RU2292866C1 - 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 calcium 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 by the dissolution-precipitation mechanism with the formation of neutral (pH ~ 7) phosphates. Tricalcium phosphate in combination with calcium hydroxide or 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) calcium, 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 eventually coarsens to form a durable hydrocapapite cement stone 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.

Closest to the technical solution is phosphate cement (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, 36, No. 9, p.1148-1152), consisting of a mixture of powders of hydroxyapatite (HA) and heat-treated calcium dihydrogen phosphate, water is used as a coolant. With the addition of a shutting fluid, the components of the mixture react with each other with the formation of an amorphous phase, which during the setting process turns into crystalline HA.

A significant drawback of this material is its low strength (not more than 30 MPa) and fast setting time - 2-3 minutes. Fast setting and low strength do not allow the formation of complex implant bone implants, 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 HA and tricalcium phosphate (TKF) powders as an RPS and a solution of magnesium and calcium phosphates in phosphoric acid as a coolant, which can significantly increase the strength of a HA-based cementitious material. Cement consisting of a reaction mixture of HA and TCF and GF based on magnesium and calcium phosphates is not known. The content in the RPS TKF is 20-80 wt.% The ratio of the amount of introduced coolant liquid ZH (ml) to the number of RPS (g) should be in the range 0.25-0.65 (ZZ (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 partially dissolves, followed by precipitation as 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 shutting fluid in an amount less than the lower limit (GJ (ml) / solid (g) <0.25) or using highly concentrated solutions of GJ with a magnesium phosphate content of more than 70 wt.% And calcium phosphate more than 50 wt.% 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 dilute solutions with a high water content of more than 45 wt.%, Magnesium phosphate content of less than 15 wt.% And calcium phosphate of less than 5 wt.% the mixture was too liquid, which did not allow to form the product due to the spreading of the mixture, in addition, significantly set time, 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 acids (40 wt.% Magnesium phosphate and 40 wt.% Calcium phosphate, phosphoric acid 12 wt.%., 8 wt.% Water). Mixing is carried out for 1-2 minutes with a metal spatula on the 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 at a temperature of 37 ° C and a relative humidity of 100% . After 24 hours, the cured sample has a compressive strength of 110 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 calcium phosphates in phosphoric acid - and is characterized by higher strength.

Composition and properties of cement materials ZH, ml / RPS powder, g The ratio of components in the RPS, wt.% The composition of the fatty acids, wt.% Setting time (37 ° C, 100%
relative
humidity),
min Compressive strength, MPa ¹ GA Tkf Phosphate
magnesium Phosphate
calcium Phosphoric
acid Water one 0.5 40 60 40 40 12 8 10 110 2 0.25 80 twenty 25 5 65 5 6 45 3 0.65 60 40 70 5 10 fifteen 25 38 four 0.4 twenty 80 fifteen twenty twenty 45 35 34 5 0.4 60 40 twenty fifty twenty 10 8 6 (prototype) 0.3 GA Calcium dihydrogen phosphate - - - one hundred 3 thirty 7 0.15 95 5 80 0 twenty 0 - The sample crumbled 8 0.4 10 90 10 40 0 fifty More than 60 6 9 0.8 70 thirty 0 thirty 70 0 More than 60 2 ¹ Tests were performed 24 hours after mixing.

Claims (1)

Material for filling bone maxillofacial and dental defects based on a reaction-hardening powder mixture containing hydroxyapatite and a hardening liquid, characterized in that the hardening reaction mixture further comprises tricalcium phosphate powder and, as a hardening liquid, a solution of magnesium phosphate and calcium phosphate 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 Calcium phosphate 5.0-50.0 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.