Dental resin materials and antibacterial dentures

Abstract

To provide a dental resin material comprising, mechanical properties and chemical properties which are usable as a dental resin material, exhibiting continuous antibacterial properties with respect to, periodontal disease factor bacteria, cariogenic bacteria, and fungus, suppressing adhesion of denture plaque, or suppressing foul breath factor substances such as methyl mercaptan, and a dental article, especially antibacterial artificial tooth which is produced from the same dental resin material.SOLUTION: There are provided, a dental resin material in which surface modified oxidized zinc powder is dispersed, and an antibacterial artificial tooth which is produced from the same dental resin material.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a dental resin material and an antibacterial denture. [Background technology]

[0002] It has been shown that dental caries and periodontal disease, the two major diseases in the dental field, are both caused by resident oral bacteria. Plaque bacteria, which are composed of resident oral bacteria such as Streptococcus mutans and their metabolic products, are the direct cause of caries induction, while the proliferation of anaerobic gram-negative bacteria such as Porphyromonas gingivalis in the subgingival space causes gingival inflammation and periodontal tissue destruction. Therefore, it is clear that inhibiting the proliferation of plaque-forming bacteria is important for preventing these diseases.

[0003] Denture stomatitis is an inflammation of the mucosa beneath removable dentures and orthodontic appliances, and is closely related to oral microorganisms, including Candida, which is found on the mucosal surface of the denture base. albicans It has been reported that denture plaque, which is primarily composed of Candida albicans, is an important factor in denture stomatitis. The main bacteria that make up denture plaque are reported to be facultative anaerobic gram-positive cocci and facultative anaerobic gram-positive rods. It has also been reported that there is a correlation between denture stomatitis and Candida and Staphylococcus, and that Candida species, primarily Candida albicans, are frequently detected in denture plaque.

[0004] The harmful effects of denture plaque include not only harmful effects on the body such as denture stomatitis and angular cheilitis, but also the promotion of denture plaque accumulation due to its penetration into denture materials and the resulting deterioration of the denture materials, which may further exacerbate denture stomatitis and other conditions.

[0005] In particular, the area around dentures made from resin is an environment where bacteria can easily grow, and if bacteria that cause dental caries or periodontal disease are present in the oral cavity, these bacteria can easily grow around the dentures, causing damage to healthy teeth around the dentures. Furthermore, periodontal disease patients often suffer from strong bad breath due to methyl mercaptan and other substances produced by periodontal disease-causing bacteria. Therefore, dentures must always be kept clean.

[0006] However, for example, elderly people who cannot clean their dentures themselves require assistance from a caregiver, but there are situations where a caregiver is unavailable or cannot always clean thoroughly. Neglecting to clean dentures increases the risk of oral bacteria and food particles entering the trachea and causing aspiration pneumonia in elderly people with weakened immune systems. Keeping dentures clean not only helps prevent caries and periodontal disease, but also aspiration pneumonia.

[0007] Therefore, dentures have been proposed that are molded by uniformly mixing an organic antibacterial composition into the resin that forms the dentures, and it has been reported that they can suppress the main bacteria that cause periodontal disease and dental caries for a long period of time (Patent Document 1).

[0008] Meanwhile, inorganic materials known to exhibit antibacterial activity and be safe for the human body include silver, titanium oxide, magnesium oxide, calcium oxide, and zinc oxide. In the fields of hygiene management products and textile products, research and development is underway to develop resin compositions that have been endowed with antibacterial and bactericidal properties. In the field of dentistry, the development of dental materials that inhibit the growth of oral bacteria over the long term is considered essential, especially in relation to whole-body care in the coming super-aging society.

[0009] Zinc oxide is known to have photocatalytic activity, ultraviolet absorbing activity, sterilizing, antibacterial, deodorizing, and other functions. Patent Documents 2 and 3 disclose surface-treated zinc oxide powder in which the surface of the zinc oxide powder is subjected to a surface treatment to suppress the photocatalytic activity of zinc oxide while maintaining functions such as ultraviolet absorption activity, sterilization, antibacterial properties, and deodorization. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent No. 6172713 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-109601 [Patent Document 3] Japanese Patent Application Publication No. 8-59890 Summary of the Invention [Problem to be solved by the invention]

[0011] The main object of the present invention is to provide a dental resin material that has mechanical and chemical properties that enable it to be used as a dental resin material, has sustained antibacterial properties against bacteria that cause periodontal disease, bacteria that cause dental caries, fungi, etc., and can inhibit the adhesion of denture plaque or reduce substances that cause bad breath, such as methyl mercaptan, and to provide dental articles, particularly antibacterial dentures, made using the same.

