Compositions for dental treatment

Abstract

The present invention provides a composition for dental treatment. [Solution] The composition of the first embodiment of the present invention contains apatite particles, calcium phosphate particles, titanium oxide particles, and silicon dioxide particles, and is used in the production of an inorganic welded hardened layer by laser-induced inorganic fusion bonding. A composition of the second embodiment of the present invention contains fluoroapatite particles and silicon dioxide particles and is used for surface hardening in the production of an inorganic weld-hardened layer.

Description

【Technical Field】 【0001】 The present invention relates to a dental treatment composition. More specifically, it relates to a dental treatment composition used for producing an inorganic welded and hardened layer by laser-induced inorganic fusion bonding. 【Background Art】 【0002】 Conventionally, in the field of dental treatment, dental treatment preparations such as composite resin, MTA cement mainly composed of calcium silicate, or glass ionomer cement are used for filling and coating on dental affected parts such as cavities from which caries have been removed. However, the above preparations have poor biocompatibility with the dental pulp and the like, are likely to cause irritation pain and inflammation, and also have low affinity between the adhesive and the tooth substance, so that sufficient adhesiveness cannot be obtained, resulting in poor long-term stability. In addition, the above dental treatment preparations are expensive and require a long time for curing. [[ID=…]] 【0003】 In recent years, attention has been paid to hydroxyapatite, which has high biocompatibility and extremely high affinity with tooth substance, and it has been studied to use a hydroxyapatite film cured by irradiating hydroxyapatite particles with laser light for dental treatment (see Patent Document 1). 【Prior Art Documents】 【Patent Documents】 【0004】 【Patent Document 1】 Tokkai 2008-069048 Kokai 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0005】 However, although the hydroxyapatite film disclosed in Patent Document 1 has the advantage of being obtained at a low cost in a short time, it has problems in that its strength is not sufficient and its surface hardness is also insufficient. 【0006】 In view of the above problems, the present invention aims to provide a dental treatment composition that can be used to produce an inorganic weld-hardened layer that exhibits excellent adhesion to tooth structure without the use of adhesives and has sufficient strength and surface hardness. [Means for solving the problem] 【0007】 As a result of diligent research, the inventors have found that by adding titanium oxide particles and silicon dioxide particles to a composition containing apatite particles, the composition becomes more easily dissolved by irradiation with Nd:YAG laser light, and dissolution also becomes more likely to occur on the tooth surface. As a result, welding to the tooth structure becomes easier, achieving excellent adhesion while maintaining sufficient strength and surface hardness. The present invention was completed based on these findings. 【0008】 In other words, the present invention provides a dental treatment composition containing apatite particles, calcium phosphate particles, titanium dioxide particles, and silicon dioxide particles, which is used in the production of an inorganic welded hardened layer. 【0009】 The apatite particles are hydroxyapatite particles, and the titanium oxide particle content is preferably 2 to 20% by weight. 【0010】 The content of the above silicon dioxide component is preferably 10 to 90% by weight. 【0011】 The apatite particles mentioned above are preferably fluoroapatite particles. 【0012】 The present invention also provides a dental treatment composition containing fluoroapatite particles and silicon dioxide particles, which is used in the production of an inorganic weld-hardened layer and for forming a surface layer in the inorganic weld-hardened layer. 【0013】 The fluoroapatite particles described above are preferably fluoroapatite-coated titanium oxide particles. 【0014】 The present invention also provides a method for producing an inorganic weld-hardened layer, comprising the step of irradiating a layer made of a composition containing apatite particles, calcium phosphate particles, titanium oxide particles, and silicon dioxide particles with laser light. 【0015】 The present invention also includes the step of irradiating a layer made of a first composition containing hydroxyapatite particles, calcium phosphate particles, titanium dioxide particles, and silicon dioxide particles with laser light to form a base layer, The present invention provides a method for manufacturing an inorganic weld-hardened layer, comprising the step of irradiating a layer made of a second composition containing fluoroapatite particles and silicon dioxide particles with laser light to form a surface layer on the surface of the base layer. [Effects of the Invention] 【0016】 By using the dental treatment composition of the present invention, an inorganic weld-hardened layer exhibiting excellent adhesion to tooth structure, sufficient strength, and surface hardness can be obtained inexpensively and quickly without the use of adhesives. [Brief explanation of the drawing] 【0017】 [Figure 1] The image shows a scanning electron microscope (SEM) view of the cross-section of the welded portion with a natural tooth in the inorganic welded hardened layer sample of Example 1. 【0018】 [Figure 2] The elements contained in the welded portion with the natural tooth in the inorganic welded hardened layer sample of Example 2 are shown. [Modes for carrying out the invention] 【0019】 Preferred embodiments of the present invention will be described below in detail, but the present invention is not limited to the following description and can be modified and applied as appropriate without altering the essence of the invention. 