WO2024245258A1 - Expansion-type root canal filling medical instrument combination based on tooth root tip biological sealing, and use - Google Patents

Abstract

An expansion-type root canal filling medical instrument combination based on tooth root tip biological sealing, and a use. The medical instrument comprises a sealant composition and a titanium material root canal obturating point; the sealant composition is composed of a liquid agent, component-A powder, and component-B powder that are isolated from each other before use, the component-A powder comprises 75%-95% of tricalcium silicate and 5%-25% of β-tricalcium phosphate, and the component-B powder is composed of 45%-55% of nano zirconium dioxide, 44.7%-52% of calcium hydroxide, and 0.3%-3% of calcium oxide; the surface of a root canal section (1) of the titanium material root canal obturating point is provided with a thread (102) tending to be horizontal, and a thread groove of the root canal obturating point is used for being filled with a prepared sealant; the surface of a dental crown section (2) is provided with a retention groove section. The medical instrument combination solves the problems of root canal treatment failure or poor long-term effect and the like caused by volume shrinkage after existing sealants and gutta percha points are filled, and can realize high-safety, high-biocompability, high-quality and high-density root canal filling.

Description

Expandable root canal filling medical device combination and its application based on biological sealing of tooth apex

This application claims the priority of two Chinese patent applications, the entire contents of which are incorporated herein by reference. The two prior Chinese patent applications are:

1. Application number: 202310643104.3, application date: June 1, 2023;

2. Application number: 202310794572.0. Application date: June 30, 2023.

Technical Field

The present application relates to dental medical devices, and in particular to a root canal filling device based on biological sealing of tooth root apex and its application.

Background Art

Root canal treatment is the main treatment for pulp and periapical lesions. After completing the preliminary root canal preparation and disinfection, how to safely and tightly fill each root canal and perfectly seal the apical foramen has become the focus and difficulty of root canal treatment, and the defects of root canal filling equipment have become the biggest pain point in the dental root canal treatment industry.

The existing root canal filling technology is to use a root canal sealer + gutta-percha tip in combination, but almost all root canal sealers + gutta-percha tips have different degrees of volume shrinkage after filling and solidification. In order to solve the problem of volume shrinkage of sealer + gutta-percha tip after root filling, the industry has emerged with the concept of "filling with as little root canal sealer as possible and as much gutta-percha as possible", that is, a root filling method that uses gutta-percha tips as the main method and root canal sealers as the auxiliary method, forming two major root canal filling technology systems currently used in clinical practice, namely, cold gutta-percha lateral extrusion filling technology and hot gutta-percha vertical pressurized filling technology. In recent years, injectable bioceramics + gutta-percha tip single-point root canal filling technology has emerged, but the problem of volume shrinkage of root filling materials has not been completely solved. A document entitled "Difficulties and Misunderstandings in Root Canal Filling" (Zhang Chen, West China Journal of Stomatology, Vol. 35, No. 3) reported that the gutta-percha tip will have a 7% shrinkage rate after heating and cooling, resulting in microgaps, microleakage, incomplete apical sealing and secondary infection in the apical sealing area after the root canal filling is completed, ultimately leading to failure of root canal treatment.

In summary, the volume shrinkage of root canal sealers and gutta-percha fillings leads to incomplete apical sealing, microgaps, and microleakage. This is a difficult problem that needs to be solved urgently in the industry and is also one of the main reasons for the failure of root canal treatment.

In addition, the potential harm that the toxic and harmful components contained in root canal sealers and gutta-percha tips themselves may bring to patients is also an important issue that needs to be addressed urgently.

Gutta-percha points have been used for nearly 180 years. The current mainstream root canal filling technology still relies on the ideas related to gutta-percha points, which results in many problems remaining unsolved.

The following is a brief analysis of the composition and characteristics of several commonly used root canal sealers and gutta-percha tips, some of which are quoted from "Progress in Research on Root Canal Sealers" (Yang Xueying et al., Electronic Journal of General Stomatology, 2019).

1. Clove oil/zinc oxide root canal sealer

Clove oil/zinc oxide is a traditional root canal filling agent, mainly composed of zinc oxide, rosin and eugenol. It is characterized by strong disinfection effect and can promote the regeneration of granulation tissue. However, its disadvantage is that the volume shrinkage after solidification causes it to peel off from the root canal wall and produce micro gaps, making it impossible to achieve complete root canal sealing. Its cytotoxicity is also controversial, and it is now mostly used as a control group in new material testing.

2. Resin root filling materials

Resin root filling paste materials have the characteristics of good fluidity, stable volume, and strong bonding with root canal dentin. The disadvantage is that they contain toxic and harmful ingredients such as formaldehyde and resorcinol.

3. Calcium hydroxide root canal sealer

Calcium hydroxide provides a strong alkaline environment (pH value can be as high as 12.5), destroys bacterial cell membranes and protein structures, thereby inhibiting bacterial growth, and can promote the activation of calcium-mediated adenosine triphosphatase in the process of hard tissue formation, active dentin and cementum formation, induce healing of periapical lesions, and enhance apical adhesion. However, its disadvantage is that the volume of calcium hydroxide paste shrinks to a certain extent after solidification, and it has a certain solubility and absorption when in contact with tissue fluid. The absorption comes from the continuous consumption of calcium ions during bone tissue reconstruction, and the long-term efficacy stability of single calcium hydroxide is poor.

4. Glass ionomer root canal sealer

Glass ionomer is a mixture of polyacrylic acid aqueous solution and aluminum silicate glass powder. It has physical properties very similar to those of dentin and can bond to the dentin surface through the chain effect of ultrastructure. The polyacrylate ions therein can undergo irreversible substitution reaction with the phosphate groups in hydroxyapatite, and have long-term adhesion to dentin even in humid conditions. It also has certain biocompatibility and can release fluoride ions to have anti-caries function.

The main disadvantage of glass ionomer is that it still shrinks significantly after solidification. Studies have shown that its apical sealing performance is significantly worse than the first three types of root filling agents, and it is not easy to remove after solidification, making secondary treatment very difficult.

5. Calcium silicate bioceramic root canal sealer

The advantages of calcium silicate bioceramics are good biocompatibility, low cytotoxicity, good long-term stability, and the ability to maintain a high pH value during solidification and for a period of time thereafter, inhibiting bacterial growth. Bioceramic materials should be the development direction of root canal filling materials, but existing bioceramic sealers also have many shortcomings that need to be addressed. For example, some brands of bioceramics contain harmful ingredients such as bismuth oxide, and some injectable bioceramic sealers contain resin thickeners. Resin thickeners may produce some carcinogens in the high-temperature environment of hot gutta-percha filling. During root filling, the sealer will inevitably be squeezed out of the apical foramen and enter the apical physiological environment area, which may pose potential hazards to the human body. In addition, the thickener in the injectable calcium silicate root filling agent will cause the silicon and calcium ions therein to be in a "suspended" state, which is not conducive to the precipitation and penetration of silicon and calcium ions into the micro-gap of the root canal, the dentinal tubules, etc. In addition, like the shortcomings of all other types of root canal sealers, the existing calcium silicate root canal sealers still need to be used in combination with gutta-percha tips. Once overfilled, the harmful substances in the gutta-percha tips may also damage the human body.

Composition and characteristics of gutta-percha tips:

The main components of gutta-percha tips are gutta-percha, zinc oxide, barium sulfate, and various pigments such as ultramarine, chromium oxide, and dye yellow. Among them, barium sulfate and chromium oxide contain toxic ingredients, and zinc oxide has also been reported to be cytotoxic. If the operation is not careful, the gutta-percha tip will cause it to extend beyond the apical end point of the tooth root and enter the physiological environment zone. Long-term contact with blood and bone tissue will cause chronic inflammation in the apical area, apical cysts, bone resorption, necrosis and other hazards. Overfilling of gutta-percha tips is not uncommon in clinical practice.

Summary of the invention

In order to solve the problem that the existing root canal sealers and gutta-percha fillings have volume shrinkage that affects the apical sealing and leads to root canal treatment failure, and the toxic and harmful components they contain cause potential harm to patients, the present application proposes an expandable root canal filling medical device combination and application based on apical biological sealing.