[0012] The present inventors have discovered that surface-modified zinc oxide powder, which is known as an inorganic antibacterial agent that is safe for the human body and effective against common bacteria, has been surface-modified to improve its dispersibility in resin, and that this surface-modified zinc oxide powder also exhibits antibacterial properties against oral bacteria such as periodontal disease-causing bacteria, caries-causing bacteria, and fungi.

[0013] There is a concern that antibacterial dentures using the aforementioned organic antibacterial composition may be exposed to saliva and other fluids in the oral cavity over a long period of time, which may accelerate decomposition of the organic antibacterial compounds present especially near the surface of the dentures, resulting in a decline in the antibacterial properties of the dentures.In contrast, inorganic antibacterial agents have the advantage that they do not decompose even in the oral cavity and maintain their antibacterial properties for a long period of time.

[0014] The present inventors have developed a dental resin material with antibacterial properties, which is made by uniformly dispersing surface-modified zinc oxide powder in a resin used in dentistry, particularly a resin used for forming dentures, and then molding it, as well as antibacterial dentures made using the same.

[0015] The present inventors have also found that a dental resin material made of a resin containing the surface-modified zinc oxide powder can reduce methyl mercaptan and other substances that cause strong bad breath in patients with periodontal disease.

[0016] Furthermore, the present inventors have also found that a dental resin material made of a resin containing the surface-modified zinc oxide powder inhibits the adhesion of bacteria that cause denture plaque.

[0017] Dental articles, particularly dentures, which are placed in the oral cavity for long periods of time, not only have antibacterial properties but also have the ability to decompose substances that cause strong bad breath, such as methyl mercaptan, and to inhibit the adhesion of denture plaque, which is expected to inhibit the worsening of periodontal disease and reduce bad breath.

[0018] The present inventors have discovered that dental resin materials, particularly dentures, formed by dispersing surface-modified zinc oxide powder in dental resin materials, can suppress bacteria that cause periodontal disease and dental caries for a long period of time, can reduce bad breath substances such as methyl mercaptan, and can inhibit the adhesion of denture plaque, and have completed the present invention. [Means for solving the problem]

[0019] According to the present invention, the following dental resin material, antibacterial denture, etc. are provided. 1. Dental resin material with surface-modified zinc oxide powder dispersed therein. 2. The dental resin material according to 1, wherein the zinc oxide powder has an average particle size in the range of 1 to 500 nm. 3. The dental resin material according to 1, wherein the surface modification is coating with a zinc sulfide film. 4. The dental resin material according to 1, wherein the surface modification is coating with a coupling agent. 5. The dental resin material according to any one of 1 to 4, wherein the surface modification is partial coating of the surface of the zinc oxide powder. 6. The dental resin material according to 3 or 4, wherein the coating amount of the zinc sulfide or coupling agent is 0.1 to 30% by mass. 7. The dental resin material according to any one of 1 to 5, wherein the amount of the surface-modified zinc oxide powder blended is 0.1 to 10 mass %. 8. A dental resin material according to any one of 1 to 7, which is a material for dental crowns, a composite resin, a dental filling material, a resin cement, a dental adhesive or luting material, a fissure sealant, a coating material, a resin for crowns, bridges and inlays, abutment construction material, a denture resin, a denture base resin, a denture base repair resin, a resin for toothbrush bristles, a toothbrush handle, or a resin for a mouthpiece. 9. A dental resin material according to any one of 1 to 8, which inhibits the growth of periodontal disease-causing bacteria, caries-causing bacteria and / or fungi. 10. A dental resin material according to any one of 1 to 9, which inhibits the adhesion of denture plaque. 11. A dental resin material according to any one of 1 to 10, which reduces substances that cause bad breath. 12. An antibacterial denture made of the dental resin material according to any one of 1 to 11. 13. A night guard made of the dental resin material according to any one of 1 to 11. [Effects of the Invention]

