A removable denture and a method of making the same

Abstract

The present application relates to the technical field of denture, in particular to a removable denture and a preparation method thereof, which comprises the following steps in sequence: model receiving and checking, maxillary frame fixing, clasp bending and spot welding, model buffering and separate jaw type tooth arrangement, standardized wax type trimming, silicon rubber embedding and injection polymerization, mold opening and occlusion adjustment, and grading polishing process. The present application sets a gypsum buffer layer in the sensitive anatomical area of the oral cavity, uniformly controls the thickness of the wax type to be 2.5 mm, and matches the special tooth arrangement scheme according to the first, second and third jaw types. The present application realizes stable fixation by using an integrated clasp and jaw support, and forms a base by using silicon rubber embedding, cold storage resin injection and constant temperature polymerization. The polishing process only processes the outer surface of the base, and is matched with a 240-mesh fine sand rough polishing process and a polishing wax fine polishing process. The removable denture prepared by the present application is reasonable in structure, safe in hygiene, stable in occlusion and comfortable to wear.

Description

Technical Field

[0001] This invention relates to the field of dental prosthesis technology, and in particular to a removable denture and its preparation method. Background Technology

[0002] Removable dentures are commonly used prostheses for patients with missing teeth or edentulous teeth, and are widely used in clinical practice. The current traditional removable denture preparation process mainly involves conventional procedures such as model preparation, maxillary articulation, tooth arrangement, base molding, mounting and heat treatment, and polishing. However, the existing technology has many defects in actual production and clinical use: (1) The parameters of waxing and heat treatment are not uniform, which can easily lead to problems such as base deformation, insufficient material strength and shortened service life; (2) The standardization of buffer design is not made for different anatomical areas of the oral cavity. After the denture is worn, it is easy to compress the oral mucosa, causing pressure pain, foreign body sensation and poor wearing comfort; (3) The bending of clasps and tooth arrangement are not standardized, resulting in clasp position deviation, irregular artificial tooth arrangement, and imperfect balance adjustment of centric jaw, protruding jaw and lateral jaw. During use, the bite is unstable and the chewing experience is poor; (4) The thickness of wax pattern is arbitrarily controlled, the thickness of the base is uneven, the appearance of the finished product is poor and the mechanical properties are inconsistent; (5) The grinding and polishing process is prone to accidentally grinding the denture tissue surface, damaging the clasps and jaw rest, causing product scrap and low production yield.

[0003] Given the shortcomings of the existing technologies, there is an urgent need to develop a removable denture with standardized processes, good hygiene, stable occlusion, comfortable wear, and a high rate of finished product qualification, as well as its preparation method. Summary of the Invention

[0004] The purpose of this invention is to provide a removable denture and its preparation method, which results in a removable denture with a reasonable structure, good hygiene and safety, stable occlusion, and comfortable wear.

[0005] To achieve the above objectives, the present invention provides a method for preparing a removable denture, comprising the following steps: S1. Register and inspect the received oral models; return unqualified oral models for rework; disinfect qualified oral models and clean the plaster lumps on the model surface to obtain the upper and lower jaw models. S2. Fix the upper and lower jaw models obtained in S1 onto the jaw frame, ensuring that the midline of the upper and lower jaw models is aligned with the midline of the jaw frame. Fix the upper and lower jaw models with plaster and use weights to press down the jaw frame to obtain the upper and lower jaw models with the jaw frame in place. S3. Remove the occlusal recording wax from the upper and lower jaw models with the articulated jaw in S2, clean the residual wax from the upper and lower jaw models, then mark the abutment teeth to be bent into the upper and lower jaw models and determine the common path of insertion. Bend the clasp below the undercut line, and spot weld it after inspection to obtain the upper and lower jaw models with bent clasps. S4. Measure and record the occlusal distance of the upper and lower jaws after bending the clasp in S3. Bisect the occlusal distance, mark the buffer zone on the upper and lower jaw models and make a plaster buffer. Measure and mark the midline and tooth arrangement guide line on the upper and lower jaw models. Arrange artificial teeth according to the jaw type. After the arrangement is completed, verify the occlusal tightness. S5. On the upper and lower jaw models where teeth have been arranged in S4, a wax model of the base plate is made using wax sheet or melted wax method. The thickness of the base plate wax model is controlled to be 2.5mm. After shaping the physiological morphology of the gums on the base plate wax model, the surface of the wax model is polished. S6. Remove the upper and lower jaw models that have been wax-shaped and trimmed in S5 from the jaw frame. Use silicone rubber to completely embed the upper and lower jaw models that have been wax-shaped and trimmed in S5. After the silicone rubber solidifies and forms a solid shape, remove it and open the injection hole on it. Then remove the artificial teeth from the upper and lower jaw models and remove the wax from the artificial teeth and the upper and lower jaw models respectively. After removing the wax, fix the artificial teeth in their original positions in the corresponding imprints in the silicone rubber and glue them firmly. Then tightly reposition the silicone rubber onto the upper and lower jaw models. Prepare a thin paste-like mixture of denture base powder and inject it into the cavity between the silicone rubber and the upper and lower models through the injection hole. Heat and polymerize for 20-30 minutes to solidify and form a denture base. S7. After heating and polymerization, remove the entire workpiece and the upper and lower jaw models. Cut off the sprue and excess resin on the denture base. Adjust the denture base on the jaw frame to match the original height. Remove the denture base, grind and polish the surface, clean it, and then inspect and ship it.

