Method for making metal-ceramic dentures

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

 

The invention relates to medicine, namely to orthopedic dentistry for the manufacture of metal-ceramic dental prostheses.

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

The closest in technical essence is a method of manufacturing a metal-ceramic dental prostheses, including the fabrication of the metal substrate, cleaning, handling, application of the ceramic coating [2].

The object of the invention is to reduce the complexity of manufacture of the prosthesis, the improvement of its quality, reliability and aesthetic characteristics.

The task is achieved in that in the known method, including the fabrication of the metal substrate, cleaning, handling, depositing a ceramic coating according to the proposed invention on a metal base made of metal gate group, microarc ACS�derounian form a ceramic layer, with a minimum thickness of 50 microns, in an aqueous electrolyte solution on the basis of aluminum sulfate, followed by application of the glaze and heat treatment of the prosthesis in a vacuum at temperatures not exceeding the temperature allotropic transformations in the material of the metal substrate, but not less than 830°C, soak time of not less than 15 minutes, with the speed of temperature rise should be no more than 15°C/min, cooling rate of not 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 to 0.8.

The method is as follows: the prosthesis is made with application of technology of CAD/CAM, the purification is carried out and is treated in a sand blasting apparatus. Then it is placed in an electrolytic bath of an aqueous electrolyte solution. Current is applied to the electrodes, one of which (anode) attached to the prosthesis, the other (the cathode) on the inner surface of the bath. In the interaction of the electric current, the electrolyte and the material of the prosthesis is the formation on its surface of the ceramic layer. After the process of forming a ceramic layer current is shut off, the prosthesis is washed and dried. Then, on the surface of the prosthesis put a layer of glaze. Further, the prosthesis is placed in a vacuum oven and calcined, getting a ceramic coating.

The introduction of a new trait provides obtaining metalloceramic�fir structures, to the greatest extent meet the aesthetic standards with the required physical properties and high strength characteristics, not collapsing under the influence of occlusal load, which enables to produce prostheses with less intensity, high quality, reliability, and aesthetic characteristics. Metal-ceramic restorations are biocompatible - not have pathological effects on the teeth and surrounding tissues are not having allergic reactions, since the proposed method implements the possibility of obtaining bioinert ceramic layer, with the outer and inner side of the crown.

The method is illustrated by photographs.

Fig.1 is a perspective view of the metal substrate (titanium VT1 - 0) of the prosthesis large molar tooth. Fig.2 - General view of the metal substrate (titanium VT1 - 0) of the prosthesis lateral incisors. Fig.3 - General view of the metal substrate (zirconium E) of the prosthesis large molar tooth. Fig.4 - General view of the metal substrate (zirconium E) of the prosthesis lateral incisors. Fig.5 - General view of the prosthesis of a large molar tooth with a ceramic layer (metal base titanium VT1 - 0). Fig.6 - General view of the prosthesis side cutter with a ceramic layer (metal base titanium VT1 - 0). Fig.7 - General view of the prosthesis of a large molar tooth with a ceramic layer (metallic�Skye basis of zirconium E). Fig.8 - General view of the prosthesis side cutter with a ceramic layer (metal base cubic Zirconia E). Fig.9 - General view of the prosthesis of a large molar tooth with a ceramic coating after firing (metal base titanium VT1 - 0). Fig.10 - General view of the prosthesis of a large molar tooth with a ceramic coating after firing (metal base cubic Zirconia E). Fig.11 - General view of the prosthesis of a large molar tooth with traces of destruction of the ceramic coating (metal base titanium VT1 - 0). Fig.12 - General view of the prosthesis side cutter with traces of destruction of the ceramic coating (metal base titanium VT1 - 0). Fig.13 - General view of the prosthesis of a large molar tooth with traces of destruction of the ceramic coating (metal base cubic Zirconia E). Fig.14 - General view of the prosthesis side cutter with traces of destruction of the ceramic coating (metal base cubic Zirconia E). Fig.15 - metal-ceramic prosthetic bicuspid in natural lighting. Fig.16 - metal-ceramic prosthetic bicuspid in artificial light. Fig.17 - General view of the prosthesis of a large molar tooth with traces of cracks on the surface of the ceramic coating (metal base titanium VT1 - 0). Fig.18 - General view of the workpiece of the prosthesis with traces of cracks on the surface of the ceramic coating (metal base Titus�n VT1 - 0). Fig.19 - General view of the prosthetic bicuspid with traces of cracks on the surface of the ceramic coating (metal base cubic Zirconia E). Fig.20 - General view of the workpiece of the prosthesis with traces of cracks on the surface of the ceramic coating (metal base cubic Zirconia E).

Example. Metal base dentures were made from dental metal gate groups: commercially pure titanium (VT1 - 0, Fig.1, 2) and commercially pure zirconium (A, Fig.3, 4) and were cleaned and processed in a sandblasting machine. Further, the prosthesis was subjected to the microarc oxidation of 10 minutes, at a current density of 80 A/DM2, a voltage of 200 V in an aqueous solution on the basis of aluminum sulfate (Al2(SO4)3) - 50 g/l. After the process of forming a ceramic layer current is shut off, the prosthesis is washed and dried (Fig.5, 6, 7, 8). Then, on the surface of the prosthesis put a layer of glaze so that the ratio of thickness of the ceramic layer to the total thickness of the coating was 0.7. Further, the prosthesis is placed in a vacuum oven and calcined, getting ceramic coating (Fig.9, 10). The rate of rise of temperature up to 830°C was 15°C/min, cooling rate of 7°C/min, a vacuum of 50 HPa.