[0020] According to the present invention, it is possible to provide a dental resin material that has sustained antibacterial properties against bacteria that cause periodontal disease, bacteria that cause dental caries, fungi, etc., and that can reduce substances that cause bad breath, such as methyl mercaptan, or can suppress the adhesion of denture plaque, as well as dental articles, particularly antibacterial dentures, made using the same. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a graph showing the results of the water absorption test described in Test Example 1. [Figure 2] 1 is a graph showing the results of a bending strength test described in Test Example 2. [Figure 3] 1 is a graph showing the results of a flexural modulus test described in Test Example 2. [Figure 4] 1 is a graph showing the results of an antibacterial test of the surface-modified zinc oxide powder against P. gingivalis described in Test Example 3. [Figure 5] 1 is a graph showing the results of an antibacterial test of the surface-modified zinc oxide powder against S. mutans described in Test Example 3. [Figure 6] 1 is a graph showing the results of an antibacterial test of the surface-modified zinc oxide powder against C. albicans described in Test Example 3. [Figure 7] 10 is a graph showing the results of a test to inhibit adhesion of oral bacteria to a resin material containing the surface-modified zinc oxide powder described in Test Example 4. DETAILED DESCRIPTION OF THE INVENTION

[0022] The dental resin material of the present invention is characterized by comprising a resin in which surface-modified zinc oxide powder is dispersed. Here, "dental resin material" refers to a resin material used to form articles primarily for use in dentistry within the oral cavity. The form (properties) of the "dental resin material" is not particularly limited before molding and solidification, and may be in any form such as powder, particles, beads, pellets, paste, or solid, and will have a specific shape after solidification. Examples of articles made of or manufactured using the "dental resin material" include dentures, denture bases, toothbrush bristles, toothbrush handles, night guards, mouthpieces, etc., with dentures and denture bases being particularly preferred.

[0023] The term "dental resin material" as used in the present invention encompasses not only the above-mentioned articles but also all resin dental materials widely used in dental treatment and oral care, such as dental crown resins, dental crown materials such as artificial teeth, composite resins, root canal filling materials, dental filling materials such as bonding materials, dental adhesives and luting materials such as resin cements and orthodontic adhesives, fissure sealants, coating materials, resins for crowns, bridges, and inlays, abutment construction materials, denture base resins, and denture base repair resins. It also includes fillings and prostheses used temporarily during treatment, so-called dentures used in the oral cavity over a long period of time, replacement teeth for implants, denture bases, etc. Furthermore, "denture" includes so-called false teeth, implant tooth replacement parts, and denture bases.

[0024] The dental resin material of the present invention includes a base material (such as a resin) to which surface-modified zinc oxide powder has been added and which has been uniformly mixed to give a fluid state, i.e., both before and after application to the affected area, before hardening, and after hardening.

[0025] Zinc oxide is used as an inorganic antibacterial agent that has antibacterial properties against common bacteria, but it has never been used in dental resin materials such as dentures and prosthetic restorations.

[0026] Zinc oxide is also known as a UV absorber because it absorbs UV rays below 380 nm. When zinc oxide absorbs UV rays, it exerts its oxidizing and reducing power through photocatalysis. In particular, the oxidizing power of zinc oxide can oxidize resins, accelerating their deterioration.

[0027] In the present invention, "surface modification" of zinc oxide powder refers to a process in which the surface of zinc oxide powder is partially coated to suppress the photocatalytic activity of zinc oxide and improve its dispersibility in resin, without impairing its antibacterial properties against periodontal disease-causing bacteria, caries-causing bacteria and fungi, and its deodorizing effects against bad breath.

[0028] In the present invention, examples of the method for "surface modification" of zinc oxide powder include the methods described in Patent Documents 2 and 3. The sulfurization treatment described in Patent Document 2 is a method in which zinc oxide powder is brought into contact with hydrogen sulfide or sulfur dioxide gas to sulfurize the surface of the zinc oxide powder and coat the surface of the zinc oxide powder with zinc sulfide. Specifically, zinc oxide powder is placed in a glass container, and hydrogen sulfide gas or sulfur dioxide gas is passed through the container while it is vibrated to bring the powder into contact with the zinc oxide powder.

[0029] The coating treatment with a coupling agent described in Patent Document 3 is a method in which the surface of zinc oxide powder is coated with a coupling agent to produce coated zinc oxide powder. The coating treatment of the surface of zinc oxide powder with a coupling agent may be carried out by any of the following methods: a wet method in which a coupling agent is added while stirring a slurry of zinc oxide powder in water or a non-aqueous solvent; a dry method in which a coupling agent is sprayed or dropped onto the zinc oxide powder while stirring it at high speed using a Henschel mixer or high-speed mixer capable of high-speed rotation; and a gas phase method in which a coupling agent carried by an inert gas such as nitrogen is introduced into a reaction vessel containing zinc oxide powder to perform coating treatment.

