Dental pretreatment materials

Abstract

To provide dental pretreatment materials that can provide the good adhesion of a dental restoration to a tooth, especially dentin by using a dental adhesive and can be expected to provide high bactericidal effect.SOLUTION: There is provided a dental pretreatment material used in combination with a dental adhesive containing a polymerizable monomer component containing a polymerizable monomer having an acidic group and a polymerization initiator, the dental pretreatment material consisting of a hypochlorous acid aqueous solution with a pH of 6 to 7 in which molecular hypochlorous acid (HClO) that functions as a disinfectant and polyvalent metal ions with a valence of 2 or more such as Sr2+ are dissolved, and being able to prevent the formation of Hybridized smear layer by dissolving and removing organic components while leaving inorganic components in the smear layer.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a dental pretreatment material. Specifically, it relates to a dental pretreatment material for pretreating a tooth to which a dental adhesive is applied when adhering a dental restorative material to a tooth using a dental adhesive containing a polymerizable monomer having an acidic group and a polymerization initiator.

Background Art

[0002] For the restoration of cavities after removing dental caries, when it is a relatively small cavity in the early to middle stage, direct restoration with composite resin is often performed from the viewpoints of aesthetics, simplicity, and speed of operation. On the other hand, for the restoration of relatively large cavities, prostheses made of metal, ceramics, or dental resin are frequently used. Since these dental restorations such as composite resins and prostheses do not have adhesiveness to dentin, a dental adhesive for adhering them to dentin is used in combination. When cavity formation is performed using a dental cutting instrument, a smear layer with cutting chips sticking thereto is formed on the cutting surface. In order to obtain good adhesiveness in adhesion using a dental adhesive, it is common to dissolve the inorganic component with an acid component blended in a pretreatment material or a dental adhesive to remove the smear layer and at the same time demineralize (etch) the dentin surface.

[0003] By the way, the hard tissue of teeth consists of enamel and dentin, and clinically, adhesion to both is required. However, since enamel is composed of almost inorganic substances, its adhesion mechanism is relatively simple, while dentin contains about 20% of organic substances such as collagen fibers, so its adhesion mechanism is somewhat complicated. For example, in order to obtain good adhesiveness, it is necessary to penetrate the adhesive into the fine gaps of the spongy substrate collagen fibers exposed on the dentin surface by demineralization (etching). However, since this spongy collagen fiber easily shrinks, the penetration of the adhesive is hindered, the formation of an optimal bonding interface is inhibited, and the adhesion performance is reduced.

[0004] In recent years, self-etching pretreatment materials and self-etching dental adhesive systems (sometimes called one-step adhesives or one-step bonding materials, as these adhesive systems themselves have etching properties and therefore do not require special pretreatment) have been developed, taking these points into consideration (see Patent Documents 1 and 2). These self-etching pretreatment materials and self-etching dental adhesive systems all contain polymerizable monomers having acidic groups (hereinafter also referred to as "acid monomers") and polymerizable monomers not having acidic groups (hereinafter also referred to as "non-acid monomers"), water, polymerization initiators, and functional fillers. They demineralize and remove the inorganic components of the smear layer, while simultaneously allowing the acid monomers to penetrate between the collagen fibers of the dentin matrix, achieving relatively good adhesion to dentin as well.

[0005] Patent Document 3 describes a pretreatment agent that simultaneously has the function of removing and / or modifying dentin collagen and the function of removing and / or modifying hydroxyapatite, which includes "(A) a compound capable of dissolving or decomposing proteins or collagen, at least one urea compound selected from the group consisting of urea and urea phosphate, and (B) a compound capable of demineralizing tooth structure, at least one selected from the group consisting of an acidic compound (b1) and a chelating compound (b2), where the acidic compound (b1) is phosphoric acid, hydrochloric acid, nitric acid, sulfuric acid, and formic acid." The description includes a dental pretreatment material composition characterized by containing (A) urea, (B) citric acid, (C) water, and (D) ferric chloride, after treating a human molar tooth with exposed dentin by cutting with a dental pretreatment material composition containing (A) urea, (B) citric acid, (C) water, and (D) ferric chloride, followed by rinsing and drying, and then bonding composite resin or acrylic resin using a dental adhesive.