In order to achieve the above objectives, this application provides the following technical solutions:

An expandable root canal filling medical device combination based on biological sealing of tooth root apex, comprising a sealing agent combination and a titanium root canal plug tip;

The sealing agent combination is composed of a liquid, a component A powder and a component B powder which are isolated from each other before use, wherein the liquid is used to mix the component A powder into a paste when in use; the component A powder contains: 75%-95% tricalcium silicate, 5-25% beta tricalcium phosphate, and the component B powder contains: 45%-55% nano zirconium dioxide, 44.7%-52% calcium hydroxide, and 0.3%-3% calcium oxide;

The titanium root canal plug tip is an integrated structure, including a root canal segment and a crown segment coaxially arranged in sequence from bottom to top; the root canal segment is a cone, the surface of the root canal segment body is provided with an external thread, and the surface of the root canal segment close to the crown segment is provided with multiple circles of horizontal blades, which are respectively recorded as a root canal thread segment and a root canal horizontal blade segment, and the grooves of the root canal thread segment and the root canal horizontal blade segment are used to fill the prepared sealant; the crown segment is a cylinder, and a retention groove segment is provided on the surface.

Optionally, the liquid is distilled water or an aqueous solution of chitosan oligosaccharides.

Optionally, the B component powder is replaced with an antibacterial enhanced powder, which contains 45% nano zirconium dioxide, 42%-44.7% calcium hydroxide, 0.3%-3% calcium oxide, and 10% iodoform.

Optionally, the physical axial taper of the root canal segment is smaller than the taper of the outer contour of the root canal segment.

Optionally, the physical axis of the root canal segment is narrowed near the crown segment to form a frustum portion, and a thinner cone portion (which serves as the main body of the physical axis of the root canal segment) is formed below the frustum portion, and the taper of the cone portion is smaller than that of the frustum portion.

Optionally, the taper of the outer contour and the solid axis of the root canal segment refers to the taper specification of the machine expansion needle for dental root canal preparation, wherein the taper of the outer contour of the root canal segment is 04 taper, 06 taper or 08 taper, and the taper of the solid axis of the root canal segment is 01 taper, 02 taper or 03 taper.

Optionally, for titanium root canal plug tips with a root canal segment outer contour taper of 04 or 06, the maximum end diameter of the root canal segment outer contour is equal to the diameter of the crown segment outer contour; for titanium root canal plug tips with a root canal segment outer contour taper of 08 or above, the crown segment outer contour is radially indented relative to the root canal segment outer contour, so that a shoulder is formed between the root canal segment and the crown segment.

Optionally, the crown segment retention groove segment is in the form of a thread or multiple circles of horizontal blades or horizontal grooves.

A self-expanding sealant combination for biological sealing of tooth root apex, comprising a liquid, a component A powder and a component B powder which are isolated from each other before use, wherein the liquid is used to mix the component A powder into a paste when in use; the component A powder comprises: 75%-95% of tricalcium silicate and 5-25% of beta tricalcium phosphate, and the component B powder comprises: 45%-55% of nano zirconium dioxide, 44.7%-52% of calcium hydroxide and 0.3%-3% of calcium oxide.

An application of a bioceramic root canal sealer combination, the bioceramic root canal sealer combination consisting of a liquid, a component A powder, and a component B powder that are isolated from each other before use, wherein the liquid is used to mix the component A powder into a paste when in use;

The A component powder comprises: 75%-95% tricalcium silicate and 5-25% beta tricalcium phosphate;

The B component powder comprises: 45%-55% nano zirconium dioxide, 44.7%-52% calcium hydroxide, and 0.3%-3% calcium oxide; or, the B component powder comprises 45% nano zirconium dioxide, 42%-44.7% calcium hydroxide, 0.3%-3% calcium oxide, and 10% iodoform;

The application is specifically a two-layer root canal filling method: the first layer of filling: firstly, the A component paste is introduced into the entire root canal with a titanium root canal plug tip and ultrasonically vibrated for a few seconds. During the introduction process, a small amount of the A component paste will inevitably enter the physiological environment area outside the apical stop point. The bioactive ceramic components of the A component will promote the proliferation of bone cells in the apical area and apical mineralization to form a biological apical closure; the second layer of filling: the titanium root canal plug tip root canal segment with the A component paste remaining is placed in the B component dry powder and rotated so that its surface is coated with the B component dry powder. At this time, the titanium material The root canal plug tip is a arbitrarily shaped drug stent with expandable bioceramic powder coated on its surface. It is quickly inserted into the root canal to form an AB component mixture. The calcium oxide contained in the B component will undergo a chemical expansion reaction with the water in the A component paste, and serve as the second layer of filling material to densely fill the non-physiological environment area of the root canal. The self-expansion force of the second layer of AB component mixture filling material and the spiral propulsion compression force of the conical root canal section of the titanium root canal plug tip will further squeeze the first layer of A component paste into all micro-gaps on the inner wall of the tooth's root canal and the apical physiological environment area.

A titanium root canal plug tip, which adopts an integrated structure and includes a root canal segment and a crown segment coaxially arranged in sequence from bottom to top; the root canal segment is a cone, the surface of the root canal segment body is provided with an external thread, and the surface of the root canal segment near the crown segment is provided with multiple circles of horizontal blades, which are respectively recorded as a root canal thread segment and a root canal horizontal blade segment, and the grooves of the root canal thread segment and the root canal horizontal blade segment are used to fill with a prepared sealant; the crown segment is a cylinder, a cuboid or a triangular prism, and the surface is provided with a retention groove segment.

A new root canal filling mode uses a titanium root canal plug tip as a root canal metal stent, rapidly delivers and controls the chemical expansion reaction of a self-expanding bioceramic root canal sealer in the root canal, and forms a new uniform and dense root canal filling mode by combining the self-expansion force of the bioceramic material and the spiral compression force of the titanium root canal plug tip advancing in the root canal.

Compared with the prior art, this application has at least the following beneficial effects:

1. This application is based on the concept of biological apical sealing. The sealant does not contain any thickener or other harmful substances. The root canal plug tip is made of medical titanium material with excellent biocompatibility, which is used for partitioning, layering and material filling: the first layer of filling uses component A paste to ensure the high purity and high safety of bioactive ceramics entering the physiological environment area of the tooth, avoiding the harm caused by harmful components contained in existing sealants entering the physiological environment area of the tooth, and component A paste can also stimulate the proliferation of new bone cells and apical mineralization after entering the apical physiological environment area, so as to achieve ideal biological apical sealing; The second layer of filling is in the non-physiological environment area within the apical base point of the tooth root canal, and is filled with a mixed sealer of components A and B. Component B contains calcium oxide, which will react chemically with the water in the previous component A paste to expand rapidly. When used in combination with the titanium material root canal plug tip of the present application, the expansion process of the sealer can be accurately and quickly controlled in the root canal, and the micro-gaps of the root canal cavity are filled by expansion and extrusion, which solves the problems of root canal treatment failure or poor long-term efficacy caused by volume shrinkage after filling with existing sealers and gutta-percha tips, and ultimately achieves high safety, high biocompatibility, high quality and high density root canal filling.

2. The titanium root canal plug tip in the present application makes it possible to effectively implement the zoned and layered filling of the bioceramic sealant: after the first layer of component A paste completes the root canal filling, the titanium root canal plug tip with the surface of the root canal segment coated with component B dry powder sealant is equivalent to a drug stent with both plasticity and certain elasticity. Its conical thread structure rotates and advances in the conical root canal cavity. The sealant is evenly divided, compressed and filled in the root canal cavity by each circle of thread of the root canal segment of the titanium root canal plug tip. The filling density is much greater than the filling density of the existing root canal sealing paste plus gutta-percha tip, which provides a strong guarantee for stable long-term efficacy.

