RU2292865C1 - Material for filling maxillofacial and dental bone defects - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: material has reactive hardening powder mixture containing hydroxyapatite and tricalcium phosphate as base and magnesium phosphate and potassium phosphate in phosphoric acid as closing liquid when taking the ingredients in known quantitative proportions in the closing liquid. The closing liquid quantity to reactive hardening powder mixture proportion is equal to 0.25:0.65 (in g).

EFFECT: wide range of functional applications for correlating alveolar process fragments, closing bone tissue cavities and treating traumatic cracks.

1 tbl

Description

The invention relates to medicine, namely to use for correlation of fragments of the alveolar ridge, closure of cavities in bone tissue and the treatment of various cracks of traumatic origin.

Calcium phosphate cements are obtained on the basis of a reaction-hardening powder mixture (RPS) of two or more calcium phosphates and a solidifying liquid (GC). The starting powder is a mixture of acidic and basic phosphates. When GIs are added to the mixture, the components begin to interact with each other through the liquid phase according to the precipitation dissolution mechanism with the formation of neutral (pH ~ 7) phosphates. Tricalcium phosphate in combination with calcium hydroxide or calcium carbonate was used as the initial mixture (S. Takagi, LCChow, K. Ishikawa, “Formation of hydrohyapatite in new calcium phosphate cements”, Biomaterials, 19 (1998), pp. 1593-1599) amorphous calcium phosphate with calcium hydroxide, dicalcium phosphate with calcium hydroxide or calcium carbonate. An aqueous solution of sodium hydroxide or disubstituted sodium orthophosphate was used as a ZH. When a mixture of calcium phosphate powders is mixed with a coolant, a dough-like mass is formed, which sets over time until a strong hydroxyapatite cement stone is formed, consisting of crystalline hydroxyapatite (HA).

The proposed materials can be used as cement pastes for filling bone maxillofacial and dental defects. The disadvantage of these materials is their low strength - less than 8 MPa. The closest technical solutions are phosphate cements (VV Samuskevich, N.Kh. Belous, L.N. Samuskevich, A.A.Dobryshevskaya. Water mixing cement based on hydroxyapatite and heat-treated calcium dihydrogen phosphate. Inorganic materials, 2000, t .36, No. 9, p.1148-1152) consisting of a mixture of HA powders and calcium dihydrogen phosphate, water was used as a coolant. When adding a shutter fluid between the components, an interaction occurs with the formation of an amorphous phase, which in the process of setting changes to crystalline HA.

A significant drawback of this material is its low strength (not more than 30 MPa) and a quick setting time of 2-3 minutes. Quick setting and low strength does not allow the formation of bone implants of complex configuration, heal bone defects of a large area and volume.

The technical result of the invention is to increase the strength of calcium phosphate cement material. To achieve a technical result, it is proposed to use a mixture of powders of HA and tricalcium phosphate (TKF) as an RPS and as a ZH solution of magnesium and potassium phosphates in phosphoric acid, which can significantly increase the strength of a cement based on HA. Cement consisting of a mixture of HA and TKF and ZJ based on magnesium and potassium phosphates is not known. The content in the RPS TKF is 20-80 wt.% The ratio of the amount of introduced mixing liquid (ml) to the number of RPS (g) should be in the range 0.25-0.65 (LJ (ml) / RPS (g) = 0.25-0, 65). The setting time varied from 6 to 35 minutes depending on the amount and composition of the fatty acid and the ratio of phosphates in the RPS. After the addition of fatty acids in the RPS, the liquid phase enters into a reaction, in this case, the RPS is partially dissolved, followed by precipitation in the form of an amorphous phase. During the setting process, a structure is formed consisting of HA crystals, which are coated with layers of cementing amorphous phase, which provides strong adhesion of the crystals to each other. The introduction of HA in amounts of more than 80 wt.% Leads to a quick setting of the hardening mixture, and vice versa, with the introduction of less than 20 wt.%, Setting takes place very slowly, and in either case it complicates the use of this material in medicine. In the case of using a shutter fluid in an amount less than the lower limit (GJ (ml) / solid (g) <0.25) or the use of highly concentrated solutions of GJ with a magnesium phosphate content of more than 70 wt.% And potassium phosphate more than 25%, the resulting mixture had a high viscosity, which led to the formation of numerous cracks during molding of the product of the required configuration. When using ZH in an amount above the upper limit (ZZ (ml) / CPS (g)> 0.65) and diluted solutions with a high water content of more than 45 wt.%, Magnesium phosphate content of less than 15 wt.% And potassium phosphate less than 3.5 wt. %, on the contrary, the mixture turned out to be too liquid, which did not allow to form the product due to the spreading of the mixture. In addition, the setting time was significantly increased, which led to a decrease in strength, especially in the first minutes of hardening.

An example of obtaining sample No. 1. Powders consisting of 16 g of HA and 24 g of TCP are mixed in a vibratory mill with corundum balls for 20 minutes. The resulting RPS in the amount of 0.6 g is mixed with 0.3 ml of fatty acid (70 wt.% Magnesium phosphate, 8 wt.% Potassium phosphate, 12 phosphoric acid, 10 water). Mixing is carried out for 1-2 minutes with a metal spatula on glass until a sour cream-like state, after which the mixture is placed in a cylindrical shape with a diameter of 0.8 cm. After a few minutes, the molded sample is taken out and placed in a thermostat with a temperature of 37 ° C at 100% relative humidity . After 24 hours, the cured sample has a compressive strength of 150 MPa.

Similarly, samples were made having compositions within the claimed, and their properties were determined in comparison with the prototype. The results are summarized in table.

The proposed calcium phosphate cement consists of a mixture of powders of HA and TKF and ZH - solutions of magnesium and potassium phosphates in phosphoric acid and is characterized by higher strength.

Composition and properties of cement materials LC ml /
Powder
RPS, g Ratio of components in
RPS,% wt. The composition of the fatty acids, wt.% Time
setting
(37 ° C, 100%
relative
humidity),
min Durability on
compression,
MPa ¹ GA Tkf Magnesium phosphate Potassium phosphate Phosphoric acid Water one 0.5 40 60 70 8 12 10 10 150 3 0.25 80 twenty fifteen fifteen 65 5 6 46 5 0.65 60 40 75 3,5 10 11.5 25 48 7 0.4 twenty 80 17 25 13 45 35 40 9 (prototype) 0.3 GA Dihydrogen phosphate - - - one hundred 3 thirty calcium eleven 0.15 95 5 80 0 twenty 0 - Sample crumbled 12 0.8 10 90 10 40 0 fifty More than 60 2  13 0.8 70 thirty thirty 10 55 5 More than 60 10 ¹ Tests were performed 24 hours after mixing.

Claims (1)

Material for filling bone maxillofacial and dental defects on the basis of a reaction-hardening powder mixture containing hydroxyapatite and a mixing fluid, characterized in that the reaction-hardening powder mixture additionally contains tricalcium phosphate powder, and a solution of magnesium and potassium phosphates as a mixing fluid in phosphoric acid, while the content of components in the reaction-hardening mixture is, wt.%: Hydroxyapatite 20.0-80.0 Tricalcium phosphate 20.0-80.0 the content of components in the closing fluid is, wt.%: Magnesium Phosphate 15.0-70.0 Potassium phosphate 3,5-25,0 Phosphoric acid 10.0-65.0 Water 5.0-45.0 and the amount of mixing liquid to the amount of the reaction-hardening mixture is, g: 0.25-0.65.