Denture cleaning tablet and preparation method thereof

Abstract

The invention relates to the technical field of oral hygiene products, and particularly provides a denture cleaning tablet and a preparation method thereof, the denture cleaning tablet comprises a cleaning layer and a coating layer at least partially coating the surface of the cleaning layer; the coating layer comprises pullulan or pectin; the cleaning layer sequentially comprises an upper layer, a middle layer and a lower layer from top to bottom; wherein the upper layer comprises effervescent particles, a surfactant, an activating agent, a color developing agent, essence, filler, a preservative and a scale inhibitor; the middle layer comprises water-soluble matrix microspheres and a chelating agent; the lower layer comprises a rice bran bioactive component, sodium phytate and an adhesive; in the upper layer, the effervescent granules comprise quick-release granules and slow-release granules, and the mass ratio of the quick-release granules to the slow-release granules is (1.5-2): (1-1.3). According to the denture cleaning sheet, the effective sterilization and microorganism inactivation process is observed through the color development reaction between the color developing agent and the oxidizing agent, the color change in an aqueous solution is changed from blue to green, and the sterilization effect can be detected more visually and rapidly.

Description

Technical Field

[0001] This invention relates to the field of oral hygiene products technology, and more specifically, it provides a denture cleaning sheet and its preparation method. Background Technology

[0002] Dentures, also known as prostheses, are artificial devices that replace missing teeth and help restore chewing, aesthetics, and speech functions. Proper care is essential to prolong their lifespan and maintain oral health. The development of denture cleaning technology is as follows: 1. First-generation cleaning technology (1980-2000): The main component is sodium perborate, which requires hot water activation; cold water reduces its sterilization efficiency by 83%. 2. Second-generation cleaning technology (2000-2015): Improvements include the introduction of TAED activator; however, the determination of the reaction endpoint relies on experience (bubble observation method), and the color indicator has poor stability (a 45% failure rate after 6 months of storage).

[0003] However, with the continuous development of denture cleaning technology, the following problems still exist: 1. The sterilization effect is not visible: Commercially available products generally lack a real-time effect feedback mechanism, and users cannot intuitively judge the degree of cleaning; 2. Alkaline corrosion risk: High pH value cleaners (pH>11) cause corrosion of metal clasps, and clinical data show that the average annual damage rate is as high as 17%; 3. Insufficient biofilm removal: The removal rate of Streptococcus mutans biofilm is less than 60%, which can easily cause denture stomatitis.

[0004] In response to the key shortcomings of existing technologies, such as the lack of visible cleaning effects and insufficient sterilization efficiency, there is an urgent need to develop a new generation of breakthrough denture cleaning tablets to upgrade traditional cleaning products to have the dual functions of powerful sterilization and visible effects, thereby significantly improving the hygiene and safety of the products and the user experience. Summary of the Invention

[0005] The present invention aims to solve at least one of the above-mentioned problems.

[0006] This invention provides a denture cleaning tablet, comprising: a cleaning layer and a coating layer at least partially covering the surface of the cleaning layer; the coating layer comprises pullulan or pectin; the cleaning layer comprises, from top to bottom, an upper layer, a middle layer, and a lower layer; wherein, the upper layer comprises effervescent particles, a surfactant, an activator, a color developer, a fragrance, a filler, a preservative, and a scale inhibitor; the middle layer comprises water-soluble matrix microspheres and a chelating agent; the lower layer comprises rice bran bioactive components, sodium phytate, and a binder; in the upper layer, the effervescent particles comprise immediate-release particles and sustained-release particles, with a mass ratio of immediate-release particles to sustained-release particles of (1.5~2):(1~1.3).

[0007] In the above technical features, the mass ratio of the upper, middle and lower layers in the cleaning layer is 1:(0.3~0.4):(0.6~0.7); the thickness of the coating layer is 8~12μm.

[0008] In any of the above technical features, in the upper layer, the mass ratio of effervescent granules, surfactant, activator, color developer, fragrance, filler, preservative and scale inhibitor is 1:(0.001~0.03):(0.001~0.1):(0.001~0.1):(0.001~0.1):(0.001~0.1):(0.001~0.1):(0.001~0.08); in the middle layer, the mass ratio of water-soluble matrix microspheres and chelating agent is (1~3):1; in the lower layer, the mass ratio of rice bran bioactive components, sodium phytate and binder is 5:(1~1.2):(2~2.2).

[0009] In any of the above technical features, the immediate-release particles include sodium percarbonate and sodium bicarbonate; the sustained-release particles include sodium bicarbonate, sodium carbonate, and anhydrous citric acid; the surfactant includes sodium dodecyl sulfate; the activator includes tetraacetyl ethylenediamine; the color developer includes indigo carmine and tartrazine aluminum lake; the filler includes microcrystalline cellulose and polyvinyl alcohol; the preservative includes sodium benzoate; the scale inhibitor includes sodium tripolyphosphate; the water-soluble matrix microspheres include dextrin microspheres and / or isomaltitol microspheres; the chelating agent includes sodium gluconate; the rice bran bioactive components include rice bran polyphenols and γ-oryzanol; and the binder includes polyvinyl alcohol and copovidone.

[0010] This invention also provides a method for preparing a denture cleaning tablet, used to prepare a denture cleaning tablet as described in any of the above technical features, the preparation method comprising the following steps: S100, a clean layer is obtained by pressing lower layer powder, middle layer powder and upper layer powder into tablets from bottom to top; S200: The cleaning layer is sprayed with a coating solution and then dried sequentially to obtain a denture cleaning sheet; The lower layer powder includes rice bran bioactive components, sodium phytate, and binders; the middle layer powder includes water-soluble matrix microspheres and chelating agents; the upper layer powder includes effervescent granules, surfactants, activators, color developers, fragrances, fillers, preservatives, and scale inhibitors. The effervescent granules include immediate-release granules and sustained-release granules, with a mass ratio of (1.5~2):(1~1.3); the coating layer solution includes pullulan polysaccharide solution or pectin solution.

[0011] In any of the above technical features, the lower layer powder contains rice bran bioactive components in the form of microcapsules of rice bran bioactive components, and the preparation method of the microcapsules of rice bran bioactive components includes the following steps: S101. Add γ-oryzanol and lecithin to edible oil and heat until dissolved to obtain the oil phase; S102. Add maltodextrin and gum arabic to deionized water and stir. Then add rice bran polyphenol concentrate and continue stirring. Adjust the pH to obtain an aqueous phase. S103. The oil phase is added to the aqueous phase for emulsification treatment to obtain a crude emulsion; S104. Add antioxidants to crude emulsion and stir evenly, then perform spray treatment and second drying treatment to obtain microcapsules of rice bran bioactive components.

[0012] In any of the above technical features, in S101, the heating temperature is 40~45℃; in S102, the stirring temperature is 40~50℃; in S102, the pH is adjusted to 5.0~6.0; in S103, the emulsification speed is 10000~15000rpm; in S104, the inlet air temperature of the spray treatment is 140~160℃, and the outlet air temperature is 85~95℃; in S104, the second drying treatment is vacuum drying.

