Titanium cast post core with polished surface and preformed shoulder

Abstract

The present application relates to a kind of titanium cast post core with polishing surface and pre-shoulder, the edge of post core is consistent with the edge of entire defective area of tooth, the subgingival part of post core restores the shape of defective area and directly contacts with gum, and the surface is highly polished;Pre-shoulder is set on post core, and is flush with the edge of gum in defective part of tooth;Pre-shoulder is consistent with the width of shoulder prepared in advance on tooth and is connected and continues.The present application utilizes the excellent biocompatibility of pure titanium, combines gum with polishing surface, forms good, similar natural tooth attachment, avoids forming deep periodontal pocket, ensures the health and stability of gum in defective part, and provides technical support for the repair of tooth originally judged as unable to retain and deep subgingival defect.

Description

Technical Field

[0001] This invention relates to the field of dental restoration, and in particular to a pure titanium cast post core with a polished surface and a pre-formed shoulder. Background Technology

[0002] Splits and decay often cause tooth defects. In dental restoration, tooth integrity is often restored by making crowns (commonly known as porcelain crowns / all-ceramic crowns), including three situations: First, for defects located above the gum line, the tooth can be directly ground down and a crown can be made; Second, for defects located relatively shallowly below the gum line (usually no more than 3-4 mm below the gum line), a crown lengthening procedure can be performed to remove part of the gum and bone tissue, fully exposing the defect margin. After restoring the basic shape of the tooth with a metal post / core / fiber post / core, the tooth can be ground down and a crown made; Third, for defects located very deep below the gum line (usually more than 4 mm below the gum line), or for cases where a periodontist determines that a crown lengthening procedure is not possible or appropriate, the current treatment plan is usually to extract the affected tooth and then restore the missing tooth through dental implants, porcelain / all-ceramic fixed bridges, or removable dentures.

[0003] However, both the second and third scenarios have their own drawbacks. The roots of natural teeth are firmly suspended from the alveolar bone by the periodontal ligament (periodontal ligament). This ligament is rich in sensory nerves, allowing it to sense vertical and lateral forces acting on the teeth and regulate occlusal forces. Through the transmission of these nerves, the occlusal forces effectively stimulate the metabolism of the bone tissue surrounding the tooth root, promoting periodontal health and tooth strength. For the second type of tooth, while crown lengthening can move the tooth defect above the gum line, transforming it into a first-type tooth, it is not the optimal solution. Crown lengthening requires the removal of a portion of the gum and alveolar bone at the deep defect site, leading to permanent and irreversible defects: such as gum / alveolar bone loss around the root, creating interdental spaces that accumulate more food debris; varying degrees of exposure of adjacent healthy natural tooth roots, resulting in sensitivity to hot and cold; and bone loss around the root leading to varying degrees of root loosening, reduced load-bearing capacity, and shorter lifespan. Therefore, crown lengthening is often a last resort. For Class III teeth, if the tooth only shows deep defects but the periapical bone tissue is good and not loose, extracting the tooth is a great pity. Furthermore, there is no periodontal ligament around the implant, so it cannot sense biting forces and cannot be compared with natural teeth; porcelain / all-ceramic fixed bridges require grinding down the natural teeth adjacent to the missing tooth, damaging more normal natural teeth; and the foreign body sensation and repeated removal and insertion of removable dentures cannot be avoided.

[0004] For Class II and III teeth, if crowns are made directly without crown lengthening, the crown will directly contact the defect margin below the gum line, resulting in deep periodontal pockets in the gum at the defect site. This will prevent effective cleaning, leading to gum redness and swelling, secondary periodontal tissue inflammation, and serious periodontal disease.

[0005] Pure titanium has excellent biological properties, allowing it to form good contact with human tissue cells, creating an attachment similar to that of natural teeth. Pure titanium posts and cores have been used extensively and are highly effective in clinical dental restorations. However, traditional metal posts and cores are only suitable for shallow tooth defects (Class I and Class II after crown lengthening), and the crown must completely enclose the post, preventing it from contacting the gingiva. Therefore, if the tooth defect is too deep, making crown lengthening impossible or unsuitable, existing posts and cores are ineffective, and the tooth is generally extracted.

[0006] The modern dental treatment philosophy aims to preserve as many natural teeth as possible. Therefore, how to preserve as many teeth as possible that are currently deemed unsalvageable, and how to avoid crown lengthening as much as possible while preserving the precious gum / bone tissue around the tooth roots, has been a long-standing challenge. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a pure titanium cast post core with a polished surface and a pre-formed shoulder. Utilizing the excellent biocompatibility of pure titanium, the gingiva is bonded to the polished surface, forming a good attachment similar to that of a natural tooth. This avoids the formation of deep periodontal pockets, ensures the health and stability of the gingiva at the defect site, and provides technical support for the restoration of teeth with deep subgingival defects that were originally deemed unsalvageable.