Testing and analysis of ceramic layers and coatings were carried out according to standard methods. Determined pace�atorny the coefficient of linear expansion, thermal conductivity linear shrinkage, porosity, chemical solubility, bond strength of the ceramic coating to the base metal, tensile strength, Flexural strength, microhardness, wear resistance, chemical resistance to the environment of the oral cavity, sterility, pyrogen-free, the value of the index of toxicity, altering the pH value, the content in water extracts: the restoration and organic impurities; copper; lead; chromium; cadmium; barium; tin; formaldehyde.

The results of the tests and studies are presented in tables 1-10.

Table 1
The results of testing the bond strength of the ceramic coating to the base metal
№ p/pControllable parameters of the processThe bond strength of the ceramic coating to the base metal, MPa
The base metal with ceramic coating
W 1-0EW 1-0EVT1-0EVT1-0E VT1-0E
123456789101112
2Firing temperature, °C882*862*860850840840830830825825
3-58±1,7569±2,08163±4,89185±5,54268±8,05306±9,17350±10,50369±10,96335±to 10.06352±10,55
Notes: * the indicated temperature corresponds allotropical the transformation.

If �emperature firing corresponds to the temperature allotropic transformations (tab.1, columns 3, 4), then the destruction of the coating (cracks, spalls, delamination - Fig.11, 12, 13, 14) as a result of low adhesion strength of the metal substrate with the ceramic layer.

It does not provide any implementation of internal and surface modification of the color ceramic layer.

If the firing temperature is lower than temperature allotropic transformations, that defect is not formed, and the bond strength of the ceramic coating to the base metal increases, reaching its maximum when the firing temperature, component 830°C (tab.1, columns 9, 10). Further decrease of temperature leads to a reduction in strength (table.1, columns 11, 12) by reducing the amount of the crystalline phase.

In addition, when the firing temperature is 830°C is ensured implementation of internal and surface modification of the color ceramic layer after applying the glaze to obtain a high degree of fluorescently (Fig.15) that, in turn, contributes to the reproduction of natural colors. In this case, any natural characteristic of the color reproduced by the frequency of occurrence of the regimes microarc oxidation and firing. A high degree of fluorescently that corresponds to fluorescently natural teeth, strengthens the vital view metal frames (Fig.15). Natural�th species is preserved and artificial light (Fig.16).

The proposed method provides the desired color concept coverage, including primary (basic) and secondary (derivative) in color, which gives the opportunity to meet the requirements of different aesthetic restorations. The bond strength of the ceramic coating to the base metal satisfies the requirements of ceramic and metal-ceramic dental materials.

Table 2
The results of testing the bond strength of the ceramic coating to the base metal
№ p/pControllable parameters of the processThe bond strength of the ceramic coating to the base metal, MPa
The base metal with ceramic coating
VT1-0EVT1-0EVT1-0EVT1-0EVT1-0E
12 3456789101112
2The speed of temperature rise, °C/min5555353525251551414
3-70±2,1081±2,43140±4,21156±4,67257±7,70265±7,96344±of 10.32369±11,06347±10,41372±11,16
Notes: the table shows the mechanical properties obtained in the best mode of firing, the firing temperature is 830°C (columns 9, 10 in table 1).

In that case, if the rate of temperature rise of 15°C/min, when formed�and ceramic coating increases the proportion of the crystalline phase, provides high bond strength of the ceramic coating to the base metal (table.2, columns 9, 10), high tensile strength, Flexural strength, microhardness (table.3) and wear resistance, such as ceramic layer (PL.4, rows 1, 2) and the ceramic coating (PL.4, rows 3, 4). The reduction of the temperature rise reduces the performance of the process, whereas properties are changed slightly (less than 1% - see table.2, columns 11, 12).

If the rate of temperature rise of 15°C/min, during formation of the ceramic coating decreases the proportion of the crystalline phase up to 30-40%, which reduces the adhesion strength of the metal substrate with the ceramic layer and, consequently, reduces the bond strength of the ceramic coating to the base metal (table.2, columns 8 and 3).

Table 3
The results of tests on the strength and hardness
№ p/pMaterial nameDefined features
Flexural strength, MPaTensile strength, MPaMicrohardness, GPA
12345
1Samples with the ceramic layer after microarc oxidation (metal base titanium VT1-0)240±7,20503±15,0910,20±0,32
2Samples with the ceramic layer after microarc oxidation (metal base cubic Zirconia E)264±7,92384±11,5211,00±0,33
3Samples with ceramic coating after firing (metal base titanium VT1-0)312±9,36510±15,307,50±0,22
4Samples with ceramic coating after firing (metal base cubic Zirconia E)343±7,92390±11,70To 7.60±0,23
Notes: the table shows the properties obtained in the best mode of firing, the firing temperature is 830°C (columns 9, 10 in table 1); lift speed the�of erature 15°C/min (columns 9, 10 in table 2); the holding time 15 min (columns 9, 10 in table 5); the 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), the ratio of thickness of the ceramic layer to the total thickness of the coating is 0.7 (columns 7, 8 in table 8).

