JPH0548204B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a plaster material used for creating dental models in dental care. (Prior art and its problems) In general, tooth molds are formed in dentistry by applying pressure from the patient's teeth to the gums with an impression material containing alginate or agar as a main ingredient, and hardening (gelling) it to form a concave impression. Then, a dental technician injects plaster into the concave mold of this impression material, takes out the hardened plaster mold, and adds techniques to create a dental model. Here, since the above-mentioned impression material comes into direct contact with the patient's oral cavity during use, body fluids such as saliva and blood as well as stains such as dental plaque and food residue adhere to the impression material, which inevitably causes bacteria and bacteria carried by the patient to adhere to the impression material. become contaminated with viruses. Naturally, the contamination also transfers to the plaster mold that is molded from this contaminated impression material. Therefore, among dental healthcare workers, especially dental technicians who are involved in making dental molds, it is important to avoid touching your hands and fingers when handling contaminated plaster molds and using sharp tools such as carbide burs during the technique. There are many opportunities to get scratched or inhale fine powder generated by polishing plaster molds, and there is a great risk of various infections, and in recent years there has been a particular concern about hepatitis B and AIDS infections. (Means for Solving the Problems) In view of the above-mentioned circumstances, the present invention provides an innovative plaster material that itself has a sterilizing function for use in creating dental models, and provides dental treatment. The purpose is to eliminate the risk of various infections in technicians. That is, in order to achieve the above object, the plaster material for dental models of the present invention has a composition in which 0.025 to 1.0 parts by weight of benzethonium chloride and/or benzalkonium chloride are blended with 100 parts by weight of gypsum powder. This is what was adopted. (Detailed structure and operation of the invention) Benzethonium chloride mixed into plaster in the present invention has the following structural formula; Benzalkonium chloride is represented by the following structural formula; [R: C ₈ H ₁₇ - C ₁₈ H ₃₇ ], both of which are known as antibacterial agents that have a broad antibacterial spectrum and have the effect of inactivating HBs antigen (hepatitis B surface antigen). It has excellent suitability, especially for plaster for dental models. In other words, in order to prevent the gypsum powder containing it from solidifying before use, antibacterial agents for use in plaster formulations should be solid at room temperature and contain as little free water as possible, and should be used when forming gypsum powder during mold formation. When dissolved in water, it must immediately dissolve in the water and exhibit antibacterial action, and of course it is also required that the compound be stable and have excellent sustainability of action. Both benzethonium chloride and benzalkonium chloride are obtained as powders at room temperature, are easily water-soluble, and have high antibacterial activity even at low concentrations (for example, the minimum effective concentration for inactivating HBs antigen is with benzethonium
0.01% and 0.04% for benzalkonium chloride), and because it is a compound with excellent stability, it satisfies all the necessary properties for use in plaster formulations. In contrast, HBs has a broad antibacterial spectrum and
Other antibacterial agents that exhibit antigen inactivation effects include chlorine-based antibacterial agents such as sodium hypochlorite and high-grade salashi powder, and cocoyl alginate ester (CAE...N ^a
−Cocoyl−L−arginine etylester−DL−
Cationic surfactant-based antibacterial agents such as pyroglntamic acid salt) and Irgasan DP-300 (trade name of Ciba Geigy, Switzerland, 2,4,4'-trichloro-2'-hydroxy-diphenyl ether) are known. , these are all unsuitable for use in plaster formulations. In other words, chlorine-based antibacterial agents have poor stability and difficulty in maintaining antibacterial action, and there are also problems with toxicity and corrosion due to the _Cl2 gas produced by decomposition.
Since CAE and Irgasan DP-300 are poorly soluble in water, they have the disadvantage of being difficult to develop antibacterial effects. The blending amount of benzethonium chloride and/or benzalkonium chloride in the plaster material for dental models of the present invention is 0.025 to 100 parts by weight of plaster powder.
It should be in the range of 1.0 part by weight. In other words, when this amount is less than 0.025 parts by weight, the antibacterial effect against bacteria transferred from the impression material is sufficient, and even when it is more than 1.0 parts by weight, the antibacterial effect is almost saturated. Since it is also expensive, it is uneconomical and may have a negative effect on the properties of gypsum. Note that benzethonium chloride and benzalkonium chloride may be used together. The benzethonium chloride and/or benzalkonium chloride can be blended into the gypsum powder by mixing it with the gypsum powder in powder form, or by adding a small amount of highly concentrated ethyl alcohol (for example, 1 to 3 times the volume of ethyl alcohol). ) may be sprayed or directly added to gypsum powder as a solution dissolved in a volatile solvent, and the gypsum powder may be stirred and mixed after the solvent has volatilized. In addition, in these formulations, in order to uniformly disperse benzethonium chloride and/or benzalkonium chloride, this is first mixed with a small amount of gypsum powder, and then gypsum powder is added to this mixture in several portions. It is preferable to stir and mix the ingredients to finally form a plaster material containing the required amount of benzethonium chloride and/or benzalkonium chloride. Further, if agglomeration occurs when the above-mentioned solution is added, it may be pulverized using a pulverizer. Thus, the plaster material for dental models containing benzethonium chloride and/or benzalkonium chloride is superior to conventional plaster materials for dental models that do not contain antibacterial agents in terms of properties such as hardenability, volume change during curing, and strength of the cured product. is equivalent to To use it, as with conventional products, mix it with water, inject this mix into the concave mold of the hardened impression material after taking the impression, and after hardening, release the mold and perform the required technique. It is possible to obtain a tooth model with no problems in terms of molding accuracy and strength. (Example) Examples of the present invention will be described below, including performance comparison tests. In addition, in the following, parts mean parts by weight. Example 1 After putting 0.1 part of benzethonium chloride powder into a mixer containing 5 parts of gypsum powder and stirring,
Add 15 parts of gypsum powder and mix and stir, then add 30 parts and 50 parts of gypsum powder one by one and mix and stir in the same way to create an antibacterial mixture in which 0.1 part of benzethonium chloride is evenly mixed with 100 parts of gypsum powder. A plaster material containing the agent was obtained. On the other hand, an impression covering the entire lower teeth of a 50-year-old man was taken on a sterilized tray using an impression material that was a combination of agar for impression materials and alginate for impression materials, and this impression material was then placed on a metal plate. It was divided into two approximately along the midline. Then, regular modeling plaster mixed with water is injected into the right half of this impression material, and the above antibacterial agent-containing plaster mixed with water is injected into the left half, and each is placed in a wet tank. After curing at room temperature, they were taken out to obtain a plaster model. Next, set the tooth numbers 7, 6, 5, 4, 3 on the right half plaster model and the tooth numbers 3, 4, 5, 6, 7 on the left half plaster model with a carbide bar for the technician. The powder was collected by scraping and inoculated into standard agar medium plates. and,
Leave each inoculated medium in a thermostat at 36 ± 1°C,
When examining the presence or absence of tooth reproduction, the results shown in Table 1 were obtained. In addition, the symbol (+) in the table means bacterial propagation, and the symbol (-) means no bacterial propagation.

