JPH0774140B2 - Fluoride colloid liquid - Google Patents

Description

The present invention relates to a fluoride colloidal liquid and a method for producing the same. Especially as a fluoride ion concentration of saturated aqueous solution of 1 to 1000
A colloidal solution of a sparingly soluble fluoride giving 0 ppm, wherein the colloid of the present invention is used as an oral composition having a composition such that the fluorine content is 10 to 100,000 ppm alone or together with other substances. It can be used for eclipse prevention.

[Conventional technology]

Conventionally, various compounds have been proposed as active ingredients for preventing dental caries. Among these, fluorides such as sodium fluoride, sodium monofluorophosphate, and stannous fluoride are currently considered to be most effective. It is considered that the action of fluoride is mainly the effect of improving the acid resistance of teeth by fluoride ions and the effect of promoting remineralization of early caries in which decalcification has progressed to some extent. The effect of improving tooth acid resistance is explained by the fact that fluoride ions penetrate into the hydroxyapatite crystal lattice, which is the main constituent of tooth enamel, that is, partially fluorinate hydroxyapatite and at the same time repair lattice irregularities. It In addition, remineralization is a reaction that does not promote caries by returning the shortened, altered, or lost hydroxyapatite to the original state or a state close to the original state by the decalcification reverse reaction by demineralizing the enamel. is there.
This reaction, which occurs routinely with deashing, is significantly accelerated by the presence of fluoride ions.

These actions are extremely characteristic of fluoride ions,
It is hard to think of a substance that can replace this. Therefore, fluoride is currently used for addition to waterworks, chewable tablets, addition to foods, application to tooth surfaces, mouthwash, dentifrice and the like.

By the way, if we describe to what extent fluoride has a caries-suppressing effect, it is 50-65% when added to the water supply, 30-40% when applied to the tooth surface, 20% for mouthwashes and dentifrices. A caries inhibition rate of ~ 50% is reported. It can be said that this is an extremely high caries inhibitory effect as compared with other caries preventive agents, but on the other hand, it is ideal that caries can be completely prevented, and from that point of view, it is still a sufficient effect. Is unthinkable.
Among them, a method of directly acting on teeth without swallowing (topical application) like a mouthwash and a dentifrice has a low caries suppressing effect, and there is room for improvement.

Therefore, new compounding methods, new treatment methods, or new fluorine compounds that enhance the effect of fluoride have been researched. Especially, in topical application, fluorine uptake efficiency is low, and exhalation is ineffective. Because there is a lot of fluorine,
Much research has been done to increase the uptake of fluorine.

Specifically, a successful example of research is sodium acid fluoride phosphate. This is mixed with phosphoric acid,
Increasing the amount of fluorine taken in. This drug is already widely used.

Moreover, in recent years, it is usually 1500 to 2000 ppm (normal 1.5 to dentifrice)
(2 times) is blended with fluorine to increase the uptake of fluorine. This is also considered to be effective.

The reason for these high effects is explained as follows. That is,
Topical application of fluoride is only a very short-acting action, so there is little direct fluorination of the tooth, other fluorine decomposes part of the tooth to produce calcium fluoride, which later It dissolves in saliva, and this fluoride ion fluorinates the tooth, but treatment with sodium acid fluoride fluoride or high-concentration fluoride produces a large amount of this calcium fluoride. This indirectly strengthens the teeth.

However, in the case of treatment with sodium phosphate fluoride or high-concentration fluoride, it is necessary to decompose a part of the tooth,
It cannot be said that problems do not occur after long-term use. Furthermore, the acute toxicity of fluorine is not very low, and it is not a desirable method to raise the concentration of fluorine when considering accidental ingestion.

Then, what is expected as another formulation for promoting the uptake of fluorine is a method of blending various metal ions with a fluoride. For example, aluminum ion, calcium ion (Kyushu Dental Society, 4 (1), 247-259) and lantern (pediatric dentistry magazine, 25 (1), 1-11) have been found to have a fluorine uptake promoting effect. The mechanism of action is that the insoluble fluoride formed is
It is considered to be adsorbed on apatite, and when the metal ion is calcium, the insoluble fluoride is exactly calcium fluoride, which is in principle similar to the high concentration fluoride treatment. However, the enamel is not destroyed as in the high concentration fluoride treatment.

Furthermore, it is known that the addition of metal ions has a secondary effect other than the promotion of fluorine uptake.