[0006] Preferably, in S1, the examination includes: checking the integrity of the oral model, the condition of the abutment teeth, anatomical landmarks, and occlusal relationships.

[0007] Preferably, in S2, the jaw frame is a simple frog-style jaw frame, the weight of the weight is 1000-1200g, and the gypsum curing time is 15-20min.

[0008] Preferably, in S3, the retaining ring is made of medical steel wire and the retaining ring and jaw support are an integral structure.

[0009] Preferably, in S4, the buffer zone corresponds to the oral cavity sensitive area, including the maxillary incisor mastoid region, hard palate region, maxillary tuberosity region, mandibular lingual protuberance region, retromolar pad region, hyoid fossa region, and hyoid muscle region.

[0010] Preferably, in S4, the artificial teeth are arranged in three types: Class I jaw, Class II jaw, and Class III jaw, and the artificial teeth are firmly bonded to the upper and lower jaw models using model wax.

[0011] Preferably, in S6, the silicone rubber embedding thickness is 4-6 mm; the denture powder mixture is a mixture of denture powder and monomer at a mass ratio of 20:13, the monomer is a denture base polymer, and the monomer is refrigerated at 0-5℃ before use.

[0012] Preferably, in S7, grinding is performed by using a grinding machine with a silicon carbide grinding head or a diamond grinding head to shape and smooth the edges of the outer surface of the denture base, without grinding the tissue surface; the polishing surface is first coarsely polished with 240-grit wet silicon carbide sand mixed with water and a cotton wheel to remove grinding marks, and then finely polished with polishing wax with a brush wheel or a cloth wheel to achieve a bright mirror effect. During the polishing process, the polishing wheel should be kept away from contact with the clasps and jaw rest to prevent deformation of the clasps or damage to the denture.

[0013] The present invention also provides a method for preparing removable dentures.

[0014] The beneficial effects of this invention are: (1) This invention reduces the pressure of the denture base on the mucosa from the production end by setting a plaster buffer zone in the sensitive anatomical areas of the upper and lower jaws and matching it with a standardized wax pattern with a thickness of 2.5mm that replicates the shape of natural gums; at the same time, it adds a clinical trial fitting and adjustment process, which can specifically adjust the high point of occlusion, excessively long edges and tender areas, greatly reducing the feeling of foreign body and mucosal pressure pain, and effectively improving the comfort of wearing dentures.

[0015] (2) This invention relies on the jaw frame to accurately transfer the original occlusal relationship, and provides exclusive tooth arrangement standards for three different jaw types. The occlusal calibration is performed twice before and after molding. It is combined with an integrated clasp and jaw rest with the undercut area precisely bent. This ensures that the denture is stable and not easy to fall off, and also achieves uniform force on multi-directional occlusion, resulting in a better chewing experience. At the same time, the silicone rubber embedding, cold-pressed monomer injection molding and constant temperature polymerization process make the base structure dense, not easy to crack or deform, and extend the service life.

[0016] (3) The preparation process of this invention is fully quantitatively controlled. Calipers are used to control the thickness of the wax pattern, and the thickness standards of silicone rubber embedding and buffer plaster are standardized. Grinding and polishing distinguish the tissue surface and the outer surface and are matched with two-level polishing process. This not only reduces manual operation error and improves the yield of finished products, but also makes the dentures look natural and have a smooth surface. It fully covers the technician processing and clinical trial wearing process, forming a closed loop of process and reducing the need for rework in the later stage.