Table 4
The test results for abrasion resistance
№ p/pMaterial nameDefined features
The intensity of wear of Ig·10-2g/m3The percentage of wear (i·10-3, %The relative wear resistance of the substrate (Iq1/Iqi)
12345
1Samples with the ceramic layer after microarc oxidation (metal base titanium W 1-0)To 1.141,108,11
2Abruzzes ceramic layer after microarc oxidation (metal base cubic Zirconia E) 1,130,9510,58
3Samples with ceramic coating after firing (metal base titanium VT1-0)1,551,50Of 11.29
4Samples with ceramic coating after firing (metal base cubic Zirconia E)A 1.541,2914,39
Notes: the table shows the properties obtained in the best mode of firing, the firing temperature is 830°C (columns 9, 10 in table 1); the rate of temperature rise of 15°C/min (columns 9, 10 in table 2); the holding time 15 min (columns 9, 10 in table 5); the cooling rate of 7°C/min (columns 9, 10 in table 6) thickness of the ceramic layer 50 μm (columns 9, 10 in table 7), the ratio of thickness of the ceramic layer to the total thickness of the coating is 0.7 (columns 7, 8 in table 8).

Table 5
The results of testing the bond strength of the ceramic coating to the base metal
No. �/n Controllable parameters of the processThe bond strength of the ceramic coating to the base metal, MPa
The base metal with ceramic coating
VT1-0EVT1-0EVT1-0EVT1-0EVT1-0E
123456789101112
2The time of exposure, min5577101015151717
3 -128±3,84133±3,98186±5,59193±5,80233±6,70248±7,43338±10,15357±10,70341±10,23360±10,80
Notes: the table shows the mechanical properties obtained in the best mode of firing, the firing temperature is 830°C (columns 9, 10 in table 1); the rate of temperature rise of 15°C/min (columns 9, 10 in table 2).

When the exposure time is less than 15 minutes the process of forming a ceramic coating is not fully implemented, and the proportion of the crystalline phase does not exceed 40-50%, which reduces the bond strength of the ceramic coating to the base metal (table.5, columns 3, 4).

When the exposure time of 15 minutes the process of forming a ceramic coating occurs in full, and the fraction of the crystalline phase increases to 80-90%, which increases the bond strength of the ceramic coating to the base metal (table.5, columns 9, 10). In addition, increased tensile strength, Flexural strength, microhardness (table.3) and wear resistance, such as ceramic layer (PL.4, rows 1, 2) and the ceramic coating (PL.4, rows 3, 4).

I�lechenie exposure time reduces the productivity of the process, and the properties vary negligibly (less than 1% - see table.5, columns 11, 12).

Table 6
The results of testing the bond strength of the ceramic coating to the base metal
№ p/pControllable parameters of the processThe bond strength of the ceramic coating to the base metal, MPa
The base metal with ceramic coating
VT1-0EVT1-0EVT1-0EVT1-0EVT1-0E
123456789101112
2 The cooling rate, °C/min3030202010107755
3-82±2,4598±2,94146±4,37167±5,00303±9,10328±9,85350±10,50380±11,40353±10,59383±11,49
Notes: the table shows the mechanical properties obtained in the best mode of firing, the firing temperature is 830°C (columns 9, 10 in table 1); the rate of temperature rise of 15°C/min (columns 9, 10 in table 2); the holding time 15 min (columns 9, 10 in table 5).

In the case where the cooling rate is not more than 7°C/min, the base metal forms with ceramic coating durable chemical bond due to the mutual diffusion of metal ions and the ceramic layer, which provides high strength adhesion of the base metal with ceramic coating and prevents �steam chips. The bond strength of the ceramic coating to the base metal reaches 350-380 MPa (tab.6, lines 9, 10). The cooling speed of less than 7°C/min does not lead to a significant increase in strength properties (no more than 1% - see table.6, row 11, 12), but reduces the performance of the process.

When increase a cooling rate of more than 7°C/min, the strength of the chemical bond of metal with a ceramic layer is reduced, decreasing the proportion of the crystalline phase in the coating, which reduces the bond strength of the ceramic coating to the base metal (table.6, columns 3 through 8) and reduces the tensile strength, Flexural strength, microhardness (table.3) and wear resistance, such as ceramic layer (PL.4, rows 1, 2) and the ceramic coating (PL.4, rows 3, 4).

Table 7
The results of testing the bond strength of the ceramic coating to the base metal
№ p/pControllable parameters of the processThe bond strength of the ceramic coating to the base metal, MPa
The base metal with ceramic coating
VT1-0E VT1-0EVT1-0EVT1-0EVT1-0E
123456789101112
2The thickness of the ceramic layer, µm20203030404050506060
3-268±8,08288±8,64280±of 8.39294±of 8.82332±9,97363±10,90344±of 10.34380±11,44347±1040 383±11,49
4Coefficient of thermal conductivity λ, W/(m·K)3,293,734,945,606,587,478,229,349,8611,21
Notes: the table shows the mechanical properties obtained in the best mode of firing, the firing temperature is 830°C (columns 9, 10 in table 1); the rate of temperature rise of 15°C/min (columns 9, 10 in table 2); the holding time 15 min (columns 9, 10 in table 5); the cooling rate of 7°C/min (columns 9, 10 in table 6).

When the thickness of the ceramic layer is less than 50 μm, the strength of bonding of the ceramic coating to the base metal decreases with 344-380 MPa (tab.7, columns 9, 10), 268-288 MPa (tab.7, columns 3, 4), while remaining high and appropriate strength requirements for dental materials. The coefficient of thermal conductivity λ is reduced 2.5 times, respectively, 2.5 times and increases thermal conductivity (tab.7, line 4, columns 10 and 3) that impairs the protection of the tooth from temperature extremes and will inevitably lead to neo�the need for the removal of the nerve and blood vessels from the channel and, consequently, to a deterioration in the functioning of the jaw - tooth - prosthesis.