For example, calcium ion is an ion known to have a remineralization promoting effect, and it is recognized that it is effective to use it in combination with a fluorinating agent. Examples thereof include JP-A-47-039642 of Beecham and JP-A-51-091339 of Procter & Gamble, and there are also commercially available products.

Further, titanium, tin, etc. are known to have an acid resistance improving effect due to a coating effect.

From these points, the formulation composed of a combination of fluorine ion and metal ion is expected to be extremely useful.

[Problems to be Solved by the Invention]

At the same time, however, the formulation composed of a combination of fluorine ion and metal ion has various problems to be solved in actual use.

That is, caries preventive effect is evaluated calcium, magnesium, strontium, lanthanides represented by lanthanum, molybdenum, manganese, aluminum, fluorides such as indium are insoluble or poorly soluble in water, for a while to prepare a solution. Then, it precipitates and loses its reactivity almost completely, and not only the high fluorine uptake but also the effect of ordinary fluoride is not found.

Therefore, studies have been conducted on formulations that can maintain the high effects of these fluorides.

As a specific example, the method shown in JP-A-57-212112 of Colgate Co., which holds aluminum and fluorine separately in an oil layer and a water layer so that mixing occurs at the time of use, or calcium ion of Procter & Gamble Co. The method of JP-A-58-219107, which protects most by chelation,
Alternatively, the company's characteristic feature is that the pH is extremely lowered.
There is a method of 50-091339.

However, each of these methods has drawbacks. That is, the emulsified system has a special texture, and the feeling of use as a dentifrice has to be poor, and the chelation of calcium ions has to sacrifice the effect. Also, low pH
Has limited prescriptions and is bad for teeth.

[Means for Solving the Problems]

As a result of intensive research to solve the above-mentioned problems, the present inventors have improved the uptake of fluorine into tooth enamel by colloidalizing a poorly soluble fluoride precipitate, and the erroneous and taken-in fluorine is long-termed. To provide a composition that is gradually released for a long time and has a much higher effect than usual with good storage stability and is not complicated, and to effectively realize dental caries prevention by an oral composition using this colloidal solution. Succeeded and completed the present invention.

That is, the present invention, the sparingly soluble fluoride that gives a fluorine ion concentration of 1 to 10,000 ppm in a saturated aqueous solution is colloidalized by a deflocculant selected from the group consisting of polyol phosphoric acid, polyol sulfuric acid, polyol carboxylic acid and salts thereof. The present invention provides a colloidal fluoride solution in which colloidal fine particles having a particle size of 0.005 to 1 μm are dispersed in a formed state.

In the present invention, the confirmation of colloid formation was judged by the following method, for example.

(1) The sample solution was filtered through a Millipore filter with a pore size of 0.8μ, and 8-9 ml (10PC bottle) of filtrate was ultracentrifuged (SCP70H manufactured by Hitachi, rotor: SRP70AT, 50000rpm, 20hr, 15)
A precipitate is observed when subjected to (.degree. C.).

(2) When the sample solution is filtered with a Millipore filter and the dynamic light scattering of the filtrate is measured, particles of 0.005 to 1 μm are detected (DLS-700 manufactured by Otsuka Electronics).

(3) Transmission electron microscope (Hitachi H-7000)
When observed with, particles of 0.005 to 1 μm are observed. still,
As the observation sample, a sample solution obtained by filtering the sample solution with a Millipore filter, placing the sample on a carbon support membrane which was previously subjected to hydrophilic treatment (JEOL JFC-1100) and removing water was used.

(4) When the precipitation amount or turbidity of the sample solution and the solution obtained by removing the peptizer from the sample solution (control solution) is compared, the former is smaller than the latter. The deflocculating agent in the present invention is one which forms a colloid before, simultaneously with or after the formation of a poorly soluble fluoride, and is selected from the group consisting of polyol phosphoric acid, polyol sulfuric acid, polyol carboxylic acid and salts thereof. Be done.

According to the present invention, a compound that causes precipitation is originally retained stably in a colloidal state, but when it undergoes a change such as being administered into the oral cavity, the balance is lost and the colloidal particles begin to precipitate, for example, the oral cavity. Inside, it sticks to the teeth. At this time, since the colloidal particles contain fluorine, this adsorbate can serve as a fluorine sustained-release agent. Empirically, it is effective that the amount of fluorine in the colloid particles, which is the amount of fluorine in the entire colloid solution, is 10 wt% or more.