[0006] On the other hand, studies are also being conducted on pretreatment agents consisting solely of protein solubilizers that do not have a decalcifying effect. However, as described in the above-mentioned Patent Document 3, sufficient effects have not been obtained with protein solubilizers alone.

[0007] Incidentally, sodium hypochlorite (NaOCl) aqueous solutions and weakly acidic low-concentration hypochlorous acid (HOCl) aqueous solutions, which are used as cleaning solutions for endodontic treatment, not only have bactericidal properties but also function as oxidizing agents that can decompose proteins. Furthermore, when the cut dentin surface is treated with these solutions, it does not have a demineralizing effect, so only the organic components in the smear layer can be dissolved and removed, and applications that take advantage of this property can be considered. For example, in self-etching adhesive systems with mild etching capabilities, the smear layer is not completely removed and organic components remain, so these solutions may be usable as pretreatment agents. However, Non-Patent Literature 1 states that NaOCl treatment actually reduces adhesive strength, and although the effect of HOCl treatment is less, adhesive strength tends to decrease when the concentration is high and the application time is long. According to Non-Patent Literature 1, this is because in pretreatment methods using these solutions, the oxidizing effect that acts to dissolve proteins also acts to inhibit the polymerization and hardening of the adhesive. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 10-236912 [Patent Document 2] Japanese Patent Publication No. 2001-72523 [Patent Document 3] Patent No. 4678911 [Patent Document 4] Japanese Patent Publication No. 2001-278724 [Non-patent literature]

[0009] [Non-Patent Document 1] Journal of dentistry 38 (2010)261-268 [Overview of the project] [Problems that the invention aims to solve]

[0010] Self-etching pretreatment materials and self-etching dental adhesive systems, such as those disclosed in Patent Documents 1 and 2, can dissolve the inorganic components of the smear layer, but they do not contain components that remove organic matter. As a result, a hybridized smear layer is formed at the dentin bonding interface by the remaining organic components of the smear layer. This hybridized smear layer is a defect at the bonding interface, leading to reduced adhesive penetration and weakening of the adhesive layer, thus reducing adhesive strength.

[0011] The method using the pretreatment material described in Patent Document 3 states that it is necessary to remove or modify not only the organic components of the dentin surface but also the inorganic components. When the cut dentin surface is treated with this pretreatment agent, it is thought that the matrix dentin will also be demineralized, but it is not clear whether the organic components of the dentin matrix exposed by the demineralization action are completely dissolved and removed. Therefore, the reduction in inorganic components on the adherend dentin surface may reduce the supply of calcium ions that crosslink with acid monomers such as phosphate monomers in the adhesive applied after pretreatment to strengthen the adhesive layer, and sufficient adhesion may not be obtained due to damage to the dentin side caused by residual demineralized dentin. In addition, since urea and urea phosphate have low bactericidal properties, a bactericidal effect on the cavity surface after caries removal cannot be expected.

[0012] Therefore, the present invention aims to provide a pretreatment material that can be expected to have a high bactericidal effect and dissolve and remove only the organic components in the smear layer, thereby enabling good adhesion of dental restorations to tooth structure, especially dentin, using a self-etching dental adhesive system. [Means for solving the problem]

[0013] The present invention solves the above problems, and the first embodiment of the present invention is a dental pretreatment material for pretreatment of a tooth to which a dental restorative material is to be bonded to the tooth using a dental adhesive containing a polymerizable monomer component including an acidic group and a polymerization initiator, characterized in that it consists of a hypochlorous acid aqueous solution with a pH of 6 to 7 in which molecular hypochlorous acid and divalent or higher polyvalent metal ions are dissolved.

[0014] In the dental pretreatment material of the above form (hereinafter also referred to as "the pretreatment material of the present invention"), it is preferable that the polymerizable monomer component in the dental adhesive further contains a polymerizable monomer that does not have an acidic group. Furthermore, it is preferable that the molecular hypochlorous acid concentration based on the total mass of the dental pretreatment material is 10 to 300 ppm by mass. Moreover, it is preferable that the divalent or higher polyvalent metal ion is at least one selected from the group consisting of magnesium, calcium, strontium, copper, and zinc, and that the total concentration of the dissolved divalent or higher polyvalent metal ion based on the total mass of the dental pretreatment material is 0.1 to 20% by mass.