[0013] In any of the above technical features, the preparation method of water-soluble matrix microspheres includes the following steps: S111. Dissolve dextrin and / or isomalt in deionized water to form a solution; S112. The solution is dropped into liquid nitrogen or a low-temperature plate for freeze-drying to form water-soluble matrix microspheres.

[0014] In any of the above technical features, in S112, the freeze-drying temperature is -40~-45℃.

[0015] In any of the above technical features, the concentration of the coating layer solution in S200 is 3-6%.

[0016] The technical effects that can be achieved by adopting the technical solution of the present invention are as follows: 1. The denture cleaning tablet of the present invention observes the effective sterilization and microbial inactivation process through the color reaction between the color developer and the oxidant. The color change in the aqueous solution is from blue to green, which can more intuitively and quickly detect the sterilization effect; 2. Indigo carmine and lemon yellow aluminum lakes are prone to fading or hue shifting under oxidizing conditions. Rice bran polyphenols and γ-oryzanol in the lower layer can complex the metal elements in the color developer or capture the oxidant, so that the color development can be stopped at a controllable endpoint. In this way, users can accurately judge the completion of cleaning by observing the color. 3. The effervescent granules in the upper layer include immediate-release granules and slow-release granules. The immediate-release granules include sodium percarbonate and sodium bicarbonate, which can quickly release CO2, immediately dissolve and disperse the active ingredients, and form strong agitation to play a preliminary role in cleaning. The slow-release granules include sodium bicarbonate, sodium carbonate and anhydrous citric acid, which can delay some acid-base reactions, release gas smoothly, and avoid excessive instantaneous foaming that could lead to overflow. 4. The middle layer can prevent the reaction from being too violent, while extending the time of the intermediate reaction, continuously generating small bubble disturbances, providing system stability, protecting the efficiency of reactive oxygen species, and the release of water-soluble matrix microspheres through different swelling and dissolution rates to ensure continuous bubble disturbance in the middle section and avoid the break in cleaning power. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings to be used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort: Figure 1 This is a schematic diagram of a denture cleaning sheet according to an embodiment of the present invention; Explanation of reference numerals in the attached diagram: 1-Coating layer, 2-Cleansing layer, 21-Upper layer, 22-Middle layer, 23-Lower layer. Detailed Implementation

[0018] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0019] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0020] To make the above-mentioned objectives, features and advantages of this aspect more apparent and understandable, specific embodiments of this aspect are described in detail below.

[0021] Among related technologies, denture cleaning technology has the following problems: 1. The sterilization effect is not visible: commercially available products generally lack a real-time effect feedback mechanism, and users cannot intuitively judge the degree of cleaning; 2. Alkaline corrosion risk: high pH value cleaners (pH>11) cause corrosion of metal clasps, and clinical data show that the average annual damage rate is as high as 17%; 3. Insufficient biofilm removal: the removal rate of Streptococcus mutans biofilm is less than 60%, which can easily cause denture stomatitis.

[0022] In view of this, the present invention addresses the key shortcomings of existing technologies, such as the lack of visualization of cleaning effects and insufficient sterilization efficiency, by providing a groundbreaking new generation of denture cleaning tablets. This product maintains excellent stain removal performance while achieving two core technological breakthroughs: first, it constructs a broad-spectrum and highly efficient sterilization system, ensuring a kill rate of over 99.9% against bacteria, fungi, and other microorganisms; second, it employs a color-developing system that uses a blue-green color gradient induced by an oxidation-reduction reaction to achieve real-time visualization and verification of the sterilization effect, and locks in the final color. This upgrades traditional cleaning products to possess both powerful sterilization and visible effects, significantly improving product hygiene and safety and user experience.

[0023] Specifically, embodiments of the present invention provide a denture cleaning tablet, comprising: a cleaning layer 2 and a coating layer 1 at least partially covering the surface of the cleaning layer 2; the coating layer 1 comprises pullulan or pectin; the cleaning layer 2 comprises, from top to bottom, an upper layer 21, a middle layer 22 and a lower layer 23; wherein, the upper layer 21 comprises effervescent particles, surfactants, activators, colorants, fragrances, fillers, preservatives and scale inhibitors; the middle layer 22 comprises water-soluble matrix microspheres and chelating agents; the lower layer 23 comprises rice bran bioactive components, sodium phytate and binders; in the upper layer 21, the effervescent particles comprise immediate-release particles and sustained-release particles, and the mass ratio of immediate-release particles to sustained-release particles is (1.5~2):(1~1.3).

[0024] Preferably, the denture cleaning tablet of the present invention is designed with a coating layer 1 covering a cleaning layer 2. A natural, edible, and safe film material, pullulan or pectin, is used as the coating layer 1 to cover the cleaning layer 2. This prevents the cleaning layer 2 from directly contacting moisture, bacteria, etc., before use, delaying the decomposition of the cleaning layer 2 due to moisture, protecting the active ingredients in the cleaning layer 2, and also improving the mechanical strength of the tablet, reducing breakage during transportation. The thickness of the coating layer 1 is preferably 8~12μm, which is sufficient to protect the cleaning layer 2 without significantly prolonging the time required for the cleaning layer 2 to disintegrate. The cleaning layer 2 is the main functional layer of the denture cleaning tablet, consisting of layers from top to bottom... The system comprises an upper layer 21, a middle layer 22, and a lower layer 23. In the upper layer 21, effervescent granules rapidly absorb water and disintegrate upon contact with water, generating numerous bubbles that physically wash away loose dirt. Surfactants reduce surface tension, aiding in cleaning and wetting the denture surface; sodium dodecyl sulfate (SLS) is preferred, as adding a low dose of SLS improves cleaning efficiency and effectively prevents excessive foaming. Activators enhance the bactericidal and bleaching efficiency of oxidants such as sodium percarbonate; tetraacetylethylenediamine (TAED) is preferred, as TAED reacts with sodium percarbonate in the effervescent granules to produce peracetic acid, providing powerful bactericidal and bleaching effects. This enhances the effectiveness of oxidative cleaning, especially against fungi and stains. The color developer indicates the reaction progress through color changes, signaling to the user that cleaning is complete. The color developers include indigo carmine and tartrazine aluminum lake. Since effervescent granules are primarily alkaline, the oxidation and fading process is accelerated in an alkaline environment. The reactive oxygen species generated by the peroxides slowly oxidize the pigments, causing them to fade. Natural pigments are more easily oxidized and faded. When multiple indicators are released simultaneously, the solution will initially show the color of a higher proportion of natural pigments. However, when some of the natural pigments are oxidized and combine with ordinary pigments in a certain proportion, the solution will change to other colors. The denture cleaning tablets of this invention observe the effective sterilization and microbial inactivation process through a colorimetric reaction between a chromogenic agent and an oxidizing agent. The color change in the aqueous solution from blue to green allows for more intuitive and rapid detection of the sterilization effect. The flavoring masks oxidative and medicinal tastes, enhancing the palatability. The fillers include microcrystalline cellulose and polyvinyl alcohol. Microcrystalline cellulose enhances the mechanical strength of the tablets and increases physical disturbance during disintegration, further enhancing the cleaning effect. Polyvinyl alcohol provides adhesion, stabilizing particle formation. Preservatives ensure the microbial stability of the formulation during storage; sodium benzoate is preferred. The scale inhibitor can complex Ca... 2+ Mg 2+ This helps prevent plaque buildup on dentures and keeps them clean.