The amount of fluorine in the colloidal particles has been experimentally confirmed to be 100%.

The concentration of fluorine in the colloidal solution was experimentally 10 to 100,000 pp
m is possible.

Although these reasons are not clear, it is expected to be related to the mechanism of colloid formation.

Such a colloid has a fluoride concentration of 1 to 10000 ppm in a specific poorly soluble fluoride, that is, a saturated aqueous solution.
It is obtained by selecting a sparingly soluble fluoride that gives

Specifically, the fluoride is calcium fluoride, aluminum fluoride, magnesium fluoride, barium fluoride, titanium fluoride, strontium fluoride, indium fluoride, lanthanide fluoride such as lanthanum fluoride,
Alternatively, a compound containing these components in the structure is desirable.

Further, the use of the deflocculant is particularly effective for stabilizing the colloid and maintaining the adsorptivity to the object such as the tooth.

As the deflocculant, compounds having a structure of polyol phosphoric acid such as glucose-1-phosphoric acid, glucose-6-phosphoric acid, etc., polyol sulfuric acid such as sucrose sulfuric acid, polyolcarboxylic acid such as gluconic acid, or salts thereof. Is desirable.

It was found that the dispersibility of the colloidal solution was particularly high when sugar phosphate ester was used, and that a colloidal solution containing up to 100,000 ppm of fluorine was obtained.

The amount of fluorine in the colloidal particles is 100 for all colloidal solutions
The following test was conducted in order to confirm that a colloidal solution up to 100% was obtained.

That is, 4.87 g of glucose-1-calcium phosphate (4
Water salt) and 1.1 g of sodium fluoride, add water and add 50
ml of the solution and water to 1.44 g of calcium chloride and add 5
After mixing with a solution made up to 0 ml, one day later, ¹⁹ F-NMR (JNMGX-270 manufactured by JEOL Ltd.) was measured (Fig. 1), and the content ratio of fluorine in the colloidal particles and fluorine ion in the solution was measured as a peak. It was calculated by the integral value. The chemical shift at this time is 90% CF ₃ COO
H (solvent CDCl _3): - 76.5ppm was the external reference. As a result, the content ratio of fluorine (−108 ppm) and fluorine ion (−121 ppm) in the colloid particles was fluorine: fluoride ion = 100: 0 in the colloid particles, and all the added fluorine was contained in the colloid particles. You can see that

Take 4.87 g of glucose-1-calcium phosphate (tetrahydrate) and 1.1 g of sodium fluoride, add water and add 100 m.
One day later, ¹⁹ F-NMR of the solution adjusted to l (JNMGX-27 manufactured by JEOL Ltd.
When 0) was measured, peaks of fluorine (−108 ppm) and fluorine ions (−121 ppm) in the colloidal particles were confirmed as shown in FIG.

Conventionally, a high effect could be expected at a high concentration, but since the solubility of sodium fluoride is 20000 ppm as fluorine, the above colloid is superior to this.

In order to produce the fluoride colloidal liquid targeted by the present invention, it is desirable to use the following method, for example.

i) Soluble fluoride such as sodium fluoride and a soluble cation salt such as calcium chloride are mixed in an amount and a mixing ratio that cause precipitation of the fluoride when water is added, and an appropriate amount of water is added to the mixture to cause precipitation. At the time of occurrence of, the peptizer is added at the same time and the mixture is stirred. Or put in an ultrasonic cleaner.

ii) An aqueous solution of a soluble fluoride such as sodium fluoride and an aqueous solution of a soluble cation salt such as aluminum chloride are prepared, and a peptizer is added to at least one of the aqueous solutions and dissolved. Then, these solutions are mixed and stirred. Alternatively, apply to an ultrasonic cleaner.

iii) a deflocculant as used herein, for example a salt of glycerophosphoric acid,
For example, a calcium salt and a soluble fluoride are mixed, water is added, and the mixture is stirred. Alternatively, apply to an ultrasonic cleaner.

iv) The already produced colloid can be obtained as a solid by, for example, ultracentrifugation, vacuum drying, addition of alcohol and the like. The dried colloid is dissolved again in water to obtain a sol-like colloid liquid.

The colloidal solution of the poorly soluble fluoride obtained by these methods has colloidal fine particles having a particle size of 0.005 to 1 μm dispersed therein, has the same physical and chemical properties, and no difference due to the manufacturing method is observed. That is, there is no difference in physical properties such as viscosity, electric conductivity, light scattering, and elemental analysis result.