[0015] A second embodiment of the present invention is a dental adhesive kit characterized by comprising a dental adhesive containing a polymerizable monomer having an acidic group and a polymerization initiator, and a dental pretreatment material consisting of a hypochlorous acid aqueous solution with a pH of 6 to 7 in which molecular hypochlorous acid and divalent or higher polyvalent metal ions are dissolved (hereinafter, the dental adhesive kit of this second embodiment is also referred to as "the kit of the present invention"). [Effects of the Invention]

[0016] According to the present invention, a sterilizing effect can be expected during pretreatment, and dental restorations can be well bonded to tooth structure, especially dentin, using dental adhesives. For example, higher adhesive strength can be obtained than in systems using a self-etching pretreatment material and dental adhesives in combination, or in systems using a one-step adhesive (self-etching dental adhesive system) alone. [Modes for carrying out the invention]

[0017] The inventors of the present invention focused on the fact that when a dental adhesive (self-etching dental adhesive system) containing an acid monomer having an etching ability for inorganic components, particularly a dental adhesive containing an acid monomer and a non-acid monomer, is used alone on dentin, the inorganic components of the smear layer can be removed, but the organic components remain. They considered that if a pretreatment material containing hypochlorous acid and no acid component is used for pretreatment to at least partially remove the organic components while leaving the inorganic components of the smear layer, the self-etching dental adhesive system can adhere while dissolving the inorganic components of the smear layer, thereby eliminating the adverse effects of the smear layer (preventing the formation of a Hybridized smear layer) without damaging the dentin and achieving the above object, and conducted studies. However, when a neutral aqueous solution of hypochlorous acid was used alone as a pretreatment material, the desired effect could not be obtained.

[0018] Therefore, when various additive effects capable of maintaining the neutrality of the aqueous hypochlorous acid solution were studied, it was found that the adhesiveness is improved when divalent or higher polyvalent metal ions coexist, and the present invention has been completed.

[0019] Metal ions are known to have pharmacological effects such as redox effects and antibacterial effects, and to have a bioactive effect by binding to proteins. Although the reason for the improvement of the adhesive force due to the coexistence of divalent or higher polyvalent metal ions in the present invention is not clear, since there is no difference in the dissolution and removal effect of organic components by the addition, it is considered that the presence of polyvalent metal ions suppresses the polymerization inhibition of the adhesive due to the oxidation action of hypochlorous acid remaining on the tooth surface.

[0020] Incidentally, Japanese Patent Application Laid-Open No. 2001-278724 (Patent Document 4), which is the publication of Patent Document 3, states that hypochlorite salts such as hypochlorous acid, lithium hypochlorite, sodium hypochlorite, and potassium hypochlorite can be used as compounds capable of dissolving or decomposing (A) protein or collagen, but the effects have not been demonstrated. Since an aqueous solution of hypochlorite shows strong alkalinity, it is unclear whether an etching effect can be obtained even if an acidic compound is contained. Even when hypochlorous acid is used, an acidic compound coexists, so the possibility that dentin is damaged cannot be excluded.

[0021] Hereinafter, the present invention will be described in more detail. In this specification, unless otherwise specified, the notation "x to y" using numerical values x and y means "x or more and y or less". In such a notation, when a unit is attached only to the numerical value y, the unit is also applied to the numerical value x. Further, in this specification, the term "(meth)acrylic" means both "acrylic" and "methacrylic". Similarly, the term "(meth)acrylate" means both "acrylate" and "methacrylate", and the term "(meth)acryloyl" means both "acryloyl" and "methacryloyl".

[0022] As can be seen from the fact that the pretreatment material of the present invention has a pH of 6 to 7, it does not substantially contain an acid component. Therefore, since it does not have a decalcification (etching) action and cannot remove the inorganic components of the smear layer, after performing pretreatment using the pretreatment material of the present invention, a dental adhesive having a decalcification (etching) action, specifically, It is necessary to use a dental adhesive containing a polymerizable monomer component containing an acid monomer and a polymerization initiator. This dental adhesive is a self-etching dental adhesive system and also corresponds to the dental adhesive in the kit of the present invention.

[0023] First, regarding the dental adhesive (self-etching dental adhesive system) mentioned above, any dental adhesive containing a polymerizable monomer component including an acid monomer and a polymerization initiator, including the self-etching type adhesive, that is commonly used can be used without any particular limitations.

