JPH05317405A - Anti-mildew treatment method for hydraulic calcium phosphate cement curing liquid - Google Patents

Abstract

PURPOSE:To enable the blocking of the generation of mildew for a lone time by repeating plural times a process of holding a hydraulic calcium phosphate cement curing liquid containing water soluble saccharides with a specified pH under a dry condition at a specified temperature for a specified period of time. CONSTITUTION:Phosphoric acid, citric acid, sodium carbonate, sodium hydroxide and the like are added to a hydraulic calcium phosphate cement curing liquid to control a pH value thereof to a range of 4.0-10.0. The hydraulic liquid with this range of pH is held under a dry condition to meet treating requirements of 50-90 deg. and 30-120min. Anti-milldew treatment is performed by repeating this holding process a plurality of times. In the heating treatment under the dry condition, it is preferable that the hydraulic liquid is preserved in a dry container set to 50-90 deg.C together with a heat resisting container or others. The heating holding treatment under the dry condition is repeated two to eight times preferably. A sample of the water soluble polysaccharides to be added to the hydraulic liquid is chitin, chitosan or soluble starch or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antifungal treatment method for a cement hardening liquid used for hardening a cement for living body, particularly a hydraulic calcium phosphate cement useful as a dental cement.

[0002]

2. Description of the Related Art Hydraulic calcium phosphate cement is known to be useful as a cement for medical and dental purposes because it undergoes a kneading reaction in a neutral region to form a hardened cement, which is converted to apatite after hardening. ing. As the curing liquid used in the kneading reaction, water is also sufficient, but in order to improve the fluidity and filling of the kneaded cement paste, it is preferable to use a curing liquid containing a water-soluble polymer. A hardening liquid containing a polysaccharide such as sodium chondroitin sulfate, which is preferably excellent in biocompatibility, has been proposed (JP-A-3-141955). However, the curing liquid has a problem that mold is generated during storage and it is easily decomposed. Antifungal methods include cold and dark storage, sterilization treatment, etc., but the former is difficult to store for a long time, and the latter requires re-sterilization when reusing the residual curing liquid after use, At this time, the polysaccharide is apt to undergo thermal denaturation, and therefore autoclave sterilization, γ-ray sterilization, dry sterilization, etc. cannot be carried out. Absent.

Therefore, a hydraulic calcium phosphate cement hardening liquid containing an antibacterial agent has been proposed (JP-A-3-
267067). However, since the antibacterial agent itself contained in the hardening liquid has toxicity to the living body, there is a problem that the biocompatibility of the hydraulic calcium phosphate cement is impaired and the physical properties of the hardened hydraulic calcium phosphate cement are lowered.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an antifungal treatment method for a hydraulic calcium phosphate cement hardening liquid which is capable of preventing the development of mold for a long period of time and has excellent storage stability.

Another object of the present invention is antifungal treatment of a hydraulic calcium phosphate cement hardening liquid which can be easily and small amount treated and does not adversely affect workability such as consistency and viscosity and hardening conditions after the treatment. To provide a method.

Still another object of the present invention is to provide an antifungal treatment method for a hydraulic calcium phosphate cement hardening liquid which does not adversely affect the physical properties of the calcium phosphate cement hardening product.

[0007]

According to the present invention, a water-soluble polysaccharide hardening cement of calcium hydroxide phosphate having a pH value of 4.0 to 10.0 and a holding temperature of 50 to 90 in a dry state is used. There is provided a method for antifungal treatment of a hydraulic calcium phosphate cement hardening liquid, which is characterized in that the step of holding under treatment conditions of 30 ° C. and a holding time of 30 to 120 minutes is repeated a plurality of times.

The present invention will be described in detail below.

The hydraulic calcium phosphate cement hardening liquid used in the antifungal treatment method of the present invention is a hydraulic calcium phosphate cement hardening liquid having a pH value in a specific range and containing a water-soluble polysaccharide. The pH value in the specific range is 4.0 to 10 because the hydraulic calcium phosphate cement to be hardened is hardened by the hydration reaction in a substantially neutral range and the biostimulation of the obtained hardened cement is eliminated. It must be in the 0 range. Outside the above range, the setting of the hydraulic calcium phosphate cement will be significantly delayed, and the physical properties of the obtained cement hardened product will be deteriorated, resulting in biostimulation. In order to adjust the pH value, for example, phosphoric acid, citric acid, sodium hydrogen carbonate, sodium hydroxide or the like can be added to obtain a desired pH.