[0030] As the coupling agent, a silane coupling agent having a silanol group, an epoxy group, a methacryl group, a vinyl group, a mercapto group, an amino group, etc. Alternatively, other coupling agents such as titanium-based, aluminum-based, zirconium-based, and zircoaluminate-based coupling agents or silanes may be used.

[0031] The average particle size of the zinc oxide powder is preferably in the range of 1 to 500 nm, more preferably 10 to 400 nm, and even more preferably 50 to 300 nm. Within the above range, the dispersibility in the dental resin is not impaired, and the powder can be mixed uniformly.

[0032] The specific surface area of ​​zinc oxide powder by the BET method is 10 to 500 m 2 / g, and 10 to 400m 2 / g is more preferable, and 20 to 300m2 / g is more preferred.

[0033] In order to partially coat the surface of the zinc oxide powder, the amount of coating with the zinc sulfide coating and coupling agent can be adjusted taking into account the specific surface area of ​​the zinc oxide powder, and can be determined appropriately depending on the intended use of the surface-modified zinc oxide powder. In the case of a dental resin material, the coating amount is preferably in the range of 0.1 to 30% by mass, more preferably 0.2 to 20% by mass, and even more preferably 0.2 to 15% by mass. Within the above range, zinc oxide can be easily dispersed uniformly in the resin, its antibacterial properties against bacteria that cause periodontal disease, bacteria that cause dental caries, fungi, etc. are not impaired, and its ability to decompose substances that cause bad breath, etc., can be maintained.

[0034] An example of a commercially available "surface-modified zinc oxide powder" that can be used in the dental resin material of the present invention is AD-PSJ (manufactured by Nissho Chemical Co., Ltd.).

[0035] The "resin" that serves as the base material for dispersing the surface-modified zinc oxide powder is not particularly limited, and any type of resin commonly used in the dental field can be used. When the dental resin material of the present invention is used as a denture material, the "resin" that serves as the base material is a base resin for dentures.

[0036] Widely used denture resins can be used as the base material (resin) for dentures. Preferred denture resins include microwave-polymerized (microwave oven) and thermally polymerized (hot water). Commercially available denture resins include Basis Resin (manufactured by Yamahachi Dental Materials Co., Ltd., heat-polymerized), Acron (manufactured by GC Corporation, heat-polymerized), Acron MC (manufactured by GC Corporation, microwave-polymerized), Quick Acron (manufactured by GC Corporation, heat-polymerized / heat shock), Laxon (manufactured by GC Corporation, heat-polymerized), Fit Resin (manufactured by Matsufuku Co., Ltd., room-temperature polymerized resin), Pore Resin (manufactured by Matsufuku Co., Ltd., room-temperature polymerized resin), and Urban (manufactured by Matsufuku Co., Ltd., heat-polymerized resin).

[0037] The means for mixing the surface-modified zinc oxide powder with the denture molding resin may be selected from methods commonly used by those skilled in the art. For example, in the case of a two-component denture molding resin consisting of a powder (polymerization initiator) and a liquid (polymerizable monomer), the surface-modified zinc oxide powder may be added to the liquid (polymerizable monomer) in advance and then mixed with the powder (polymerization initiator), or the surface-modified zinc oxide powder may be added to the powder (polymerization initiator) in advance and then mixed with the liquid (polymerizable monomer). The means for molding and curing the resin material mixed with the surface-modified zinc oxide powder may be selected from methods commonly used by those skilled in the art that are suitable for the base material.

[0038] In recent years, the use of 3D printers to manufacture dentures has become widespread. When manufacturing dentures using a 3D printer, powdered or pelleted resin material containing surface-modified zinc oxide powder is used as the raw material for 3D printing, and the desired denture shape can be created.

[0039] The amount of surface-modified zinc oxide powder in the dental resin material of the present invention varies depending on the resin used and the application, but is usually within the range of 0.1 to 10 mass%, preferably 0.3 to 5 mass%, and more preferably 0.5 to 3 mass%.

[0040] The dental resin material of the present invention and dental articles such as antibacterial dentures made therefrom may contain various additives in addition to the surface-modified zinc oxide powder depending on the intended use, as long as the effects of the surface-modified zinc oxide powder are not impaired. Examples of additives include various additives that are added to dental articles, such as fillers and colorants. Furthermore, the dental resin material of the present invention may further contain inorganic antibacterial agents other than zinc oxide or organic antibacterial agents.

[0041] Dental resin materials and dental articles such as dentures made therefrom can be manufactured by methods commonly used in the industry, in accordance with the methods described in the Examples or Test Examples, taking into account the base material used and the desired dental article.