[0024] To briefly explain the components and composition of the above dental adhesive, the acid monomers include (meth)acrylates having acidic groups such as carboxyl groups, sulfo groups, phosphone groups, phosphate monoester groups, or phosphate diester groups. Specifically, these include 2-(meth)acroyloxyethyl hydrogen maleate, 2-(meth)acroyloxyethyl hydrogen succinate, 2-(meth)acroyloxyethyl hydrogen phthalate, 11-(meth)acroyloxyethyl-(1,1-undecanedicarboxylic acid, 2-(meth)acroyloxyethyl-3'-methacroyloxy-2'-(3,4-dicarboxybenzoyloxy)propyl succinate, 4-(2-(meth)acroyloxyethyl) trimellitate anhydride, N-(meth)acroylglycine, N Carboxylic acidic radical polymerizable monomers such as (meth)acroylaspartic acid; 2-(meth)acryloyloxyethylphenylhydrogen phosphate, bis((meth)acryloyloxyethyl)hydrogen phosphate, (meth)acryloyloxyethyl dihydrogen phosphate, 10-(meth)acryloyloxydecyl dihydrogen phosphate, 6-(meth)acryloyloxyhexyl dihydrogen phosphate, and other phosphoric acid-containing radical polymerizable monomers; phosphonic acid-containing radical polymerizable monomers such as vinylphosphonic acid; and sulfonic acid-containing radical polymerizable monomers such as styrenesulfonic acid, 3-sulfopropane(meth)acrylate, and 2-(meth)acrylamide-2-methylpropanesulfonic acid can be suitably used.

[0025] Furthermore, the amount of acid monomers in the polymerizable monomer component is preferably 5 to 80% by mass, particularly 10 to 60% by mass, and it is preferable that the remaining component includes non-acid monomers.

[0026] Suitable non-acid monomers include ethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, glycidyl (meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, nonaethylene glycol di(meth)acrylate, 2,2'-bis[4-(meth)acryloyloxyethoxyphenyl]propane, 2,2'-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane, trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, and the like.

[0027] As a polymerization initiator, any photopolymerization initiator and / or chemical polymerization initiator commonly used in dental hardening compositions can be used without particular limitation. Furthermore, from the viewpoint of etching effect, it is preferable to include 5 to 100 parts by mass of water per 100 parts by mass of polymerizable monomer component. In addition, if necessary, water-soluble organic solvents, fillers, etc. may be included.

[0028] Next, the composition (aqueous hypochlorous acid solution) that constitutes the pretreatment material of the present invention will be described.

[0029] The form of hypochlorous acid in aqueous solution changes depending on the pH. Specifically, in the weakly acidic range of pH 3 to 6, it exists almost entirely as molecular hypochlorous acid (HClO), while in the basic range of pH 9 or higher, it dissociates into hypochlorite ions (OCl). - The presence of HClO as HClO becomes dominant, and in the strongly acidic region (for example, less than pH 3), the generation of chlorine molecules (Cl2) becomes dominant as the pH decreases. The relative abundance of HClO in an aqueous solution is defined by equation (1), and at pH 7, the proportion of HClO is approximately 76.0%, and at pH 6, it is 96.9%, meaning that more than half exists as HClO. In the pretreatment material of the present invention, the pH is set to 7 or lower in order to enhance the oxidative decomposition of organic matter by having the majority of the hypochlorous acid exist as molecular hypochlorous acid.

[0030] Ratio of HClO = 1 / (1+10) pH-pKa ) Formula (1) pKa = 7.5 (25℃) Furthermore, from the viewpoint of improving adhesive strength, it is preferable to set the pH as close to neutral as possible in order to suppress damage to the underlying tooth structure. Hydroxyapatite, an inorganic component of tooth structure, dissolves in acid, so if the pH of the pretreatment agent is low, the underlying healthy tooth structure will dissolve, weakening the tooth structure and denaturing the collagen in the tooth structure, which hinders the penetration of the adhesive applied later, leading to a decrease in adhesive strength. In addition, calcium ions have the effect of strengthening the adhesive layer by crosslinking with phosphate monomers in the adhesive that is applied after tooth surface pretreatment, but if the inorganic components in the smear layer (which dissolve more easily than tooth structure) are dissolved and removed by the pretreatment agent, the amount of calcium ions will be insufficient, and the strengthening effect by crosslinking described above may be reduced.