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

Metal-ceramic restorations fabricated 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 depth of preparation and safety zones for each group of teeth.

It is important to note that metal-ceramic crowns fabricated by the proposed method can form such a circular cervical ledge (if necessary) in the preparation of the tooth, which will provide a high aesthetic effect of the ceramic-metal construction and will reduce the risk of negative influence of the edges of the crowns on the fabric of marginal periodontium.

Table 8
The results of testing the bond strength of the ceramic coating to the base metal
№ p/p Controllable parameters of the processThe bond strength of the ceramic coating to the base metal, MPa
The base metal with ceramic coating
VT1-0EVT1-0EVT1-0EVT1-0EVT1-0E
123456789101112
2The ratio of thickness of the ceramic layer to the total thickness of the coating0,50,50,60,60,70,70,80,80,90,9
3-210±6,29211±system 6.34303±9,09317±9,51315±9,45328±9,85309±9,27325±9,75227±about 6,82242±7,26
Notes: the table shows the mechanical properties obtained in the best mode of firing, the firing temperature is 830°C (columns 9, 10 in table 1); the rate of temperature rise of 15°C/min (columns 9, 10 in table 2); the holding time 15 min (columns 9, 10 in table 5); the 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 thickness of the ceramic layer to the total thickness of the coating is more than 0.8, then decreasing the thickness of the glaze that does not provide a rational ratio with the thickness of the ceramic layer. The bond strength of the ceramic coating to the base metal is reduced (tab.8, columns 11, 12). Reducing the thickness of the glaze reduces the degree of fluorescently, which are fluorescently natural teeth and does not contribute to the reproduction of natural colors.

If the ratio of the thickness of the ceramic layer to the total thickness� cover less than 0,6, it increases the thickness of the glaze, which leads to the formation of cracks on its surface (Fig.17, 18, 19, 20), and the strength of bonding of the ceramic coating to the base metal decreases (tab.8, columns 3, 4).

If the ratio of thickness of the ceramic layer to the total coating thickness is 0.6-0.8, which provides a rational ratio of the thickness of the ceramic layer and the thickness of the glaze, which, in turn, in the formation of the coating allows to obtain a rational amount of crystalline phase. The bond strength of the ceramic coating to the base metal remains high (tab.8, columns 5 through 10).

Ceramic-metal structures, fabricated by the proposed method allows to preserve the anatomic thickness ratio of the walls of the tooth cavity, which improves the functioning of the jaw - tooth - prosthesis.

Table 9
The test results of the sintered metal
Defined features
№ p/pMaterial nameTemperature coefficient of linear expansion (TCLE), α·10-6°C Linear shrinkage during firing L, %Porosity, number of pores on the surface of 1 mm2Chemical solubility Δ, %
123456
1Samples with the ceramic layer after microarc oxidation (metal base titanium VT1-0)9,2±0,2002, with a diameter of 5 µm0
2Samples with the ceramic layer after microarc oxidation (metal base cubic Zirconia E)7,2±0,3003, with a diameter of 3 µm0
3Samples with ceramic coating after firing (metal base titanium VT1-0)9,3±0,30000
4Samples with ceramic coating after firing (metal base MIDC�A) 7,3±0,20000
Notes: the table shows the properties obtained in the best mode of firing, the firing temperature is 830°C (columns 9, 10 in table 1); the rate of temperature rise of 15°C/min (columns 9, 10 in table 2); the holding time 15 min (columns 9, 10 in table 5); the cooling rate of 7°C/min (columns 9, 10 in table 6) thickness of the ceramic layer 50 μm (columns 9, 10 in table 7), the ratio of thickness of the ceramic layer to the total thickness of the coating is 0.7 (columns 7, 8 in table 8).

The test results presented in table.9 indicate that the requirements of the dental porcelain fused to metal.

Thermal mismatch of metal and the base metal (column 3, table 9) is within error of measurement (in the range of temperatures that determine thermal expansion) and does not exceed 3%, which eliminates the likelihood of residual stresses, compression and stretching in metal-ceramic construction. As a result, not on the inside, not on the outer surfaces of the metal-ceramic restoration of defects (cracks, spalls and delaminations) is formed.

Porosity, linear shrinkage and chemical solubility Kera�quarter of layers and coatings (table.9, columns 4, 5, 6) does not exceed the values applicable to dental materials.

Table 10
The results of the test for resistance to chemical agents in the environment of the oral cavity
№ p/pMaterial nameDefined features
The resistance, %Acid resistance, %The alkali resistance, %
12345
1Ceramic layer after microarc oxidation (the base metal titanium VT1-0)99,99±0,005A 99.97±0,00699,98±0,007
2Ceramic layer after microarc oxidation (the base metal zirconium E)99,98±0,004Of 99.96±0,005A 99.97±0,006
3Ceramic� coating after firing (the base metal titanium VT1-0) A 99.97±0,00398,96±0,00499,87±0,005
4Ceramic coating after firing (the base metal zirconium E)Of 99.96±0,00298,95±0,003Of 99.86±0,004
Notes: the table shows the properties obtained in the best mode of firing, the firing temperature is 830°C (columns 9, 10 in table 1); the rate of temperature rise of 15°C/min (columns 9, 10 in table 2); the holding time 15 min (columns 9, 10 in table 5); the cooling rate of 7°C/min (columns 9, 10 in table 5); the thickness of the ceramic layer 50 μm (columns 9, 10 in table 7); the ratio of thickness of the ceramic layer to the total thickness of the coating is 0.7 (columns 7, 8 in table 8).