[Table] Example 2 An antibacterial agent-containing gypsum material was obtained in the same manner as in Example 1, except that 0.1 part of benzalkonium chloride was used in place of benzethonium chloride. Then, using this plaster material and ordinary plaster for modeling, an impression material obtained from a 40-year-old man in the same manner as in Example 1 was used.
According to Example 1, a plaster model was prepared and a bacterial propagation test by seeding was conducted, and the results shown in Table 2 below were obtained.

[Table] Example 3 Using the same method as in Examples 1 and 2, 100% gypsum powder was prepared.
0.0125 parts and 0.025 parts of benzethonium chloride powder and benzalkonium chloride powder, respectively.
Gypsum materials containing antibacterial agents were prepared containing 0.05 parts, 0.05 parts, and 0.1 parts. For each gypsum material and gypsum powder containing no antibacterial agent, for each 100g of gypsum powder, bacteria water with a number of bacteria of approximately 5 x 10 ³ /ml collected from the garbage receptacle of the kitchen sink (standard agar medium 36℃, 48 hours Using 24 ml of kneading water to which 1 ml of viable bacteria was added (after measuring the number of viable bacteria) and 24 ml of kneading water to which 10 ml of contaminant water was added, each was kneaded for 1 minute, and immediately after kneading () and 10 minutes after kneading. At time point (), take two samples of 2 to 3 g of kneaded gypsum into a shear dish, and immediately pour 20 ml of standard agar medium at about 50°C into each shear dish, and after the medium has solidified,
The samples were left in a thermostat at 36±1°C, and the presence or absence of bacterial growth in the vicinity of the plaster and in the culture medium was examined for each number of days, and the results shown in Tables 3-1 to 3-4 were obtained. In addition, the symbol (+) in the table means bacterial propagation, and (-) means no bacterial propagation.

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[Table] From the results in Tables 3-1 to 3-4, it is clear that sufficient antibacterial effects can be obtained with benzethonium chloride and benzalkonium chloride in amounts of 0.025 parts or more per 100 parts of gypsum powder. be. Example 4 0.1 part of benzethonium chloride 99.5% of 3 times the volume
This solution was added to 6 parts of gypsum powder at 40℃ under stirring, and after the ethyl alcohol had evaporated, 14 parts of gypsum powder was added and mixed with stirring, followed by 30 parts and 50 parts. gypsum powder was added in sequence and mixed and stirred to obtain antibacterial agent-containing gypsum material A.
For this gypsum material A and the antibacterial agent-containing gypsum material B obtained in Example 1, the mixed water amount was 24 ml/100 g, respectively.
When the gypsum properties were measured according to JIS-T6605,
The results shown in Table 4 were obtained.

[Table] From the results in Table 4, the gypsum material of the present invention has hardening properties,
It is clear that there is no problem in volume change during curing, strength, etc., and that the plaster has sufficient suitability as a plaster for dental models. (Effects Unique to the Invention) According to the plaster material for dental models of the present invention, since the plaster material itself has an excellent antibacterial effect, it is possible to avoid contamination with bodily fluids and dirt in the patient's oral cavity during the creation of dental models. Transfer contamination of bacteria and viruses from the impression material to the plaster tooth model is prevented, thereby avoiding the risk of various infections in dental techniques. Furthermore, this plaster material has sufficient suitability as a plaster for dental models in terms of plaster properties such as hardenability, volume change after hardening, and strength.

Claims (1)

[Claims] 1 Benzethonium chloride or/and benzalkonium chloride per 100 parts by weight of gypsum powder
A plaster material for dental models containing 0.025 to 1.0 parts by weight.