【0020】 The dental treatment composition of the first form of the present invention contains apatite particles, calcium phosphate particles, titanium oxide particles and silicon dioxide particles, and is a composition used for manufacturing an inorganic weld-hardened layer, and is a composition for laser curing. 【0021】 Further, the dental treatment composition of the second form of the present invention contains fluoroapatite particles and silicon dioxide particles, and is used for manufacturing an inorganic weld-hardened layer and for forming a surface layer in the inorganic weld-hardened layer, and is a composition for laser curing. 【0022】 The dental treatment composition of the first form and the dental treatment composition of the second form may be collectively referred to as the "dental treatment composition of the present invention". In the inorganic weld-hardened layer manufactured using the dental treatment composition of the present invention, due to the local heating point of high heat caused by the action of titanium oxide on water (for example, water supplied together with the composition or water that may be contained in the composition) that efficiently absorbs laser light, after part or all of each particle contained in the composition melts, an amorphous glass phase containing Ca, Si and P or F is reconfigured so as to surround the apatite recrystallized phase, resulting in a strong structure showing sufficient strength or surface hardness. At the same time, it can be presumed that the adhesiveness to dentin is excellent due to the laser-induced inorganic fusion bond that forms a welded part that mutually diffuses and fuses with the melted apatite on the dentin surface. 【0023】 [Dental treatment composition of the first form] The method for manufacturing an inorganic weld-hardened layer using the dental treatment composition of the first form (the first composition) described above includes a step of irradiating a layer composed of the composition containing apatite particles, calcium phosphate particles, titanium oxide particles and silicon dioxide particles with laser light. The layer composed of the first composition is preferably provided on the surface of the dentin. By such a method, an inorganic weld-hardened layer having excellent adhesiveness to dentin and showing sufficient strength and surface hardness can be obtained at low cost in a short time without using an adhesive. 【0024】 The first composition described above is a composition containing apatite particles, calcium phosphate particles, titanium oxide particles, and silicon dioxide particles, which are dispersed in a dispersion medium. The first composition may also contain other components besides apatite particles, calcium phosphate particles, titanium oxide particles, silicon dioxide particles, and the dispersion medium, to the extent that it does not impair the effects of the present invention. Known methods such as stirring, shaking, vibration, and ultrasonic waves can be used for dispersion. 【0025】 The apatite particles described above are preferably hydroxyapatite particles or fluoroapatite particles. Using hydroxyapatite particles makes it easier to obtain adhesion to tooth structure in the resulting inorganic welded hardened layer, while using fluoroapatite particles makes it easier to obtain high surface hardness in the resulting inorganic welded hardened layer. Hydroxyapatite particles and fluoroapatite particles may be used in combination as needed. The apatite particles described above may be used by one type only, or by two or more types. 【0026】 The average particle size of the above apatite particles, as measured using a laser diffraction particle size distribution analyzer, is not particularly limited, but is preferably 0.1 to 50 μm, more preferably 1 to 25 μm, and even more preferably 1.5 to 15 μm. When the average particle size is 0.1 μm or more, the composition tends to be more stable, and when it is 50 μm or less, the composition tends to exhibit sufficient viscosity. 【0027】 The hydroxyapatite particles described above are particles that contain hydroxyapatite as the main component, and preferably are particles that are essentially composed of hydroxyapatite. 【0028】 The hydroxyapatite particles mentioned above may be commercially available as is, or their particle size may be appropriately adjusted by known grinding methods. For example, they may be prepared by a manufacturing method that involves mixing and reacting an aqueous solution of alkali phosphate with a calcium hydroxide slurry. 【0029】 The Ca / P molar ratio of the above-mentioned hydroxyapatite particles is not particularly limited as long as it is a value that hydroxyapatite can take, but it is preferably, for example, 1.30 or more and less than 1.67. 【0030】 When the apatite particles are hydroxyapatite particles, the content of the hydroxyapatite component is preferably 10 to 60% by weight, more preferably 20 to 50% by weight, and even more preferably 30 to 45% by weight, based on 100% by weight of the solid content of the first composition. When the content of the hydroxyapatite component is 10% by weight or more, the strength of the inorganic welded hardened layer tends to be sufficient, and when it is 60% by weight or less, the strength of the inorganic welded hardened layer also tends to be sufficient. 【0031】 The fluoroapatite particles mentioned above may be particles containing fluoroapatite as the main component, or fluoroapatite-coated titanium oxide particles may be used. 【0032】 The fluoroapatite particles mentioned above may be commercially available as is, or their particle size may be adjusted appropriately by known grinding methods before use. 【0033】 When the apatite particles are fluoroapatite particles, the content of the fluoroapatite component is preferably 2.5 to 20% by weight, more preferably 3.0 to 15% by weight, and even more preferably 3.5 to 11% by weight, based on 100% by weight of the solid content of the first composition. When the content of the fluoroapatite component is 2.5% by weight or more, the hardness of the inorganic welded hardened layer tends to be sufficient, and when it is 20% by weight or less, the hardness of the inorganic welded hardened layer also tends to be sufficient. 