[0008] The technical solution of the present invention is as follows: the post and core are matched with the entire defect area of ​​the tooth, a polished surface is made at the contact area between the post and core and the gingiva at the defect, and a pre-formed shoulder is formed at the edge of the gingiva.

[0009] In the above technical solution, the polished surface is anastomosed with and in direct contact with the gingiva at the tooth defect site, and the pre-formed shoulder is set on the post core and is flush with the edge of the gingiva at the tooth defect site.

[0010] In the above technical solution, the pre-formed shoulder has the same width as the pre-prepared shoulder on the tooth and is connected and continuous.

[0011] The beneficial effects of this invention are that it sets a highly polished surface and a pre-formed shoulder on a traditional pure titanium post, allowing the post to fit tightly into the tooth structure at the subgingival defect site. Utilizing the excellent biocompatibility of pure titanium, the gingiva integrates with the polished surface, forming a good, natural-tooth-like attachment, avoiding the formation of deep periodontal pockets, and ensuring the health and stability of the gingiva at the defect site. This provides technical support for the restoration of teeth with deep subgingival defects that were previously deemed unsalvageable. The pre-formed shoulder, formed on the post at the gingival margin, is continuous with the shoulder prepared on the tooth, facilitating crown installation and completing the restoration of the defective tooth. This solves the problem of "preserving as many teeth as possible that are currently deemed unsalvageable, avoiding crown lengthening as much as possible, and preserving the valuable gingival / bone tissue around the tooth root." Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of the present invention when a tooth has a single-sided defect;

[0013] Figure 2 This is a schematic diagram of the invention and its assembly with a tooth when one side of the tooth is missing.

[0014] Figure 3 This is a schematic diagram of the structure of the present invention when both sides of the tooth are missing;

[0015] Figure 4 This is a schematic diagram of the invention and its assembly with a tooth when both sides of the tooth are damaged;

[0016] Figure 5 It is an X-ray of a damaged tooth that is recommended for extraction;

[0017] Figure 6 This is a photograph of the affected tooth after routine dental preparation;

[0018] Figure 7 The image shows a photograph of a finished pure titanium cast pile core with a polished surface and pre-formed shoulder.

[0019] Figure 8 These are photographs of the pure titanium cast post core of this invention mounted and cemented onto a tooth:

[0020] Figure 9 These are photographs of teeth restored using the pure titanium cast post and core of this invention;

[0021] Figure 10 These are photos taken three months after my dental restoration.

[0022] Figure 11 These are photos taken six months after the dental restoration.

[0023] Figure 12 These are photos taken twelve months after the dental restoration.

[0024] Figure 13 These are photos taken during a follow-up examination 24 months after the dental restoration. Detailed Implementation

[0025] like Figure 1As shown, a pure titanium cast post and core with a polished surface and a pre-formed shoulder is provided. The post and core 1 conforms to the entire defect area of ​​the tooth 6. A polished surface 2 is made at the contact area between the post and core 1 and the gingiva 4 at the defect site. The polished surface 2 conforms to and directly contacts the gingiva 4 at the defect site. Utilizing the excellent biocompatibility of pure titanium, the gingiva and the polished surface of the post and core are combined to form a good attachment similar to a natural tooth, thereby achieving the purpose of repairing the defective tooth. A step is ground on the post and core 1 at the level of the edge of the gingiva 4 at the defect site, which is the pre-formed shoulder 3. The pre-formed shoulder 3 has the same width as the pre-prepared shoulder 5 on the tooth and extends and connects with it, forming a complete shoulder at the height of the gingival margin of the tooth. The crown sits on the complete shoulder.

[0026] During the fabrication of the post and core 1, the tooth, after complete root canal treatment, is ground down according to the tooth preparation requirements to form an appropriate shoulder 5 on the tooth 6. A highly polished surface 2 and a pre-formed shoulder 3 are then provided on the traditional pure titanium post and core.

[0027] The fabrication process of core 1 is as follows:

[0028] Step 1: Post and Core Preparation: After complete root canal treatment, the affected tooth is prepared according to the requirements for full crown preparation, forming a smooth, continuous, and clearly defined shoulder. Appropriate root canals are selected (1-2 canals for premolars, 2 canals for molars), and the canals are prepared step-by-step to the appropriate depth and width. If the gingiva covers the defect margin, under local anesthesia, a laser is used to partially remove the gingiva covering the deep defect surface, completely exposing the defect margin and achieving complete hemostasis. A post and core impression is made using silicone rubber. The model is poured and refined.