3. In the prior art, gutta-percha tips contain harmful ingredients such as barium sulfate, chromium oxide, and dye yellow. Once overfilled, these toxic chemical components will come into contact with blood in the apical physiological environment, causing inflammation, cysts, bone resorption and other toxic side effects. Titanium root canal plug tips have excellent biocompatibility, and the excess titanium tip will guide new bone cells to adhere and deposit on its surface, forming a biological closure of the apical foramen.

4. The titanium root canal plug tip can replace the gutta-percha tip, fiber post and root canal nail in the prior art. No secondary posting is required after root filling, which avoids unnecessary secondary preparation damage to the root canal caused by secondary posting in the prior art, and root fracture caused by stress concentration of the root canal post in the middle of the root canal. At the same time, there are one or more titanium metals in the tooth body from the root tip to the occlusal surface of the crown, and the overall anti-fracture strength of the tooth is greatly improved.

In order to more intuitively illustrate the prior art and the present application, several exemplary drawings are given below. It should be understood that the specific shapes and structures shown in the drawings should not generally be regarded as limiting conditions for implementing the present application; for example, those skilled in the art are capable of easily making conventional adjustments or further optimizations to the addition/reduction/attribution division, specific shapes, positional relationships, connection methods, dimensional ratios, etc. of certain units (components) based on the technical concepts and exemplary drawings disclosed in the present application.

FIG1 is a schematic structural diagram of a root canal plug tip made of titanium material used in one embodiment of the present application;

FIG2 is a schematic diagram of the root canal plug tip being introduced into the root canal;

FIG3 is a schematic structural diagram of a root canal plug tip (with a shoulder) made of titanium material used in another embodiment of the present application.

FIG. 4 is a modification of the embodiment shown in FIG. 3 .

FIG. 5 is an axonometric view of a sample of the first embodiment of the present application.

FIG. 6 is an axonometric view of a sample of the second embodiment of the present application.

FIG. 7 is an axonometric view of a sample of the third embodiment of the present application.

Description of reference numerals:
1. root canal segment; 101. root canal segment solid axis; 102. root canal segment external thread; 103. root canal segment horizontal blade;
2. crown segment; 201. solid axis of the crown segment; 202. external thread of the crown segment.

DETAILED DESCRIPTION

The present application is further described below in detail through specific embodiments in conjunction with the accompanying drawings.

In the description of this application: the terms "first", "second", etc. are intended to distinguish the objects referred to, and do not have any special meaning in terms of technical connotation (for example, they should not be understood as emphasizing the importance or order, etc.). The expressions "including", "comprising", "having", etc. also mean "not limited to" (certain units, components, materials, steps, etc.).

The terms such as "upper", "lower", "left", "right", "middle", etc. used in this application are usually used to facilitate intuitive understanding by comparing with the accompanying drawings, and are not absolute limitations on the positional relationship in the actual product. Without departing from the technical concept disclosed in this application, changes in these relative positional relationships should also be regarded as the scope of this application.

The present application proposes for the first time in the dental root canal treatment industry the division of physiological and non-physiological environmental zones of teeth based on the concept of biological closure of the root apex, and adopts a root canal treatment approach of filling in zones, layers and materials in sequence.

The high-purity bioactive ceramic of component A enters the physiological environment zone as the first layer of filling: in the physiological environment zones such as the micro-flared apical foramen area, the periapical area, and the accessory root canals on each side and the micro-channels on the surface of the tooth root outside the narrowest part of the root canal apex (apical base point) where blood circulation occurs and metabolism occurs, what is squeezed in or filled is the high-purity, degradable, bone cell-stimulating silicon/calcium phosphate bioactive ceramic hydrated gel of component A, which induces apical mineralization and closure, and induces osteoblasts to proliferate, differentiate, deposit and grow into the apical physiological zone and apical foramen in the apical area to form a good biological apical closure.

The mixed bioceramics of components A and B enter the non-physiological environment area, which is the second layer of filling. In the non-physiological environment area without vital pulp and metabolism, the pulp cavity and root canal area within the narrow part of the root apex is filled with nano zirconium dioxide, calcium hydroxide, calcium oxide, etc. Calcium hydroxide is strongly alkaline and has the effect of sterilization and disinfection. The chemical expansion reaction characteristics of calcium oxide when it comes into contact with water can form a good physical seal; while calcium oxide and calcium hydroxide can maintain a dry and sterile root canal environment. Nano zirconium dioxide, as a biologically inert ceramic, does not degrade itself. In the dry and sterile root canal environment, all filling materials of the AB component mixture do not degrade, and a stable chemical root canal seal is formed.

In particular, in combination with the titanium root canal plug tip proposed in the present application (the titanium material can specifically be medical pure titanium or titanium alloy), its circles of thread grooves can cleverly and quickly and evenly bring the B component composite bioceramic containing calcium oxide into the root canal filled with the A component silicon/calcium phosphate hydrate gel, and quickly and accurately transport and control the chemical reaction process of the composite bioceramic expansion in the root canal.

Taking tooth 6 as an example, this embodiment uses a two-layer filling method, specifically: after the conventional root canal preparation is completed, a post channel about 3mm deep is prepared by grinding at the root canal mouth, and the inner diameter of the post channel is larger than the maximum outer diameter of the horizontal blade of the root canal segment of the root canal plug tip. The first layer of filling: first, the A component paste is introduced into the entire root canal with a titanium material root canal plug tip and ultrasonically vibrated. The introduction and vibration process will inevitably cause a small amount of A component paste to enter the physiological environment area outside the apical stop point. The bioactive ceramic component of A component will promote the proliferation of bone cells in the apical area and apical mineralization to form a biological apical seal; the second layer of filling : Place the titanium root canal plug tip with the A component paste remaining in the B component dry powder and rotate it, so that its surface is covered with the B component dry powder, and insert it into the root canal to form an AB component mixture. The calcium oxide contained in the B component will react with the water in the A component paste to chemically expand, and densely fill the non-physiological environment area of the root canal as the second layer of filling material; the self-expansion force of the second layer of AB component mixture filling material and the spiral push compression force of the titanium root canal plug tip cone root canal segment will further squeeze the first layer of A component paste into all micro gaps on the inner wall of the tooth root canal and the apical physiological environment area. Finally, use a three-way gun to quickly rinse the excess filling agent in the root canal post channel, blow dry it, and then inject light-cured fluid resin or glass ionomer to complete it.

The root canal sealer combination in the present application can be divided into a basic formulation and an antibacterial enhanced formulation, and both of these two sealer combinations are composed of liquid and powder.

Basic dosage form:

Liquid preparation: distilled water or chitosan oligosaccharide/distilled water (500 mg/L mass concentration) solution;

The powder is divided into component A powder and component B powder; the composition of component A is (mass fraction): tricalcium silicate 75%-95%, beta tricalcium phosphate 5-25%; the composition of component B is (mass fraction): nano zirconium dioxide 45%-55%, calcium hydroxide 44.7%-52%, calcium oxide 0.3%-3%;

Enhanced antibacterial type:

Liquid preparation: distilled water or chitosan oligosaccharide/distilled water (500 mg/L mass concentration) solution;

The powder is divided into component A powder and component B powder; wherein the composition of component A is (by mass fraction): tricalcium silicate 75%-95%, beta tricalcium phosphate 5-25%; the composition of component B is (by mass fraction): nano zirconium dioxide 45%, calcium hydroxide 42%-44.7%, calcium oxide 0.3%-3%, iodoform 10%;

The basic dosage form is suitable for most cases, and the enhanced antibacterial dosage form is suitable for a small number of root canal cases with chronic exudative inflammation and some difficult-to-treat cases.

The specific experimental groups are shown in Table 1.

Table 1

The above experimental groups can all achieve the effects expected by the inventors, and the specific analysis is described in detail below.