[0025] Furthermore, effervescent granules include immediate-release granules and sustained-release granules. Immediate-release granules include sodium percarbonate and sodium bicarbonate, with a particle size in the range of 50~120µm. They can quickly release CO2, immediately dissolve and disperse the active ingredients, and form strong agitation, playing a preliminary role in cleaning. Suppressed-release granules include sodium bicarbonate, sodium carbonate, and anhydrous citric acid, with a particle size in the range of 200~350µm. They can delay part of the acid-base reaction, smoothly release gas, and avoid excessive instantaneous foaming that leads to overflow. If there are too many immediate-release granules, the reaction will be concentrated, and the instantaneous foaming will be too strong, which may lead to foam overflow and insufficient agitation in the middle and later stages, resulting in a decrease in cleaning power. If there are too many sustained-release granules, the foaming will not be fast enough, and the user will perceive a slow cleaning effect and a poor experience. Therefore, the mass ratio of immediate-release granules to sustained-release granules is (1.5~2):(1~1.3), which can ensure rapid foaming without getting out of control, with less overflow and a longer cleaning process.

[0026] Furthermore, the immediate-release granules are prepared using the following method: sodium percarbonate and sodium bicarbonate granules in a mass ratio of (2~3.5):1 are ball-milled or pulverized with blades and then sieved to a size of 50~120µm to obtain immediate-release granules. During the preparation process, excessively fine dust should be avoided, and the water content should be strictly controlled to prevent pre-reaction. The sustained-release granules are prepared using the following method: sodium bicarbonate, sodium carbonate, and anhydrous lemon are mixed evenly in a mass ratio of (1-3.5):1:1, and then added to molten polyethylene glycol 4000 and stirred evenly. After cooling and granulation, sustained-release granules with a particle size of 200~350µm are obtained. Finally, the sustained-release granules are dried to ensure that the water content is below 1%. A small amount of silica can also be added during the preparation of sustained-release granules to improve flowability.

[0027] Preferably, before preparing immediate-release granules and sustained-release granules, sodium percarbonate, sodium bicarbonate, sodium carbonate and anhydrous citric acid need to be vacuum dried in a vacuum drying oven at 40~45℃ for 4~6 hours to reduce their moisture content to below 2% and avoid pre-reaction.

[0028] Preferably, in the upper layer 21, the mass ratio of effervescent granules, surfactant, activator, color developer, fragrance, filler, preservative, and scale inhibitor is 1:(0.001~0.03):(0.001~0.1):(0.001~0.1):(0.001~0.1):(0.001~0.1):(0.001~0.1):(0.001~0.08). Effervescent granules provide the material basis for gas generation, oxidative sterilization, and color development reactions; therefore, they require the largest mass to ensure sufficient CO2 and H2O2 release. They also reduce surface tension, provide humidification, and help remove grease and protein stains. The cleaning power is amplified, but a large amount is not needed to achieve the desired effect. Since the surfactant used is SLS, it is irritating and has a bitter taste upon contact with the mouth. Therefore, the amount used must be limited to ensure a good user experience. Excessive SLS can also lead to excessive foam, oral irritation, or residual foam. If the amount of activator is too small, it will not enhance the sterilization and bleaching efficiency. If too much is used, it will lead to side reactions. To ensure safety, this ratio is appropriate. The color developer uses indigo carmine and lemon yellow aluminum lake for visual cues. The color is very prominent, and a small amount is required to produce a visible color. The fragrance is used to mask the oxidative taste and enhance the taste experience. Flavorings have a strong olfactory effect, so only a small amount is needed; the amount of filler should not be too much, otherwise the effervescent body in the upper layer 21 will be diluted, reducing the cleaning and color intensity. An appropriate amount can improve the processing performance and mechanical stability; preservatives are used to ensure that tablets are not contaminated by microorganisms during humid or long-term storage. If too much is used, there will be safety issues, so a small amount is sufficient; the amount of scale inhibitor should not be too high to avoid oral ion balance problems or the formation of undesirable precipitates with other chelating agents.

[0029] Preferably, the middle layer 22 comprises water-soluble matrix microspheres and a chelating agent. The purpose of the middle layer 22 is mainly to avoid excessively vigorous reactions, prolong the intermediate reaction time, continuously generate small bubble disturbances, provide system stability, and protect reactive oxygen species efficiency. The water-soluble matrix microspheres are released by regulating different swelling and dissolution rates to ensure continuous bubble disturbance in the middle section and avoid cleaning force discontinuity. The chelating agent can gently complex Ca. 2+ and Fe 3+To prevent the peroxidant from decomposing too quickly and to assist in scale inhibition and stabilize the oxidation system, sodium gluconate is preferred as a chelating agent. Sodium gluconate is a mild chelating agent that not only acts as a buffer but also protects the metal rings of dentures from oxidation. The water-soluble matrix microspheres include dextrin microspheres and / or isomaltitol microspheres. Dextrin is a starch hydrolysis product that swells rapidly, forming a slightly viscous environment that effectively prolongs bubble retention. Isomaltitol has low hygroscopicity and slow solubility, forming a porous structure that can gradually prolong CO2 release. Dextrin microspheres and isomaltitol microspheres can be added individually or together. If dextrin microspheres and isomaltitol microspheres are added simultaneously, a mass ratio of 3:7 between dextrin microspheres and isomaltitol microspheres can be used to take advantage of both.

[0030] Preferably, in the middle layer 22, the mass ratio of water-soluble matrix microspheres to chelating agent is (1~3):1. If there are too few water-soluble matrix microspheres, the chelating agent will be released too quickly, losing the significance of the slow-release regulation of the middle layer 22. In the early stage, the superposition of the outer layer components may lead to excessively high foam peaks. If there are too many water-soluble matrix microspheres, the chelating agent will be diluted. Although the slow-release effect is good, the dosage of chelating agent is relatively insufficient, and the scale prevention and stabilization effects are weakened. Therefore, the mass ratio of water-soluble matrix microspheres to chelating agent is preferably (1~3):1.