【0034】 The calcium phosphate particles described above are particles that mainly contain calcium phosphate, and are preferably particles that are essentially composed of calcium phosphate. 【0035】 Examples of calcium phosphate, which is the main component of the calcium phosphate particles mentioned above, include tricalcium phosphate, dicalcium phosphate, tetracalcium phosphate, and octacalcium phosphate. Only one type of calcium phosphate particle may be used, or two or more types may be used. Among these, it is preferable that the calcium phosphate particles contain tricalcium phosphate particles, as this makes it easier to obtain a strong inorganic welded hardened layer. Furthermore, it is preferable that the calcium phosphate, which is the main component of the tricalcium phosphate particles, contains β-calcium phosphate. 【0036】 The calcium phosphate particles mentioned above may be commercially available as is, or their particle size may be adjusted appropriately using a known grinding method before use. 【0037】 The average particle size of the calcium phosphate particles, as measured using a laser diffraction particle size distribution analyzer, is not particularly limited, but is preferably 0.1 to 50 μm, more preferably 0.3 to 10 μm, and even more preferably 0.7 to 5 μm. When the average particle size is 0.1 μm or more, the composition tends to be more stable, and when it is 50 μm or less, the composition tends to exhibit sufficient viscosity. 【0038】 When the apatite particles are hydroxyapatite particles, the calcium phosphate content is preferably 2 to 20% by weight, more preferably 4 to 15% by weight, and even more preferably 6 to 12% by weight, based on 100% by weight of the solid content of the first composition. When the calcium phosphate content is 2% by weight or more, the strength of the inorganic welded hardened layer tends to be sufficient, and when it is 20% by weight or less, the adhesion of the inorganic welded hardened layer to the tooth structure tends to be sufficient. 【0039】 When the apatite particles are hydroxyapatite particles, the content of calcium phosphate component per 100 parts by weight of hydroxyapatite component in the first composition is preferably 1 to 200 parts by weight, more preferably 10 to 75 parts by weight, and even more preferably 15 to 30 parts by weight. When the content of calcium phosphate component is 1 part by weight or more, the strength of the inorganic welded hardened layer tends to be sufficient, and when it is 200 parts by weight or less, the adhesion of the inorganic welded hardened layer to the tooth structure tends to be sufficient. 【0040】 When the apatite particles are fluoroapatite particles, the calcium phosphate content is preferably 15 to 50% by weight, more preferably 20 to 45% by weight, and even more preferably 25 to 35% by weight, based on 100% by weight of the solid content of the first composition. When the calcium phosphate content is 15% by weight or more, the surface hardness of the inorganic welded hardened layer tends to be sufficient, and when it is 50% by weight or less, the adhesion of the inorganic welded hardened layer to the tooth structure tends to be sufficient. 【0041】 When the apatite particles are fluoroapatite particles, the content of calcium phosphate component per 100 parts by weight of fluoroapatite component in the first composition is preferably 75 to 2000 parts by weight, more preferably 130 to 1500 parts by weight, and even more preferably 250 to 1000 parts by weight. When the content of calcium phosphate component is 75 parts by weight or more, the surface hardness of the inorganic weld-hardened layer tends to be sufficient, and when it is 2000 parts by weight or less, the adhesion of the inorganic weld-hardened layer to the tooth structure tends to be sufficient. 【0042】 The inorganic welded hardened layer achieves sufficient strength and surface hardness by containing titanium oxide particles in the first composition. 【0043】 Examples of titanium dioxide that can be the main component of the above-mentioned titanium dioxide particles include rutile-type, anatase-type, and brookite-type titanium dioxide. Only one type of titanium dioxide particle may be used, or two or more types may be used. Among these, it is preferable to include anatase-type titanium dioxide particles because it is easier to obtain strength and surface hardness in the inorganic welded hardened layer. 【0044】 The titanium oxide particles mentioned above may be commercially available as is, or their particle size may be adjusted appropriately using a known grinding method before use. 【0045】 The average particle size of the titanium oxide particles is not particularly limited, but is preferably 5 to 200 nm, more preferably 10 to 150 nm, and even more preferably 15 to 100 nm. When the average particle size is 5 nm or more, the strength and surface hardness of the inorganic welded hardened layer tend to be sufficient, and when it is 200 nm or less, the strength and surface hardness of the inorganic welded hardened layer also tend to be sufficient. 【0046】 When the apatite particles are hydroxyapatite particles, the titanium dioxide content is preferably 2 to 20% by weight, more preferably 4 to 15% by weight, and even more preferably 6 to 12% by weight, based on 100% by weight of the solid content of the first composition. When the titanium dioxide content is 2% by weight or more, the strength of the inorganic welded hardened layer tends to be sufficient, and when it is 20% by weight or less, the adhesion of the inorganic welded hardened layer to the tooth structure tends to be sufficient. 【0047】 When the apatite particles are hydroxyapatite particles, the content of titanium oxide component per 100 parts by weight of hydroxyapatite component in the first composition is preferably 1 to 200 parts by weight, more preferably 10 to 75 parts by weight, and even more preferably 15 to 30 parts by weight. When the content is 1 part by weight or more, the strength of the inorganic welded hardened layer tends to be sufficient, and when it is 200 parts by weight or less, the adhesion of the inorganic welded hardened layer to the tooth structure tends to be sufficient. 