RU2585575C1 - Method of producing calcium phosphate cement for bone defect filling - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to a method of producing cement materials for plastic reconstruction of injured bone tissues. Cement material is obtained by mixing powder tricalcium phosphate and shut off fluid based on aqueous solution of magnesium phosphate and potassium. After mixing obtained kneaded mass is placed in mold and subjected to pressing at pressure not less than 50 MPa. Cement samples with compression strength 200-240 MPa are obtained.

EFFECT: improved mechanical characteristics and availability of raw materials enable to widely use said material for closing cavities in bone tissues.

1 cl, 1 tbl, 1 ex

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 prepared on the basis of a reaction-hardening powder mixture of calcium phosphate powder and a mixing liquid (GC). When the components are mixed, a cement solution is formed in which the components begin to interact with each other through the liquid phase by the dissolution-precipitation mechanism with the formation of neutral (pH ~ 7) calcium phosphates. As it sets, the viscosity of the cement increases to form a test-like mass (setting process), which hardens over time to form a strong cement stone consisting of crystalline or amorphous phases based on hydroxyapatite (HA). The proposed materials can be used as cement materials for filling bone maxillofacial and dental defects.

The closest to the technical solution is cement, consisting of a mixture of powders of HA and tricalcium phosphate (TCF) and a mixing fluid, which is a solution of phosphoric acid containing potassium and magnesium phosphates (patent No. 2292865). Cement stone was obtained by mixing powder and coolant for 1-2 minutes until a dough-like mass was formed. After mixing, the resulting mass is placed in a mold in which the cement gradually hardens to form a strong cement stone. The maximum compressive strength of the finished material is from 40 to 150 MPa, depending on the ratio of the starting components. The disadvantages of the material include the low strength of the material. This limits the use of cement as bone structures that can withstand physiological stresses.

The technical result of the invention is an increase in the strength of the cement material.

The technical result is achieved by the fact that in the method of producing calcium phosphate cement for filling bone defects, which consists in mixing a powder of tricalcium phosphate and a mixing fluid based on a cement solution containing magnesium and potassium phosphates, according to the invention, the cement components are mixed in the following mass ratio. %:

TKF powder 40-60 ZJ 40-60

the content of components in the coolant, mass. %

Magnesium Phosphate 10-40 Potassium phosphate 5-20 Water rest

within 4-7 minutes, the resulting dough-like mass is placed in the mold and subjected to pressing at a pressure of at least 50 MPa, resulting in the formation of samples with a strength of at least 200-240 MPa.

As a result of mixing, a cement mortar is formed, which gradually sets with the formation of a solid stone-like body. In the process of hardening, new amorphous compounds of calcium phosphates are formed, which are formed on the surface of cement particles, cementing them together. As a result, a cement stone is formed, the strength of which increases as the material hardens. If external pressure is applied to the cement specimen during the hardening process, conditions are created under which a more tight contact arises between the cement particles, which, as a result, leads to an increase in strength.

When mixing cement powder and coolant for less than 4 minutes, the mixture turns out to be very liquid, and for more than 7 minutes, the cement hardens, which does not allow to obtain samples of the desired configuration and desired strength during the pressing process. In the case of using a powder of more than 60%, and ZH less than 40%, the amount of liquid is not enough for uniform alteration. In the case of using a coolant of more than 60%, and a powder of less than 40%, the resulting solution becomes highly diluted, which leads to a decrease in the strength of the samples. When going beyond the limits of the composition of the ZH, cement materials have low strength values, and the setting and hardening process takes place in a very short - less than 1-2 minutes or a long period - more than 7 minutes. When pressing a cement mass under a pressure of less than 50 MPa, the cured sample has a compressive strength of less than 200 MPa.

Example. A powder of 0.6 g (60%) of TCP was mixed with 0.4 g (40%) of ZH (solution of the composition of magnesium phosphate - 40%, potassium phosphate 5%) for 5 minutes, then the resulting mass is pressed into a mold at 100 MPa The result is a sample with a strength of 220 MPa in compression.

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.

Claims (1)

A method of producing calcium phosphate cement for filling defects in bone tissue, comprising mixing a powder of tricalcium phosphate (TCF) and a blocking fluid (JL), including magnesium and potassium phosphates and water, characterized in that the cement components are mixed in the following ratio, wt.%:
TKF powder 40-60 ZJ 40-60
the content of components in the coolant, wt.%
Magnesium Phosphate 10-40 Potassium phosphate 5-20 Water rest
within 4-7 minutes, the resulting dough-like mass is placed in the mold and subjected to pressing at a pressure of at least 50 MPa, resulting in the formation of samples with a strength of at least 200-240 MPa.