[0031] Preferably, the lower layer 23 includes rice bran bioactive components, sodium phytate, and an adhesive. The rice bran bioactive components have an inhibitory effect on common oral pathogens such as Streptococcus mutans and Porphyromonas gingivalis. The rice bran bioactive components include rice bran polyphenols and γ-oryzanol. Rice bran polyphenols are rich in phenolic acids such as ferulic acid and p-coumaric acid, and have a polyhydroxy structure, which can directly react with residual ·OH and O2. - Reactive oxygen species such as H2O2 undergo hydrogen donor reactions or electron transfer reactions, converting free radicals into stable phenoxy radicals, thereby halting the oxidation chain reaction. γ-oryzanol, a sterol ester, while not as directly scavenging of reactive oxygen species as polyphenols, has a lipid-soluble structure that can insert into the stain / deposit interface, synergistically improving dispersion and antioxidant efficiency with polyphenols. Adding rice bran polyphenols and γ-oryzanol can effectively prevent further oxidation by residual H2O2, preventing damage to denture materials. Typically, after oxidative cleaning, the denture surface is relatively exposed and easily re-adhesive. Rice bran polyphenols can inhibit bacterial extracellular polysaccharide synthases, reducing biofilm matrix formation. γ-oryzanol, through its surface-like effect, can reduce bacterial adhesion to the denture surface. Adding rice bran polyphenols and γ-oryzanol can prolong the time before re-contamination and reduce rapid bacterial re-adhesion in the oral cavity. Sodium phytate has a positive effect on Fe... 3+ Cu 2+ Ni 2+Plasma has complexing ability and can inhibit the Fenton reaction catalyzed by metal ions, forming a mild protective film. After rice bran polyphenols and γ-oryzanol scavenge free radicals, sodium phytate blocks the metal ion catalysis of hydrogen peroxide, and the two form a complementary barrier. H2O2 and ·OH are rapidly consumed in 8~20 min.

[0032] Furthermore, the metal clasps of dentures commonly use Co-Cr alloys, Ni-Cr alloys, or stainless steel. In strong oxidizing environments, the surface passivation film is easily damaged, leading to pitting corrosion, loss of shine, rough surfaces, and increased susceptibility to dirt and bacteria buildup. Sodium phytate, by chelating Fe... 2+ Cr 3+ Dissolved ions reduce localized electrochemical corrosion. Rice bran polyphenols form a hydrophobic protective film on the metal surface through adsorption, further enhancing protection and thus protecting the metal clasps of dentures.

[0033] Furthermore, indigo carmine and lemon yellow aluminum lakes are prone to fading or hue shifting under oxidizing conditions. Rice bran polyphenols and γ-oryzanol can complex the metal elements in the color developer or capture the oxidant, allowing the color development to remain at a controllable endpoint. In this way, users can accurately judge the completion of cleaning by observing the color, avoiding poor experience caused by excessive time or unstable color.

[0034] Preferably, the lower layer 23 also includes a binder to form a stable tablet structure and prevent delamination. The binder is preferably polyvinyl alcohol (PVA) and copovidone. PVA has good film-forming properties and mechanical strength, enabling it to firmly bind the powder during tableting and slowly swell in solution, thus protecting rice bran polyphenols, γ-oryzanol, and sodium phytate from excessively rapid release or oxidative decomposition in the initial stage. Copovidone (PVP / VA) has excellent hydrophilicity and dispersing and solubilizing effects, improving the release of γ-oryzanol while ensuring the stability of the tablet's interlayer structure. Using PVA alone leads to slow release, making it difficult for the active substances to exert their effects in a timely manner; using PVP / VA alone can easily result in insufficient protection and increased tablet brittleness. The combination of the two achieves a balance between sustained-release protection and moderate rapid release, allowing the active ingredients in the lower layer 23 to be released stably over a longer period, ensuring both the quenching of residual reactive oxygen species and the locking of the colorimetric endpoint, while also enhancing the structural integrity and storage stability of the tablet.

[0035] Preferably, in the lower layer 23, the mass ratio of rice bran bioactive components, sodium phytate, and binder is 5:(1~1.2):(2~2.2). The rice bran bioactive components are the core functional substances, requiring sufficient content to quench residual reactive oxygen species, provide antioxidant effects, and inhibit biofilm regeneration; therefore, they are set at the maximum proportion as the main component. Sodium phytate plays an auxiliary role in metal ion chelation, scale prevention, and metal ring protection; its dosage is controlled at approximately 1 / 5 of the rice bran component, ensuring effectiveness while avoiding safety hazards caused by excessive calcium ion complexation. The binder ensures the formability and interlayer bonding of the lower layer 23, and moderately swells to regulate the release rate of active substances; its proportion is controlled between 40% and 45% of the rice bran bioactive components to prevent tablet brittleness or excessive sustained release. This ratio not only ensures the cleaning tablet completes functional release and endpoint color locking but also balances safety and stability.

[0036] Preferably, in the cleaning layer 2, the mass ratio of the upper layer 21, the middle layer 22, and the lower layer 23 is 1:(0.3~0.4):(0.6~0.7). The upper layer 21 has the largest proportion, ensuring rapid initiation of effervescence and oxidation reactions at the initial stage of water introduction and triggering color development. The middle layer 22 has a smaller proportion, used to smoothly release bubbles in the middle stage, maintain reaction stability, and avoid foam overflow due to excessive instantaneous reaction. The lower layer 23 has a slightly lower proportion than the upper layer 21 but a significantly higher proportion than the middle layer 22, ensuring sufficient release of rice bran polyphenols, γ-oryzanol, and sodium phytate at the end, thereby effectively quenching residual reactive oxygen species, locking the color development endpoint, and inhibiting biofilm regeneration. This ratio achieves a three-stage design of powerful initiation, smooth transition, and functional termination, allowing the cleaning power, color development effect, and functional release of the cleaning tablet to be balanced.

[0037] In some embodiments of the present invention, a method for preparing a denture cleaning tablet is provided, for preparing a denture cleaning tablet as described in any of the above-mentioned technical features, the preparation method comprising the following steps: S100, a clean layer is obtained by pressing lower layer powder, middle layer powder and upper layer powder into tablets from bottom to top; S200: The cleaning layer is sprayed with a coating solution and then dried sequentially to obtain a denture cleaning sheet; The lower layer powder includes rice bran bioactive components, sodium phytate, and binders; the middle layer powder includes water-soluble matrix microspheres and chelating agents; the upper layer powder includes effervescent granules, surfactants, activators, color developers, fragrances, fillers, preservatives, and scale inhibitors. The effervescent granules include immediate-release granules and sustained-release granules, with a mass ratio of (1.5~2):(1~1.3) for immediate-release granules to sustained-release granules; the coating layer solution includes pullulan polysaccharide solution or pectin solution.