Analysis of the results of the water resistance, acid resistance, alkali resistance of ceramic layers and coatings revealed high rates of these values - fluctuations: water resistance from of 99.96% to 99.99%, (table.10, column 3); acid resistance from 98,95% up to 99.97% (table.10, column 4); from alkali resistance of 99.86% up to 99.98% (table.10, column 5).

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

- content of recovery of impurities in water extracts of the samples was found in �the consumption of 0.04 N solution of sodium thiosulfate, amounted to 0, with the limit of criterion of 0.1 ml;

- changing the pH of the extract compared with the control 0,78, with the limit of criterion of not more than 1.0;

- the content of organic impurities in water extracts of the samples, determined by spectrophotometric optical density in the range 230-360 nm, was 0,156, with the limit criterion of no more than 0,300;

- the copper content is determined by atomic absorption spectrophotometry in aqueous extracts of the samples was 0.01 mg/l, with the limit of criterion of 1 mg/l;

- the lead content is determined by atomic absorption spectrophotometry in aqueous extracts of the samples was 0.01 mg/l, with the limit of criterion of 0.03 mg/l;

- the content of chromium is determined by atomic absorption spectrophotometry in aqueous extracts of the samples was 0.01 mg/l, with the limit of criterion of 0.1 mg/l;

- the cadmium content is determined by atomic absorption spectrophotometry in aqueous extracts of the samples amounted to 0.0001 mg/l, with the limit of criterion of 0.001 mg/l;

- the barium content is determined by atomic absorption spectrophotometry in aqueous extracts of the samples was 0.01 mg/l, with the limit of criterion of 0.1 mg/l;

the content of tin, determined�my method of atomic absorption spectrophotometry in aqueous extracts of the samples, was 0.01 mg/l, with the limit of criterion of 0.1 mg/l;

the formaldehyde content amounted to 0, with the limit of criterion of 0.1 mg/L.

Sanitary-chemical researches (base metal zirconium E) installed:

- content of recovery of impurities in water extracts from samples found in the consumption of 0.04 N solution of sodium thiosulfate, amounted to $ 0, with the limit of criterion of 0.1 ml;

- changing the pH of the extract compared with the control 0,38 valid when the criterion value is not more than 1.0;

- the content of organic impurities in water extracts of the samples, determined by spectrophotometric optical density in the range 230-360 nm, was 0,096, with the limit criterion of no more than 0,300;

- the copper content is determined by atomic absorption spectrophotometry in aqueous extracts of the samples amounted 0,009 mg/l, with the limit of criterion of 1 mg/l;

- the lead content is determined by atomic absorption spectrophotometry in aqueous extracts of the samples was 0.008 mg/l, with the limit of criterion of 0.03 mg/l;

- the content of chromium is determined by atomic absorption spectrophotometry in aqueous extracts of the samples amounted 0,009 mg/l, with the limit of criterion of 0.1 mg/l;

- the content of cadmium, op�adesive by the method of atomic absorption spectrophotometry in aqueous extracts of the samples, amounted to 0.0001 mg/l, with the limit of criterion of 0.001 mg/l;

- the barium content is determined by atomic absorption spectrophotometry in aqueous extracts of the samples was 0.01 mg/l, with the limit of criterion of 0.1 mg/l;

the tin content is determined by atomic absorption spectrophotometry in aqueous extracts of the samples was 0.01 mg/l, with the limit of criterion of 0.1 mg/l;

the formaldehyde content amounted to 0, with the limit of criterion of 0.1 mg/L.

If a Toxicological study has demonstrated:

- in an acute experiment on albino mice (males) with intraperitoneal administration of extracts at a dose of 50 ml/kg of body weight was not observed death;

- in animals revealed no clinical signs of intoxication: General condition, behavioral responses, the condition of the fur, eating poop in the experimental group did not differ from control;

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

- the weights of internal organs (liver, kidney, spleen) in mice experienced in the normal range and similar indicators of control;

- in experiments in vitro with isolated and washed rabbit erythrocytes is not marked GE�politicheskogo effect of extracts;

- in experiments on rats and rabbits demonstrated no local irritating action of extracts on skin and mucous membranes;

- sample testing for sterility - sterile;

- sample test for pyrogen-free - aerogene;

- the value of the toxicity index was 71% (metal basis titanium W 1-0) and 70% (metal basis Zirconia E), with the limit of criterion of 70 to 120%.

Samples meet the requirements of the medical devices that have contact with the tissues of the body: in the experiment, sintered materials showed chemical stability, hoods of them had no adverse effects on biological objects.

Sources of information

1. Method for producing ceramic coatings on the surface of dentures and implants. Application: No. 2002127503/142002127503/14, 14.10.2002 G. date of publication of application: 10.04.2004.

2. A method of manufacturing a metal-ceramic dental prostheses. The patent of the Russian Federation on request: No. 2010100640/14, 11.01.2010 G. publication date: 20.06.2011

A method of manufacturing a metal-ceramic dental prostheses, including the fabrication of the metal substrate, cleaning, handling, depositing a ceramic coating, characterized in that the metal-based metal gate group, microarc oxidation, to form a ceramic� layer, with a minimum thickness of 50 microns, in an aqueous electrolyte solution on the basis of aluminum sulfate, followed by application of the glaze and heat treatment of the prosthesis in a vacuum at temperatures not exceeding the temperature allotropic transformations in the material of the metal substrate, but not less than 830°C, soak time of not less than 15 minutes, with the speed of temperature rise should be no more than 15°C/min, cooling rate of not 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 to 0.8.