[0042] The term "antibacterial" as used herein encompasses a range of properties, from "bactericidal" which kills bacteria to "bacteriostatic" which inhibits bacterial growth, but "bacteriostatic" is preferred. This is because it is preferable to inhibit the growth of periodontal disease-causing bacteria, caries-causing bacteria, fungi, etc., while maintaining the oral cavity's immunity without killing the normal oral bacteria.

[0043] Antibacterial dentures made from the dental resin material of the present invention have the properties required for dentures, such as mechanical strength and low water absorption, and not only are they antibacterial, but they can also inhibit the adhesion of denture plaque and reduce the malodor of methyl mercaptan and other substances that cause bad breath.

[0044] Furthermore, the dental resin material of the present invention can also be used for flexible dental articles such as night guards, and can inhibit the growth of bacteria that cause periodontal disease, bacteria that cause dental caries, fungi, and the like while sleeping, and reduce the generation of substances that cause bad breath. [Example]

[0045] The present invention will be explained in more detail below with reference to examples and test examples, but the present invention is not limited to these examples in any way.

[0046] Example 1: Preparation of resin material containing surface-modified zinc oxide powder Surface-modified zinc oxide powder AD-PSJ (manufactured by Nissho Chemical Co., Ltd.) was blended with acrylic resin at concentrations of 1.5 mass%, 1.0 mass%, and 0.5 mass%, and molded into resin materials (acrylic resin discs) containing the surface-modified zinc oxide powder as follows.

[0047] A cylindrical silicone mold with a diameter of 17.5 mm and a height of 50 mm was embedded in a flask. 20 g of powdered Basis Resin (acrylic resin, manufactured by Yamahachi Dental Materials Co., Ltd.) was mixed with 8.6 mL of liquid and left to stand at room temperature for 20 minutes. The resulting acrylic resin was poured into the silicone mold and pressed at 40 kg / cm using a hydraulic press (TD-607; manufactured by Yoshida Seisakusho). 2 The flask was immersed in a water bath (Ibo-1; manufactured by Hakusui Trading Co., Ltd.), heated, and the polymerization was completed 30 minutes after boiling.

[0048] The flask was removed from the water bath and left at room temperature for 30 minutes, then placed in water to cool completely. The polymerized acrylic resin was then excavated. The excavated cylindrical acrylic resin was cut into 1.2 mm thick pieces using an automatic rotary cutter (ISOMET 11-1180 Low Speed ​​Saw; Buehler Ltd., IL, USA). The top and bottom surfaces were then polished with #1000 waterproof abrasive paper to obtain acrylic resin discs with a diameter of 17.5 ± 0.5 mm and a thickness of 1.0 ± 0.2 mm.

[0049] The diameter of the prepared acrylic resin disk was measured at two locations and the thickness at five locations using a micrometer (Mitutoyo; manufactured by Shinano Seisakusho Co., Ltd.) with an accuracy of 0.001 mm, and the volume V of the acrylic resin disk was calculated from the average diameter and thickness values.

[0050] The prepared acrylic resin disk was dried in a desiccator and repeatedly weighed on an electronic balance (AUW120D; Shimadzu Corporation) until the mass reached 0.2 mg within 24 hours. Once the mass reached a constant value, the disk was immersed in water at 37°C.

[0051] Test Example 1: Water absorption test of resin material containing surface-modified zinc oxide powder It was confirmed whether the water absorption of the resulting resin material would change by adding the surface-modified zinc oxide powder.

[0052] A water absorption test was conducted using acrylic resin discs (test pieces) containing surface-modified zinc oxide powder AD-PSJ at concentrations of 1.5 mass%, 1.0 mass%, and 0.5 mass%, respectively, and, as a comparative control, an acrylic resin disc (control piece) not containing the surface-modified zinc oxide powder.

[0053] Acrylic resin discs of test and control specimens were stored in water at 37°C for 1 day, 7 days, and 28 days. After each storage period, the acrylic resin discs were removed from the water, the surface moisture was wiped off with a dry towel, and they were shaken in air for 15 seconds. After 1 minute, they were weighed and the mass was recorded as m1. After weighing, the acrylic resin discs were again dried in a desiccator, and the mass at which they reached a constant weight was recorded as m2. The water absorption amount was calculated from the obtained mass data of the acrylic resin discs using the following formula. Five acrylic resin discs (test and control specimens) were used for each group. W sp =(m1-m2) / V During the ceremony, W sp : Water absorption amount (μg / mm 3 ) m1: Mass (μg) of the acrylic resin disc immediately after immersion in water m2: Dry mass of acrylic resin disc (μg) V: Volume of the acrylic resin disc (mm 3 )

