a prosthesis, increasing its quality, reliability and aesthetic characteristics.

The problem is achieved in that in the known method, including the manufacture of a metal base, cleaning, processing, applying a ceramic coating, according to the proposed invention, on a metal base of valve group metals, microarc oxidation forms a ceramic layer, at least 50 microns thick, in an aqueous electrolyte solution based on aluminum sulfate, followed by the application of glaze and heat treatment of the prosthesis in vacuum at temperatures not exceeding allotropic transformation temperatures variations in the material of the metal base, but not less than 830 ° C, the exposure time of at least 15 minutes, while the rate of temperature rise should be no more than 15 ° C / min, the cooling rate should be no more than 7 ° C / min, and the ratio of the thickness of the ceramic layer to the total thickness of the coating should be 0.6-0.8.

The method is as follows: the prosthesis is made using CAD / CAM technology, cleaned and processed in a sandblasting machine. Then it is placed in an electrolytic bath with an aqueous solution of electrolyte. The current is supplied to the electrodes, one of which (the anode) is mounted on the prosthesis, the other (cathode) on the inner surface of the bath. In the interaction of electric current, electrolyte and prosthesis material, a ceramic layer forms on its surface. After completion of the process of forming the ceramic layer, the current is turned off, the prosthesis is washed and dried. Then a layer of glaze is applied to the surface of the prosthesis. Next, the prosthesis is placed in a vacuum oven and fired, getting a ceramic coating.

The introduction of a new feature ensures the production of cermet structures that meet the aesthetic standards to the greatest extent, have the required physical properties and high strength characteristics, and are not destroyed under the influence of the occlusal load, which makes it possible to produce prostheses with less laboriousness, high quality, reliability and aesthetic characteristics. Ceramic-metal restorations are biocompatible - they do not have a pathological effect on the teeth and surrounding tissues, they do not have allergic reactions, since the proposed method realizes the possibility of obtaining a bioinert ceramic layer, both from the outside and from the inside of the crowns.

The method is illustrated by photographs.

Figure 1 presents a General view of the metal base (titanium VT1 - 0) of the prosthesis of a large molar. Figure 2 - General view of the metal base (titanium VT1 - 0) of the prosthesis of the lateral incisor. Figure 3 is a General view of the metal base (zirconium E125) of the prosthesis of the large molar. Figure 4 - General view of the metal base (zirconium E125) of the prosthesis of the lateral incisor. Figure 5 is a General view of the prosthesis of a large molar with a ceramic layer (metal base titanium VT1 - 0). Figure 6 - General view of the prosthesis of the side incisor with a ceramic layer (metal base titanium VT1 - 0). 7 is a General view of the prosthesis of a large molar with a ceramic layer (metal base of zirconium E125). On Fig - General view of the prosthesis of the lateral incisor with a ceramic layer (metal base zirconium E125). In Fig.9 is a General view of the prosthesis of a large molar with ceramic coating after firing (metal base titanium VT1 - 0). Figure 10 is a General view of the prosthesis of a large molar with ceramic coating after firing (metal base zirconium E125). Figure 11 is a General view of the prosthesis of the large molar with traces of destruction of the ceramic coating (metal base titanium VT1 - 0). On Fig - General view of the prosthesis of the side incisor with traces of destruction of the ceramic coating (metal base titanium VT1 - 0). On Fig - General view of the prosthesis of the large molar with traces of destruction of the ceramic coating (metal base zirconium E125). On Fig - General view of the prosthesis of the lateral incisor with traces of destruction of the ceramic coating (metal base zirconium E125). On Fig - cermet prosthesis of the small molar in natural light. In Fig.16 - cermet prosthesis of a small molar tooth under artificial lighting. On Fig - General view of the prosthesis of the large molar with traces of cracks on the surface of the ceramic coating (metal base titanium VT1 - 0). On Fig - a General view of the workpiece of the prosthesis with traces of cracks on the surface of the ceramic coating (metal base titanium VT1 - 0). On Fig - General view of the prosthesis of a small molar tooth with traces of cracks on the surface of the ceramic coating (metal base zirconium E125). In Fig.20 is a General view of the prosthesis blank with traces of cracks on the surface of the ceramic coating (metal base zirconium E125).

