JPS6257601B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a dental cement, and more specifically to a novel cement that can effectively suppress secondary caries. Traditionally, when caries occurs, treatment has been generally performed by removing the affected area, forming a cavity, and filling it with cement.The dental cements used for this are zinc phosphate cement and zinc oxide eugenol. Known examples include cement, polycarboxylate cement that combines organic polymers and metal oxides, and glass ionomer cement. However, although these dental cements have been used for many years, they still have various problems that need to be improved, and in particular, the induction of secondary caries has become a serious problem. For example, zinc phosphate cement, which is the most widely used material, does not have adhesive properties to the cavity walls of the tooth, so there are many cases where bacteria can invade the gaps around the edges and lead to caries again. Furthermore, even with cement that has a certain degree of adhesiveness, it is difficult to avoid the formation of minute gaps between the tooth substance and the hardened cement body, which often leads to secondary caries. As a result of extensive research into dental cement that can suppress the occurrence of secondary caries, the present inventors discovered that phytic acid and phytic acid derivatives (phytic acid and its derivatives have caries-inhibiting effects) It has long been widely known that phytic acid has an anti-erosion effect, and toothpastes containing phytic acid in combination with alkali metal monofluorophosphate and sodium fluoride have been proposed (British Patent No. 1384375).
No. 1408922>) reacts with metal salts in the presence of water to form a hardened product suitable for dental cement and strong (for example, compressive strength of 200 to 350 kg/cm ² ), and from this hardened product, phytic acid The present inventors have discovered that a small amount of phytic acid is eluted and that secondary caries can be effectively suppressed by the action of this eluted phytic acid, leading to the completion of the present invention. That is, the present invention is composed of an agent A containing phytic acid or a derivative thereof as a main component and an agent B containing a metal salt as a main component, and when used, by mixing these agents A and B in the presence of water. The present invention provides a dental cement, which is characterized by forming a hardened cement body having a secondary caries inhibiting effect. The present invention will be explained in detail below. The phytic acid used in the dental cement according to the present invention is expressed by the following formula (1): Phytic acid derivatives include phytic acid such as sodium phytate and potassium phytate in which some or all of the hydrogen atoms of the phosphoric acid groups at positions 1 to 6 of phytic acid are replaced with alkali metal groups. Alkali metal salts or alkaline earth metal salts of phytate such as calcium phytate,
Furthermore, phytic acid in which some or all of the hydrogen atoms of the phosphoric acid groups at positions 1 to 6 are substituted with an alkyl group, an allyl group, etc. can be used. In this case, phytic acid shows the strongest reactivity among phytic acid or its derivatives, and by adding alkali hydroxide to phytic acid, the hydrogen atoms of the phosphoric acid groups at positions 1 to 6 of phytic acid are converted into alkali metal groups or When substituted with an alkaline earth metal group, the higher the degree of substitution, the slower the curing speed when mixed with agent B, which will be described later. In addition, phytic acid in which the hydrogen atoms of the phosphoric acid group at positions 1 and 4 are replaced with alkyl groups, allyl groups, etc. are inferior in reactivity to phytic acid, but still have considerable reactivity;・If the hydrogen atoms of the phosphoric acid group at the 5th and 6th positions are substituted with an alkyl group, an allyl group, etc., the reactivity is even more drastically reduced. Therefore, depending on the required curing time etc., an appropriate one may be selected from the above-mentioned phytic acid or its derivatives, or an appropriate combination thereof may be used, but from the viewpoint of reactivity, phytic acid or its derivatives may be used. Examples include phytic acid, partial alkali metal salts of phytic acid, especially sodium salts, and the following general formula (2) (However, R ₁ , R ₂ , R ₃ , and R ₄ are at least one alkyl group or allyl group having 1 to 12 carbon atoms, or some of the hydrogen atoms of these alkyl groups or allyl groups are substituted with a halogen atom or an amino group. A compound represented by the following formula, in which the phosphoric acid groups at the 1st and 4th positions of phytic acid are partially substituted, is preferably used. The A agent is composed mainly of the above-mentioned phytic acid or its derivative, but if necessary, a curing regulator such as aluminum phosphate may be added in an amount of 0.1 to 1% by weight based on the A agent. Further, Agent A is usually prepared in the form of an aqueous solution or a water-containing paste. As the metal salt constituting Agent B, salts of valent metals or metals of higher valence than alkali metals are used, and in particular, oxides of magnesium, calcium, barium, zinc, aluminum, titanium,