The water-soluble polysaccharide used as a component of the hydraulic calcium phosphate cement hardening liquid is a component for improving the fluidity and filling property of the cement paste during kneading, and is particularly preferable as long as it is a biopolymer having excellent biocompatibility. Specific examples thereof include, but are not limited to, chitin, chitosan, soluble starch, glycogen, alginic acid, chondroitin sulfate, hyaluronic acid, and salts thereof. The content ratio of the water-soluble polysaccharide may be within a range that can impart desired consistency, viscosity, etc. to the curing liquid, and does not impair fluidity, and is particularly 1 to 30 wt% with respect to the entire curing liquid. It is preferably in the range of%.

The antifungal treatment method of the hydraulic calcium phosphate cement hardening liquid of the present invention is carried out by holding the above-mentioned hydraulic calcium phosphate cement hardening liquid in a dry state at a specific holding temperature for a specific number of times. It is characterized by being repeated.

The antifungal treatment method of the present invention must be carried out in a dry state. The dry state does not require a drying treatment and means that the treatment can be performed in an ordinary room which does not require a humidity. Preferably, the range of RH is 0 to 60%.

In order to treat the hydraulic setting agent for calcium phosphate cement according to the antifungal treatment method of the present invention, first, the holding temperature of the setting solution is 50 to 90 ° C., preferably 60 to 80.
The above-mentioned dry state is maintained under the holding condition of the temperature of 30 to 120 minutes. At this time, it is desirable to store the curing liquid in a heat-resistant container for processing, and store the curing liquid together with the container in a dryer set at 50 to 90 ° C,
It is preferably placed on a hot plate for processing. Further, the treatment may be carried out in the state where it is packaged in a packaging container such as a paper box together with the container containing the curing liquid. The holding temperature is 5
If the temperature is below 0 ° C, a sufficient antifungal effect cannot be obtained,
If the temperature exceeds ℃, the hydraulic calcium phosphate cement hardening liquid will be deteriorated. The holding time is 30 to 120.
Within the range of minutes, it is not necessary to strictly fix it, and it can be set according to the type of the curing liquid and the storage state, but it generally depends on the holding temperature. That is, the higher the holding temperature is, the shorter the holding time is.
0 minutes, 30 minutes is desirable at a holding temperature of 90 ° C. When the holding conditions are high temperature and long time, modification of the water-soluble polysaccharide which is a component of the hydraulic calcium phosphate cement hardening solution is likely to occur, and when low temperature and short time, sufficient antifungal effect is obtained. I can't get it.

In the antifungal treatment method of the present invention, the step of maintaining the above conditions as one cycle is repeated a plurality of times, preferably 2 to 8 times, particularly preferably 3 to 5 times, to obtain a desired antifungal agent. The effect can be obtained. If the number of repetitions is less than 2 times, a sufficient antifungal effect may not be obtained in some cases, and if it exceeds 8 times, deterioration of the hydraulic calcium phosphate cement hardening liquid may occur and the treatment operation may become complicated.

The temperature condition and the standing time between the respective holding steps are not particularly limited, but in order to prevent the water-soluble polysaccharide from being deteriorated by heat and to germinate only heat-sensitive mold spores and then to treat it, It is desirable to leave the curable liquid held under the above holding conditions in a dry state at a temperature of 20 to 25 ° C. for 15 hours or more.

The hardening of the hydraulic calcium phosphate cement using the hydraulic calcium phosphate cement hardening liquid of the present invention can be carried out by a conventional kneading and hardening method, and water which can be hardened by the hardening liquid is used. Specific examples of the main component of the hard calcium phosphate cement include α-type tricalcium phosphate, quaternary calcium phosphate,
β-type tricalcium phosphate, hydroxyapatite, dibasic calcium phosphate dihydrate, monobasic calcium phosphate 1
Preferable examples include hydrates and mixtures thereof, and particularly, for example, a mixture of α-type tribasic calcium phosphate and dibasic calcium phosphate dihydrate or monobasic calcium phosphate monohydrate, quaternary calcium phosphate and dibasic calcium phosphate 2 Preferable examples thereof include a hydrate or a mixture with monocalcium phosphate monohydrate, a mixture of β-type tricalcium phosphate or hydroxyapatite and monocalcium phosphate monohydrate, and the like.

[0017]

The antifungal treatment method of the hydraulic calcium phosphate cement hardening liquid of the present invention can impart excellent long-term storability to the hardening liquid. In addition, this treatment method can easily treat even a small amount, and the workability of the curing liquid after treatment can be improved.
Since the curing conditions are not adversely affected and the physical properties of the cured product do not change, the antifungal treatment can be appropriately performed even during the period of use, and the antifungal state of the curable liquid can be maintained.