Example. The metal base of the prostheses was made of dental metals of the valve group: technically pure titanium (VT1-0, Fig.1, 2) and technically pure zirconium (E125, Fig.3, 4) and were cleaned and processed in a sandblasting machine. Next, the prosthesis was subjected to microarc oxidation for 10 minutes at a current density of 80 A / dm ² , a voltage of 200 V in an aqueous solution based on aluminum sulfate (Al ₂ (SO ₄ ) ₃ ) - 50 g / L. After completion of the process of forming the ceramic layer, the current is turned off, the prosthesis is washed and dried (Figs. 5, 6, 7, 8). Then, a layer of glaze is applied to the surface of the prosthesis so that the ratio of the thickness of the ceramic layer to the total coating thickness is 0.7. Next, the prosthesis is placed in a vacuum oven and fired, getting a ceramic coating (Fig.9, 10). The rate of temperature rise to 830 ° C was 15 ° C / min, the cooling rate was 7 ° C / min, and the vacuum was 50 GPa.

Tests and studies of ceramic layers and coatings were carried out according to standard methods. The temperature coefficient of linear expansion, thermal conductivity, linear shrinkage, porosity, chemical solubility, bond strength of the ceramic coating with the base metal, tensile strength, bending strength, microhardness, wear resistance, chemical resistance to the oral environment, sterility, pyrogen-free, toxicity index were determined , change in pH, content in aqueous extracts: reducing and organic impurities; copper; lead chromium; cadmium; barium; tin; formaldehyde.

The test results and studies are presented in tables 1-10.

Table 1 The test results of the bond strength of the ceramic coating with the base metal No. p / p Variable process parameters The bond strength of the ceramic coating with the base metal, MPa Ceramic coated metal base VT 1-0 E125 VT 1-0 E125 VT1-0 E125 VT1-0 E125 VT1-0 E125 one 2 3 four 5 6 7 8 9 10 eleven 12 2 Firing temperature, ° C 882 * 862 * 860 850 840 840 830 830 825 825 3 - 58 ± 1.75 69 ± 2.08 163 ± 4.89 185 ± 5.54 268 ± 8.05 306 ± 9.17 350 ± 10.50 369 ± 10.96 335 ± 10.06 352 ± 10.55 Notes: * - the indicated temperature corresponds to allotropic transformation.

If the firing temperature corresponds to the temperatures of allotropic transformations (Table 1, columns 3, 4), then the coating is destroyed (cracking, chips, delamination - 11, 12, 13, 14) as a result of the low adhesive strength of the metal base with a ceramic layer .

However, the implementation of internal and surface color modification of the ceramic layer is not ensured.

If the firing temperature is lower than the temperature of allotropic transformations, then no defects are formed, and the bond strength of the ceramic coating with the base metal increases, reaching maximum values at the firing temperature of 830 ° C (Table 1, columns 9, 10). A further decrease in temperature leads to a decrease in strength (Table 1, columns 11, 12) as a result of a decrease in the amount of crystalline phase.

In addition, at a firing temperature of 830 ° C, the implementation of internal and surface color modification of the ceramic layer is ensured, which makes it possible to obtain a high degree of fluorescence after applying the glaze (Fig. 15), which, in turn, helps to reproduce the natural color. Moreover, any natural color characteristic is reproduced by the repeatability of microarc oxidation and firing modes. A high degree of fluorescence, which corresponds to the fluorescence of natural teeth, enhances the vital appearance of ceramic-metal frames (Fig. 15). The natural look is preserved under artificial lighting (Fig.16).

The proposed method provides the desired color concept of the coating, including primary (basic) and secondary (derived) colors, which makes it possible to meet the requirements of various aesthetic restorations. The bond strength of the ceramic coating with the base metal satisfies the requirements for ceramic and cermet dental materials.

table 2 The test results of the bond strength of the ceramic coating with the base metal No. p / p Variable process parameters The bond strength of the ceramic coating with the base metal, MPa Ceramic coated metal base VT1-0 E125 VT1-0 E125 VT1-0 E125 VT1-0 E125 VT1-0 E125 one 2 3 four 5 6 7 8 9 10 eleven 12 2 The rate of temperature rise, ° C / min 55 55 35 35 25 25 fifteen 5 fourteen fourteen 3 - 70 ± 2.10 81 ± 2.43 140 ± 4.21 156 ± 4.67 257 ± 7.70 265 ± 7.96 344 ± 10.32 369 ± 11.06 347 ± 10.41 372 ± 11.16 Notes: the table shows the strength properties obtained by the best firing mode - firing temperature of 830 ° C (columns 9, 10 in table 1).