Since the production method described here is merely an example, an insoluble or sparingly soluble fluoride is generated, and a peptizing agent is allowed to exist in the same system before, at the same time with, or after this to generate a colloidal solution. If so, any generation method may be used.

As for the manufacturing temperature, it seems that heating to room temperature or about 40 ° C. is preferable, but different conditions may be used.

The following test was conducted to confirm that the minimum particle size of the colloidal fine particles in the colloidal solution of the present invention was 0.005μ.

That is, glucose-1-calcium phosphate (tetrahydrate) and sodium fluoride were mixed and dissolved at a molar ratio of 1: 2 and a total fluorine concentration of 5000 ppm, and dynamic light scattering was measured after 1 day. The result is shown in FIG.

As is clear from FIG. 3, particles having a particle diameter of about 0.005 μm were confirmed.

The sparingly soluble fluoride used in the present invention is not limited except for its solubility. When used as a saturated aqueous solution, the fluorine ion concentration is 1 to 10,000 ppm, preferably 1
It must be a poorly soluble fluoride that gives ~ 4000 ppm because it does not precipitate when soluble and cannot be colloidized by peptization, while some dissolves and releases moderate fluoride ions. This is because it is indispensable for strengthening teeth when used as an oral composition, for example.

The soluble fluoride used for the purpose of obtaining the hardly soluble fluoride as referred to in the present invention is not limited as long as it provides fluorine ions. However, considering that it is used for the oral cavity, sodium fluoride and potassium fluoride, which give a colloidal solution that does not have a bad taste, are most suitable.

The soluble cation salt used for the purpose of obtaining the poorly soluble fluoride of the present invention is not limited at all, but water-soluble salts such as calcium, aluminum, magnesium and strontium, for example, hydrochloride, nitrate and acetate. Etc. can be used. Incidentally, glycerophosphate, glucose-1-phosphate, glucose-6- used as a peptizer.
When the phosphate or the like has water solubility, it can also serve as a soluble cation salt.

〔Example〕

Now, the effect of applying the colloidal solution of the present invention to teeth will be described based on Examples.

The present invention is based on the exact opposite of the methodology that the prior art sought to prevent the formation of water-insoluble or sparingly soluble precipitates. That is, it is based on the idea that even if a water-insoluble or sparingly soluble precipitate is formed, if it is fine particles, the effect of the fluoride ion can be maintained. In fact, in the fine particle solution of the present invention, for example, a colloidal solution of calcium fluoride, calcium ions and fluorine ions having a solubility higher than usual were detected. Also, when diluted with water, it dissolved with a much higher dissolution rate than normal calcium fluoride and released fluorine ions. An example thereof is shown as the first embodiment.

Example 1 Moreover, surprisingly, the colloidal particles were colloids that adsorb hydroxyapatite, which is a constituent of teeth. Therefore, it was found that the effect of fluorine was not observed only for a short time when the composition was present in the oral cavity, but remained in the mouth for a long time, and the fluorine concentration in the oral cavity could be maintained. .

Furthermore, the addition of a deflocculant dramatically improved the stability of the colloidal solution.

Example 2 is a result of summarizing an example of the state of the colloidal liquid and the fluorine uptake effect after the storage test at room temperature for 6 months by the following method.

Further, this stability is maintained even with respect to salts and activators which are usually incorporated in the oral composition.

<Test method> Glucose-1-phosphate disodium salt (tetrahydrate), calcium chloride and sodium fluoride were mixed at a molar ratio of 1: 1: 2, and distilled water was added so that the amount of fluorine ion became 2000 ppm. A drug solution was prepared.

1g of hydroxyapatite powder was treated for 1 minute with 10ml of this chemical, washed twice with 40ml of distilled water, and after this treatment, apatite was dissolved by adding 3ml of concentrated hydrochloric acid, and diluted appropriately. (Orion)
Was used to measure the amount of incorporated fluorine. The results are shown in the table below.

Example 2 Effect of glucose-1-phosphate / disodium on room temperature 6 months and fluorine uptake effect The actual caries-suppressing effect on teeth was confirmed separately.