The titanium root canal plug tip is an integrated structure, as shown in Figures 1, 3, and 4, including a root canal segment 1 and a crown segment 2 coaxially arranged from bottom to top; the root canal segment 1 is a cone, and the external taper of the root canal segment is consistent with the specification taper of the dental root canal preparation machine expansion needle (the configurable models are, for example, 04 taper, 06 taper, and 08 taper), and the root canal segment surface is provided with a root canal segment external thread 102, and its thread groove is used to fill the prepared sealant, so a horizontal thread form is preferred, for example, the thread lead angle is 0 to 30 degrees. The crown segment 2 is a cylinder, and the surface is provided with a crown segment external thread 202, and the thread therein mainly plays a role of retention, and can also be changed to a horizontal blade form; after the root canal plug tip is filled in place, the crown segment is in the position of the cavity in the crown, and is used to fix the root canal plug tip in the tooth body after filling with fluid resin or glass ion adhesive.

In one embodiment, the root canal plug tip of titanium material with an integrated structure, the root canal segment 1 is a cone, the external taper of the root canal segment is consistent with the specification taper of the dental root canal preparation machine expansion needle (the configurable models are, for example, 04 taper, 06 taper, 08 taper), and the root canal segment surface is provided with a root canal segment external thread 102, and its thread groove is used to fill the prepared sealant, so a horizontal thin blade non-standard thread form is preferred, for example, the thread lead angle is 0 to 30 degrees. In order to further improve the filling effect of the agent, it is recommended that the thread profile angle of the root canal thread segment is not greater than 60 degrees, for example, 15 to 45 degrees. The crown segment 2 is a cylinder (the cylinder here means that the main body of the crown segment is a cylinder, and according to actual needs, a shape that is more convenient for clamping can be processed locally based on the cylinder), and the surface is provided with a crown segment external thread 202, which mainly plays a retention role and can also be changed to a horizontal blade form; after the root canal plug tip is filled in place, the crown segment is in the position of the cavity in the crown, and is used to fix the root canal plug tip in the tooth body after filling with fluid resin or glass ion adhesive. In addition to being a cylinder, the crown segment can also be designed as a rectangular parallelepiped or a triangular prism, and the specific form of the retention groove segment provided on the surface is not limited to a thread, but can also be a horizontal blade or a horizontal annular groove, etc.

The state of the titanium root canal plug tip being introduced into the root canal is shown in FIG2 .

A root canal segment horizontal blade 103 is also provided in the area near the crown segment on the upper surface of the root canal segment. The functions of the root canal segment horizontal blade 103 are: 1. To form a blind groove in the thread groove of the root canal segment, so that the sealant in the thread groove will not overflow from the groove when rotating into the root canal, ensuring that there is a sufficient amount of sealant in the root canal and it is compressed and compacted in the groove between the root canal cavity and the thread groove. 2. The groove of the horizontal blade can be filled with sealant or fluid resin adhesive or glass ionomer and other dental filling materials, as a boundary mark between the sealant and the dental filling material. 3. To prevent the water flow from washing away the sealant in the thread groove of the root canal segment when the excess sealant in the crown is rinsed after the root filling is completed. Each circle of the thread groove has a connected groove, and the sealant will be washed away by the water flow, while each circle of the horizontal blade has a groove that is not connected to each other, and each circle is an independently closed groove, which will not be washed away by the water flow, and can protect the sealant in the root canal from being washed away, diluted, and contaminated by saliva.

The root canal segment physical axis 101 (the metal physical axis at the bottom of the root canal threaded segment and the horizontal blade segment groove) and the crown segment physical axis 201 (the metal physical axis at the bottom of the crown threaded segment groove) have a smooth transition, but the root canal segment physical axis 101 may not be a standard cone. The thread of the crown segment 2 only serves to fix the root canal plug tip in the tooth body after filling with fluid resin or glass ion adhesive. Therefore, the crown segment physical axis 201 may be thicker; further, as shown in Figures 1 and 3, the portion of the root canal segment physical axis 101 close to the crown segment (specifically, it may be the upper portion of the physical axis at the bottom of the root canal horizontal blade segment groove) may be significantly narrowed, so that the main body of the root canal segment physical axis 101 is relatively thinner.

The tapers of the solid axis 101 of the root canal segment include 01 taper, 02 taper, and 03 taper. Reducing the taper of the solid axis can increase its flexibility to better adapt to small and curved root canals.

For titanium root canal plugs with a taper of 08 or above, they can also be modified as follows: the outer contour of the crown segment is radially indented relative to the outer contour of the root canal segment, so that a shoulder is formed between the root canal segment and the crown segment, as shown in Figures 3 and 4. Specifically, the maximum diameter of the largest end of the external thread of the root canal segment (i.e., the connection with the crown segment) is larger than the diameter of the external thread of the crown segment, and the diameter of the external thread of the crown segment is narrower than the maximum diameter of the largest end of the external thread of the root canal segment by about half the width of the thread, that is, a narrow shoulder is provided between the root canal segment and the crown segment. The narrow shoulder is provided to reserve a larger gap at the root canal orifice after the root canal is filled to facilitate flushing and drying of excess sealant, to facilitate better flow of fluid resin or glass ion adhesive into the root canal orifice, and to better fix the root canal plug tip in the crown.

In order to more intuitively express the various embodiments of the present application, Figures 5, 6 and 7 respectively show the axonometric views of the three embodiment samples; among them, Figure 6 mainly changes the radial dimension of the crown segment compared to Figure 5; the retention groove segment set on the surface of the crown segment shown in Figure 7 is specifically in the form of a groove representing the scale, and the horizontal blade of the root canal segment is made slightly thicker in the center. Of course, the details of the drawings of these samples should not be regarded as limiting the products claimed for protection in this application.

The specific operation steps of performing two-layer root canal filling using the titanium root canal plug tip are as follows:

Step 1: Select a basic or antibacterial enhanced root canal sealer according to the indication of the affected tooth, select a titanium root canal plug tip that matches the taper and length of the root canal to be filled, mix the sealer component A with the liquid agent to form a paste, scrape the paste into the thread groove of the root canal segment (1), introduce the paste into the root canal through the root canal plug tip, continuously and quickly pressurize several times, and repeat the above action 1-2 times (after withdrawal, apply the paste again and introduce it into the root canal), complete the sealing and filling of the physiological environment area of the tooth root apex and the first layer of high-purity bioactive ceramic coating and filling of the inner wall of the root canal under the action of the vertical force and horizontal force of the cone of the root canal segment of the root canal plug tip, and then rotate in the opposite direction of the thread entry to withdraw;

Step 2: Place the root canal segment of the root canal plug tip in the dry powder of the sealant component B and rotate it so that the surface of the residual paste in the thread groove is covered with the dry powder of the component B bioceramic containing calcium oxide. At this time, the titanium root canal plug tip is an arbitrarily shaped drug stent, and the surface is coated with expandable bioceramic powder (this is similar to the spraying of hydroxyapatite bioceramics on the surface of the titanium implant of the implant, except that the implant must sinter the hydroxyapatite on the titanium surface at high temperature, while in this embodiment, it is only necessary to coat the bioceramics in the thread groove of the titanium root canal plug tip); after light rolling and preliminary compaction, rotate it along the thread entry direction to insert it into the preset position of the root canal; because the prepared root canal cavity and the root canal plug tip are both round The titanium material root canal plug has a conical shape, so the B-component bioceramic powder in the thread groove of the root canal plug tip will be further compressed and compacted in the root canal cavity. The calcium oxide in the B-component powder in the thread groove of the titanium material root canal plug tip will expand rapidly when it meets water, so that the calcium oxide in the A-component paste in the root canal cavity will undergo a chemical expansion reaction with the water. At this time, a small part of the nano zirconium dioxide in the B component will enter the micro-gap of the root canal cavity, the lateral root canal, and the dentinal tubules under the extrusion of the expansion force, completing the root canal filling of the second layer of bioceramics. The second layer of bioceramics will further squeeze the first layer of hydrated calcium silicate/calcium phosphate gel coated on the inner wall surface of the root canal cavity into the physiological environment area of the tooth and the micro-gap and dentinal tubules adjacent to the physiological environment area.

During the root canal filling process, the titanium root canal plug tip can also be directly electrically connected to the dental root measuring instrument to accurately measure the root canal length while filling. There is no need to measure the root canal in advance or take X-rays to confirm the tooth length, and there is no need to pre-set the working length of the root canal plug tip. The filling and measurement are synchronized with digital operations, and ultra-precise root canal filling can be completed in seconds.