In that case, if the temperature rise rate is not more than 15 ° C / min, then the formation of the ceramic coating increases the fraction of the crystalline phase, which provides high bond strength of the ceramic coating with the base metal (Table 2, columns 9, 10), high tensile strength , bending, microhardness (Table 3) and wear resistance of both the ceramic layer (Table 4, lines 1, 2) and the ceramic coating (Table 4, lines 3, 4). Reducing the time of temperature rise reduces the productivity of the process, while the properties change slightly (no more than 1% - Table 2, columns 11, 12).

If the rate of temperature rise is more than 15 ° C / min, then when the ceramic coating is formed, the fraction of the crystalline phase decreases to 30-40%, which reduces the adhesive strength of the metal base with the ceramic layer and, as a result, reduces the bond strength of the ceramic coating with the base metal (table .2, columns 8 to 3).

Table 3 Strength and Hardness Test Results No. p / p Name of material Defined Characteristics Bending Strength, MPa Tensile strength, MPa Microhardness, GPa one 2 3 four 5 one Samples with a ceramic layer after microarc oxidation (metal base titanium VT1-0) 240 ± 7.20 503 ± 15.09 10.20 ± 0.32 2 Samples with a ceramic layer after microarc oxidation (metal base of zirconium E125) 264 ± 7.92 384 ± 11.52 11.00 ± 0.33 3 Samples with ceramic coating after firing (metal base titanium VT1-0) 312 ± 9.36 510 ± 15.30 7.50 ± 0.22 four Samples with ceramic coating after firing (metal base of zirconium E125) 343 ± 7.92 390 ± 11.70 7.60 ± 0.23 Notes: the table shows the properties obtained by the best firing mode - firing temperature of 830 ° C (columns 9, 10 in table 1); a temperature rise rate of 15 ° C / min (columns 9, 10 in table 2); exposure time 15 min (columns 9, 10 in table 5); cooling rate 7 ° C / min (columns 9, 10 in table 6), the thickness of the ceramic layer 50 μm (columns 9, 10 in table 7), the ratio of the thickness of the ceramic layer to the total coating thickness is 0.7 (columns 7, 8 in table 8).

Table 4 Wear test results No. p / p Name of material Defined Characteristics The wear rate of Ig · 10 ^-2 , g / m ³ The proportion of wear i · 10 ^-3 ,% Wear resistance to base material (Iq ₁ / Iq _i ) one 2 3 four 5 one Samples with a ceramic layer after microarc oxidation (titanium metal base VT 1-0) 1.14 1.10 8.11 2 Samples with a ceramic layer after microarc oxidation (metal base of zirconium E125) 1.13 0.95 10.58 3 Samples with ceramic coating after firing (metal base titanium VT1-0) 1.55 1,50 11.29 four Samples with ceramic coating after firing (metal base of zirconium E125) 1,54 1.29 14.39 Notes: the table shows the properties obtained by the best firing mode - firing temperature of 830 ° C (columns 9, 10 in table 1); a temperature rise rate of 15 ° C / min (columns 9, 10 in table 2); exposure time 15 min (columns 9, 10 in table 5); cooling rate 7 ° C / min (columns 9, 10 in table 6), the thickness of the ceramic layer is 50 μm (columns 9, 10 in table 7), the ratio of the thickness of the ceramic layer to the total coating thickness is 0.7 (columns 7, 8 in the table 8).

Table 5 The test results of the bond strength of the ceramic coating with the base metal No. p / p Variable process parameters The bond strength of the ceramic coating with the base metal, MPa Ceramic coated metal base VT1-0 E125 VT1-0 E125 VT1-0 E125 VT1-0 E125 VT1-0 E125 one 2 3 four 5 6 7 8 9 10 eleven 12 2 Holding time, min 5 5 7 7 10 10 fifteen fifteen 17 17 3 - 128 ± 3.84 133 ± 3.98 186 ± 5.59 193 ± 5.80 233 ± 6.70 248 ± 7.43 338 ± 10.15 357 ± 10.70 341 ± 10.23 360 ± 10.80 Notes: the table shows the strength properties obtained by the best firing mode - firing temperature of 830 ° C (columns 9, 10 in table 1); the rate of temperature rise is 15 ° C / min (columns 9, 10 in table 2).