As an experimental method, the extracted tooth of a person without caries was vertically divided into 3 parts, and after polishing the surface, each of them was coated with oil paint to prevent the tooth from being attacked by acid, and only the enamel part was covered. An exposed window of about 1 mm square was created. After that, each of these tooth samples had a total fluorine concentration of 10
A 0 ppm fluoride colloidal solution (manufacturing method is similar to that of Example 2), and a sodium fluoride solution having the same total fluorine concentration of 100 ppm, and deionized water separately as a control at room temperature.
The exposed enamel surface was chemically treated by soaking for a minute. Then, it was immersed in 0.1 M lactate buffer (pH 5.0) at room temperature for 12 hours to decalcify the exposed part of the enamel. This chemical treatment and decalcification operation were repeated 6 times in succession, after which the oily paint was removed and the white spots (initial state of caries) formed on the decalcified portion were observed. That is, when decalcification occurs, teeth are clouded, and thus the caries inhibitory effect was judged by the degree of white spot formation on the exposed part. As a result, almost no white spots were observed in the acid-exposed portion after the treatment with the fluoride colloid solution, whereas considerable white spots were formed in the acid-exposed portion after the deionized water treatment. Some white spots were also formed on the acid-exposed area after the treatment, indicating that the treatment with the fluoride colloid solution of the present invention was extremely effective.

The 0.1M lactate buffer was prepared as follows. That is, 1%
Carbopol 907 (polyacrylic acid) pH 4.0 with 10N NaOH
To this solution, add 2 g of lactic acid to 40 ml, and add 200 ml with distilled water.
And adjusted to pH 5.0 with 10 N NaOH. This was used as an apatite unsaturated liquid. Of this, 110 ml was added with 0.22 g of hydroxyapatite, adjusted to pH 5.0 with 1N hydrochloric acid, then spun down, and the supernatant was filtered with a 1.0 μm Millipore filter to obtain a saturated apatite solution. The apatite saturated solution and the apatite unsaturated solution were mixed in equal amounts to prepare a 0.1M lactate buffer solution.

As mentioned above, an example of the fluoride colloidal liquid of the present invention has been shown.
Similar effects are observed with other fluorides and colloid solutions obtained by using other peptizers according to the present invention. About the main ones, the solubility and storage stability of the colloidal liquid and the effect of incorporating fluorine are summarized in the following table as Example 3.

The test solution was prepared by the method of ii) above. That is, the cation (chloride) containing the peptizer is adjusted so that the molar ratio of peptizer, cation (chloride) and sodium fluoride is 1: 1: 2 and the concentration of fluorine in the solution is 2000 ppm. The aqueous solution and the sodium fluoride aqueous solution were mixed and stirred.

Confirmation of the colloid, fluorine in the colloidal particles with respect to total fluorine in the colloidal solution (fluorine content of the colloidal particles), and fluorine incorporation into the apatite were evaluated for the solution one day after the preparation of the test solution.

Example 3 Solubility and storage stability of main fluoride colloidal solutions, fluorine uptake (Note) For the confirmation of colloid, the results evaluated by the method of (1) above are shown. The fluorine content in the colloidal particles was calculated by subtracting the amount of fluorine ions in the colloidal solution (measured with a fluorine ion electrode) from the total fluorine in the solution.

The amount of fluorine incorporated into the apatite was in accordance with the test method of Example 2.

The combinations listed below the dotted line differ from the colloids described here.

In the case of using zinc or tin, no colloid is generated.

In the case of using manganese, colloid was produced, but the fluorine uptake effect was not different from the control.

Colloids that can be said to be superior to the present fluorine agents were limited to cases where the content of fluorine in colloid particles was 10% or more.

In Example 3, the colloid using strontium has a fluorine content of 18% in the colloid particles, but the fluorine uptake amount is 6 times that of the control, and it can be said that it is superior to the current fluorine agent.

Polyphosphoric acid acts as a deflocculant, but does not seem to have tooth adsorption.

These fluorine uptake amounts are extremely small as compared with the colloidal solution of the present invention.

The colloidal solution of the present invention can be used alone or together with other substances so as to have a fluorine content of 10 to 100,000 ppm, or a composition mixed with another carrier after generation can be used as an oral composition. The object can be used for caries prevention.

The application examples using the colloidal solution of the present invention are shown below.