Finally, rinse and dry the excess bioceramics in the root canal opening, crown cavity and the thread groove of the crown segment of the root canal plug, inject light-curing fluid resin into the root canal opening and crown cavity, light-curing or natural curing of glass ionomer adhesive, and quickly complete a high-quality root canal treatment.

In the above embodiments, if common tools such as root canal enlargement needles, smooth probes, gutta-percha tips, etc. are used, it may be difficult to ideally fill the dry powder of component B and the hydrated gel of component A into the root apex area proportionally, evenly, and quickly before the chemical expansion reaction. However, by using the titanium root canal plug tip, the chemical reaction process of the composite bioceramic expansion can be accurately delivered and controlled in the root canal.

Chemical composition analysis of various bioceramics in the root canal sealer of this medical device combination:

1. Tricalcium silicate:

Tricalcium silicate has excellent biological activity and the ability to induce the deposition of bone-like hydroxyapatite, and has the function of promoting the formation of chemical bonds with soft/hard tissues. Tricalcium silicate reacts with water at room temperature to form hydrated calcium silicate gel (CSH) and calcium hydroxide. CSH biomaterials have a significant effect on stimulating the proliferation and differentiation of osteoblasts, and on the proliferation and differentiation of dental pulp stem cells into odontoblast-like cells. Silicon ions play an important role in promoting metabolism, collagen synthesis, and bone tissue mineralization, and are an important factor in bone and blood vessel formation. The induced hydroxyapatite deposition can penetrate into the dentinal tubules and form chemical bonds with the dentin, so it has better root canal sealing performance.

In addition, the hydration reaction of calcium silicate also produces a small amount of calcium hydroxide, which has a certain antibacterial effect, while β-tricalcium phosphate does not have antibacterial properties.

Wang Xiaohong, Chang Jiang, Sun Hongchen and others reported in the academic paper "Experimental Study on Blocking of Dentin Tubules by Tricalcium Silicate" that the self-curing process of CSH biomaterials will generate amorphous calcium phosphate ions of about 100nm-300nm on the dentin surface to block dentinal tubules, and induce dentin remineralization under physiological conditions.

Fei Lisha, Sun Jiao and others reported in the academic paper "Preliminary Study on the In Vitro Osteogenic Effect of Calcium Silicate Bioceramics with Different Contents" that calcium silicate (GS) has a significant ability to induce bone cell proliferation and differentiation in vitro, and the osteogenic effect is proportional to the content of CS, and is significantly better than β-tricalcium phosphate (β-TCP).

In the paper "Study on the in vitro and in vivo degradability of α-calcium silicate and β-calcium silicate", Liu Yong et al. reported an animal model of implanting α-calcium silicate, β-calcium silicate and β-tricalcium phosphate in rabbits, and discussed in detail the mechanism of α-calcium silicate, β-calcium silicate and β-tricalcium phosphate in vivo degradation and stimulation of osteoblast proliferation and differentiation, demonstrating that the osteogenic activity and speed of calcium silicate are higher than those of β-tricalcium phosphate.

2. β-tricalcium phosphate:

β-tricalcium phosphate has good biodegradability, osteoinductivity and conductivity, biocompatibility and biosafety. When it is implanted into the human body, the degraded Ca ions and P ions can enter the living circulatory system to form the basic substance of new bone and induce new bone regeneration. β-tricalcium phosphate alone can also achieve bone-cementum-dentin osseous bonding and achieve biological closure of the root apex.

The curing process of β-tricalcium phosphate does not generate heat, and its combination with calcium silicate has a positive effect on maintaining the normal physiological environment balance of the root apex.

The solidification strength of β-tricalcium phosphate is lower than that of calcium silicate after solidification. When used in combination with calcium silicate, it can reduce the strength of root canal fillings, which is beneficial for the subsequent removal of root canal fillings for root canal retreatment.

The degradation rate of β-tricalcium phosphate in the physiological environment is lower than that of calcium silicate. For areas with large apical bone absorption, the proliferation rate of bone cells often cannot keep up with the degradation rate of calcium silicate materials. The combined use of calcium silicate and β-tricalcium phosphate will make the degradation rate of the material closer to the proliferation rate of bone cells.

The hydration reaction of tricalcium silicate generates calcium silicate hydrate gel and a small amount of calcium hydroxide, and the calcium hydroxide reacts with β-tricalcium phosphate to generate hydroxyapatite.

3. Nano zirconium dioxide:

Nano zirconium dioxide is an excellent biologically inert material with high strength and good chemical stability. It does not react with other chemical components, does not cause hemolytic reactions, is non-degradable, non-cytotoxic, has no rejection reaction when in contact with bone cells, has a large specific surface area, strong oxygen storage capacity, and a relatively high density. It has a radioblocking effect on X-rays and can be used as a developer, which is beneficial for radiography after root filling. Please refer to the paper "Effects of Nano-Scale Zirconium Dioxide Toughened Hydroxyapatite Biocomposite Ceramics on the Proliferation and Differentiation of Rabbit Bone Marrow Stromal Stem Cells" (Tang Yuejun, Wang Xinling, Zhou Zhonghua, and Lu Chuntang).

4. Calcium hydroxide:

Calcium hydroxide, also known as slaked lime, is strongly alkaline with a pH value as high as 12.5. It can damage bacterial cell membranes and denature bacterial proteins. The released hydroxide ions cause bacterial DNA chains to break, thereby killing bacteria. It can also penetrate into dentinal tubules to kill bacteria.

Calcium hydroxide can neutralize the acidic substances produced during the inflammation process, eliminate lactic acid produced by osteoclasts, inhibit acid phosphatase, inhibit apical inflammatory absorption, and prevent further destruction of hard tissue. At the same time, it can activate alkaline phosphatase to promote the formation of hard tissue.

Calcium hydroxide has good biocompatibility, is non-irritating and non-toxic to the body and pulp tissue, and can promote and induce the formation of dentin bridges, promote the closure of the apical foramen, and promote the repair of periapical bone tissue.

5. Calcium oxide:

Calcium oxide, also known as quicklime, is hygroscopic and reacts with water to form calcium hydroxide. After the hydration reaction, its volume expansion rate is about 200%.

Although calcium oxide only accounts for 0.3%-3% of component B in this embodiment, it undergoes a chemical reaction when in contact with water and moisture and can expand rapidly, thus giving the bioceramic sealant a self-expanding property. It is the only, irreplaceable and important component in component B.

Analysis of the combined effects of the composite bioceramic root canal sealer and the root canal tip plugging medical device in this embodiment:

Chitosan oligosaccharides in the liquid can inhibit the resorption of osteoclasts, increase the activity of osteoblasts, and promote the synthesis of bone morphogenetic protein (BMP) by osteoblasts, so as to repair bone damage or bone resorption caused by inflammation, trauma, etc. in the root apex.

When component A is mixed with chitosan oligosaccharide/distilled water solution, the calcium silicate therein reacts with water to generate hydrated calcium silicate gel (CSH) and a small amount of calcium hydroxide.

In the root canal, calcium silicate hydrate gel CSH can enter the micro-gaps such as dentinal tubules and lateral root canals to form an obstruction seal.

A small portion of calcium silicate hydrate gel (CSH) will be squeezed out of the narrow area of the root canal apex and enter the apical physiological environment area, inducing cementum mineralization, stimulating the proliferation and differentiation of osteoblasts, inducing the deposition of bone-like hydroxyapatite to generate new bone to close the apical foramen, and promoting the formation of chemical bonds with soft/hard tissues.

Calcium hydroxide generated by the hydration reaction of calcium silicate reacts with β-tricalcium phosphate to form hydroxyapatite.

Among them, after β-tricalcium phosphate enters the physiological environment of the tooth root, the degraded Ca ions and P ions can enter the living body's circulatory system to form the basic substance of new bone and induce new bone regeneration to close the apical foramen.