When the exposure time is less than 15 minutes, the process of forming the ceramic coating does not occur in full, and the fraction of the crystalline phase does not exceed 40-50%, which reduces the bond strength of the ceramic coating with the base metal (Table 5, columns 3, 4).

When the exposure time is 15 minutes or more, the process of ceramic coating formation takes place in full, and the fraction of the crystalline phase increases to 80-90%, which increases the bond strength of the ceramic coating with the base metal (Table 5, columns 9, 10). In addition, tensile strength, bending, microhardness (Table 3) and wear resistance of both the ceramic layer (Table 4, lines 1, 2) and the ceramic coating (Table 4, lines 3, 4) increase.

An increase in the exposure time reduces the productivity of the process, while the properties change slightly (no more than 1% - Table 5, columns 11, 12).

Table 6 The test results of the bond strength of the ceramic coating with the base metal No. p / p Variable process parameters The bond strength of the ceramic coating with the base metal, MPa Ceramic coated metal base VT1-0 E125 VT1-0 E125 VT1-0 E125 VT1-0 E125 VT1-0 E125 one 2 3 four 5 6 7 8 9 10 eleven 12 2 Cooling rate, ° C / min thirty thirty twenty twenty 10 10 7 7 5 5 3 - 82 ± 2.45 98 ± 2.94 146 ± 4.37 167 ± 5.00 303 ± 9.10 328 ± 9.85 350 ± 10.50 380 ± 11.40 353 ± 10.59 383 ± 11.49 Notes: the table shows the strength properties obtained by the best firing mode - firing temperature of 830 ° C (columns 9, 10 in table 1); a temperature rise rate of 15 ° C / min (columns 9, 10 in table 2); the exposure time of 15 minutes (columns 9, 10 in table 5).

In the case when the cooling rate is not more than 7 ° C / min, the base metal forms a strong chemical bond with the ceramic coating due to the mutual diffusion of metal ions and the ceramic layer, which ensures high adhesion of the base metal to the ceramic coating and prevents chip formation. Moreover, the bond strength of the ceramic coating with the base metal reaches 350-380 MPa (table 6, lines 9, 10). A decrease in the cooling rate of less than 7 ° C / min does not lead to a significant increase in strength properties (not more than 1% - Table 6, lines 11, 12), but reduces the productivity of the process.

With an increase in the cooling rate of more than 7 ° C / min, the chemical bond strength of the metal with the ceramic layer decreases, the fraction of the crystalline phase in the coating decreases, which reduces the bond strength of the ceramic coating with the base metal (Table 6, columns 3 through 8) and decreases the strength by tensile, bending, microhardness (Table 3) and wear resistance of both the ceramic layer (Table 4, lines 1, 2) and the ceramic coating (Table 4, lines 3, 4).

Table 7 The test results of the bond strength of the ceramic coating with the base metal No. p / p Variable process parameters The bond strength of the ceramic coating with the base metal, MPa Ceramic coated metal base VT1-0 E125 VT1-0 E125 VT1-0 E125 VT1-0 E125 VT1-0 E125 one 2 3 four 5 6 7 8 9 10 eleven 12 2 The thickness of the ceramic layer, microns twenty twenty thirty thirty 40 40 fifty fifty 60 60 3 - 268 ± 8.08 288 ± 8.64 280 ± 8.39 294 ± 8.82 332 ± 9.97 363 ± 10.90 344 ± 10.34 380 ± 11.44 347 ± 10.40 383 ± 11.49 four Thermal conductivity coefficient λ, W / (m · K) 3.29 3.73 4.94 5.60 6.58 7.47 8.22 9.34 9.86 11.21 Notes: the table shows the strength properties obtained by the best firing mode - firing temperature of 830 ° C (columns 9, 10 in table 1); a temperature rise rate of 15 ° C / min (columns 9, 10 in table 2); exposure time 15 min (columns 9, 10 in table 5); cooling rate 7 ° C / min (columns 9, 10 in table 6).