[0029] Step 2: Wax Model Fabrication: Fill the pulp chamber wall of the model and remove undercuts. Create a post-core wax model using an indirect method. Apply a separating agent to the inner wall of the pulp chamber and the inner wall of the root canal, and blow it evenly with an air gun to form a thin layer of separating agent on the model surface. Melt the inlay wax and inject it into the root canal. Stack the inlay wax on the model to form a post-core wax model. At the defective area, create a pre-formed shoulder 3 at the gingival margin, with the same width as the shoulder 5 prepared on the abutment tooth in step 1, connecting and continuing to form a complete shoulder around the tooth. After the wax model has completely cooled, separate it from the model.

[0030] Step 3: Install the casting channel: Connect the completed pile core mold to the main casting channel using casting channel wax.

[0031] Step 4: Cleaning the mold: Spray the mold surface with a mold surfactant (or wipe the mold surface with alcohol and dry it with an air gun after washing) to clean the surface of the mold of dirt and grease, reduce the surface tension of the mold, improve the adsorption and wettability of the mold surface to the embedding material, and form a smooth and clear inner wall of the mold.

[0032] Step 5: Embedding: According to the instructions for use of the embedding material, take out the embedding material and liquid with an appropriate water-to-powder ratio, mix them evenly with a vacuum mixer, and slowly pour the embedding material around the casting mold under the vibration of the vibrator.

[0033] Step 6, Baking and Firing: After the embedding material has solidified, remove it from the mold and let it sit at room temperature for 12 hours. Place the mold with the runner facing down in an electric oven to bake and fire it: raise the room temperature to 300°C for no less than 60 minutes, and maintain it at 300°C for 40-60 minutes.

[0034] Step 7, Casting: Inside the casting machine, centrifugal, negative pressure and pressure casting methods are used in sequence. The negative pressure is formed by drawing air from the bottom and sides of the mold. Centrifugal force is used to inject the molten pure titanium metal into the mold cavity. At the same time, a large inert gas pressure is added to the surface of the molten metal, so that the molten metal is injected into the mold cavity quickly and completely.

[0035] Step 8, Cooling: Rapid cooling is adopted, that is, the cast mold is immersed in cold water for rapid cooling, which shortens the contact time between the cast metal and the embedding material at high temperature, so as to reduce the contamination reaction layer.

[0036] Step 9: Cleaning and Sandblasting: Remove the post and core from the mold. Vibrate in an oscillator to remove most of the embedding material. Use a sandblasting machine to remove any remaining embedding material from the post and core surface. Use a coarse-grained diamond grinding head to grind away any obvious metal nodules on the surface of the pure titanium cast post and core. Reposition the pure titanium post and core onto the model, check the fit of the post and core at the tooth edge contact point, and use a coarse-grained grinding head to correct the edges, removing excess material to ensure a tight fit between the post and core and the tooth defect edge. Clamp the cast channel of the pure titanium post and core with a needle holder, and use a sandblasting machine in liquid sandblasting mode to sandblast all surfaces of the post and core to remove the surface oxide layer. Cut off the cast channel and immerse in acid for acid washing to completely remove the contaminant layer from the post and core surface.

[0037] Step 10, Grinding and Polishing: Use a tungsten carbide (or ordinary silicon carbide) grinding head to initially grind the polished surface 2 of the post core, ensuring even pressure to create a smooth surface. The polished surface 2 should not extend beyond the pre-formed shoulder 3. Use a silicon carbide (or alumina) abrasive grinding head to carefully grind the polished surface 2. Reposition the pure titanium casting post core onto the model. Under magnification, re-check the fit between the post core and the edge of the tooth defect and refine it. Carefully polish the smoothed polished surface 2 using a diamond abrasive rubber wheel. Under magnification, first use a medium-grinding rubber wheel / axis for polishing, then use a fine-grinding rubber wheel / axis for fine polishing, ensuring that even the smallest parts of the polished surface achieve a high level of polish. Use a small brush / felt wheel dipped in polishing compound to highly polish the polished surface, especially the edges, until the entire polished surface 2 achieves a mirror-like finish, completing the fabrication of the pure titanium casting post core with the polished surface and pre-formed shoulder.

[0038] During the procedure, completely remove any temporary filling material from the pulp chamber and root canals of the abutment tooth, ensuring there is no bleeding from the gums at the defect site. Try on the pure titanium post and core, adjusting and grinding it until it is fully in place, being careful not to adjust or polish the surface. Clean the pure titanium post and core, the pulp chamber, and the root canal channels of the abutment tooth with alcohol, dry them completely, and strictly isolate them from moisture. Use polycarboxylate cement to cement the post and core, cleaning up any excess cement, especially any excess cement at the subgingival defect margin. Finally, cement the crown onto the complete shoulder consisting of shoulder 5 and pre-formed shoulder 3, completing the restoration of the defective tooth.