Hydroxides, silicates, sulfates, phosphates, carbonates, fluorides, etc. are preferably used. Specifically, magnesium oxide, zinc oxide, titanium oxide, barium oxide, aluminum oxide, aluminum hydroxide, aluminum silicate, aluminum sulfate, tribasic calcium phosphate, calcium carbonate, calcium fluoride, calcium hydroxide, stannous oxide, Magnesium carbonate and the like may be used alone or in an appropriate combination of two or more. In this case, especially zinc oxide, magnesium oxide, barium oxide, calcium hydroxide,
The curing reaction proceeds quickly when using calcium carbonate, magnesium carbonate, etc., while the curing reaction of titanium oxide, calcium fluoride, stannous oxide, tribasic calcium phosphate, and aluminum salts such as aluminum oxide is slower, so It is preferable to select and use appropriate metal salts depending on the curing time and the like, and to use them in combination as necessary. Furthermore, since aluminum phosphate and aluminum fluoride delay the reaction, they can be added as necessary to adjust the curing time. If commercially available metal salt powders are used as they are, the curing reaction may be too fast and curing may be completed within one minute. 6 at ~1300℃
It is also possible to use a product which is calcined for up to 10 hours and pulverized using various types of pulverizers such as a jet pulverizer. In this case, the finer the particle size, the higher the curing speed. The above-mentioned agent B, which is mainly composed of metal salts, may be further mixed with polymer powder for the purpose of increasing strength, pigment powder, etc. to match the color tone of the teeth, if necessary. Prepared in powder form. The A agent and the B agent are mixed and kneaded in the presence of water (usually provided by the water in the A agent, but a small amount of water may be added depending on the case) at the time of use. As a result, phytic acid or its derivative in agent A reacts with the metal salt in agent B,
It hardens, and the curing reaction proceeds even without a catalyst. In this case, the mixing ratio of agent A and agent B (mixing ratio of phytic acid or its derivative and metal salt) is not necessarily limited, but preferably 0.7 parts by weight of the metal salt is mixed with 1 part by weight of the aqueous solution of phytic acid or its derivative. ~2 parts by weight.
In this case, the curing rate increases as the proportion of metal salt increases. It is preferable to use phytic acid or its derivatives as an aqueous solution of 40 to 80% by weight, especially 50 to 70% by weight; if the content is more than 80% by weight, the curing speed will be slow, and if the content is less than 40% by weight, the curing rate will be slow. Since the strength of the resulting cured product may be weakened, it is desirable to use an aqueous solution within the above-mentioned range. Furthermore, since the higher the reaction temperature, the faster the curing occurs, it may be preferable to cool the material when used for teeth. The curing time can be determined by selecting the phytic acid or its derivative used, the type of metal salt, its mixing ratio, water content, reaction temperature, whether or not the metal salt is fired, the particle size of the metal salt powder, etc. The time can be arbitrarily adjusted, and the curing time can be 3 to 8 minutes (JIS standard), which is suitable for dental filling operations. The obtained cured product is strong and has a compressive strength of, for example, 200 to 350 kg/cm ² . In particular, this cured product is very effective in suppressing secondary caries due to the caries-inhibiting action of phytic acid, since a trace amount of phytic acid is eluted in the oral cavity. For this reason,
The dental cement of the present invention is suitably used as a bonding material, a filling material, and the like. In addition, phytic acid or its derivatives can also be added to a commercially available dental cement, especially a zinc phosphate cement solution. As explained above, the dental cement according to the present invention is composed of agent A whose main component is phytic acid or a derivative thereof and agent B whose main component is a metal salt. By mixing in the presence of water, a strong hardened product is formed, and this hardened product also releases trace amounts of phytic acid, which has a caries-inhibiting effect, after treatment, making it effective in preventing secondary caries. It also has very excellent properties as a dental cement, such as being able to adjust the curing time arbitrarily and curing in a suitable curing time of 1 to 10 minutes. It can be widely used for bonding crowns, etc., filling cavities, lining, repairing anterior teeth, etc., and can effectively suppress the occurrence of secondary caries. Hereinafter, the present invention will be specifically explained with reference to Examples. In addition, in the following examples, all percentages are by weight.
shows. Example 1 Various commercially available metal salts shown in Table 1 were mixed with 0.5 g of a 50% phytic acid aqueous solution at room temperature, and the curing reactivity was examined. The results are also listed in Table 1.