Component A is a biodegradable bioactive ceramic material that can induce mineralization of dentin and cementum in the apical area, induce differentiation and proliferation of cementoblasts and osteoblasts, form bone-cementum-dentin osseous bonding, and achieve the most ideal root canal treatment effect of biological closure of the root apex.

Nano zirconium dioxide in component B is a non-degradable bio-inert ceramic material that can directly enter the dentinal tubules (dentinal tubules are about 2-4 microns in diameter) and lateral root canals to form blocking and sealing. In the root canal, nano zirconium dioxide acts as a transmission medium for the internal expansion force and the external titanium thread rotation compression force, which will further squeeze the first layer of tricalcium silicate/tricalcium phosphate hydrate gel coated on the inner wall of the root canal into the deeper part of the dentinal tubules and other micro gaps to achieve a better sealing effect.

The pH value of calcium hydroxide is as high as 12.5, which can maintain a strong alkaline environment in the root canal and play a role in sterilization and disinfection.

Calcium oxide reacts with the water in component A to generate calcium hydroxide and expands in volume by 200%. By utilizing its property of rapid expansion due to chemical reaction when in contact with water or moisture, the bioactive ceramic sealant expands as it is filled to form a dense root canal filling, thus ensuring the physical sealing advantage of the root canal. When used in combination with titanium root canal plug tips, it can solve the industry problem of volume shrinkage after root canal filling.

Calcium oxide also has a drying effect. After the chemical reaction, it will consume excess water in the root canal. After the A and B components are mixed, they can maintain a dry and sterile root canal environment for a long time. The mixed bioceramics of A and B components will not degrade in a dry and sterile non-physiological environment, and can maintain the long-term stable density of the filling in the root canal and good long-term efficacy.

Calcium oxide generates calcium hydroxide after hydration reaction, which works together with the original calcium hydroxide component in component B to keep the root canal dry and sterile, ensuring the advantage of chemical sealing of the root canal.

The titanium root canal plug tip compresses a mixture of tricalcium silicate, calcium hydroxide and zirconium dioxide into the root canal, forming "reinforced concrete" of the tooth.

Quantitative analysis of the expansion rate and heat generation rate of this medical device combination:

During use of the medical-device combination of this embodiment, after the B component material is brought into the root canal by the titanium root canal plug tip, the volumes of the A and B component materials each account for about 50% (the specific usage ratio can be controlled at A:B=1:0.8-1.2), and the calcium oxide content in the B component accounts for about 0.3%-3%, and the volume expansion rate of the calcium oxide hydration reaction is about 200%. It can be calculated that the expansion rate of the root canal apical segment sealer is approximately: 1*50%*0.3%*200%=0.3%, 1*50%*3%*200%=3%, and the volume expansion rate of the root canal apical segment sealer is about 0.3%-3%, which should be able to meet clinical applications (the calcium oxide content ratio can be increased or decreased according to clinical needs).

Furthermore, the side effect of calcium oxide in the self-expanding composite bioceramic is the heat generated during the hydration reaction. After the composite bioceramic root filling is mixed, the volume of the B component brought into the root canal by the thread groove of the root canal plug tip accounts for about 50%, and the calcium oxide content in the B component accounts for 0.3%-3%. By calculation, the content of calcium oxide in the root canal accounts for 1*50%*0.3%=0.15%, 1*50%*3%=1.5%, and the content of calcium oxide in the root canal accounts for about 0.15%-1.5%. The heat generated is much lower than the heat in the root canal caused by the traditional hot gutta-percha filling method.

Compared with the existing bioceramic sealants, the sealant combination of this embodiment has the following advantages:

When filling the root canal, it is inevitable that a portion of the sealant will be squeezed out of the apical narrow area into the physiological environment area with blood circulation and metabolism, including the apical foramen and the periapical area outside it.

Some existing brands of bioceramic sealants contain harmful ingredients such as bismuth oxide, and some injectable bioceramics contain resin thickeners. Resin thickeners may produce some carcinogens in the high-temperature environment of hot gutta-percha filling. Since it is impossible to divide the tooth into zones and fill them in layers, harmful substances will inevitably exceed the apical foramen and enter the physiological environment zone, which may pose potential harm to the human body. The existing calcium silicate root canal sealers used in combination with gutta-percha tips still face the safety hazards of large shrinkage of gutta-percha tips and toxic ingredients in the gutta-percha tips themselves after overfilling. In addition, the thickener in the injectable calcium silicate root canal filling agent will cause the silicon and calcium ions therein to be in a "suspended" state, which is not conducive to the precipitation and penetration of silicon and calcium ions into the micro-gaps of the root canal, dentinal tubules, etc.

The sealer component A of this embodiment is mixed with distilled water to form a calcium silicate hydrate gel-calcium hydroxide paste. This paste has both the fineness of a gel and a "wet sand"-like precipitation phenomenon. This "wet sand"-like precipitation phenomenon is more conducive to ultrasonic vibration after filling to make it penetrate into the micro-gap of the dentinal tubules and the root apex. After root filling, dry cotton balls can be used to absorb excess water, which can increase the concentration of tricalcium silicate and the root filling density, forming an ideal root apex biological seal and dense root canal filling.

The sealant of this embodiment does not contain any thickeners and other harmful substances, etc. The root canal plug tip is made of medical titanium material with excellent biocompatibility. It is used in combination to divide, layer, group and fill the degradable high-purity and high-activity bioceramics and non-degradable bioceramics separately, ensuring the high purity of the bioactive ceramics entering the physiological environment area of the teeth, and avoiding the harm caused by the harmful components contained in the traditional sealant entering the physiological environment area of the teeth. Specifically: a layer of high-purity bioactive ceramics of component A is filled and coated in the physiological environment area of the teeth and the adjacent physiological environment area, as well as the micro-gaps on the inner wall of the root canal, the dentin tubules, etc. The component A is composed of 75%-95% tricalcium silicate and 5%-25% tricalcium phosphate, and is blended with distilled water or chitosan oligosaccharide/distilled water solution. It does not contain other components that are not helpful or not conducive to the growth of bone cells, such as thickeners, X-ray blocking developers, other inorganic fillers, etc., and forms the first layer of high-purity bioactive ceramic sealing barrier layer after entering the root canal.

When component A is mixed with distilled water or chitosan oligosaccharide/distilled water to form a fluid paste, the tricalcium silicate hydration reaction generates hydrated calcium silicate gel (C.S.H) and calcium hydroxide. After being introduced into the root canal, a small part of it will squeeze out of the narrow area of the apex and enter the physiological environment of the tooth to participate in metabolism, which can induce the differentiation and proliferation of cementoblasts and osteoblasts. C.S.H will induce the deposition of bone-like hydroxyapatite to generate new bone to repair bone resorption and bone defects in the apical area of the tooth caused by apical periodontitis. At the same time, it induces the mineralization of cementum and dentin in the apical area to achieve the purpose of biological closure of the apical foramen, which is in line with the concept of biological closure of the apex proposed by us.

Among them, β-tricalcium phosphate is similar to the inorganic components of dentin and bone matrix, has good osteogenic activity and osteoconductivity, can guide bone cells to grow into the apical foramen, and the degraded calcium and phosphate ions become important substances for bone cell growth. β-tricalcium phosphate reacts with calcium hydroxide to form hydroxyapatite. Hydroxyapatite deposition forms a biological apical closure of bone-cementum integration, which is in line with the concept of biological apical closure we proposed.

The non-physiological environment area within the narrow area of the apex of the tooth root canal is filled with expandable, non-degradable AB component mixed bioceramics (the nano zirconium dioxide in the B component is a bioinert ceramic that itself does not degrade. In the dry and sterile root canal in a non-physiological environment, all components of the AB component do not degrade. The advantage of non-degradation is that it can maintain long-term stable filling density in the root canal and good long-term therapeutic effects).

In addition, the sealing agent combination of this embodiment is also the result of continuous optimization by the inventor. The previously attempted formula is:

Liquid: distilled water or normal saline;

Component A powder: tricalcium silicate 55-75%, beta tricalcium phosphate 25-45%;

Component B powder: 35-40% calcium hydroxide, 21-26% nano hydroxyapatite, 20-25% nano zirconium dioxide, 10-15% nano tantalum oxide, and 3-5% calcium oxide.