When the thickness of the ceramic layer is less than 50 μm, the bond strength of the ceramic coating with the base metal decreases from 344-380 MPa (Table 7, columns 9, 10) to 268-288 MPa (Table 7, columns 3, 4), while remaining high and appropriate strength for dental materials. In this case, the thermal conductivity coefficient λ decreases by a factor of 2.5 and, accordingly, thermal conductivity increases by a factor of 2.5 (Table 7, row 4, columns 10 to 3), which impairs the protection of tooth tissues from temperature extremes and inevitably leads to the need for removal nerve and blood vessels from the canal, and, as a result, to a deterioration in the functioning of the jaw - tooth - prosthesis system.

An increase in the thickness of the ceramic layer of more than 50 μm does not lead to a noticeable increase in strength (not more than 1% - Table 7, row 3, columns 11, 12). In addition, the duration of the process increases, which increases the complexity of manufacturing the prosthesis.

Ceramic-metal restorations made by the proposed method require a minimum depth of preparation of hard tooth tissues, which eliminates the risk of damage to the pulp (traumatic pulpitis). In addition, there is no need to determine the optimal preparation depth and safety zone for each group of teeth.

It is important to note that the ceramic-metal crowns made by the proposed method make it possible to form such a cervical circular ledge (if necessary) during tooth preparation, which will provide a high aesthetic effect of the ceramic-metal construction and reduce the risk of a negative effect of the crown edge on marginal periodontal tissues.

Table 8 The test results of the bond strength of the ceramic coating with the base metal No. p / p Variable process parameters The bond strength of the ceramic coating with the base metal, MPa Ceramic coated metal base VT1-0 E125 VT1-0 E125 VT1-0 E125 VT1-0 E125 VT1-0 E125 one 2 3 four 5 6 7 8 9 10 eleven 12 2 The ratio of the thickness of the ceramic layer to the total thickness of the coating 0.5 0.5 0.6 0.6 0.7 0.7 0.8 0.8 0.9 0.9 3 - 210 ± 6.29 211 ± 6.34 303 ± 9.09 317 ± 9.51 315 ± 9.45 328 ± 9.85 309 ± 9.27 325 ± 9.75 227 ± 6.82 242 ± 7.26 Notes: the table shows the strength properties obtained by the best firing mode - firing temperature of 830 ° C (columns 9, 10 in table 1); a temperature rise rate of 15 ° C / min (columns 9, 10 in table 2); exposure time 15 min (columns 9, 10 in table 5); cooling rate of 7 ° C / min (columns 9, 10 in table 6), the thickness of the ceramic layer 50 μm (columns 9, 10 in table 7).

If the ratio of the thickness of the ceramic layer to the total thickness of the coating is more than 0.8, then the thickness of the glaze decreases, which does not provide a rational ratio with the thickness of the ceramic layer. In this case, the bond strength of the ceramic coating with the base metal will decrease (Table 8, columns 11, 12). Reducing the thickness of the glaze reduces the degree of fluorescence, which does not correspond to the fluorescence of natural teeth and does not contribute to the reproduction of natural color.

If the ratio of the thickness of the ceramic layer to the total thickness of the coating is less than 0.6, the thickness of the glaze increases, which leads to the formation of cracks on its surface (Fig.17, 18, 19, 20), and the bond strength of the ceramic coating with the base metal decreases (table .8, columns 3, 4).

If the ratio of the thickness of the ceramic layer to the total thickness of the coating is 0.6-0.8, then a rational ratio of the thickness of the ceramic layer and the thickness of the glaze is ensured, which, in turn, during coating formation allows a rational amount of the crystalline phase to be obtained. At the same time, the bond strength of the ceramic coating with the base metal remains high (Table 8, columns 5 through 10).

Ceramic-metal constructions made by the proposed method allow maintaining the anatomical ratio of the wall thicknesses of the tooth cavity, which improves the functioning of the jaw-tooth-prosthesis system.

Table 9 Ceramic test results Defined Characteristics No. p / p Name of material The temperature coefficient of linear expansion (TEC), α · 10 ^-6 ° C Linear shrinkage during firing L,% Porosity, the number of pores on the surface of 1 mm ² Chemical solubility Δ,% one 2 3 four 5 6 one Samples with a ceramic layer after microarc oxidation (metal base titanium VT1-0) 9.2 ± 0.20 0 2, with a diameter of 5 microns 0 2 Samples with a ceramic layer after microarc oxidation (metal base of zirconium E125) 7.2 ± 0.30 0 3, diameter 3 μm 0 3 Samples with ceramic coating after firing (metal base titanium VT1-0) 9.3 ± 0.30 0 0 0 four Samples with ceramic coating after firing (metal base of zirconium E125) 7.3 ± 0.20 0 0 0 Notes: the table shows the properties obtained by the best firing mode - firing temperature of 830 ° C (columns 9, 10 in table 1); a temperature rise rate of 15 ° C / min (columns 9, 10 in table 2); exposure time 15 min (columns 9, 10 in table 5); cooling rate 7 ° C / min (columns 9, 10 in table 6), the thickness of the ceramic layer is 50 μm (columns 9, 10 in table 7), the ratio of the thickness of the ceramic layer to the total coating thickness is 0.7 (columns 7, 8 in the table 8).