【table】

[Table] Example 2 50%, 60%, 75%, 80% phytic acid aqueous solution A
( _A50 agent, _A60 agent, _A75 agent, _A80 agent, respectively), zinc oxide 80 parts by weight magnesium oxide 18 calcium fluoride 2 The above mixture was calcined at 1000℃ for 6 hours, and then pulverized. Those that have passed through a 200 mesh sieve and
Those that passed through a 300 mesh sieve were designated as B agents (B ₂₀₀ agents and B ₃₀₀ agents, respectively), and these A agents and B agents were mixed and cured at room temperature (20 to 25° C.). Measurement results of curing speed with Vicat needle and JIS standards
Table 2 shows the measurement results of compressive strength using T6602. For comparison, similar experiments were conducted using commercially available zinc oxide eugenol cement and zinc phosphate cement (both manufactured by Jishi Dental Industry Co., Ltd.).

【table】

[Table] Example 3 A mixture of 50% phytic acid aqueous solution and 40% phytic acid pentasodium aqueous solution at a predetermined ratio was used as agent A. On the other hand, silica 30 parts by weight Alumina 18 Calcium fluoride 34 Aluminum fluoride 6 Aluminum phosphate 12 After melting the above mixture at high temperature, it was rapidly cooled, crushed, and passed through a 300-mesh sieve. did. Next, the A and B agents were mixed and the curing time was measured. The results are shown in Figure 1. Example 4 Using phytic acid aqueous solutions of various concentrations as the A agent and the same as in Example 3 as the B agent, the curing time when the A agent and the B agent were mixed was measured, and the second
The results shown in the figure were obtained. Example 5 In the general formula (2), R ₁ is -CH ₂ CH=CH ₂
A 50% aqueous solution (manufactured by Mitsui Toatsu Co., Ltd.) of a phytic acid derivative in which R ₂ , R ₃ , and R ₄ are hydrogen atoms
Zinc oxide 65 parts by weight Magnesium oxide 30 Aluminum silicate 5 The above mixture was calcined at 1200°C for 6 hours, finely ground, passed through a 200 mesh sieve, and used as Agent B. When the agent and agent B were mixed at room temperature in a ratio of 1:1 (weight ratio), the mixture cured in 75 minutes and had a compressive strength of 312 kg/cm ² . Example 6 A 60% aqueous phytic acid solution was used as agent A, and agent B
80 parts by weight of nitrite oxide and 20 parts by weight of magnesium oxide as agents
After baking the mixture with parts by weight at 1000℃ for 6 hours,
Use the powder that has been pulverized and passed through a 300 mesh sieve, and mix the A and B agents at 1:1 (weight ratio).
were mixed at room temperature. Pour this into a Teflon mold and harden it to a diameter of 20 mm and a thickness of 5 mm.
A disk-shaped specimen of mm size was prepared. Next, take this disc-shaped specimen in a small bottle and add purified water.
10 ml was added, the bottle was sealed tightly, and the bottle was left for a specified period of time. After a predetermined period of time had elapsed, 1 ml of the liquid in the vial was collected and placed in a 50 ml Kjeldahl digestion flask, 3 ml of concentrated sulfuric acid was added, and the mixture was heated and hydrolyzed for 8 hours. After cooling, dilute with 100 ml of purified water, and use 5 ml of this diluted solution for Fiske-
The amount of total phosphorus was determined colorimetrically using the Subbarow method, and the amount of eluted phytic acid was investigated. The results are shown in Table 3.

[Table] From the results in Table 3, it was observed that a small amount of phytic acid was eluted from the cured product, and it was found that it was effective in suppressing dental caries.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the relationship between the mixing ratio of phytic acid and pentasodium phytate and the curing time when agent A is a mixture of 50% phytic acid aqueous solution and 40% pentasodium phytic acid aqueous solution. FIG. 2 is a graph showing the relationship between phytic acid aqueous solution concentration and curing time.

Claims (1)

[Scope of Claims] 1. Consisting of agent A containing phytic acid or a derivative thereof as a main component and agent B containing metal salt (excluding alkali metal salts) as a main component, in the presence of water, the agent A is A dental cement agent, characterized in that a hardened cement body is formed by mixing agent B and agent B. 2. The dental cement according to claim 1, wherein part A is prepared in the form of an aqueous solution and mixed with part B. 3 As phytic acid or its derivatives, phytic acid, partial alkali metal salts of phytic acid, and the following formula (However, R ₁ , R ₂ , R ₃ , and R ₄ are at least one alkyl group or allyl group having 1 to 12 carbon atoms, or some of the hydrogen atoms of these alkyl groups or allyl groups are substituted with a halogen atom or an amino group. 3. The dental cement according to claim 1 or 2, which uses one or a mixture of two or more phytic acid compounds represented by the following functional groups, the remainder being hydrogen atoms. 4. Claim No. 4 in which the metal salt is an oxide, hydroxide, silicate, sulfate, phosphate, carbonate, or fluoride of a metal selected from magnesium, calcium, barium, zinc, aluminum, and titanium. The dental cement according to item 1, item 2, or item 3. 5 The metal salt is magnesium oxide, zinc oxide, titanium oxide, barium oxide, aluminum oxide, aluminum hydroxide, aluminum silicate, aluminum sulfate, tribasic calcium phosphate, calcium carbonate, calcium fluoride, calcium hydroxide, stannous oxide, The dental cement according to claim 4, which is selected from magnesium carbonate.