[0039] If the tooth defect only involves a single axial surface, a single polished surface is set on the post and core, such as... Figure 1 , Figure 2 As shown; if the defect involves two adjacent axial surfaces, a double polished surface is provided on the pile core, such as... Figure 3 , Figure 4 As shown; if the defect involves three axial surfaces, then three polished surfaces are designed; generally speaking, the subgingival defect should not exceed four axial surfaces. After the pure titanium post is cemented to the affected tooth, the highly polished surface directly contacts the gingiva at the defect site. The gingiva combines with the biocompatible pure titanium polished surface to form an attachment similar to that of a natural tooth, avoiding the formation of deep periodontal pockets and ensuring the health and stability of the gingiva at the defect site.

[0040] The pure titanium cast post and core of this invention has been applied in oral clinical treatment, such as... Figures 5 to 13 The seven photographs shown realistically reflect the clinical treatment process of the pure titanium cast core of this invention: Figure 5 The X-ray image shows a tooth with a missing edge, marked by a white line. The periodontist determined that crown lengthening was not suitable and recommended extraction. The tooth, after routine tooth preparation, appears... Figure 6 As shown; in Figure 7 The completed pure titanium casting core can be clearly seen above, featuring a polished surface and pre-formed shoulders; from Figure 8 As can be seen, the pure titanium cast post and core are cemented to the tooth, with the polished surface in direct contact with the gum line, and the pre-formed shoulder flush with the gingival margin. The zirconia crown is then cemented to the tooth and the pure titanium cast post and core. The installation and cementation are completed immediately, and the gums are healthy. Figure 9 As shown; Figures 10 to 13 The four photos show follow-up examinations of the restored teeth at three, six, twelve, and twenty-four months. The gums are healthy, without redness or swelling, and are not loose. The probing depth is stable at 2mm.

[0041] Over two years, a total of 18 cases of affected teeth were treated. Observation ranged from 3 to 24 months. All cases showed healthy gums without inflammation, normal probing depth and bleeding index, and no significant loosening, resulting in a 100% clinical success rate. See Table 1, "Statistical Table of Clinical Cases of Pure Titanium Cast Posts and Cores," for details.

[0042] Table 1. Statistical Table of Clinical Cases of Pure Titanium Cast Cores

[0043]

[0044] The technical terms in the table are explained below:

[0045] Initial defect depth: The depth of the tooth defect below the gingival margin before treatment.

[0046] Probing depth: The depth to which the periodontal probe can penetrate below the gingival margin during follow-up examinations.

[0047] Bleeding Index: The degree of gingival bleeding during periodontal probing. 0: Healthy gums; 1: Slight gingival congestion, no bleeding on probing; 2: Significantly red and swollen gums, bleeding on probing; 3: Bright red gums, bleeding spontaneously.

[0048] Looseness: 0, physiological looseness; 1, I° looseness; 2, II° looseness; 3, III° looseness.

[0049] Gum color, shape, and texture: Healthy gums are pink in color, have a normal shape without swelling, and are firm in texture.

[0050] Clinical efficacy tracking of 18 patients revealed that for teeth with defects located deep below the gum line (usually more than 4 mm below the gum line) that can only be extracted at present, these pure titanium cast post and core can be used to preserve them, achieving good, long-term, and stable clinical results with an extremely high success rate (nearly 100%). This effectively solves the problem of "preserving as many teeth as possible that are currently deemed unpreservable, avoiding crown lengthening as much as possible, and preserving the valuable gum / bone tissue around the tooth root".

Claims

1. A pure titanium cast post core with a polished surface and a pre-formed shoulder, wherein the post core (1) conforms to the entire defect area of ​​the tooth (6), characterized in that: A polished surface (2) is made at the contact point between the post (1) and the gingiva (4) at the tooth defect site, and a pre-formed shoulder (3) is formed at the edge of the gingiva. The polished surface (2) is anastomosed with and in direct contact with the gingiva (4) at the tooth defect site, and the pre-formed shoulder (3) is set on the post (1) and is flush with the edge of the gingiva (4) at the tooth defect site.

2. The pure titanium cast pile core with polished surface and pre-formed shoulder as described in claim 1, characterized in that: The pre-formed shoulder (3) has the same width as the pre-prepared shoulder (5) on the tooth and is connected and continuous.

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