【0048】 When the apatite particles are fluoroapatite particles, the titanium dioxide content is preferably 15 to 50% by weight, more preferably 20 to 45% by weight, and even more preferably 25 to 35% by weight, based on 100% by weight of the solid content of the composition. When the titanium dioxide particle content is 15% by weight or more, the surface hardness of the inorganic welded hardened layer tends to be sufficient, and when it is 50% by weight or less, the adhesion of the inorganic welded hardened layer to the tooth structure tends to be sufficient. 【0049】 When the apatite particles are fluoroapatite particles, the content of titanium oxide component per 100 parts by weight of fluoroapatite component in the first composition is preferably 75 to 2000 parts by weight, more preferably 130 to 1500 parts by weight, and even more preferably 250 to 1000 parts by weight. When the content of titanium oxide component is 75 parts by weight or more, the surface hardness of the inorganic weld hardened layer tends to be sufficient, and when it is 2000 parts by weight or less, the adhesion of the inorganic weld hardened layer to the tooth structure tends to be sufficient. 【0050】 The silicon dioxide particles described above are particles that mainly contain silicon dioxide, and are preferably particles that are essentially made of silicon dioxide. One type of silicon dioxide may be used, or two or more types may be used. 【0051】 The silicon dioxide particles mentioned above may be commercially available as is, or their particle size may be appropriately adjusted by known grinding methods before use. Furthermore, fumed silica or colloidal silica can preferably be used as the silicon dioxide particles. 【0052】 The average particle size of the silicon dioxide particles is not particularly limited, but is preferably 1 to 500 nm, more preferably 2 to 100 nm, and even more preferably 5 to 50 nm. 【0053】 When the apatite particles are hydroxyapatite particles, the silicon dioxide component content is preferably 10 to 90% by weight, more preferably 20 to 80% by weight, and even more preferably 30 to 60% by weight, based on 100% by weight of the solid content of the first composition. When the silicon dioxide component content is 10% by weight or more, the strength of the inorganic welded hardened layer tends to be sufficient, and when it is 90% by weight or less, the adhesion of the inorganic welded hardened layer to the tooth structure tends to be sufficient. 【0054】 When the apatite particles are hydroxyapatite particles, the content of silicon dioxide component per 100 parts by weight of hydroxyapatite component is preferably 15 to 900 parts by weight, more preferably 40 to 400 parts by weight, and even more preferably 60 to 200 parts by weight. When the content of silicon dioxide component is 15 parts by weight or more, the strength of the inorganic welded hardened layer tends to be sufficient, and when it is 900 parts by weight or less, the adhesion of the inorganic welded hardened layer to the tooth structure tends to be sufficient. 【0055】 When the apatite particles are fluoroapatite particles, the silicon dioxide component content is preferably 5 to 80% by weight, more preferably 10 to 60% by weight, and even more preferably 15 to 40% by weight, based on 100% by weight of the solid content of the first composition. When the silicon dioxide component content is 5% by weight or more, the surface hardness of the inorganic weld hardened layer tends to be sufficient, and when it is 80% by weight or less, the adhesion of the inorganic weld hardened layer to the tooth structure tends to be sufficient. 【0056】 When the apatite particles are fluoroapatite particles, the content of silicon dioxide component per 100 parts by weight of fluoroapatite component is preferably 25 to 3000 parts by weight, more preferably 60 to 2000 parts by weight, and even more preferably 150 to 1200 parts by weight. When the content of silicon dioxide component is 25 parts by weight or more, the surface hardness of the inorganic weld hardened layer tends to be sufficient, and when it is 3000 parts by weight or less, the adhesion of the inorganic weld hardened layer to the tooth structure tends to be sufficient. 【0057】 Examples of dispersion media included in the first composition described above include water and organic solvents (ethanol, methanol, 1-propanol, isopropyl alcohol, acetone, etc.). One or more dispersion media may be used. Among these, the dispersion media is preferably water or ethanol, and more preferably water, because it has little to no toxicity to the human body. 【0058】 The content of the dispersion medium in the first composition described above is not particularly limited, but is preferably 10 to 1000 parts by weight, more preferably 20 to 750 parts by weight, and even more preferably 40 to 500 parts by weight, per 100 parts by weight of solids in the first composition. When the content of the dispersion medium is 10 parts by weight or more, the composition tends to have sufficient operability, and when it is 1000 parts by weight or less, the composition tends to exhibit sufficient viscosity. 【0059】 Other components that may be included in the first composition described above are not particularly limited, but include, for example, metal salt compounds that can form a hardened layer (e.g., calcium carbonate), pigments, binders, etc. The content of each of these in the first composition described above is preferably 5% by weight or less, more preferably 1% by weight or less, and even more preferably 0.5% by weight or less, based on 100% by weight of solids. The lower limit may be, for example, 0% by weight. 【0060】 To provide a layer consisting of the first composition on the surface of the tooth structure, known methods such as spraying or coating can be used. There are no particular restrictions on the thickness of the layer consisting of the first composition, and it can be appropriately selected depending on the purpose. 