 

Same patents:

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EFFECT: higher corrosion resistance.

1 tbl, 1 dwg

FIELD: electricity.

SUBSTANCE: manufacturing technique of high-build wear-resistant coating in microarc oxidation mode includes installation of a part in electrolyte at a current-conducting holder coated by insulating material, generation of operating voltage between a part and electrolyte, increase of voltage till microarc discharge occurs at the surface of a part. Aqueous solution of potassium hydroxide and soluble glass is used as electrolyte at concentration of each substance of 2.5 g/l, microarc oxidation process is carried during 2.5-3.5 hours at current of I=4.5-12 A, ratio of anodic and cathodic current is 1:1 and voltage at anode is Ua=200-415 V.

EFFECT: invention allows manufacturing high-build wear-resistant coating by microarc oxidation with increased values of microhardness, reducing labour intensity and energy consumption due to optimal concentration of substances included into the electrolyte composition and optimal parameters of microarc oxidation process.

FIELD: machine building.

SUBSTANCE: device comprises the power supply, electrolyte tank, electrolyte pump, electrochemical cell, also it contains the shunt for current measurement, electrical power meter, computing unit with a frequency converter, connected with the electrolyte pump, which is designed as regulated. The electrochemical cell is formed by an anode detail, upper and lower covers, and in the upper cover the electrolyte outlet hole and the cathode hole are made, and be the cylindrical hollow cathode with the holes facing towards the interelectrode interval, and also the hole for electrolyte supply.

EFFECT: increase of power delivered into the interelectrode interval, decrease of detail treatment time at optimum ratio of consumed power, detail treatment time and blank surface quality.

1 dwg

FIELD: electricity.

SUBSTANCE: device contains a power supply unit and an electrolytic bath, two uncontrolled rectifiers and two controlled rectifiers, a capacitor and a control system, a current sensor and two voltage sensors, a key and a choke. The bath case is connected to the power supply unit terminal while its second terminal is connected to the anode of the first uncontrolled rectifier, the first capacitor plate and the first output of the key. The second key output is connected to the second capacitor plate, the anode of the second uncontrolled rectifier and the cathode of the second controlled rectifier. The cathode of the second uncontrolled rectifier is connected to the cathode of the second uncontrolled rectifier and the anode of the first controlled rectifier. One output of the current sensor is connected to the cathode of the first and second controlled rectifiers while the other output is connected to the first choke output. The second choke output is connected to the processed part. The inputs of the control system are connected to the outputs of current and voltage sensors and its outputs are connected to the control electrodes of the controlled rectifiers with the control key component.

EFFECT: improving strength of oxidation coating to increase in its thickness.

2 dwg

FIELD: metallurgy.

SUBSTANCE: proposed method consists in micro arc oxidising and/or anodising at different parts of metallic article and comprises processing said article. Parts of the article are located in two tightly isolated tanks to subjected to AC effects brought about two counter electrodes arranged in said tanks filled with electrolyte. Surface area of every counter electrode is larger than that of article part by more than five times.

EFFECT: preset properties and depth, twofold reduction on power consumption.

5 cl, 2 dwg, 3 ex

FIELD: metallurgy.

SUBSTANCE: proposed method comprises electrolytic plasma oxidation in aqueous electrolyte containing PTFE powder particles. Note here that oxidation is performed in galvanostatic conditions at current density of 0.03-0.05 A/cm2 for 20-30 min in alkaline electrolyte containing 40-60 g/l of PTFE powder and, additionally, it comprises siloxane-acrylate emulsion in amount of 40-100 ml/g.

EFFECT: higher electrolyte stability, better wear resistance and hydrophobic properties of coatings.

2 cl, 8 ex, 5 dwg

FIELD: metallurgy.

SUBSTANCE: electro-chemical cell consists of bath, of electro-conducting cover designed for pressing sample to end of cell, and of thermostat. Also, a case of the cell is closed and consists of two coaxial cylinders filled with electrolyte. The case in equipped with connecting pipes for pumping electrolyte through the electro-chemical cell and for removal of gaseous products. An end wall not absorbs roentgen or neutron radiation and has a window transparent for above said radiations. The thermostat controls temperature of electrolyte within the ranges from -30 to +200°C.

EFFECT: expanded functionality of device and facilitation of control over process of anode oxidation of metals and semi-conductors by means of small-angle scattering radiation of various kinds of radiation in real time.

2 dwg, 1 ex

FIELD: metallurgy.

SUBSTANCE: here is disclosed device consisting of power source connected to secondary power source, and of bath for electrolyte, case of which is connected with oxidised part via successively connected voltage sensor and current sensor. Further, the device consists of a control machine on base of personal computer and of a step-up transformer. Additionally, the device consists of a thyristor voltage converter, of system of pulse-phase control, of driver unit, of the first and the second analogue-digital converters, of a manual control panel, of a micro-controller, of a remote control panel, of successively connected the first rectifier, the first filter, the first pulse voltage converter and operation mode switch, and also, successively connected the second rectifier, the second filter and the second pulse voltage converter.

EFFECT: extended assortment of treated materials and versatility of process of treatment for various metals and their alloys.

2 dwg

FIELD: metallurgy.

SUBSTANCE: device for application of coating by micro-arc oxidation of parts out of valve metals and alloys at alternate voltage consists of power transformer, and of power unit connected to latter and to bath for electrolyte and measuring unit. Also the bath is connected with input of the power unit, while it output is connected with the power transformer. Additionally, the device is equipped with a control unit, a regulating element is introduced into the power block to control voltage, time of beginning and end and duration of anode and cathode cycles independently from each other. The regulating element corresponds to a diode bridge, into diagonal of which there is introduced a switching element - bi-polar of filed transistor - and connected to the control unit.