The formula of the basic dosage form in this embodiment is:

Liquid: chitosan oligosaccharide/distilled water 500mg/L solution;

Component A powder: tricalcium silicate 75%-95%, beta tricalcium phosphate 5-25%;

Component B powder: nano zirconium dioxide 45%-55%, calcium hydroxide 44.7%-52%, calcium oxide 0.3%-3%.

By consulting the latest research reports and conducting clinical verification, the inventors realized that calcium silicate is better than tricalcium phosphate in promoting bone cell proliferation, and there is a significant statistical difference. Therefore, the content of tricalcium silicate in component A was increased from 55-75% to 75%-95%, and the content of β-tricalcium phosphate was reduced from 25-45% to 5-25%, so as to achieve a better effect of promoting the proliferation of bone cells in the root apex.

In addition, the titanium root canal plug tip has also been improved. The handle of the root canal plug tip has been removed, and the length of the root canal plug tip has been reduced, making it easier for doctors to operate, especially for patients with limited mouth opening. The external thread taper of the root canal segment of the titanium root canal plug tip and the taper of the solid axis at the bottom of the thread groove have also been redesigned with a differentiated design. The taper and radial size of the solid axis are smaller and thinner, so that the root canal segment of the root canal plug tip has better flexibility and plasticity, which is more suitable for filling small and curved root canals, expanding the indications for the use of titanium root canal plug tips.

The tip of the root canal segment is arc-shaped, and the taper of the outer contour and the tip diameter of the root canal segment are consistent with the taper and tip diameter specifications of the machine expansion needle used for dental root canal preparation. The specific 04 taper commonly used specifications series include 04/025, 04/030, 04/035, and the specific 06 taper commonly used specifications series include 06/025, 06/030, etc., and can be expanded up and down based on this series of data.

The physical axis taper of the root canal segment can be designed as a single through-taper taper according to the actual clinical application scenario, which has 01 taper, 02 taper, or 03 taper. Any external contour taper data of the root canal plug tip can be designed in combination with any physical axis inner taper data. In order to increase the flexibility and plasticity of the root tip half of the root canal thread groove segment of the root canal plug tip, and also increase the strength of the horizontal blade segment of the root canal, the physical axis taper of the root canal segment can also be designed as a variable taper according to the actual clinical application scenario, that is, the lower half of the physical axis of the root canal thread groove segment of the root canal plug tip near the root tip is 01 taper, the upper half of the physical axis of the root canal thread groove segment of the root canal plug tip is 02 taper, and the physical axis of the horizontal blade segment of the root canal is 03 taper. Or other combination designs from 01 to 03 tapers from the root canal plug tip physical axis from bottom to top.

The commonly used length parameters of the root canal plug tip series are 13mm (root canal segment length 7.5mm, crown segment length 5.5mm), 15mm (root canal segment length 8.5mm, crown segment length 6.5mm), 17mm (root canal segment length 9.5mm, crown segment length 7.5mm), 19mm (root canal segment length 10.5mm, crown segment length 8.5mm) 21mm (root canal segment length 11.5mm, crown segment length 9.5mm), 23mm (root canal segment length 12.5mm, crown segment length 10.5mm), 25mm (root canal segment length 13.5mm, crown segment length 11.5mm), 27mm (root canal segment length 15.5mm, crown segment length 11.5mm), 29mm (root canal segment length 17.5mm, crown segment length 11.5mm). Due to the large differences in tooth morphology, the data in this series can also be expanded up and down.

The overall advantages of this medical device combination:

1. The composite bioceramic root canal sealer in this medical device combination has high safety, high biocompatibility, high quality and high density for root canal filling.

High safety means that the AB two-component bioceramics do not contain any ingredients that are harmful to the human body. The partitioned and layered filling method is adopted. The first layer is filled with high-purity bioactive ceramics of component A. This ensures the high purity and high safety of the bioactive ceramics entering the physiological environment area of the tooth, and avoids the damage caused by harmful ingredients contained in existing sealants entering the physiological environment area of the tooth.

High biocompatibility and high quality root canal filling means: the bioactive ceramic calcium silicate hydrate gel and β-tricalcium phosphate paste of component A that enter the physiological environment of the tooth are degradable, can stimulate the proliferation and differentiation of osteoblasts and cementoblasts, stimulate the deposition of new bone in the apical area to grow into the apical foramen or promote the mineralization and closure of the apical foramen to bring about the most ideal biological closure of the apical foramen. The existing sealer plus gutta-percha root canal filling is only a physical apical closure.

High-density root canal filling means that the non-physiological environment area within the apical stop point of the tooth's root canal is filled with an expandable AB component mixed bioceramic root canal sealer. Component B contains calcium oxide. After the AB components are mixed, the calcium oxide will chemically react with the water in the A component paste and expand rapidly. When used in combination with the root canal plug tip, the expansion process of the sealer can be accurately controlled in the root canal, and the second layer of expansion and extrusion filling is performed on the micro-gap of the root canal cavity, which solves the problems of root canal treatment failure or poor long-term efficacy caused by volume shrinkage after filling with existing root canal sealing paste and gutta-percha tip.

Calcium oxide has a drying effect. After the expansion chemical reaction, it generates calcium hydroxide and consumes excess water in the root canal. Together with the calcium hydroxide in component B, it keeps the root canal dry and sterile. In the dry and sterile root canal environment, all ingredients of component AB do not degrade. The beneficial effect of non-degradation is that it can maintain long-term stable filling density in the root canal and good long-term therapeutic effect.

2. The titanium root canal plug tip in this medical device combination brings high safety, high biocompatibility, high quality and high density root canal filling.

1. Medical pure titanium or titanium alloy and other titanium materials are non-toxic to the human body and have excellent safety and biocompatibility. They have been widely used in orthopedics, surgery and other fields. Root canal plugs made of titanium materials are allowed to extend beyond the root apex base point into the root apex physiological environment area. The surface of the titanium tip that exceeds the limit will form bone cell adhesion and deposition, forming a dense apical bone plate. Titanium root canal plugs are used in combination with layered, partitioned and grouped fillings of high-purity bioceramics to induce the growth of new bone cells into the root apex and induce root apex mineralization to form a biological seal.

2. The titanium root canal plug tip provided by this medical device combination enables the implementation of partitioned and layered filling of bioceramic sealers: in addition to the expansion of the sealer itself, the cone thread design structure of the titanium root canal plug tip itself rotates and pushes in the cone-shaped root canal cavity, which itself also has the function of compressing the sealer. After the first layer of component A paste completes the root canal filling, the titanium root canal plug tip coated with component B dry powder sealer is equivalent to a drug stent with both plasticity and certain elasticity. The thread structure of the cone of the root canal section rotates and pushes in the cone-shaped root cavity. The sealer is evenly divided, compressed and filled in the root canal cavity by each circle of the root canal plug tip, and the filling density is much greater than the existing sealer plus gutta-percha filling density, which provides a strong guarantee for stable long-term efficacy.

3. The titanium root canal plug tip greatly improves the tooth's resistance to breakage and prolongs the tooth's service life.

The titanium root canal plug tip in this medical device combination has a certain degree of flexibility. During the early stage of root canal preparation, compared with the amount of tooth preparation using gutta-percha tips, the use of titanium root canal plug tips can effectively reduce unnecessary preparation and cutting damage to the healthy tooth root canal and improve the anti-fracture ability of the affected tooth.

After the traditional sealer + gutta-percha tip root filling is completed, it is necessary to reinforce it with a second root canal nail or fiber post. The titanium root canal plug tip in this medical device combination adopts an integrated design of the apical section and the crown section. The crown section can replace the root canal nail or fiber post in the crown cavity, and there is no need to drive the root canal nail or fiber post for the second time, which reduces the unnecessary damaging cutting preparation of the healthy root canal tissue when driving the root canal post after the root canal filling, retains more healthy tooth tissue, and improves the anti-fracture ability of the affected tooth.