The test results presented in table 9, indicate compliance with the requirements for dental cermet.

The thermal inconsistency of cermet and base metal (column 3, table 9) is within the measurement error (in the temperature range at which the thermal expansion coefficient is determined) and does not exceed 3%, which eliminates the likelihood of residual stresses, both compression and tension in the cermet structure . As a result of this, no defects (microcracks, chips, and delaminations) are formed on the internal or external surfaces of the ceramic-metal restoration.

The porosity, linear shrinkage, and chemical solubility of the ceramic layers and coatings (Table 9, columns 4, 5, 6) do not exceed the values shown for dental materials.

Table 10 Test results for chemical resistance in the environment of the oral cavity No. p / p Name of material Defined Characteristics Water resistance,% Acid resistance,% Alkali resistance,% one 2 3 four 5 one Ceramic layer after microarc oxidation (base metal titanium VT1-0) 99.99 ± 0.005 99.97 ± 0.006 99.98 ± 0.007 2 Ceramic layer after microarc oxidation (metal base zirconium E125) 99.98 ± 0.004 99.96 ± 0.005 99.97 ± 0.006 3 Ceramic coating after firing (base metal titanium VT1-0) 99.97 ± 0.003 98.96 ± 0.004 99.87 ± 0.005 four Ceramic coating after firing (metal base zirconium E125) 99.96 ± 0.002 98.95 ± 0.003 99.86 ± 0.004 Notes: the table shows the properties obtained by the best firing mode - firing temperature of 830 ° C (columns 9, 10 in table 1); a temperature rise rate of 15 ° C / min (columns 9, 10 in table 2); exposure time 15 min (columns 9, 10 in table 5); cooling rate 7 ° C / min (columns 9, 10 in table 5); the thickness of the ceramic layer is 50 μm (columns 9, 10 in table 7); the ratio of the thickness of the ceramic layer to the total thickness of the coating is 0.7 (columns 7, 8 in table 8).

The analysis of the results of indicators of water resistance, acid resistance, alkali resistance of ceramic layers and coatings revealed high indicators of these values - fluctuations in: water resistance from 99.96% to 99.99%, (table 10, column 3); acid resistance from 98.95% to 99.97% (Table 10, column 4); alkali resistance from 99.86% to 99.98% (Table 10, column 5).

Sanitary-chemical studies (base metal titanium VT1-0) established:

- the content of reducing impurities in aqueous extracts from the samples found at a rate of 0.04 N sodium thiosulfate solution was 0, with an acceptable criterion of 0.1 ml;

- a change in the pH value of the extract compared with the control of 0.78, with an allowable value of the criterion of not more than 1.0;

- the content of organic impurities in aqueous extracts from the samples, determined spectrophotometrically by the value of optical density in the range of 230-360 nm, amounted to 0.156, with an allowable value of the criterion of not more than 0,300;

- the copper content, determined by atomic absorption spectrophotometry in aqueous extracts from the samples, amounted to 0.01 mg / l, with a valid criterion of up to 1 mg / l;

- the lead content, determined by atomic absorption spectrophotometry in aqueous extracts from the samples, was 0.01 mg / l, with a valid criterion of up to 0.03 mg / l;

- the chromium content, determined by atomic absorption spectrophotometry in aqueous extracts from the samples, amounted to 0.01 mg / l, with a valid criterion value of up to 0.1 mg / l;

- the cadmium content, determined by atomic absorption spectrophotometry in aqueous extracts from the samples, amounted to 0.0001 mg / l, with an acceptable criterion value of up to 0.001 mg / l;

- the barium content, determined by atomic absorption spectrophotometry in aqueous extracts from the samples, amounted to 0.01 mg / l, with an acceptable criterion value of up to 0.1 mg / l;

- the tin content, determined by atomic absorption spectrophotometry in aqueous extracts from the samples, was 0.01 mg / l, with an acceptable criterion value of up to 0.1 mg / l;

- the formaldehyde content was 0, with an acceptable criterion value of up to 0.1 mg / L.