[0038] Preferably, in step S100, the tableting process is carried out in a bottom-up order. The bottom layer contains easily oxidized and slow-release active substances such as rice bran polyphenols and γ-oryzanol. By pressing them at the bottom, they can avoid being affected by the external environment during the tableting process, and at the same time, they are conducive to stable release in the final stage. The middle layer powder mainly consists of water-soluble matrix microspheres and chelating agents. Located in the middle, it plays a role in smoothing the release of bubbles and stabilizing the reaction. Pressing it in the middle layer can achieve mid-stage release. The top layer powder consists of immediate-release and slow-release effervescent particles and color developers. Placing it in the outermost layer can ensure that strong effervescence and color development reactions are initiated immediately after water is added. Therefore, this bottom-up tableting sequence helps to achieve a three-stage cleaning sequence. The tableting process can be carried out using a single-layer tablet press, with the corresponding powder being filled in each compression. The first compression involves filling the lower layer of powder with a pressure of 5-8 kN for light compression, the second compression involves filling the middle layer of powder with a pressure of 8-10 kN for light compression, and the third compression involves filling the lower layer of powder with a pressure of 10-15 kN for main compression to form the clean layer. Alternatively, a multi-layer tablet press can be used to fill each layer of powder at once and then compress them sequentially to form the clean layer.

[0039] Furthermore, in the lower layer of powder, the rice bran bioactive components are microcapsules of rice bran bioactive components. The preparation method of the microcapsules of rice bran bioactive components includes the following steps: S101. Add γ-oryzanol and lecithin to edible oil and heat until dissolved to obtain the oil phase; S102. Add maltodextrin and gum arabic to deionized water and stir. Then add rice bran polyphenol concentrate and continue stirring. Adjust the pH to obtain an aqueous phase. S103. The oil phase is added to the aqueous phase for emulsification treatment to obtain a crude emulsion; S104. Add antioxidants to crude emulsion and stir evenly, then perform spray treatment and second drying treatment to obtain microcapsules of rice bran bioactive components.

[0040] Preferably, γ-oryzanol and lecithin are first added to edible oil and heated until dissolved. This ensures stable dispersion and prevents instability in the aqueous phase. The heating temperature is 40-45℃, which dissolves γ-oryzanol and lecithin while preventing high-temperature degradation. Then, maltodextrin and gum arabic are added to the aqueous phase and stirred. This serves as a film-forming wall material and stabilizes the emulsion. Simultaneously, rice bran polyphenols are placed in a hydrophilic environment and stirred further, with the pH adjusted to 5.0-6.0. The stirring temperature is 40-50℃, which maintains the antioxidant activity of the rice bran polyphenols. Through emulsification… The process involves forming a uniform O / W emulsion between the oil and aqueous phases, achieving co-encapsulation of hydrophilic and hydrophobic active substances. The emulsification process is carried out at 10,000–15,000 rpm to ensure the formation of uniform nano- or submicron-sized droplets, improving microcapsule uniformity. Subsequent spray drying rapidly shapes the microcapsules and reduces degradation of active ingredients under antioxidant protection. The inlet air temperature for spray drying is 140–160°C, and the outlet air temperature is 85–95°C, ensuring rapid shaping while preventing thermal degradation of the active substances. Finally, vacuum drying further reduces the moisture content to below 3%, improving storage stability. The resulting microcapsules have uniform particle size and high encapsulation efficiency. They not only maintain the activity of rice bran polyphenols and γ-oryzanol during tablet compression and storage but also achieve delayed release during use, thereby quenching residual reactive oxygen species and locking in color at the final stage.

[0041] Furthermore, the preparation method of water-soluble matrix microspheres includes the following steps: S111. Dissolve dextrin and / or isomalt in deionized water to form a solution; S112. The solution is dropped into liquid nitrogen or a low-temperature plate for freeze-drying to form water-soluble matrix microspheres.

[0042] Preferably, the water-soluble matrix microspheres are prepared by dissolving dextrin and / or isomaltitol in water, then dropping the solution into liquid nitrogen or a cryogenic plate, followed by freeze-drying at -40 to -45°C. This method utilizes the low-temperature freeze-drying process to avoid degradation of heat-sensitive components while simultaneously creating a porous structure. This allows the resulting water-soluble matrix microspheres to swell rapidly and release gradually upon contact with water, thus prolonging bubble release and maintaining reaction stability. This method is simple, safe, and suitable for food-grade raw materials. Alternatively, water-soluble matrix microspheres can also be prepared using spray drying, spray freeze-drying, fluidized bed granulation, or melt spray condensation processes, which can be selected by those skilled in the art based on the specific circumstances.

[0043] Preferably, in step S200, pullulan or pectin are selected as natural edible coating materials for the coating treatment, which can improve the mechanical strength and moisture resistance of the tablets, ensure oral safety, and avoid the toxic risks that may be brought about by synthetic polymers; the concentration of the coating solution is controlled between 3 and 6% to ensure that the coating is uniform and dense, and to avoid being too thick and delaying disintegration.

[0044] Example 1 This embodiment provides a denture cleaning sheet, comprising: a cleaning layer and a coating layer that at least partially covers the surface of the cleaning layer; The coating layer is pullulan polysaccharide with a thickness of 8 μm; the clean layer consists of an upper layer, a middle layer and a lower layer from top to bottom, and the mass ratio of the upper layer, the middle layer and the lower layer in the clean layer is 1:0.3:0.6. The upper layer includes effervescent granules, surfactants, activators, color developers, fragrances, fillers, preservatives, and scale inhibitors; the middle layer includes water-soluble matrix microspheres and chelating agents; and the lower layer includes rice bran bioactive components, sodium phytate, and binders. In the upper layer, the mass ratio of effervescent granules, surfactant, activator, color developer, fragrance, filler, preservative, and scale inhibitor is 1:0.001:0.001:0.001:0.001:0.001:0.001. The effervescent granules include immediate-release granules and sustained-release granules. The immediate-release granules include sodium percarbonate and sodium bicarbonate, and the sustained-release granules include sodium bicarbonate, sodium carbonate, and anhydrous citric acid. The mass ratio of immediate-release granules to sustained-release granules is 1.5:1. The surfactant is sodium dodecyl sulfate, the activator is tetraacetyl ethylenediamine, the color developer is indigo carmine and tartrazine aluminum lake, the filler is microcrystalline cellulose and polyvinyl alcohol, the preservative is sodium benzoate, and the scale inhibitor is sodium tripolyphosphate. In the middle layer, the mass ratio of water-soluble matrix microspheres to chelating agent is 1:1. The water-soluble matrix microspheres are dextrin microspheres, and the chelating agent is sodium gluconate. In the lower layer, the mass ratio of rice bran bioactive components, sodium phytate, and binder is 5:1:2. The rice bran bioactive components are rice bran polyphenols and γ-oryzanol, and the binder is polyvinyl alcohol and copolyvinyl ketone.