[0018]

The present invention will be described in more detail based on the following examples and comparative examples, but the present invention is not limited thereto.

[0019]

Example 1 2 g of sodium chondroitin sulfate (manufactured by Wako Pure Chemical Industries, Ltd., special grade) was dissolved in 8 ml of water to prepare a 20 wt% sodium chondroitin sulfate aqueous solution (pH 6.2), which was used as a curing liquid A. 1 g of soluble starch (manufactured by Wako Pure Chemical Industries, Ltd., special grade) was dissolved in 9 ml of water to prepare a 10 wt% soluble starch aqueous solution (pH 7.0), which was used as a hardening liquid B. 0.1 g of sodium hyaluronate (manufactured by Chisso Corporation) was added to 9.9 m of water.
1 wt% sodium hyaluronate aqueous solution (p
H6.3) was prepared and used as a hardening liquid C.

A dryer (trade name "DX
31 type ", manufactured by Yamato Scientific Co., Ltd.) and held under the holding conditions shown in Table 1, and then at room temperature (20 to 25 ° C.) for 20 hours.
The step of leaving for a time was repeated the number of times shown in Table 1. Immediately after the treatment, a fungus-free test described in the Japanese Pharmacopoeia was performed to observe the state of the hardening liquid. Also, in Table 1, condition (2)
About (6), the cap of the container is opened every month to break the sterilized state, antifungal treatment is performed under the same conditions every three months, and the fungus-free test is performed after one year has passed. The state of the curing liquid was observed. The results are shown in Table 1.

[0021]

[Table 1]

[0022]

Comparative Example 1 1 g of sodium chondroitin sulfate (manufactured by Wako Pure Chemical Industries, Ltd., special grade) was dissolved in 9 ml of water to prepare a 10 wt% sodium chondroitin sulfate aqueous solution (pH 6.4), which was used as a curing liquid D. Antifungal treatment was performed on the curing liquid D under the conditions shown in Table 2, and a fungus-free test similar to that of Example 1 was performed to observe the state of the curing liquid. The results are shown in Table 2.

[0023]

[Table 2]

[0024]

[Example 2] Using the curing liquid D prepared in Comparative Example 1, using a dryer (trade name "DX31 type", manufactured by Yamato Scientific Co., Ltd.), and holding at 80 ° C for 30 minutes, Then, leaving at room temperature (20 to 25 ° C.) for 20 hours was repeated 3 times.

On the other hand, as hydraulic calcium phosphate cement, α-type tribasic calcium phosphate and dibasic calcium phosphate cement dihydrate (manufactured by Wako Pure Chemical Industries, special grade) were used as Ca /
Cement powder was prepared by mixing so that the P ratio was 1.48.

Next, the cement powder material and the treated hardening liquid D were kneaded at a powder liquid ratio of 100: 40 (weight ratio) to obtain a cement paste. The consistency of the obtained cement paste conforms to the JIST6602 standard consistency test method, and the viscosity is "Vismetron" (trade name, manufactured by Shibaura System Co., Ltd., single cylinder type rotational viscometer, model VG-D).
H) was used for the workability. Next, the cement paste was filled into a cylindrical mold having a diameter of 7 mm and a height of 14 mm, and the time until curing was measured according to JISR5201 and was defined as the curing time. The obtained cement hardened product was dipped in a simulated body fluid at 37 ° C. for 7 days, then taken out, and using a “Instron universal testing machine 1125 type” (trade name, manufactured by Instron Co., Ltd.), a load speed 0.5 mm
The compressive strength was measured at 1 / min. The results are shown in Table 3.

[0027]

Comparative Example 2 The same operation as in Example 2 was carried out except that the curing liquid D prepared in Comparative Example 1 was used as it was, and the workability of the cement paste, the curing time, and the compressive strength of the cement cured product were measured. .. The results are shown in Table 3.

[0028]

[Table 3]

Claims (1)

[Claims] 1. A pH value of 4.0 containing a water-soluble polysaccharide.
10.0% hydraulic calcium phosphate cement hardening liquid,
In the dry state, the holding temperature is 50 to 90 ° C, the holding time is 30 to
An antifungal treatment method for a hydraulic calcium phosphate cement hardening liquid, which comprises repeating the step of maintaining the treatment condition for 120 minutes a plurality of times.