[0017] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] Figure 1 This is a schematic flowchart of a method for preparing a removable denture according to the present invention. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments. Unless otherwise defined, the technical or scientific terms used in this invention should be understood in their ordinary sense by those skilled in the art. The features mentioned above or in the specific examples mentioned in this invention can be combined arbitrarily, and these specific embodiments are only used to illustrate the invention and are not intended to limit the scope of the invention.

[0020] Example 1 like Figure 1 As shown, the present invention provides a removable denture, the preparation method of which includes the following steps: S1. Model Receiving, Registration, and Inspection: Received oral models are registered and inspected; unqualified models are returned for rework. Qualified models are disinfected and have plaster lumps removed from their surfaces to obtain maxillary and mandibular models. Patient oral models are received and uniformly registered. The integrity of the model, the condition of the abutment teeth, the completeness of anatomical landmarks, and the normality of the occlusal relationship are checked item by item. Models with defects, excessive thinness, or missing anatomical landmarks are returned for rework and repair. Qualified models have plaster lumps removed from their surfaces, completing basic pretreatment to obtain maxillary and mandibular models. Qualified models are screened, discarding blanks with congenital defects and removing excess plaster protrusions from the model surface to prevent damaged models or models with missing anatomical landmarks from entering subsequent processes, thus preventing dimensional deviations and occlusal abnormalities in subsequent tooth arrangement, buffering, and maxillary articulation. Plaster lumps are removed to eliminate occlusal interference points. This process controls product precision from the source, reduces manual rework errors, and improves the overall yield rate of finished products.

[0021] S2. Maxillary Articulation Fixation: A simple frog-style articulation was used to fix the upper and lower jaw models obtained in S1 onto the articulation, ensuring that the midline of the upper and lower jaw models was aligned with the midline of the articulation. Plaster was then applied to fill and fix the upper and lower jaw models. A 1000g weight was placed on the articulation to continuously press it down, and the model was left to cure for 15 minutes to prevent the plaster from expanding and raising the occlusion. This resulted in a well-fitted upper and lower jaw model with the articulation. This process replicates the original spatial position and occlusal relationship of the patient's upper and lower dentition, fixes the model to prevent plaster expansion and deformation, accurately transfers the occlusal height and relative position of the dentition, and uses the weight to offset the expansion of the cured plaster, preventing occlusal elevation. This ensures that the occlusal height matches the patient's original dentition after subsequent tooth arrangement and heat treatment, achieving uniform occlusal force and stable chewing.

[0022] S3. Clasp Marking, Bending, and Spot Welding Fixation: Remove the occlusal recording wax from the upper and lower jaw models with the articulated jawbone in S2. Use high-pressure steam to remove residual wax from the model surface. Then, mark the abutment tooth positions for clasp bending on the upper and lower jaw models using red and blue pencils, and determine the common insertion path of the abutment teeth. Use medical wire and specialized technician pliers to bend the clasp, molding it as a single piece with the jaw rest. Place the entire piece below the undercut line of the abutment tooth, ensuring a tight fit between the clasp and the abutment tooth. After checking that the clasp curvature and fit are correct, spot weld it to the corresponding position on the model, resulting in the upper and lower jaw models with bent clasps. Fabricate an integrated metal retention support structure and determine the denture insertion and removal path. The clasp, positioned below the undercut line, provides reliable retention. The jaw rest distributes chewing pressure, and the integrated structure prevents breakage and loosening during use. The denture has stable retention, is not easily dislodged, distributes stress, and the base is less prone to sinking and cracking, extending the denture's lifespan.

[0023] S4. Model Preprocessing and Artificial Tooth Arrangement: The maxillary and mandibular models after the clasps in S3 are measured. The occlusal distance between the upper and lower jaws is measured and recorded, and the occlusal distance is evenly divided. A buffer zone is created in the sensitive areas of the model using plaster. This buffer zone includes the maxillary incisor papilla area, hard palate area, maxillary tuberosity area, mandibular lingual protuberance area, retromolar pad area, posterior hyoid fossa area, and hyoid muscle area. The plaster layer thickness in the buffer zone is 0.4 mm. The midline and tooth arrangement guideline are measured and marked on the maxillary and mandibular models. Artificial teeth are arranged according to the specific tooth arrangement angles and spacing for Class I jaw type. The artificial teeth are temporarily fixed with model wax. After arrangement, the occlusion is repeatedly checked to ensure tight contact between tooth surfaces without gaps. Wax residue is removed, a mucosal buffer structure is established, and artificial teeth are arranged according to jaw type standards. Preliminary occlusal calibration is performed. The buffer area avoids direct pressure on the mucosa from the denture base. Differentiated tooth arrangement based on jaw type matches the dentition morphology of different patients, and the occlusal distance is evenly divided to ensure uniform contact between the upper and lower teeth. Significantly reduces mucosal pressure pain and foreign body sensation when wearing; balanced bite for a better chewing experience, suitable for patients with different jaw types.