[0045] Example 2 This embodiment provides a denture cleaning sheet, comprising: a cleaning layer and a coating layer that at least partially covers the surface of the cleaning layer; The coating layer is pectin with a thickness of 12 μm; the cleaning layer consists of an upper layer, a middle layer and a lower layer from top to bottom, and the mass ratio of the upper layer, the middle layer and the lower layer in the cleaning layer is 1:0.4:0.7. The upper layer includes effervescent granules, surfactants, activators, color developers, fragrances, fillers, preservatives, and scale inhibitors; the middle layer includes water-soluble matrix microspheres and chelating agents; and the lower layer includes rice bran bioactive components, sodium phytate, and binders. In the upper layer, the mass ratio of effervescent granules, surfactant, activator, color developer, fragrance, filler, preservative, and scale inhibitor is 1:0.03:0.1:0.1:0.1:0.1:0.08. The effervescent granules include immediate-release granules and sustained-release granules. The immediate-release granules include sodium percarbonate and sodium bicarbonate, and the sustained-release granules include sodium bicarbonate, sodium carbonate, and anhydrous citric acid. The mass ratio of immediate-release granules to sustained-release granules is 2:1.3. The surfactant is sodium dodecyl sulfate, the activator is tetraacetyl ethylenediamine, the color developer is indigo carmine and tartrazine aluminum lake, the filler is microcrystalline cellulose and polyvinyl alcohol, the preservative is sodium benzoate, and the scale inhibitor is sodium tripolyphosphate. In the middle layer, the mass ratio of water-soluble matrix microspheres to chelating agent is 3:1. The water-soluble matrix microspheres are isomaltitol microspheres, and the chelating agent is sodium gluconate. In the lower layer, the mass ratio of rice bran bioactive components, sodium phytate, and binder is 5:1.2:2.2. The rice bran bioactive components are rice bran polyphenols and γ-oryzanol, and the binder is polyvinyl alcohol and copolyvinyl ketone.

[0046] Example 3 This embodiment provides a denture cleaning sheet, comprising: a cleaning layer and a coating layer that at least partially covers the surface of the cleaning layer; The coating layer is pullulan polysaccharide with a thickness of 10 μm; the clean layer consists of an upper layer, a middle layer and a lower layer from top to bottom, and the mass ratio of the upper layer, the middle layer and the lower layer in the clean layer is 1:0.35:0.65; The upper layer includes effervescent granules, surfactants, activators, color developers, fragrances, fillers, preservatives, and scale inhibitors; the middle layer includes water-soluble matrix microspheres and chelating agents; and the lower layer includes rice bran bioactive components, sodium phytate, and binders. In the upper layer, the mass ratio of effervescent granules, surfactant, activator, color developer, fragrance, filler, preservative, and scale inhibitor is 1:0.01:0.05:0.05:0.05:0.06:0.04. The effervescent granules include immediate-release granules and sustained-release granules. The immediate-release granules include sodium percarbonate and sodium bicarbonate, and the sustained-release granules include sodium bicarbonate, sodium carbonate, and anhydrous citric acid. The mass ratio of immediate-release granules to sustained-release granules is 2:1. The surfactant is sodium dodecyl sulfate, the activator is tetraacetyl ethylenediamine, the color developer is indigo carmine and tartrazine aluminum lake, the filler is microcrystalline cellulose and polyvinyl alcohol, the preservative is sodium benzoate, and the scale inhibitor is sodium tripolyphosphate. In the middle layer, the mass ratio of water-soluble matrix microspheres to chelating agent is 2:1. The water-soluble matrix microspheres are dextrin microspheres and isomaltitol microspheres, and the mass ratio of dextrin microspheres to isomaltitol microspheres is 3:7. The chelating agent is sodium gluconate. In the lower layer, the mass ratio of rice bran bioactive components, sodium phytate, and binder is 5:1.1:2.1. The rice bran bioactive components are rice bran polyphenols and γ-oryzanol, and the binder is polyvinyl alcohol and copolyvinyl ketone.

[0047] Example 4 This embodiment provides a method for preparing a denture cleaning tablet, including the following steps: S100, a clean layer is obtained by pressing lower layer powder, middle layer powder and upper layer powder into tablets from bottom to top; S200: The cleaning layer is sprayed with a coating solution and then dried sequentially to obtain a denture cleaning sheet; The lower layer powder includes rice bran bioactive components, sodium phytate, and binder; the middle layer powder includes water-soluble matrix microspheres and chelating agents; the upper layer powder includes effervescent granules, surfactants, activators, color developers, fragrances, fillers, preservatives, and scale inhibitors. The effervescent granules include immediate-release granules and sustained-release granules, with a mass ratio of immediate-release granules to sustained-release granules of 1.5:1; the coating layer solution is a 3% pullulan polysaccharide solution.

[0048] Example 5 This embodiment provides a method for preparing a denture cleaning tablet, including the following steps: S100, a clean layer is obtained by pressing lower layer powder, middle layer powder and upper layer powder into tablets from bottom to top; S200: The cleaning layer is sprayed with a coating solution and then dried sequentially to obtain a denture cleaning sheet; The lower layer powder includes rice bran bioactive components, sodium phytate, and binders; the middle layer powder includes water-soluble matrix microspheres and chelating agents; the upper layer powder includes effervescent granules, surfactants, activators, color developers, fragrances, fillers, preservatives, and scale inhibitors. The effervescent granules include immediate-release granules and sustained-release granules, with a mass ratio of immediate-release granules to sustained-release granules of 2:1.3; the coating layer solution is a 3% pullulan polysaccharide solution. In the lower layer of powder, the bioactive components of rice bran are microcapsules of rice bran bioactive components. The preparation method of the microcapsules of rice bran bioactive components includes the following steps: S101. Add γ-oryzanol and lecithin to edible oil and heat to 40°C to obtain the oil phase; S102. Maltodextrin and gum arabic are added to deionized water and stirred at 40°C. Rice bran polyphenol concentrate is then added and stirred continuously. The pH is adjusted to 5.0 to obtain the aqueous phase. S103. The oil phase is added to the aqueous phase and emulsified at 10,000 rpm to obtain a crude emulsion. S104. Add antioxidant to crude emulsion and stir evenly, then perform spray treatment and second drying treatment. The inlet air temperature of spray treatment is 140℃ and the outlet air temperature is 85℃. In S104, the second drying treatment is vacuum drying treatment to obtain microcapsules of rice bran bioactive components. The preparation method of water-soluble matrix microspheres includes the following steps: S111. Dissolve dextrin and / or isomalt in deionized water to form a solution; S112. The solution is dropped into liquid nitrogen or a low-temperature plate and freeze-dried at -40°C to form water-soluble matrix microspheres.

[0049] Example 6 This embodiment provides a method for preparing a denture cleaning tablet, including the following steps: S100, a clean layer is obtained by pressing lower layer powder, middle layer powder and upper layer powder into tablets from bottom to top; S200: The cleaning layer is sprayed with a coating solution and then dried sequentially to obtain a denture cleaning sheet; The lower layer powder includes rice bran bioactive components, sodium phytate, and binder; the middle layer powder includes water-soluble matrix microspheres and chelating agents; the upper layer powder includes effervescent granules, surfactants, activators, color developers, fragrances, fillers, preservatives, and scale inhibitors. The effervescent granules include immediate-release granules and sustained-release granules, with a mass ratio of immediate-release granules to sustained-release granules of 2:1; the coating layer solution is a 3% pullulan polysaccharide solution. In the lower layer of powder, the bioactive components of rice bran are microcapsules of rice bran bioactive components. The preparation method of the microcapsules of rice bran bioactive components includes the following steps: S101. Add γ-oryzanol and lecithin to edible oil and heat to 45°C to obtain the oil phase; S102. Maltodextrin and gum arabic are added to deionized water and stirred at 50°C. Rice bran polyphenol concentrate is then added and stirred continuously. The pH is adjusted to 6.0 to obtain the aqueous phase. S103. The oil phase is added to the aqueous phase and emulsified at 15000 rpm to obtain a crude emulsion. S104. Add antioxidant to crude emulsion and stir evenly, then perform spray treatment and second drying treatment. The inlet air temperature of spray treatment is 160℃ and the outlet air temperature is 95℃. In S104, the second drying treatment is vacuum drying treatment to obtain microcapsules of rice bran bioactive components. The preparation method of water-soluble matrix microspheres includes the following steps: S111. Dissolve dextrin and / or isomalt in deionized water to form a solution; S112. The solution is dropped into liquid nitrogen or a low-temperature plate and freeze-dried at -45°C to form water-soluble matrix microspheres.