In the treatment scheme provided in this embodiment, there are 1-3 titanium metal root canal plug tips inside the affected tooth from the root apex to the crown, and there is no stress concentration, which greatly improves the anti-fracture ability and overall strength of the affected tooth, avoiding the stress concentration of the traditional root canal nail at 1/2 in the root canal that causes the root to break. The treatment scheme provided in this embodiment is significantly better than the existing sealant + gutta-percha tip + root canal nail treatment scheme, and effectively extends the service life of the affected tooth.

3. New filling mode brought by this medical device combination

The concept of the existing sealer + gutta-percha tip root canal filling is: gutta-percha tip is the main method and sealer is the auxiliary method; the filling mode is: in order to cope with the postoperative shrinkage of the sealer, external force is used to compress and deform the gutta-percha tip to fill the root canal, that is, the cold gutta-percha lateral pressure method and the hot gutta-percha vertical pressure method are used to seal the apical foramen and other micro gaps, which increases the doctor's time cost, operation difficulty and the risk of failure. In terms of specific operation, the existing sealer + gutta-percha tip root canal filling requires measuring the root length → trying the tip → taking an X-ray → trying the tip again → taking an X-ray again, and repeatedly confirming the working length of the gutta-percha tip. Even so, overfilling or underfilling of the gutta-percha tip root canal still occurs from time to time in clinical practice.

The root filling mode of the medical device combination of this embodiment only allows the titanium root canal plug tip to play the role of a drug stent in the root filling, allowing the sealant to undergo a chemical reaction and expand by itself to fill the root canal, and the design structure of the root canal segment cone of the titanium root canal plug tip also has the effect of secondary compression of the sealant when it is pushed into the tapered root canal. The filling mode of this embodiment greatly simplifies the existing operation process of root canal treatment and improves the quality of root filling.

In addition, the titanium root canal plug tip is conductive and can be directly connected to the electronic root length measuring instrument, so that the root canal length can be directly measured while filling. The accuracy required for the insertion length of the root canal can be controlled to 0.1mm at one time, thus realizing digital precise root canal filling.

The technical features of the above multiple embodiments can be combined arbitrarily (as long as there is no contradiction in the combination of these technical features). In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described; these embodiments that are not explicitly written should also be considered to be within the scope of this specification.

Claims (12)

An expandable root canal filling medical device combination based on biological sealing of tooth root apex, characterized in that it comprises a sealing agent combination and a titanium root canal plug tip; The sealing agent combination is composed of a liquid, a component A powder and a component B powder which are isolated from each other before use, wherein the liquid is used to mix the component A powder into a paste when in use; the component A powder contains: 75%-95% tricalcium silicate, 5-25% beta tricalcium phosphate, and the component B powder contains: 45%-55% nano zirconium dioxide, 44.7%-52% calcium hydroxide, and 0.3%-3% calcium oxide; The titanium root canal plug tip is an integrated structure, including a root canal segment and a crown segment coaxially arranged in sequence from bottom to top; the root canal segment is a cone, the surface of the root canal segment body is provided with an external thread, and the surface of the root canal segment close to the crown segment is provided with multiple circles of horizontal blades, which are respectively recorded as a root canal thread segment and a root canal horizontal blade segment, and the grooves of the root canal thread segment and the root canal horizontal blade segment are used to fill the prepared sealant; the crown segment is a cylinder, a rectangular parallelepiped or a triangular prism, and a retention groove segment is provided on the surface. The expandable root canal filling medical-device combination based on root apex biological sealing according to claim 1 is characterized in that the liquid is distilled water or chitosan oligosaccharide aqueous solution. The expandable root canal filling medical-device combination based on apical biological sealing according to claim 1 is characterized in that the B component powder is replaced with an antibacterial enhanced powder, which contains 45% nano zirconium dioxide, 42%-44.7% calcium hydroxide, 0.3%-3% calcium oxide, and 10% iodoform. The expandable root canal filling medical device combination based on root apex biological sealing according to claim 1 is characterized in that the physical axial taper of the root canal segment is smaller than the taper of the outer contour of the root canal segment. The expandable root canal filling medical device combination based on biological closure of the root apex according to claim 4 is characterized in that the physical axis of the root canal segment close to the crown segment is narrowed to form a frustum portion, and a thinner cone portion is formed below the frustum portion, and the taper of the cone portion is smaller than the taper of the frustum portion. The expandable root canal filling medical device combination based on root apex biological sealing according to claim 4 is characterized in that the taper of the outer contour of the root canal segment and the solid axis refers to the taper specification of the machine expansion needle for dental root canal preparation, wherein the taper of the outer contour of the root canal segment is 04 taper, 06 taper or 08 taper, and the taper of the solid axis of the root canal segment is 01 taper, 02 taper or 03 taper. The expandable root canal filling medical device combination based on biological sealing of the root apex according to claim 6 is characterized in that, for titanium root canal plug tips with a taper of 04 or 06 for the outer contour of the root canal segment, the maximum end diameter of the outer contour of the root canal segment is equal to the diameter of the outer contour of the crown segment; for titanium root canal plug tips with a taper of 08 or above for the outer contour of the root canal segment, the outer contour of the crown segment is radially indented relative to the outer contour of the root canal segment, so that a shoulder is formed between the root canal segment and the crown segment. The expandable root canal filling medical device combination based on root apex biological sealing according to claim 1 is characterized in that the retention groove section of the crown section is in the form of a thread or multiple circles of horizontal blades or horizontal annular grooves. A self-expanding sealant combination for biological sealing of tooth root apex, characterized in that it consists of a liquid, a component A powder and a component B powder which are isolated from each other before use, wherein the liquid is used to mix the component A powder into a paste when in use; the component A powder contains: 75%-95% tricalcium silicate and 5-25% beta tricalcium phosphate, and the component B powder contains: 45%-55% nano zirconium dioxide, 44.7%-52% calcium hydroxide and 0.3%-3% calcium oxide. An application of a bioceramic root canal sealer combination, characterized in that: the bioceramic root canal sealer combination is composed of a liquid, a component A powder, and a component B powder that are isolated from each other before use, wherein the liquid is used to mix the component A powder into a paste when in use; The A component powder comprises: 75%-95% tricalcium silicate and 5-25% beta tricalcium phosphate; The B component powder comprises: 45%-55% nano zirconium dioxide, 44.7%-52% calcium hydroxide, and 0.3%-3% calcium oxide; or, the B component powder comprises 45% nano zirconium dioxide, 42%-44.7% calcium hydroxide, 0.3%-3% calcium oxide, and 10% iodoform; The application is specifically a two-layer root canal filling method: the first layer filling: first, a paste made by mixing the liquid and component A is introduced into the entire root canal using a titanium root canal plug tip and ultrasonically vibrated for a few seconds; the second layer filling: the root canal segment of the titanium root canal plug tip with residual component A paste is placed in the component B dry powder and rotated so that its surface is coated with the component B dry powder, and then quickly inserted into the root canal and rotated and pushed into place to form a mixture of components A and B, so that the calcium oxide contained in the component B reacts chemically with the water in the component A paste. A titanium root canal plug tip, characterized in that the titanium root canal plug tip adopts an integrated structure, including a root canal segment and a crown segment coaxially arranged in sequence from bottom to top; the root canal segment is a cone, the surface of the root canal segment body is provided with an external thread, and the surface of the root canal segment near the crown segment is provided with multiple circles of horizontal blades, which are respectively recorded as a root canal thread segment and a root canal horizontal blade segment, and the grooves of the root canal thread segment and the root canal horizontal blade segment are used to fill with a prepared sealant; the crown segment is a cylinder, a cuboid or a triangular prism, and a retention groove segment is provided on the surface. A root canal filling mode, characterized in that a titanium root canal plug tip is used as a root canal metal bracket, the chemical expansion reaction process of a self-expanding bioceramic root canal sealer is quickly transported and controlled in the root canal, and a uniform and dense new root canal filling mode is formed by combining the self-expansion force of the bioceramic material and the spiral compression force of the titanium root canal plug tip advancing in the root canal.