[0031] Therefore, in order to achieve both the effect of removing organic matter by increasing the oxidizing power of the pretreatment agent and the effect of improving adhesive strength by suppressing demineralization of the smear layer and tooth structure, its pH is set to 6-7, preferably 6.3-7, and more preferably 6.5-7.

[0032] Furthermore, hypochlorous acid is known to have bactericidal properties due to its high oxidizing power. Therefore, in addition to its effect of oxidizing and removing organic matter from the smear layer, it also has a bactericidal effect on the cavity surface after caries removal. In particular, molecular hypochlorous acid (HClO) produces hypochlorite ions (ClO -It is known to have a higher bactericidal effect compared to other methods. Therefore, the concentration of molecular hypochlorous acid in the pretreatment material of the present invention is preferably 10 to 300 ppm from the viewpoint of the effect of oxidizing and removing organic matter in the smear layer, bactericidal action and safety. If the molecular hypochlorous acid concentration is less than 10 ppm, it is difficult to obtain a sufficient effect of decomposing and removing organic matter, and if it exceeds 300 ppm, the effect on the oral mucosa tends to become significant. From the viewpoint of organic matter decomposition and removal efficiency, the molecular hypochlorous acid concentration is preferably 30 ppm to 250 ppm, and more preferably 50 ppm to 200 ppm.

[0033] The molecular hypochlorous acid concentration can be measured using a spectrophotometer. The maximum absorption wavelength of molecular hypochlorous acid is 236 nm, and the molar extinction coefficient at that wavelength is 10¹±2 M. -1 cm -1 Therefore, the concentration can be calculated by measuring the absorbance at the wavelength of maximum absorption.

[0034] Such hypochlorous acid water can be produced, for example, by electrolysis, which involves electrolyzing an aqueous sodium chloride solution; by neutralization, which involves adding an acid to a basic hypochlorite aqueous solution; or by ion exchange, which involves treating a raw material aqueous solution consisting of a hypochlorite aqueous solution with an ion exchange resin. Furthermore, if the pH of the hypochlorous acid water falls below 6 or exceeds 7 during production, it can be adjusted by adding an appropriate amount of alkaline solution such as NaOH or HCl, or an acidic solution. In the case of polyvalent metal ions, which will be discussed later, if the compound that is the source of the polyvalent metal ions becomes acidic when dissolved in an aqueous solution, it is also possible to produce it by dissolving the polyvalent metal ion compound in a basic hypochlorite aqueous solution and adjusting the pH to 6-7.

[0035] Examples of polyvalent metal ions of divalent or higher valent ions contained in the pretreatment material of the present invention include magnesium, calcium, strontium, barium, titanium, zirconium, manganese, iron, nickel, copper, zinc, aluminum, nickel, and the like. Of these, magnesium, calcium, strontium, copper, and zinc are preferred because they can provide bactericidal effects and promote remineralization of tooth structure.

[0036] Methods for adding polyvalent metal ions include, for example, adding halides such as chlorides, fluorides, and bromides of these metals, hydroxides, nitrates, and sulfates, or adding metal-eluting glasses such as aluminosilicate glass or barium glass. Among these, chlorides and sulfates with high solubility in water are preferred, and strontium chloride, magnesium chloride, magnesium sulfate, and calcium chloride, which have a pH close to neutral when dissolved, are more preferred.

[0037] The concentration of polyvalent metal ions in the pretreatment material of the present invention is usually 0.1% to 20% by mass, but from the viewpoint of adhesion improvement efficiency, 0.5% to 15% by mass is preferred, and 1.0% to 12% by mass is more preferred.

[0038] The concentration of the aforementioned polyvalent metal ions can be measured using an X-ray fluorescence analyzer (XRF) or an inductively coupled plasma mass spectrometer (ICP-MS).

[0039] The pretreatment material of the present invention may contain various additives, etc., as long as they do not impair the aforementioned effects or are formulated in a manner that does not impair them. For example, a thickening agent may be added to thicken the liquid or make it gel-like in order to improve its applicability to tooth structure. As the thickening agent, inorganic particles are preferable, and it is preferable to use inorganic powder with an average primary particle diameter of 5 nm or more and 100 nm or less.