[0050] Comparative Example 1 This embodiment provides a denture cleaning tablet, which is purchased externally.

[0051] Comparative Example 2 This embodiment provides a denture cleaning sheet, which has only an upper layer and no middle, lower, or coating layers.

[0052] Comparative Example 3 This embodiment provides a denture cleaning sheet. Compared with Embodiment 1, the denture cleaning sheet only has an upper layer and a coating layer covering the upper layer, without a middle layer and a lower layer.

[0053] Performance testing Sterilization test: The denture cleaning tablets in Examples 1-3 were subjected to a 15-minute sterilization test against three common oral microorganisms, namely Escherichia coli, Staphylococcus aureus, and Candida albicans. The test results are shown in Table 1.

[0054] Table 1

[0055] As can be seen from Table 1, the denture cleaning tablets described in this invention can achieve a 99.99% sterilization rate against Escherichia coli, Staphylococcus aureus, and Candida albicans within 15 minutes. This indicates that the denture cleaning tablets described in this invention can rapidly release active ingredients in water, destroy the cell structure of microorganisms, and achieve rapid and widespread sterilization. Even short-term soaking can achieve a very ideal sterilization effect, thereby effectively preventing problems such as denture stomatitis and bad breath caused by unclean dentures.

[0056] One denture cleaning tablet from Examples 1-3 and Comparative Examples 1-3 was added to 200ml of room temperature deionized water, and the following tests were performed: Foam kinetics test: Determining the maximum foam height (H) max ), and observe the time (T) during which the foam height exceeds 50% of the maximum foam height, and whether it overflows, and calculate H respectively. max ×T and H max / T, the test results are shown in Table 2.

[0057] Table 2

[0058] As shown in Table 2, the denture cleaning tablets used in Examples 1-3 did not overflow, and H maxThe low / T ratio indicates a gentle gas release pattern in the denture cleaning tablets described in this invention. Comparative Example 2 exhibits typical "peak-shaped" foam with extremely high H₂O. max The extremely short T time leads to an abnormally high H / T ratio, and the violent instantaneous gas release is the direct cause of its overflow; while in comparative examples 1 and 3, although H... max Similar to Examples 1-3 and H max The / T ratio was only slightly higher than that of Examples 1-3, but overflow still occurred, indicating a defect in foam stability. This is because Examples 1-3 used the formulation of the denture cleaning tablets described in this invention, whose anti-overflow performance stemmed from its layered structure effectively regulating the instantaneous gas release rate, avoiding a large burst of gas in a short period of time. Simultaneously, the surfactant formulation and the solute released by the middle layer microspheres significantly improved foam stability by increasing local solution viscosity, forming an elastic liquid film, and generating a fine and uniform bubble distribution, thus delaying the process of drainage and bubble merging. Comparative Examples 1-3, however, had deficiencies in release rate control, bubble size regulation, or liquid film stability, ultimately leading to a failure even with H... max Even at or above ×T, overflow can still occur due to unfavorable factors in instantaneous dynamics and microstructure.

[0059] Residual H2O2 test: Using hydrogen peroxide test paper, liquid samples were taken at 0 min, 5 min, 8 min, 14 min, and 20 min to quickly detect the H2O2 content. The test results are shown in Table 3.

[0060] Table 3

[0061] The examples rapidly reduced the H2O2 concentration within 0-5 minutes, dropping to approximately 3-4 ppm at 8 minutes, and further stabilizing at around 1 ppm at 14-20 minutes, demonstrating a significant end-quenching effect. In contrast, Comparative Example 1 still had approximately 6 ppm remaining at 20 minutes, Comparative Example 2 even exceeded 10 ppm, and Comparative Example 3 remained above 5 ppm. This is because Examples 1-3 all adopted a three-layer structure. The upper layer provides rapid release to ensure initial cleaning power, the middle layer of water-soluble matrix microspheres releases smoothly, avoiding excessive release of reactive oxygen species in a short period of time, which would lead to excessively high residual levels, while the lower layer of rice bran polyphenols, γ-oryzanol, and sodium phytate plays an antioxidant and chelating role in the middle and later stages, actively quenching residual H2O2 and reducing it to a low value and stabilizing at around 1 ppm at 8-14 minutes, thereby fixing the colorimetric endpoint and protecting the metal components. In contrast, Comparative Example 1 lacked an end-quenching mechanism, resulting in approximately 6 ppm of residue after 20 minutes; Comparative Example 2 only had an upper layer, leading to an overly vigorous reaction that initially produced a large amount of H2O2 that was difficult to consume later, resulting in a residue as high as 10 ppm; Comparative Example 3, although having a coating layer, only served a delaying effect and could not effectively reduce end-quenching residue, remaining at around 5 ppm. Therefore, the examples achieved full-process control of rapid release, smooth maintenance, and end-quenching through layered synergy, while the comparative examples, lacking key middle and lower layer functions, resulted in incomplete elimination of residual peroxides, unstable color development, and insufficient metal protection.

[0062] Metal protection test: Standard metal sheets were taken, polished and weighed. After recording the initial weight, they were placed in the denture cleaning solution of Examples 1-3 and Comparative Examples 1-3, respectively. After 20 minutes, they were weighed again and the weight change was calculated. The test results are shown in Table 4.

[0063] Table 4

[0064] The metal weight loss in Examples 1-3 was only 0.11-0.12 mg / cm³. 2 The control groups (1-3) showed concentrations of 0.44-0.48 mg / cm³. 2 The corrosion rate was approximately four times that of the examples. This is because the lower layer of Examples 1-3 contains rice bran polyphenols, γ-oryzanol, and sodium phytate, which can effectively quench residual peroxides and complex metal ions at the end of the cleaning process. This eliminates the continuous oxidizing environment and forms a protective effect on the metal surface, thereby significantly reducing metal loss. In contrast, the comparative example lacks this end-quenching and protection mechanism, and the residual H2O2 remains at a high level even after 20 minutes, leading to continuous oxidation and corrosion of the metal. Therefore, the denture cleaning sheet described in this invention can not only achieve efficient cleaning and color endpoint locking, but also provide reliable protection for dentures with metal clasps.