[0054] The results of the water absorption are shown in the graph of FIG. From the graph in Figure 1, it can be seen that for both the control piece without surface-modified zinc oxide powder and the acrylic resin disc (test piece) without surface-modified zinc oxide powder, there was a difference in the amount of water absorbed after 7 and 28 days compared to 1 day of storage in water, but there was no difference in the amount of water absorbed after 7 and 28 days of storage in water. This shows that adding surface-modified zinc oxide powder does not affect the water absorption of acrylic resin.

[0055] Test Example 2: Evaluation of the mechanical properties of resin materials containing surface-modified zinc oxide powder It was confirmed that the antibacterial dental material of the present invention, for example, in the case of dentures, is used in the constantly moist environment of the oral cavity, and therefore its strength does not decrease due to water absorption. Three-point bending tests were conducted using plate-shaped acrylic resin (test pieces) containing surface-modified zinc oxide powder at concentrations of 1.5 mass%, 1.0 mass%, and 0.5 mass%, respectively, and, as a comparative control, plate-shaped acrylic resin (control piece) not containing surface-modified zinc oxide powder.

[0056] The test and control acrylic resin plates were prepared as follows. A plate-shaped silicone mold was embedded in a flask. 10 g of Basis Resin powder and 4.3 mL of liquid were mixed and left at room temperature for 15 minutes. The resulting mochi-like acrylic resin was poured into the plate-shaped silicone mold and pressed with a hydraulic press at 40 kg / cm. 2 The flask was immersed in a water bath and heated, and polymerization was completed 30 minutes after heating. The flask was then removed from the water and left at room temperature for 30 minutes, after which it was placed back in water to cool completely, and the polymerized acrylic resin was extracted.

[0057] The excavated acrylic resin plates were polished with waterproof sandpaper #600 to a width of 25 mm and a thickness of 3 mm, and then cut with an automatic rotary cutter to a length of 3 mm to obtain test pieces measuring 3 mm length x 25 mm width x 3 mm thickness. A control piece was prepared in the same manner as the test pieces, except that it did not contain the surface-modified zinc oxide powder.

[0058] The obtained test and control pieces of the acrylic resin plates were stored in water at 37°C for 1 day, 7 days, and 28 days. After each storage period, the acrylic resin plates were removed from the water, the surface was wiped dry with a dry towel, and then they were subjected to testing.

[0059] Three-point bending strength tests were performed using a small benchtop testing machine (EZTest; Shimadzu Corporation) with a support distance of 20 mm and a crosshead speed of 1 mm / min, and the bending strength and bending modulus were calculated using analysis software (TRAPEZUM2; Shimadzu Corporation). There were 15 test pieces and 15 control pieces in each group. The obtained results of bending strength are shown in the graph of FIG. 2, and the results of bending modulus are shown in the graph of FIG.

[0060] From the graph in Figure 2, it can be seen that the flexural strength of the test specimens on the 1st and 7th days was inferior to that of the control specimens, but on the 28th day, no difference was observed between the test specimens and the control specimens.

[0061] From the graph in FIG. 3, no difference in flexural modulus was observed between the test specimen and the control specimen on the 1st, 7th, or 28th day.

[0062] The results of Test Examples 1 and 2 show that dental resin materials containing the surface-modified zinc oxide powder of the present invention have low water absorption (swelling) even in the humid environment of the oral cavity, and do not lose mechanical strength, making them suitable as dental resin materials to be used in the oral cavity.

[0063] Test Example 3: Antibacterial test of surface-modified zinc oxide powder against oral bacteria To confirm the antibacterial properties of AD-PSJ, a surface-modified zinc oxide powder, against periodontal disease-causing bacteria, caries-causing bacteria, and fungi.

[0064] (Test strain) Periodontal disease-causing bacteria: Porphyromonas gingivalis (P. gingivalis) ATCC33277 strain Dental caries-causing bacteria: Streptococcus mutans (S.mutans) Ingbritt strain Fungus: Candida albicans (C.albicans) ATCC10231 strain

[0065] P. gingivalis was cultured at 37°C under anaerobic conditions (70% N2, 15% H2, 15% CO2) (ANX-1; HIRASAWA) using BHI blood agar medium containing 5% defibrinated sheep blood (BHI blood plates). S. mutans was cultured in a medium (BHI·YHK medium) containing brain heart infusion (BHI) broth (Becton Dickinson Co.) supplemented with yeast extract (5 mg / mL) (Becton Dickinson Co.), hemin (5 μg / mL) (Wako Pure Chemical Industries, Ltd.), and vitamin K1 (10 μg / mL) (Wako Pure Chemical Industries, Ltd.). C. albicans was cultured on nutrient agar medium (Nissui Pharmaceutical Co., Ltd.) under aerobic conditions at 37°C (Alp Co., Ltd.).