[0040] The pretreatment material of the present invention may be prepared by pre-mixing a hypochlorous acid aqueous solution and polyvalent metal ions to a predetermined concentration and using it as is, or it may be mixed with the hypochlorous acid aqueous solution and polyvalent metal ions at the time of use. When mixing at the time of use, one method is to dissolve the compound that will be the source of polyvalent metal ions in hypochlorous acid aqueous solution of a predetermined concentration, or one method is to prepare two solutions: a concentrated hypochlorous acid aqueous solution and a diluent solution consisting of a polyvalent metal ion aqueous solution whose concentration is determined based on the expected dilution ratio, and then mix the two. Alternatively, sodium hypochlorite may be mixed with acid to adjust the pH to 6-7 to produce a hypochlorous acid aqueous solution, and then the polyvalent metal ions may be mixed to a predetermined concentration. Furthermore, to save the effort of mixing, it is also possible to apply the pretreatment material of the present invention to the tooth surface by soaking the compound that will be the source of metal ions in an applicator such as a sponge, cotton ball, brush, etc., and then applying the hypochlorous acid aqueous solution to the tooth surface with the applicator.

[0041] The method of using the pretreatment material of the present invention involves applying or spraying the dental pretreatment material with a sponge, brush, paintbrush, spatula, or roller, and then rinsing it off with water. After that, bonding is performed using the dental adhesive (self-etching dental adhesive system), for example, a self-etching bonding material for bonding composite resin or a self-etching cement material for bonding prostheses. [Examples]

[0042] The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited in any way by these.

[0043] First, we will explain the metal compounds used as sources of polyvalent metal ions in the examples and comparative examples, the raw materials used in the production of slightly acidic hypochlorous acid water, the method for preparing hypochlorous acid water, and the method for evaluating weakly acidic hypochlorous acid water.

[0044] (1) Raw materials, etc. [Metal compounds that serve as sources of polyvalent metal ions] • Strontium chloride (SrCl2: manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) Zinc chloride (ZnCl) 2: (Manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) [Raw materials used in the production of hypochlorous acid water] • Dentozia (manufactured by Tokuyama Dental Co., Ltd.) Effective chlorine concentration 500 ppm weakly acidic hypochlorous acid water [Self-etching dental adhesive system] Tokuyama Bond Force II (Manufactured by Tokuyama Dental Co., Ltd., hereinafter abbreviated as "BFII".) • Clearfil Universal Bond Quick ER (Manufactured by Kuraray Noritake Dental Co., Ltd., hereinafter abbreviated as "UBQ").

[0045] (2) Method for preparing hypochlorous acid water The aforementioned Dentozia (effective chlorine concentration 500 ppm) was diluted with deionized water to prepare a solution with an effective chlorine concentration of 105 ppm. Since the pH after dilution was 4.6, an aqueous NaOH solution was added until the pH reached 6.8. The effective chlorine concentration of the resulting solution was 105 ppm. Furthermore, the molecular form HClO content was confirmed to be 59 ppm using a spectrophotometer.

[0046] The effective chlorine concentration (mass ppm) refers to the total chlorine equivalent concentration of chlorine molecules, oxidizing chlorine compounds (e.g., molecular hypochlorous acid), and oxidizing chlorine atom-containing ions (e.g., ionic hypochlorous acid) dissolved in an aqueous solution. More specifically, it refers to the concentration obtained by converting the mass-based concentration of each component to a mass-based chlorine concentration and then summing them up.

[0047] (3) Evaluation method (3-1) Molecular HClO concentration measurement The molecular HClO concentration in hypochlorous acid water was measured using a GeneSpecII spectrophotometer (Hitachi High-Technologies Corporation).

[0048] (3-2) Measurement of available chlorine concentration (manufacturing) The effective chlorine concentration of hypochlorous acid water was measured using the AQ-202 effective chlorine concentration measurement kit (Shibata Scientific Co., Ltd.).

[0049] (3-3)pH measurement The pH of the weakly acidic hypochlorous acid water and disinfectant composition was measured using a pH meter F-55 (Horiba, Ltd.).