[0024] S5. Base Wax Pattern Fabrication and Finishing: Based on the upper and lower jaw models completed in S4, a base wax pattern is fabricated using wax sheets or molten wax. A wax pattern measuring caliper is used throughout the process to control the wax pattern thickness to 2.5mm. After refining the wax pattern to reflect the physiological gingival morphology, the surface is polished. The base has a moderate thickness, is mechanically stable and not easily deformed; the finished product has a natural and aesthetically pleasing appearance, reducing the feeling of a foreign body in the mouth.

[0025] S6. Silicone Rubber Embedding, Dewaxing, and Injection Molding: Remove the upper and lower jaw models with wax pattern finishing completed in S5 from the jaw frame. Embed the entire upper and lower jaw models with wax pattern finishing completed in S5 using silicone rubber, controlling the silicone rubber embedding thickness to be 5mm. After the silicone rubber solidifies, remove it and open injection holes on it. Then remove the artificial teeth from the upper and lower jaw models. Dewax the artificial teeth and the upper and lower jaw models separately. After dewaxing, blow them with high-pressure steam once more to better remove excess wax. After dewaxing, apply a release agent to the upper and lower jaw models and allow them to dry. Then, fix the dewaxed artificial teeth in their original positions within the corresponding imprints on the silicone rubber, securing them with glue. Next, firmly reposition the silicone rubber onto the upper and lower jaw models, gluing the edges of the silicone rubber to the model edges and allowing it to dry. Mix the denture base powder and monomer at a mass ratio of 20:13 to create a thin paste. Pre-chill the monomer at 0-5℃ and stir until a thin paste is formed, suitable for injection molding. Inject the mixture into the mold cavity through the injection hole and place it in a water bath for heating and polymerization for 30 minutes (75℃ water temperature). The resin will then completely cure to form the denture base. The molded base is dense and uniform, less prone to cracking and deformation, extending the lifespan of the denture. Standardized processes ensure high dimensional consistency in mass production and improve the yield rate.

[0026] S7. Mold Opening, Occlusion Adjustment, Polishing, Inspection, and Shipment: After heating and polymerization, the entire workpiece is removed. The silicone rubber is removed, and the upper and lower jaw models are peeled off. The sprues and excess resin on the denture base are cut off. The denture base is adjusted on the articulator to match its original height. The denture base is then removed. A grinder with a silicon carbide grinding head or diamond abrasive is used to shape and smooth the edges of the outer surface of the denture base. The tissue surface is not polished. Then, 240-grit wet silicon carbide sandpaper mixed with water is used with a cotton wheel for coarse polishing to remove grinding marks. Finally, polishing wax is used with a brush wheel or cloth wheel for fine polishing to achieve a bright mirror finish. During polishing, the polishing wheel should avoid contact with the clasps and jaw rests to prevent clasp deformation or denture damage. After polishing, the denture is rinsed with clean water. A full inspection of the appearance, occlusion, and retention structure is performed. After passing the inspection, the denture is cleaned, packaged, and shipped. The occlusal height is precisely matched to the patient's oral condition; there is no mucosal irritation when wearing it; the surface of the denture is smooth and beautiful, reducing polishing waste and improving the yield rate.

[0027] Therefore, this invention employs the aforementioned removable denture and its preparation method, which sets up plaster buffer structures in the sensitive anatomical areas of the upper and lower jaws and uniformly molds the thickness of the wax pattern. It is combined with differentiated tooth arrangement for different jaw types, an integrated clasp support structure, and a constant-temperature polymerization process for silicone rubber injection molding. At the same time, it limits the grinding and polishing processing range and adopts a two-stage polishing treatment. This can effectively reduce mucosal pressure pain and foreign body sensation when wearing dentures, ensure uniform and stable occlusal force, extend the overall service life of dentures, reduce dimensional deviations caused by manual operation, improve the yield rate of mass-produced finished products, and produce a natural and smooth finished product. It fully covers the core processes of dental technician processing and significantly reduces the probability of clinical repairs in the later stages.