[0066] After overnight incubation, P. gingivalis was adjusted to an absorbance of 0.6 at a wavelength of 550 nm (viable cell count at the start of the experiment: 2.0 × 10 9 ±1.0×10 7 CFU / mL), S. mutans (viable cell count at the start of the experiment: 1.0 × 10 9 ±1.5×10 8 CFU / mL), and C. albicans (viable cell count at the start of the experiment: 3.0 × 10 7 ±7.5×10 6 Surface-modified zinc oxide powder AD-PSJ was added to a culture solution containing 1% of the surface-modified zinc oxide powder AD-PSJ at a concentration of 1% (CFU / mL). The culture was stirred with a stirrer to prevent precipitation, and the viable bacterial count (CFU / mL) was measured over time up to 24 hours. The viable bacterial count was also measured in parallel for a control sample to which no surface-modified zinc oxide powder had been added. The results are shown in the graphs in Figures 4 to 6.

[0067] The graph in Figure 4 shows that the number of viable P. gingivalis bacteria decreased over time with the addition of surface-modified zinc oxide powder, and no viable bacteria were detected after 12 hours. These results confirmed that surface-modified zinc oxide powder has strong antibacterial properties against P. gingivalis, a bacteria that causes periodontal disease.

[0068] The graph in Figure 5 shows that the number of viable S. mutans bacteria decreased over time with the addition of surface-modified zinc oxide powder. This result confirmed that the surface-modified zinc oxide powder has mild antibacterial properties against the caries-causing bacterium S. mutans.

[0069] The graph in Figure 6 shows that even when surface-modified zinc oxide powder was added, the viable cell count of C. albicans slowly increased over time, but growth was suppressed compared to the control without surface-modified zinc oxide powder. These results confirmed that the surface-modified zinc oxide powder has a growth-inhibiting effect on the fungus C. albicans.

[0070] Test Example 4: Test to inhibit adhesion of oral bacteria to dental resin materials containing surface-modified zinc oxide powder To confirm that dental resin materials containing surface-modified zinc oxide powder have the effect of inhibiting plaque adhesion.

[0071] Plaque adhesion tests were conducted using acrylic resin discs (test pieces) containing the surface-modified zinc oxide powder AD-PSJ at concentrations of 1.0 mass % and 0.5 mass %, respectively. An acrylic resin disk was immersed in 5 mL of liquid medium containing 100 μL of each culture of P. gingivalis, S. mutans, and C. albicans, and cultured for 18 hours. After culture, the acrylic resin disk was washed three times with 1% phosphate-buffered saline (PBS). The acrylic resin disk was immersed in 5 mL of PBS and sonicated for 1 minute using a Transsonic T780 (ultrasonic cleaner; manufactured by Elma Schmidbauer GmbH) to detach the bacteria from the acrylic resin disk. The detached bacterial suspension was diluted and smeared on an agar medium for culture, and the viable cell count was measured. The results are shown in the graph in Figure 7.

[0072] The graph in Figure 7 shows that for all three types of oral bacteria, the number of bacteria adhering to the acrylic resin disc decreased depending on the concentration of surface-modified zinc oxide powder. This confirmed that dental resin materials containing surface-modified zinc oxide powder have the effect of inhibiting plaque adhesion.

[0073] Test Example 5: Test of breath odor suppression effect of resin material containing surface-modified zinc oxide powder This study aims to confirm whether dental resin materials containing surface-modified zinc oxide powder can reduce the amount of methyl mercaptan, a substance that causes strong bad breath in patients with periodontal disease.

[0074] Acrylic resin discs (test specimens) containing surface-modified zinc oxide powder AD-PSJ at concentrations of 0.5%, 1.0%, and 1.5% and acrylic resin discs without surface-modified zinc oxide powder (control) were immersed in a P. gingivalis culture solution and cultured for two days. After culture, the acrylic resin discs were washed three times with sterile distilled water, placed in superior tubes, and sealed with parafilm. The discs were agitated by end-over-end mixing using a rotary incubator RT-30mini (Tytec Corporation). After two days, the acrylic resin discs were transferred to new superior tubes, sealed, and agitated by end-over-end mixing again. After 24 hours, the amount of methyl mercaptan (CH3SH) in the superior tubes was measured using an OralChroma CHM-1 (Nissha FIS Co., Ltd.). The results are shown in Table 1.