[0050] (3-4) Adhesion test evaluation The occlusal surface dentin of extracted human molars was used as the bonding surface. After treatment with the pretreatment agent of the present invention, it was rinsed with water and air-dried. Subsequently, the dental adhesive system was applied, polymerized and cured, and composite resin was filled in. After 24 hours of storage in water, the dentin bonding strength was measured using the microtensile bonding test method. The test was performed 11 to 18 times, and the average value was used as the bonding strength, while the standard deviation was examined.

[0051] Examples 1 and 2 10 ml of hypochlorous acid water with a pH of 6.8 and an effective chlorine concentration of 105 ppm, prepared in (2) above, and 20.08 g of SrCl were placed in a 20 ml screw-cap bottle and mixed by shaking for 10 seconds to prepare the pretreatment material Sr-1. Using the prepared pretreatment material Sr-1, pretreatment was performed under the conditions shown in Table 2, and adhesion tests were evaluated using the dental adhesive system (BFII) shown in Table 2. The composition of the pretreatment material is shown in Table 1, and the adhesion test evaluation results are shown in Table 2.

[0052] Examples 3-29, Comparative Examples 1-10 Pretreatment materials Sr-1 to Sr-4, Zn-1, and Zn-2 were prepared in the same procedure as in Example 1, except that 10 ml of hypochlorous acid water with a pH of 6.8 and an effective chlorine concentration of 105 ppm, prepared in (2) above, was used as pretreatment material N-1, and the amount and type of metal compound (SrCl2) added to the above 10 ml of hypochlorous acid water with a pH of 6.8 and an effective chlorine concentration of 105 ppm were changed to obtain the concentrations and polyvalent metal ions shown in Table 1. Then, using these pretreatment materials, pretreatment was performed for Examples 3 to 29 under the conditions shown in Tables 2 and 3, and adhesive tests were performed using the dental adhesive systems shown in Tables 2 and 3. For Comparative Examples 1 to 10, pretreatment was performed under the conditions shown in Table 4, and adhesive tests were performed using the dental adhesive systems shown in Table 4. The adhesive test results are shown in Tables 2 to 4.

[0053] [Table 1]

[0054] [Table 2]

[0055] [Table 3]

[0056] [Table 4]

[0057] Compared to the adhesive system of Comparative Example 1 (adhesion with BFII alone), the improvement in adhesive strength with hypochlorous acid water alone (Comparative Examples 3-6) was slight, but the adhesive strength was significantly improved with hypochlorous acid water to which SrCl2 or ZnCl2 was added (Examples 1-11 and 21-25). A similar trend was observed when using the adhesive system of Comparative Example 2 (UBQ), where hypochlorous acid water to which SrCl2 or ZnCl2 was added resulted in a significantly improved adhesive strength compared to treatment with hypochlorous acid water alone.

Claims

1. A dental pretreatment material for pretreatment of a tooth to which a dental restorative material is to be applied when bonding a dental restorative material to a tooth using a dental adhesive containing a polymerizable monomer component having an acidic group and a polymerization initiator, A dental pretreatment material characterized by comprising a hypochlorous acid aqueous solution with a pH of 6 to 7, in which molecular hypochlorous acid and polyvalent metal ions of divalent or higher are dissolved.

2. The dental pretreatment material according to claim 1, wherein the polymerizable monomer component in the dental adhesive further comprises a polymerizable monomer that does not have an acidic group.

3. The dental pretreatment material according to claim 1 or 2, wherein the molecular hypochlorous acid concentration based on the total mass of the dental pretreatment material is 10 to 300 ppm by mass.

4. The dental pretreatment material according to any one of claims 1 to 3, wherein the divalent or higher polyvalent metal ion is an ion of at least one metal selected from the group consisting of magnesium, calcium, strontium, copper, and zinc, and the total concentration of the dissolved divalent or higher polyvalent metal ions, based on the total mass of the dental pretreatment material, is 0.1 to 20% by mass.

5. A dental adhesive kit characterized by comprising: a dental adhesive containing a polymerizable monomer having an acidic group and a polymerization initiator; and a dental pretreatment material consisting of a hypochlorous acid aqueous solution with a pH of 6 to 7 in which molecular hypochlorous acid and divalent or higher polyvalent metal ions are dissolved.

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