EFFECT: simplified structure of device at simultaneous expansion of process functions of micro-arc oxidation, reduced consumption of electric power.

2 cl, 4 dwg, 2 ex

FIELD: machine building.

SUBSTANCE: procedure consists in immersion of parts into at least one processing liquid in container, also, parts are fixed on rotary drum installed inside container and are completely immersed into said processing liquid with turn of rotating drum. The said rotation facilitates escape of air bubbles off surface of parts immersed into container. The procedure is designed to be implemented at treatment of hollow parts in metal parts electro-chemical surface processing and in anode coating parts out of aluminium or alloy on base of aluminium. The container consists of the rotary drum. On external periphery of the drum there is at least one support channel receiving at least one fixed support for a part. The installation has at least one container, the first conveyor line transporting supports for parts, pushing devices, and devices for extraction of supports from the container and for placing them on the second conveyer line. The second conveyer line withdraws each support from the container.

EFFECT: upgraded quality of items, simplified processing and reduced operational expenditures.

28 cl, 7 dwg

FIELD: medicine.

SUBSTANCE: root canal of a broken tooth is filled up to a physiological opening under X-ray control. The root canal is milled at two-thirds of overall length in diameter equal to that of a fibre glass pin to be used in the tooth. A seat protrusion with a cylindrical side surface surrounding a root canal aperture is formed. The milled root canal and an outer surface of the root are imprinted in silicone to produce a model, wherein the fibre glass pin is mounted into the reflected root canal. Intraradicular and supraradicular root inlays are modelled in wax on top of the pin. Along the outline of the modelled inlay, a circular shoulder skewed at an angle of 45 degrees is milled, and the fibre glass pin is removed. The produced wax structure is scanned in a module of CAD/CAM system. The virtual image is transferred to a computer unit, followed by milling of a ceramic block. The produced structure is mounted in the oral cavity on glass-ionomer cement. An artificial crown is made and attached to the above structure.

EFFECT: method enables restoring the broken clinical crown of the tooth and a thinned broken neck subgingival root by means of a permanent orthopaedic structure made of a bioinert material with a possibility to conduct a root canal treatment, if necessary.

1 dwg

FIELD: medicine.

SUBSTANCE: device is monolithic, of soft polymer with intraoral and occlusive surfaces and a surface facing a nasal cavity. The occlusive surface is configured to mount on a fibrous ring and has retention elements 1-2 mm wide along the whole period of the occlusive part of the device facing the nasal cavity. An outer diameter of the occlusive surface is configured to exceed the diameter of the fibrous ring by 2-3 mm. The intraoral surface is configured to match a patient's hard palate and has a ring on the outer surface.

EFFECT: invention enables marking the limits of the patient's mouth and nose if observing the postoperative upper jaw defects during individual hygiene activities.

1 dwg

FIELD: medicine.

SUBSTANCE: method of repairing a demountable dental prosthesis of the upper jaw consists in matching and fixation of fragments of the demountable dental prosthesis by glue, manufacturing a stone model by the fixed prosthesis, extension by a dental cutter of fracture borders and formation on external borders of retention cavities, parallel to the fracture line, in the quantity of three, on the entire length of the fracture line, equally distant from each other. The ratio of the area of the line, which passes on the fracture line, and the area of the retention cavities must correspond as one to three, while initially the area corresponds to the diameter of the cutter, selected individually by a value obtained as a result of division of the fracture line length by five. After the described preparation the prosthesis is washed, dried, placed on the model, and the formed in the process of milling slots are filled with plastic with the following polymerisation in boiling water under pressure. The obtained prosthesis is processed, ground, polished and fixed in the oral cavity.

EFFECT: restoration of durability and functional characteristics of the broken demountable dental prosthesis by the method affordable for the patient.

1 dwg

FIELD: medicine.

SUBSTANCE: in oral cavity of patient in prosthesis bed flexibility of mucous membrane is measured in oral cavity of patient in prosthesis. Borders of poorly flexible areas are determined. Before packing basic plastic paste on model in cuvette, on prosthesis bed borders of poorly flexible areas are outlined. They are extended for 1.5-2 mm in towards flexible areas. Durable insulating material with width not less than value of flexibility of mucous membrane is fastened on said extended boarders of poorly flexible areas. Cuvette with gypsum model is filled with paste of basic plastic and placed under the press. Plastic polymerisation is carried out. After polymerisation prosthesis is extracted from cuvette and processed.

EFFECT: method, due to preparing gypsum model of jaw before packaging basic plastic, makes it possible to reduce excessive pressure, trauma and atrophy of prosthesis bed tissues in the area of poorly flexible areas of prosthetic bed.

FIELD: medicine.

SUBSTANCE: computer analysis of the patient's speech material is performed. The frequency of sound is determined in the norm for a phoneme, selected from the group: "s", "ts" and "f", the frequency of the same sound for the patient before prosthetics, the frequency of the same sound after prosthetics. After prosthetics the phonetic rehabilitation index (FRI) is calculated by the mathematical formula. If FRI is larger than one, successful phonetic adaptation of the patient to dental prosthesis by the phoneme is determined.

EFFECT: method makes it possible to increase the accuracy of estimating the quality of performed dental intervention, and correction.

3 dwg, 1 ex

FIELD: medicine.