Application Example 1 (Mouthwash) Glycerin 20.0% by weight Sorbitol 24.0 〃 Propylene glycol 3.0 〃 Polyoxyethylene polyoxypropylene glycol 1.0 〃 Methyl parahydroxybenzoate 0.1 〃 Sodium saccharin 1.0% by weight Flavor 0.9 〃 Colloidal solution (Note 1) 50.0 〃 100.0 〃 Note 1) Make a 3 mM solution of either calcium chloride or strontium chloride, add 6 mM of an equal amount of sodium fluoride to it, and at the same time disodium glycerophosphate or ribose-5 disodium phosphate 1M slurry. Is dripped. When it becomes transparent, leave it for 1 hour and use it for blending.

Application example 2 (Tablet for mouthwash) (Note 1) Fluoride dry gel (Note 2) 25.0% by weight Sodium salt 68.0 〃 Hydroxyethyl cellulose 1.0 〃 Sodium saccharin 5.0 〃 Flavoring agent 1.0 〃 100.0 〃 Note 1) 100g of tablets Dissolve in water or hot water, then use for mouthwash.

Note 2) Aluminum fluoride 12 to sodium fluoride 4.2g
g, 18 g of glucose-1-disodium phosphate tetrahydrate are added, 100 ml of water is added thereto, and the mixture is stirred. When it becomes transparent, it is centrifuged and settled for 200,000 G for 10 hours, and the obtained precipitate is dried and ground.

Application Example 3 (dentifrice) abrasives (Note 1) 40.0 wt% Glycerin 20.0 〃 sorbitol 24.0 〃 propylene glycol 3.0 〃 hydroxyethylcellulose 1.0 〃 sodium lauryl sulfate 1.0 〃 Methyl parahydroxybenzoate 0.1 〃 saccharin sodium 1.0 〃 flavoring 0.9 〃 fluoride Compound dry gel (Note 2) 1.0 〃 100.0 〃 Note 1) Either calcium hydrogen phosphate dihydrate or calcium pyrophosphate is used.

Note 2) Same as the dry gel shown in Note 2) of Application Example 2.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows that the amount of fluorine in colloidal particles is
¹⁹ F-NMR spectra of the fluoride colloid solution of the present invention is 100% Figure, ¹⁹ F-NMR of fluoride colloid solution of 2 the present invention containing a fluorine and fluoride ions in the colloidal particles in a colloidal solution FIG. 3 is a spectrum diagram and FIG. 3 is a diagram showing measurement results of dynamic light scattering of the fluoride colloidal liquid of the present invention.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takao Shinozaki 4594 Hanai-shi, Kaigamachi, Haga-gun, Tochigi Prefecture (72) Inventor Yoichi Arai 4594 Hanai-cho, Kaiga-machi, Tochigi Prefecture Masayuki Hashimoto Utsunomiya, Tochigi Prefecture Mikkogahara Town 91-12 (56) References Japanese Patent Laid-Open No. 62-19506 (JP, A)

Claims (5)

[Claims] 1. A sparingly soluble fluoride that gives a fluorine ion concentration of 1 to 10,000 ppm in a saturated aqueous solution is colloidized with a deflocculant selected from the group consisting of polyol phosphoric acid, polyol sulfuric acid, polyol carboxylic acid and salts thereof. A colloidal fluoride solution for caries prevention, which is dispersed in the form of colloidal fine particles having a particle size of 0.005 to 1 μm. 2. The fluoride colloidal solution according to claim 1, wherein the amount of fluorine in the colloidal particles is in the range of 1 to 100000 ppm as a whole, and accounts for 10 to 100% of the amount of fluorine in the total colloidal solution. . 3. When a soluble fluoride and a soluble cation salt are mixed in the presence of water to cause precipitation, a precipitate selected from the group consisting of polyol phosphoric acid, polyol sulfuric acid, polyol carboxylic acid and salts thereof. 2. A deflocculating agent is added to produce a colloidal solution of fluoride in which colloidal fine particles having a particle size of 0.005 to 1 μm are dispersed.
A method for producing the described fluoride colloidal solution. 4. An aqueous solution of a soluble fluoride and an aqueous solution of a soluble cation salt, and at least one of the aqueous solutions is peptized selected from the group consisting of polyol phosphoric acid, polyol sulfuric acid, polyol carboxylic acid and salts thereof. The method for producing a fluoride colloidal solution according to claim 1, wherein the agent is contained and mixed to produce a fluoride colloidal solution in which colloidal fine particles having a particle size of 0.005 to 1 µ are dispersed. 5. Dry colloidal particles obtained by removing water from the fluoride colloidal liquid according to claim 1.