Sanitary-chemical studies (base metal of zirconium E125) established:

- the content of reducing impurities in aqueous extracts from the samples, found at the rate of 0.04 N sodium thiosulfate solution, was 0, with an acceptable criterion of 0.1 ml;

- a change in the pH value of the extract compared to a control of 0.38 with an acceptable criterion value of not more than 1.0;

- the content of organic impurities in aqueous extracts from the samples, determined spectrophotometrically by the value of optical density in the range of 230-360 nm, amounted to 0.096, with an allowable value of the criterion of not more than 0.300;

- the copper content, determined by atomic absorption spectrophotometry in aqueous extracts from the samples, amounted to 0.009 mg / l, with a valid criterion of up to 1 mg / l;

- the lead content, determined by atomic absorption spectrophotometry in aqueous extracts from the samples, amounted to 0.008 mg / l, with a valid criterion of up to 0.03 mg / l;

- the chromium content, determined by atomic absorption spectrophotometry in aqueous extracts from the samples, amounted to 0.009 mg / l, with an acceptable criterion value of up to 0.1 mg / l;

- the cadmium content, determined by atomic absorption spectrophotometry in aqueous extracts from the samples, amounted to 0.0001 mg / l, with an acceptable criterion value of up to 0.001 mg / l;

- the barium content, determined by atomic absorption spectrophotometry in aqueous extracts from the samples, amounted to 0.01 mg / l, with an acceptable criterion value of up to 0.1 mg / l;

- the tin content, determined by atomic absorption spectrophotometry in aqueous extracts from the samples, was 0.01 mg / l, with an acceptable criterion value of up to 0.1 mg / l;

- the formaldehyde content was 0, with an acceptable criterion value of up to 0.1 mg / L.

When toxicological research found:

- in an acute experiment on white outbred mice (males) with the intraperitoneal administration of extracts at a dose of 50 ml / kg body weight, no death of animals was observed;

- the animals showed no clinical signs of intoxication: general condition, behavioral reactions, condition of the coat, eating food in the experimental group did not differ from the control;

- at the autopsy of the tissue at the injection site, regional lymph nodes, internal organs in animals exposed to the hoods had no signs of pathology;

- weight coefficients of internal organs (liver, kidney, spleen) in experimental mice within normal limits and similar control indicators;

- in in vitro experiments with isolated and washed rabbit erythrocytes, the hemolytic effect of extracts was not observed;

- in experiments on rats and rabbits, the absence of the locally irritating effect of extracts on the skin and mucous membranes was shown;

- sterility test of the sample - sterile;

- test of the sample for pyrogen-free - pyrogen-free;

- the value of the toxicity index was 71% (titanium base metal VT 1-0) and 70% (base metal zirconium E125), with an allowable value of the criterion from 70 to 120%.

The studied samples meet the requirements for medical devices that have contact with body tissues: in the experimental conditions, cermet materials showed chemical stability, extracts from them did not adversely affect biological objects.

Information sources

1. A method of producing ceramic coatings on the surface of dentures and implants. Application: No. 2002127503/142002127503/14, October 14, 2002. Date of publication of the application: April 10, 2004

2. A method of manufacturing a ceramic-metal dentures. RF patent on application: No. 201001640/14, 01/11/2010, publication date: 06/20/2011

Claims (1)

A method of manufacturing a ceramic-metal dentures, including the manufacture of a metal base, cleaning, processing, applying a ceramic coating, characterized in that on a metal base of valve group metals, microarc oxidation, a ceramic layer is formed, at least 50 microns thick, in an aqueous electrolyte solution based on aluminum sulfate, followed by the application of glaze and heat treatment of the prosthesis in vacuum at temperatures not exceeding the temperatures of allotropic transformations in the material metal base, but not less than 830 ° C, holding time of at least 15 minutes, while the rate of temperature rise should be no more than 15 ° C / min, the cooling rate should be no more than 7 ° C / min, and the ratio of the ceramic layer thickness to the total the coating thickness should be 0.6-0.8.

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