SUBSTANCE: odontopreparation is followed by impression taking. A dental model is injected into cast. Anatomic forms of retainer teeth is restored in wax, and an intermediate part of the prosthesis is modelled. The cast model is imprinted in silicone. The teeth are prepared. A reinforcing fibre tape is prepared. A segment of fibre tape impregnated with universal adhesive is placed on the teeth along the full length taking into account a profile of the masticatory surface up to an equator. The prepared segment is fixed on the teeth with the universal adhesive by polymerisation in halogen light. Self-hardening plastic is placed into the silicon impression to be inserted into the oral cavity. After the plastic is self-polymerised, the impression together with the denture is removed from the oral cavity. The denture is removed from the impression and polymerised additionally within its intermediate portion.

EFFECT: by reinforcing the denture with the fixed reinforcing fibre tape, the method enables increasing durability of the temporary denture, making the temporary denture at one visit and maintaining its aesthetic properties.

1 dwg, 2 ex

FIELD: medicine.

SUBSTANCE: invention refers to medicine, particularly to dentistry, and can be used in orthopaedic dentistry for oncologic patients. A removable resection upper jaw denture with a myogymnastic element comprises an immobilising and resection portions and a removable myogymnastic element. The immobilising portion is configured in the form of a fixing plate having a clasp fixation system on the rest teeth. The resection portion is provided with artificial plastic teeth, contacts directly the rest upper jaw tissues and form a prosthetic bed for a permanent denture. The myogymnastic element is configured in the form of an orthodontic wire individually curved for each patient and having various cross-sections with a bead of a variable diameter sliding along the orthodontic wire. Plastic deposits are made in a base in attachment points of the myogymnastic element. The orthodontic wire is fixed by tension into blind canals.

EFFECT: invention enables combining the dental prosthetics and correction of postoperative tongue dysfunction in the oncologic patients.

1 ex

FIELD: medicine.

SUBSTANCE: group of inventions refers to medicine, is applicable in dentistry and involves a method for preparing a dental instrument, the dental instrument configured to be used by a dentist, a set of pads to be used by the dentist (versions) and a method for the tooth preparation for treatment (versions). A method for making the dental instrument comprising the pad and configured to be used by the dentist; the instrument has at least one dental cutting instrument used for the tooth structure extraction, involves the stages: detecting the pad sized after the above tooth and after at least a portion of an adjacent tooth; modelling the pre-detected horizontal, vertical and inclined motions, which are supposed to be repeated by at least one dental cutting instrument to extract at least a portion of the detected portion of the tooth to be extracted; detecting the first and second guide edges inside the pad; making the above detected pad with the above first and second guide edges. The above first guide edge corresponds to the above pre-detected horizontal, vertical and inclined motions. The second guide edge inside the pad is remote from the first guide edge at a distance d. The second guide edge corresponds to the above pre-detected horizontal, vertical and inclined motions. The first and second guide edges are thereby presented to contact the dental cutting instrument to direct its horizontal, vertical and inclined motions in accordance with the pre-detected horizontal, vertical and inclined motions to remove at least the above portion of the pre-detected portion of the tooth to be extracted.

EFFECT: group of inventions enables providing the accurate tooth treatment for the following stage of treatment both by experienced and inexperienced dentists.

21 cl, 8 dwg

FIELD: medicine.

SUBSTANCE: invention refers to medicine and is applicable in treating lower molars with destruction in root bifurcation. Laboratory and radiographic examinations of an involved tooth are performed. A crown-radicular separation is followed by introducing an osteotropic material. Residual dental stumps are prepared for whole-piece crowns. A working impression of the lower jaw and an auxiliary impression of the upper jaw are made. The whole-piece crown with a washing space surrounding the separated bifurcation is made. It is fixed on dental cement.

EFFECT: method ensures the integrated treatment involving surgical and orthopaedic interventions and enables preserving the dental functions and restoring its anatomical shape.

1 ex

FIELD: medicine.

SUBSTANCE: invention refers to medicine, particularly to orthopaedic dentistry, and can be used for partial laminar and clasp prostheses. A clasp system for fixing a removable partial denture of a single tooth consists of a basis with artificial teeth and a denture clasp. One end of the clasp comprises a mechanical device consisting of an inner O-ring abutment and an outer matrix and configured as a pivot, while the other end comprises a clasp seat in a rigid socket on an artificial dental crown. The outer matrix is fixed in the prosthesis basis and detachable together with the prosthesis, while the inner O-ring abutment is ball-shaped and connected to a clasp arm. The seat of the clasp socket is mounted on the artificial dental crown vertically or horizontally either from the lingual, or palatal, or approximal surface.

EFFECT: invention enables providing a more stable fixation of the detachable clasp system, a masticatory effectiveness and an appearance, and also avoiding the negative effect on the parodontium.

3 cl, 12 dwg, 3 ex

FIELD: medical engineering.

SUBSTANCE: method involves producing an opening of diameter reaching 2 mm with diamond or hard alloy bore in adhesive cover after preparing abutment tooth and prosthesis or widening already available perforation also to diameter of 2 mm. The prosthesis is set on the abutment tooth and place is marked for creating and directing pin-canal in the area of cutting one-third of the frontal abutment tooth or in the lateral abutment tooth equator area. The pin-canal direction is to correspond to path for introducing the prosthesis. The pin is screwed-in with screwdriver and holder to a depth of about 2 mm into dentin. The prosthesis is set on the abutment for making control. The pin is filed-off to adhesive cover layer after having fixed the prosthesis on composition cement.

EFFECT: prolonged service life; high functional value.

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