【0061】 The laser light used to harden the layer made of the first composition described above is not particularly limited, but it is preferably an Nd:YAG laser light because it can form a strong inorganic welded hardened layer. 【0062】 There are no particular restrictions on the manner of irradiation of the laser light described above; for example, it may be pulsed or continuous, and among these, pulsed irradiation is preferred because it is less likely to damage tooth structure. For pulsed irradiation, the maximum irradiation energy of the laser light is preferably 0.01 to 100 J, more preferably 0.05 to 35 J, and even more preferably 0.1 to 30 J. The number of pulses of the laser light is preferably 1 to 100 pps. 【0063】 [Second form of dental treatment composition] A method for producing an inorganic weld-hardened layer using the second form of the dental treatment composition (second composition) described above includes, for example, the steps of irradiating a layer made of a composition (base composition) containing hydroxyapatite particles, calcium phosphate particles, titanium oxide particles, and silicon dioxide particles with laser light to form a base layer, and irradiating a layer made of a composition (surface layer composition) which is the second composition, containing fluoroapatite particles and silicon dioxide particles with laser light to form a surface layer on the surface of the base layer. 【0064】 The second composition described above, when used to form a surface layer on the surface of the base layer in this manner, allows for the inexpensive and rapid production of an inorganic weld-hardened layer that exhibits excellent adhesion to tooth structure, sufficient strength, and surface hardness without the use of adhesives. Furthermore, the inorganic weld-hardened layer obtained by the manufacturing method using the second composition achieves sufficient strength and surface hardness by having a surface layer with sufficient hardness on the surface of a base layer with sufficient strength. 【0065】 The process of forming the above-mentioned base layer involves applying a layer made of the above-mentioned base composition to the surface of the tooth structure, and then irradiating it with laser light to form a hardened layer with excellent adhesion to the tooth structure and strength. 【0066】 The above-mentioned base layer is a hardened layer formed on the surface of the tooth structure, which is made up of the above-mentioned base composition and hardened by laser irradiation. 【0067】 The above base composition contains hydroxyapatite particles, calcium phosphate particles, titanium oxide particles, and silicon dioxide particles, which are dispersed in a dispersion medium. The above base composition is used in the production of the above inorganic weld-hardened layer, and is used to form a base layer on the tooth surface in the production of the above inorganic weld-hardened layer. The above base composition may contain other components besides hydroxyapatite particles, calcium phosphate particles, titanium oxide particles, silicon dioxide particles, and the dispersion medium, to the extent that it does not impair the effects of the present invention. For dispersion, known methods such as stirring, shaking, vibration, and ultrasound can be used. 【0068】 The hydroxyapatite particles, calcium phosphate particles, titanium dioxide particles, and silicon dioxide particles contained in the above base composition, as well as the dispersion medium and other components, can be the same as those used in the first composition when the apatite particles are hydroxyapatite particles. Furthermore, each of the main components that may be included in the above base composition may be used individually or in combination of two or more. 【0069】 The content of the hydroxyapatite component in the above base composition is preferably 10 to 60% by weight, more preferably 20 to 50% by weight, and even more preferably 30 to 45% by weight, based on 100% by weight of the solid content of the base composition. When the content of the hydroxyapatite component is 10% by weight or more, the strength of the base layer tends to be sufficient, and when it is 60% by weight or less, the strength of the base layer also tends to be sufficient. 【0070】 The calcium phosphate content in the above base composition is preferably 2 to 20% by weight, more preferably 4 to 15% by weight, and even more preferably 6 to 12% by weight, based on 100% by weight of the solid content of the composition. When the calcium phosphate content is 2% by weight or more, the strength of the base layer tends to be sufficient, and when it is 20% by weight or less, the adhesion of the base layer to the tooth structure tends to be sufficient. 【0071】 In the above base composition, the content of calcium phosphate component per 100 parts by weight of hydroxyapatite component is preferably 1 to 200 parts by weight, more preferably 10 to 75 parts by weight, and even more preferably 15 to 30 parts by weight. When the content of calcium phosphate component is 1 part by weight or more, the strength of the base layer tends to be sufficient, and when it is 200 parts by weight or less, the adhesion of the base layer to the tooth structure tends to be sufficient. 【0072】 The titanium dioxide content in the above base composition is preferably 2 to 20% by weight, more preferably 4 to 15% by weight, and even more preferably 6 to 12% by weight, based on 100% by weight of the solid content of the base composition. When the titanium dioxide content is 2% by weight or more, the strength of the base layer tends to be sufficient, and when it is 20% by weight or less, the adhesion of the base layer to the tooth structure tends to be sufficient. 