[0065] Color development test: Using a standard white film as the background, the ΔE values ​​of 5 min, 8 min, 14 min and 20 min relative to 0 min were measured with a spectrophotometer, and the standard deviation was calculated. The test results are shown in Table 5.

[0066] Table 5

[0067] As shown in Table 5, there are significant differences between the examples and the comparative examples in terms of color development process and stability: In Example 1, the ΔE value reached approximately 18 at 5 minutes, indicating rapid color development. It approached the endpoint at 8 minutes and remained almost unchanged from 14 to 20 minutes, with a standard deviation ≤ 0.3, proving that the color development endpoint was successfully locked. In contrast, Comparative Example 1 showed delayed color development, reaching only 20.5 at 8 minutes and only approaching the endpoint at 14 minutes. It continued to rise to 23.5 at 20 minutes, indicating over-color development caused by the continuous action of residual peroxides. Comparative Example 2 developed too quickly, reaching 20 at 5 minutes, rising to 25 at 8 minutes, and exceeding 28 at 20 minutes. The color developer was continuously oxidized, resulting in severe color drift and a standard deviation as high as 2.1, indicating the worst stability. Although Comparative Example 3 had a moderate color development rate, it still rose to 24.0 at 20 minutes, indicating a lack of end-quenching and inability to fix the color. It can be seen that the denture cleaning tablet described in this invention achieves the advantages of rapid color development and endpoint locking by relying on the smooth control of the middle layer and the end quenching effect of rice bran polyphenols, γ-oryzanol and sodium phytate in the lower layer. In contrast, the comparative examples all suffer from slow, excessive or unstable color development due to the lack of key layer functions.

[0068] In the description of this specification, the terms "one embodiment," "some embodiments," "specific embodiment," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0069] While the present invention has been disclosed above, it is not limited thereto. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the invention; therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

Claims

1. A denture cleaning tablet, characterized in that, The denture cleaning sheet includes: a cleaning layer and a coating layer that at least partially covers the surface of the cleaning layer; The coating layer includes pullulan or pectin; The cleaning layer consists of an upper layer, a middle layer, and a lower layer from top to bottom; The upper layer includes effervescent granules, surfactants, activators, color developers, fragrances, fillers, preservatives, and scale inhibitors. The middle layer comprises water-soluble matrix microspheres and a chelating agent; The lower layer includes rice bran bioactive components, sodium phytate, and an adhesive; In the upper layer, the effervescent particles include immediate-release particles and sustained-release particles, and the mass ratio of the immediate-release particles to the sustained-release particles is (1.5~2):(1~1.3).

2. The denture cleaning sheet according to claim 1, characterized in that, In the cleaning layer, the mass ratio of the upper layer, the middle layer, and the lower layer is 1:(0.3~0.4):(0.6~0.7). The thickness of the coating layer is 8~12μm.

3. The denture cleaning sheet according to claim 2, characterized in that, In the upper layer, the mass ratio of the effervescent granules, the surfactant, the activator, the color developer, the fragrance, the filler, the preservative, and the scale inhibitor is 1:(0.001~0.03):(0.001~0.1):(0.001~0.1):(0.001~0.1):(0.001~0.1):(0.001~0.1):(0.001~0.08). In the middle layer, the mass ratio of the water-soluble matrix microspheres to the chelating agent is (1~3):1; In the lower layer, the mass ratio of the rice bran bioactive component, the sodium phytate and the adhesive is 5:(1~1.2):(2~2.2).

4. The denture cleaning sheet according to claim 1, characterized in that, The immediate-release granules include sodium percarbonate and sodium bicarbonate; The sustained-release granules comprise sodium bicarbonate, sodium carbonate, and anhydrous citric acid; The surfactant includes sodium dodecyl sulfate; The activator includes tetraacetylethylenediamine; The color developer includes indigo carmine and lemon yellow aluminum lake; The filler includes microcrystalline cellulose and polyvinyl alcohol; The preservative includes sodium benzoate; The scale inhibitor includes sodium tripolyphosphate; The water-soluble matrix microspheres include dextrin microspheres and / or isomaltitol microspheres; The chelating agent includes sodium gluconate; The bioactive components of the rice bran include rice bran polyphenols and γ-oryzanol; The adhesive includes polyvinyl alcohol and copolyvinyl ketone.

5. A method for preparing a denture cleaning sheet, characterized in that, The method for preparing the denture cleaning sheet as described in any one of claims 1 to 4 includes the following steps: S100: The cleaning layer is obtained by pressing the lower layer powder, the middle layer powder and the upper layer powder from bottom to top into tablets. S200: The cleaning layer is sequentially sprayed with a coating solution and then dried to obtain the denture cleaning sheet; The lower layer powder includes rice bran bioactive components, sodium phytate, and a binder; The middle layer powder comprises water-soluble matrix microspheres and chelating agents; The upper powder comprises effervescent particles, surfactants, activators, color developers, fragrances, fillers, preservatives, and scale inhibitors. The effervescent particles include immediate-release particles and sustained-release particles, and the mass ratio of the immediate-release particles to the sustained-release particles is (1.5~2):(1~1.3). The coating solution includes pullulan polysaccharide solution or pectin solution.

6. The preparation method according to claim 5, characterized in that, In the lower layer powder, the rice bran bioactive component is a microcapsule of rice bran bioactive component, and the preparation method of the microcapsule of rice bran bioactive component includes the following steps: S101. Add γ-oryzanol and lecithin to edible oil and heat until dissolved to obtain the oil phase; S102. Maltodextrin and gum arabic are added to deionized water and stirred. Then rice bran polyphenol concentrate is added and the stirring process is continued. The pH is adjusted to obtain an aqueous phase. S103. The oil phase is added to the aqueous phase for emulsification to obtain a crude emulsion; S104. Add an antioxidant to the crude emulsion and stir evenly, then perform spray treatment and a second drying treatment to obtain microcapsules of the bioactive components of rice bran.

7. The preparation method according to claim 6, characterized in that, In step S101, the heating temperature is 40~45℃; In step S102, the temperature of the stirring process is 40~50℃; In step S102, the pH is adjusted to 5.0~6.0; In step S103, the rotation speed of the emulsification process is 10000~15000 rpm; In step S104, the inlet air temperature of the spray treatment is 140~160℃, and the outlet air temperature is 85~95℃. In step S104, the second drying process is a vacuum drying process.

8. The preparation method according to claim 5, characterized in that, The method for preparing the water-soluble matrix microspheres includes the following steps: S111. Dissolve dextrin and / or isomalt in deionized water to form a solution; S112. The solution is dripped into liquid nitrogen or a low-temperature plate for freeze-drying to form the water-soluble matrix microspheres.

9. The preparation method according to claim 8, characterized in that, In step S112, the freeze-drying temperature is -40 to -45°C.

10. The preparation method according to claim 5, characterized in that, In step S200, the concentration of the coating layer solution is 3-6%.

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