[0028] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a removable denture, characterized in that: Includes the following steps: S1. Register and inspect the received oral models; return unqualified oral models for rework; disinfect qualified oral models and clean the plaster lumps on the model surface to obtain the upper and lower jaw models. S2. Fix the upper and lower jaw models obtained in S1 onto the jaw frame, ensuring that the midline of the upper and lower jaw models is aligned with the midline of the jaw frame. Fix the upper and lower jaw models with plaster and use weights to press down the jaw frame to obtain the upper and lower jaw models with the jaw frame in place. S3. Remove the occlusal recording wax from the upper and lower jaw models with the articulated jaw in S2, clean the residual wax from the upper and lower jaw models, then mark the abutment teeth to be bent into the upper and lower jaw models and determine the common path of insertion. Bend the clasp below the undercut line, and spot weld it after inspection to obtain the upper and lower jaw models with bent clasps. S4. Measure the upper and lower jaw models after bending the clasp in S3, and record the occlusal distance between the upper and lower jaws. Bisect the occlusal distance, mark the buffer zone on the upper and lower jaw models and make a plaster buffer. Measure and mark the midline and tooth arrangement guide line on the upper and lower jaw models. Arrange artificial teeth according to the jaw type. After the arrangement is completed, verify the occlusal tightness. S5. On the upper and lower jaw models where teeth have been arranged in S4, a wax model of the base plate is made using wax sheet or melted wax method. The thickness of the base plate wax model is controlled to be 2.5mm. After shaping the physiological morphology of the gums on the base plate wax model, the surface of the wax model is polished. S6. Remove the upper and lower jaw models that have been wax-shaped and trimmed in S5 from the jaw frame. Use silicone rubber to completely embed the upper and lower jaw models that have been wax-shaped and trimmed in S5. After the silicone rubber solidifies and forms a solid shape, remove it and open the injection hole on it. Then remove the artificial teeth from the upper and lower jaw models and remove the wax from the artificial teeth and the upper and lower jaw models respectively. After removing the wax, fix the artificial teeth in their original positions in the corresponding imprints in the silicone rubber and glue them firmly. Then tightly reposition the silicone rubber onto the upper and lower jaw models. Prepare a thin paste-like mixture of denture base powder and inject it into the cavity between the silicone rubber and the upper and lower models through the injection hole. Heat and polymerize for 20-30 minutes to solidify and form a denture base. S7. After heating and polymerization, remove the entire workpiece and the upper and lower jaw models. Cut off the sprue and excess resin on the denture base. Adjust the denture base on the jaw frame to match the original height. Remove the denture base, grind and polish the surface, clean it, and then inspect and ship it.

2. The method for preparing a removable denture according to claim 1, characterized in that: In S1, the examination includes checking the integrity of the oral model, the condition of the abutment teeth, anatomical landmarks, and occlusal relationships.

3. The method for preparing a removable denture according to claim 1, characterized in that: In S2, a simple toad-style jaw frame is used, the weight of the weight is 1000-1200g, and the plaster curing time is 15-20min.

4. The method for preparing a removable denture according to claim 1, characterized in that: In S3, the retaining ring is made of medical steel wire and is an integral part of the jaw support.

5. The method for preparing a removable denture according to claim 1, characterized in that: In S4, the buffer zone corresponds to the oral cavity sensitive areas, including the maxillary incisor mastoid region, hard palate region, maxillary tuberosity region, mandibular lingual protuberance region, retromolar pad region, hyoid fossa region, and hyoid muscle region.

6. The method for preparing a removable denture according to claim 1, characterized in that: In S4, artificial teeth are arranged in three types: Class I, Class II, and Class III. The artificial teeth are firmly bonded to the upper and lower jaw models using model wax.

7. The method for preparing a removable denture according to claim 1, characterized in that: In S6, the silicone rubber embedding thickness is 4-6mm; the denture powder mixture is a mixture of denture powder and monomer at a mass ratio of 20:13, the monomer is a denture base polymer, and the monomer is refrigerated at 0-5℃ before use.

8. The method for preparing a removable denture according to claim 1, characterized in that: In S7, grinding is performed using a grinding machine with a silicon carbide grinding head or a diamond grinding head to shape and smooth the edges of the outer surface of the denture base. The tissue surface is not ground. The polishing surface is first coarsely polished with 240-grit wet silicon carbide sand mixed with water and a cotton wheel to remove grinding marks. Then, polishing wax is used with a brush wheel or a cloth wheel to finely polish to a bright mirror effect. During the polishing process, the polishing wheel should be kept away from the clasps and jaw rest to prevent clasp deformation or denture damage.

9. A removable denture prepared by the method of any one of claims 1-8.

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