【0073】 In the above base composition, the content of titanium dioxide component per 100 parts by weight of hydroxyapatite component is preferably 1 to 200 parts by weight, more preferably 10 to 75 parts by weight, and even more preferably 15 to 30 parts by weight. When the content of titanium dioxide component is 1 part by weight or more, the strength of the base layer tends to be sufficient, and when it is 200 parts by weight or less, the adhesion of the base layer to the tooth structure tends to be sufficient. 【0074】 The silicon dioxide component content in the above base composition is preferably 10 to 90% by weight, more preferably 20 to 80% by weight, and even more preferably 30 to 60% by weight, based on 100% by weight of the solid content of the base composition. When the silicon dioxide component content is 10% by weight or more, the strength of the base layer tends to be sufficient, and when it is 90% by weight or less, the adhesion of the base layer to the tooth structure tends to be sufficient. 【0075】 In the above base composition, the content of silicon dioxide component per 100 parts by weight of hydroxyapatite component is preferably 15 to 900 parts by weight, more preferably 40 to 400 parts by weight, and even more preferably 60 to 200 parts by weight. When the content of silicon dioxide component is 15 parts by weight or more, the strength of the base layer tends to be sufficient, and when it is 900 parts by weight or less, the adhesion of the base layer to the tooth structure tends to be sufficient. 【0076】 The content of the dispersion medium in the above base composition is not particularly limited, but is preferably 10 to 200 parts by weight, more preferably 20 to 150 parts by weight, and even more preferably 40 to 100 parts by weight, per 100 parts by weight of solid content of the composition. When the content of the dispersion medium is 10 parts by weight or more, the base composition tends to have sufficient operability, and when it is 200 parts by weight or less, the base composition tends to exhibit sufficient viscosity. 【0077】 The content of other components that may be included in the above base composition is preferably 5% by weight or less, more preferably 1% by weight or less, and even more preferably 0.5% by weight or less, based on 100% by weight of the solid content of the composition. The lower limit may be, for example, 0% by weight. 【0078】 To provide a layer consisting of the above-mentioned base composition on the surface of the tooth structure, known methods such as spraying or coating can be used. There are no particular restrictions on the thickness of the layer consisting of the above-mentioned base composition, and it can be appropriately selected depending on the purpose. 【0079】 The laser light irradiated onto the layer made of the above-mentioned base composition can be the same as in the first embodiment of the method for manufacturing an inorganic weld-cured layer. 【0080】 The process of forming the above-mentioned surface layer involves providing a layer made of the second composition on the surface of the base layer, and then irradiating it with laser light to form a hardened layer with excellent hardness. 【0081】 The above surface layer is a cured layer formed on the surface of the base layer in the inorganic welded hardened layer, which is obtained by hardening a layer made of the second composition by laser irradiation. 【0082】 The second composition described above contains fluoroapatite particles and silicon dioxide particles, which are dispersed in a dispersion medium. The second composition is used in the production of the inorganic weld-hardened layer, forming a surface layer on the base layer and used for hardening the surface of the inorganic weld-hardened layer. The second composition may contain other components besides fluoroapatite particles, silicon dioxide particles, and the dispersion medium, to the extent that it does not impair the effects of the present invention. Known methods such as stirring, shaking, vibration, and ultrasound can be used for dispersion. 【0083】 The fluoroapatite particles and silicon dioxide particles contained in the second composition, as well as the dispersion medium and other components, can be the same as those used in the first composition. Furthermore, each of the main components that may be included in the second composition may be used individually or in combination of two or more. 【0084】 The content of the fluoroapatite component in the second composition described above is preferably 4.5 to 25% by weight, more preferably 5.0 to 20% by weight, and even more preferably 5.5 to 15% by weight, based on 100% by weight of the solid content of the second composition. When the content of the fluoroapatite component is 4.5% by weight or more, the hardness of the surface layer tends to be sufficient, and when it is 25% by weight or less, the hardness of the surface layer also tends to be sufficient. 【0085】 In the inorganic weld-hardened layer of the second embodiment, the base layer contains a titanium oxide component, so a surface layer having a welded portion fused with the base layer is formed from the layer made of the second composition by laser irradiation. The second composition may contain a titanium oxide component, such as when fluoroapatite-coated titanium oxide particles are used as fluoroapatite particles, or when titanium oxide particles are included. 【0086】 In the second composition described above, if a titanium dioxide component is included, the content of the titanium dioxide component is preferably 30 to 65% by weight, more preferably 35 to 55% by weight, and even more preferably 40 to 45% by weight, based on 100% by weight of the solid content of the second composition. When the content of the titanium dioxide component is 30% by weight or more, the hardness of the surface layer tends to be sufficient, and when it is 65% by weight or less, the adhesion of the surface layer to the base layer tends to be sufficient. 