[0075] [Table 1]

[0076] The results in Table 1 show that resin materials containing surface-modified zinc oxide powder reduce the amount of methyl mercaptan produced by P. gingivalis. It is also clear that the amount of methyl mercaptan is reduced more significantly depending on the content of surface-modified zinc oxide powder. This confirmed that resin materials containing surface-modified zinc oxide powder can reduce the amount of methyl mercaptan, a substance that causes strong bad breath in patients with periodontal disease.

[0077] Test Example 6: Bad breath suppression test using a night guard containing surface-modified zinc oxide powder Subjects (patients with periodontal disease) will be asked to wear a night guard made from a resin material containing surface-modified zinc oxide powder, and it will be confirmed whether the amount of volatile sulfides (hydrogen sulfide H2S, methyl mercaptan CH3SH, and dimethyl sulfide (CH3)2S), which are substances that cause bad breath, will decrease. A "night guard" is a mouthpiece used during sleep, and is used by periodontal disease patients to cushion and protect their teeth when they grind or clench their teeth while sleeping.

[0078] The subjects were asked to brush their teeth before going to bed, and the concentrations (unit: ppb) of three types of volatile sulfides in their breath immediately after brushing were measured using an oral odour measuring device, OralChroma (manufactured by Nissha FIS). Next, the subjects were asked to wear a night guard made of a resin material that did not contain surface-modified zinc oxide powder while sleeping. The concentrations (ppb) of three types of volatile sulfides in their breath were measured in the same way the next morning when they woke up. The next day, the subjects brushed their teeth before going to bed and wore a night guard made of a resin material containing 1% by mass of surface-modified zinc oxide powder AD-PSJ while they slept. The concentrations (ppb) of the three volatile sulfides in their breath were measured in the same way the next morning upon waking. The results are shown in Table 2.

[0079] [Table 2]

[0080] The results in Table 2 show that by wearing a night guard containing surface-modified zinc oxide powder, the concentrations of the three bad breath components were reduced by approximately half. Specifically, hydrogen sulfide was reduced by 44%, methyl mercaptan by 53%, and dimethyl sulfide by 64%. This confirmed that night guards made from resin materials containing surface-modified zinc oxide powder can reduce volatile sulfides, which are the cause of bad breath in patients with periodontal disease.

[0081] The above test results show that the dental resin material of the present invention, even when blended with surface-modified zinc oxide powder, retains properties such as water absorption and mechanical strength equivalent to those of resins that do not blend with surface-modified zinc oxide powder, has high antibacterial properties against oral bacteria, particularly bacteria that cause periodontal disease, can reduce adhesion of oral bacteria to the surface of the resin material, and can suppress volatile sulfides, which are substances that cause bad breath. [Industrial Applicability]

[0082] The dental resin material of the present invention is useful as various materials applied to the oral cavity in the dental field, temporary fillings used during treatment, adhesives such as luting cements, fixed crowns, dentures, denture bases, etc. It can also be used as night guards, toothbrush bristles, toothbrush handles, etc. Furthermore, the dental resin material of the present invention is useful not only in the dental field but also as a resin material for articles used in the oral cavity, such as mouthpieces used in sports such as boxing.

Claims

1. An antibacterial denture or night guard made of a dental resin material in which surface-modified zinc oxide powder is dispersed, The zinc oxide powder has an average particle size in the range of 50 to 300 nm, the surface modification is coating with a silane coupling agent, the surface modification is partial coating of the zinc oxide powder surface, The coating amount of the silane coupling agent is 0.2 to 15 mass %, The amount of the surface-modified zinc oxide powder is 0.1 to 1.5% by mass. Antibacterial dentures or night guards.

2. 2. The antibacterial denture or night guard according to claim 1, which inhibits the growth of periodontal disease-causing bacteria, caries-causing bacteria and / or fungi.

3. The antibacterial denture or night guard according to claim 1, which inhibits the adhesion of denture plaque.

4. The antibacterial denture or night guard of claim 1, which reduces substances that cause bad breath.

5. An antibacterial denture or night guard as described in claim 1, wherein the amount of surface-modified zinc oxide powder is 0.5 to 1.5 mass%.

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