【0087】 In the second composition described above, when a titanium dioxide component is included, the content of the titanium dioxide component per 100 parts by weight of the fluoroapatite component is preferably 120 to 1400 parts by weight, more preferably 170 to 1100 parts by weight, and even more preferably 250 to 800 parts by weight. When the content of the titanium dioxide component is 120 parts by weight or more, the hardness of the surface layer tends to be sufficient, and when it is 1400 parts by weight or less, the adhesion of the surface layer to the base layer tends to be sufficient. 【0088】 The silicon dioxide component content in the second composition described above is preferably 35 to 70% by weight, more preferably 40 to 60% by weight, and even more preferably 45 to 50% by weight, based on 100% by weight of the solid content of the second composition. When the silicon dioxide component content is 35% by weight or more, the hardness of the surface layer tends to be sufficient, and when it is 70% by weight or less, the hardness of the surface layer also tends to be sufficient. 【0089】 In the second composition described above, the content of silicon dioxide component per 100 parts by weight of fluoroapatite component is preferably 140 to 1600 parts by weight, more preferably 200 to 1200 parts by weight, and even more preferably 300 to 900 parts by weight. When the content of silicon dioxide component is 140 parts by weight or more, the hardness of the surface layer tends to be sufficient, and even when it is 1600 parts by weight or less, the hardness of the surface layer tends to be sufficient. 【0090】 The second composition described above may contain calcium phosphate components, but the content of these components is preferably 10% by weight or less, more preferably 5% by weight or less, and even more preferably 3% by weight or less, based on 100% by weight of solids. The lower limit may be 0% by weight, 0.5% by weight, or 1% by weight. When the above content is 10% by weight or less, the hardness of the surface layer tends to be sufficient. 【0091】 The content of the dispersion medium that the second composition may contain is preferably 50 to 1000 parts by weight, more preferably 100 to 800 parts by weight, and even more preferably 150 to 600 parts by weight, per 100 parts by weight of solids of the second composition. When the content of the dispersion medium is 50 parts by weight or more, the second composition tends to have sufficient operability, and when it is 1000 parts by weight or less, the second composition tends to exhibit sufficient viscosity. 【0092】 To provide a layer consisting of the second composition on the surface of the base layer, known methods such as spraying or coating can be used. There are no particular restrictions on the thickness of the layer consisting of the second composition, and it can be appropriately selected depending on the purpose. 【0093】 The laser light irradiated onto the layer made of the second composition described above can be used in the same manner as in the method for manufacturing the inorganic weld-hardened layer of the first embodiment. 【0094】 The method for producing an inorganic welded hardened layer using the dental treatment composition of the present invention can be suitably used in dental treatment. The dental treatment described above is not particularly limited and can include, for example, tooth structure reinforcement, cavity floor protection, acid resistance improvement, and dentin hypersensitivity treatment. [Examples] 【0095】 The present invention will be described in detail below with reference to examples, but the scope of the present invention is not limited to these examples. 【0096】 (Preparation Example 1: Composition 1) Composition 1 was obtained by kneading HAp (hydroxyapatite particles, product name: "Hydroxyapatite MS", manufactured by Tomita Pharmaceutical Co., Ltd., average particle size: 2.5 μm): 0.60 g, TCP (β-tricalcium phosphate particles, product name: "Osferion", manufactured by Osferion Biomaterial Co., Ltd., granule size: 0.15-0.5 mm): 0.15 g, TiO2 (titanium dioxide particles, product name: "Super Titania F-2", manufactured by Resonac Co., Ltd., average particle size: 60 nm, anatase type): 0.15 g, and colloidal silica dispersed in water (product name: "Ludox AS-40", manufactured by Grace Japan Co., Ltd., solid content 40% by weight): 2.32 g (SiO2: 0.93 g, water: 1.39 g) using a mortar and pestle (HAp: 33% by weight, TCP: 8% by weight, TiO2: 8% by weight, SiO2: 51% by weight, water: 76 parts by weight). 【0097】 (Preparation Example 2: Composition 2) Composition 2 was obtained in the same manner as Preparation Example 1, except that the amounts of each component were HAp: 0.60 g, TCP: 0.15 g, TiO2: 0.15 g, and colloidal silica dispersed in water: 1.29 g (SiO2: 0.52 g, water: 0.77 g) (HAp: 42 wt%, TCP: 11 wt%, TiO2: 11 wt%, SiO2: 36 wt%, water: 54 wt). 【0098】 (Preparation Example 3: Composition 3) Composition 3 was obtained in the same manner as in Preparation Example 1, except that the amounts of each component were HAp: 0.75 g, TCP: 0.15 g, TiO2: 0 g, and colloidal silica dispersed in water: 2.32 g (SiO2: 0.93 g, water: 1.39 g) (HAp: 41 wt%, TCP: 8 wt%, TiO2: 0 wt%, SiO2: 51 wt%, water: 76 wt). 【0099】 (Preparation Example 4: Composition 4) Composition 4 was prepared in the same manner as in Preparation Example 1, except that the amounts of each component were HAp: 1.52 g, TCP: 0.15 g, TiO2: 0.15 g, and water: 1.39 g (HAp: 84 wt%, TCP: 8 wt%, TiO2: 8 wt%, SiO2: 0 wt%, water: 76 wt). 【0100】 (Preparation Example 5: Composition A) Water-dispersed fluorapatite-coated titanium oxide slurry [Solid content (fluorapatite 12% by weight, titanium oxide 88% by weight), Product name: "NSP-S001", Manufactured by NanoWave Co., Ltd., Average particle size: 10 μm, Solid content 10% by weight]: 0.52 g (FAp: 0.006 g, TiO2: 0.046 g, Water: 0.468 g), TCP (β-tricalcium phosphate particles, Product name: "Osferion", Osferion Biomaterials) Composition A was obtained by kneading 0.05 g of granule particle size: 0.15-0.5 mm (manufactured by Al Co., Ltd.) and 0.129 g of water-dispersed colloidal silica (product name: "Ludox AS-40", manufactured by Grace Japan Co., Ltd., solids content 40% by weight) (SiO2: 0.052 g, water: 0.077 g) using a mortar and pestle (FAp: 4% by weight, TCP: 32% by weight, TiO2: 30% by weight, SiO2: 34% by weight, water: 355 parts by weight). 【0101】 (Preparation Example 6: Composition B) Composition B was obtained in the same manner as in Preparation Example 5, except that the amounts of each component were: fluorapatite-coated titanium oxide slurry dispersed in water: 0.52 g (FAp: 0.006 g, TiO2: 0.046 g, water: 0.468 g); and colloidal silica dispersed in water: 0.129 g (SiO2: 0.052 g, water: 0.077 g) (FAp: 6 wt%, TiO2: 44 wt%, SiO2: 50 wt%, water: 526 wt). 【0102】 [Table 1] 【0103】 (Example 1) Composition 1 was filled into a cavity in a natural tooth, and Nd:YAG laser light was irradiated from a distance of 2 mm using an Nd:YAG laser irradiation device (product name: "Inpulse", manufactured by Insusiv Inc.) (wavelength 1064 nm, output 120 mJ, pulse count 20 pps, total irradiation time 2 seconds) to obtain an inorganic welded hardened layer sample integrated with the natural tooth. 【0104】 (Example 2) An inorganic welded hardened layer sample was obtained in the same manner as in Example 1, except that composition A was used. 【0105】 (Example 3) Composition 1 was filled into a cavity in a natural tooth, and a base layer integrated with the natural tooth was formed by irradiating it with YAG laser light in the same manner as in Example 1. Composition B was applied to the formed base layer, and an inorganic welded hardened layer sample was obtained by further forming a surface layer by irradiating it with YAG laser light in the same manner as above. 【0106】 (Example 4) An inorganic welded cured layer sample was obtained in the same manner as in Example 3, except that composition 2 was used for the base layer. 【0107】 (Comparative Example 1) An inorganic welded hardened layer sample was obtained in the same manner as in Example 1, except that composition 3 was used. 【0108】 (Comparative Example 2) An inorganic welded hardened layer sample was obtained in the same manner as in Example 1, except that composition 4 was used. 【0109】 (Reference example) Using MTA cement (product name "ProRoot MTA"; manufactured by Dentsply Sirona Co., Ltd.), a hardened layer sample similar to that in the example was obtained. 【0110】 <Strength Evaluation> The obtained samples were measured using a Vickers thermometer (product name "MMT-X3", manufactured by Matsuzawa Co., Ltd.) under a load of 500g. Higher values ​​indicate greater rigidity and strength. The results are shown in Table 2. 【0111】 <Hardness evaluation> Five experts, including dentists, participated as panelists in a sensory evaluation. Using a dental probe (product name "Excavator #1," manufactured by YDM Co., Ltd.), the samples were rubbed, and their sensations were judged according to the following scoring criteria. The average score was calculated to evaluate the surface hardness. The results are shown in Table 2. 3 points: Extremely hard (makes a very high-pitched, glassy squeaking sound) 2 points: Hard (makes a high-pitched, glassy friction sound like "squeak") 1 point: Soft (does not produce a glassy friction sound) 0 points: Very soft (surface wears away) 【0112】 Evaluation Criteria ◎: Average score 2.5 points or more ○: Average score of 2.0 or higher but less than 2.5 points ×: Average score less than 2.0 points 【0113】 [Table 2] 【0114】 Figure 1 shows a SEM image (magnification: 100x) of the cross-section of the contact area with a natural tooth in the inorganic weld-hardened layer sample of Example 1, taken using an electro-emission scanning electron microscope (product name: "JSM-7001F", manufactured by JEOL Ltd.). Observation of the above image revealed that the tooth structure (upper part) and the inorganic weld-hardened layer (lower part) were intertwined and the welded area could be confirmed. 【0115】 Figure 2 shows the elements present in the welded portion of the inorganic welded hardened layer sample from Example 2, analyzed using an electro-emission scanning electron microscope (product name: "JSM-7001F", manufactured by JEOL Ltd.) and an energy-dispersive X-ray analyzer (product name: "Genesis APEX2", manufactured by AMETEK Corporation). The figure confirms that carbon (C) originating from organic matter in the adhesive is absent in the welded portion.

Claims

[Claim 1] A dental treatment composition containing apatite particles, calcium phosphate particles, titanium dioxide particles, and silicon dioxide particles, used in the production of an inorganic welding hardened layer. [Claim 2] The apatite particles are hydroxyapatite particles, The dental treatment composition according to claim 1, wherein the content of the titanium oxide particles is 2 to 20% by weight. [Claim 3] The dental treatment composition according to claim 2, wherein the content of the silicon dioxide component is 10 to 90% by weight. [Claim 4] The dental treatment composition according to claim 1, wherein the apatite particles are fluoroapatite particles. [Claim 5] A dental treatment composition containing fluoroapatite particles and silicon dioxide particles, used in the production of an inorganic weld-hardened layer, and used to form a surface layer in the inorganic weld-hardened layer. [Claim 6] The dental treatment composition according to claim 5, wherein the fluoroapatite particles are fluoroapatite-coated titanium oxide particles. [Claim 7] A method for producing an inorganic weld-hardened layer, comprising the step of irradiating a layer made of a composition containing apatite particles, calcium phosphate particles, titanium dioxide particles, and silicon dioxide particles with laser light. [Claim 8] A step of forming a base layer by irradiating a layer made of a first composition containing hydroxyapatite particles, calcium phosphate particles, titanium dioxide particles, and silicon dioxide particles with light, A method for producing an inorganic weld-cured layer, comprising the step of irradiating a layer made of a second composition containing fluoroapatite particles and silicon dioxide particles with laser light to form a surface layer on the surface of the base layer.

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