Manufacturing method of integrated post core based on single tooth impression, integrated post core and post core system

Abstract

The invention relates to a manufacturing method of an integrated post core based on a single tooth impression, the integrated post core and a post core system, and relates to the technical field of dental post core repair. By adopting the method, the problems of poor positioning and poor adaptability of the integrated pile core can be solved. The method comprises the following steps: preparing a tooth body of a diseased tooth according to the requirement of full-crown repair, and preparing a root canal pile way of the diseased tooth by using a reamer; performing single tooth impression on the diseased tooth to obtain a diseased tooth post nuclear impression, scanning the diseased tooth post nuclear impression to obtain a digital single tooth impression, and then performing intraoral dentition scanning on the patient; according to a digital single tooth impression and an intraoral dentition scanning result, performing digital design and processing and manufacturing of an integrated post core to obtain an initial integrated post core; and performing model try-on and adjustment on the initial integrated pile core to obtain a target integrated pile core, and performing clinical try-on and bonding on the target integrated pile core.

Description

Technical Field

[0001] The present application relates to the technical field of dental post and core restoration, and in particular to a method for manufacturing an integrated post and core based on a single tooth impression, an integrated post and core, and a post and core system. Background Art

[0002] Residual roots and crowns caused by caries and trauma are relatively common in clinical practice. Post, core and crown restoration is the main treatment method for retaining residual roots and crowns. The post and core are used to restore the defective tooth tissue and provide support and retention for crown restoration. It is the basis for the success of post and core crown restoration. Common post and core systems include cast metal post and core and prefabricated fiber post + resin core.

[0003] Cast metal posts and cores have good mechanical properties, high strength, and are not easy to break. They can be used for root canals with irregular shapes and have a high degree of fit. However, they have the following disadvantages: (1) The elastic modulus of cast metal posts and cores is 100-200 GPa, which is much higher than that of dentin (19-29 GPa), and can easily cause root fractures; (2) Cast metal posts and cores can cause discoloration of the gums, which is not conducive to the aesthetics of the affected teeth, especially the post and core restorations of the upper front teeth; (3) Cast metal posts and cores (except pure titanium materials) can interfere with magnetic resonance imaging, so patients need to remove the metal posts and cores before undergoing MRI, which brings inconvenience to patients. The elastic modulus of the prefabricated fiber post is close to that of dentin, which is not easy to cause root fracture, has good aesthetics, and does not affect magnetic resonance imaging. However, the clinical operation of the prefabricated fiber post + resin core is complicated and technically sensitive. It is prone to risks such as fiber post shedding and crown shedding caused by core rupture. Especially for root canals with irregular morphology, there is an obvious gap between the prefabricated fiber post and the root canal, which needs to be filled with resin cement. The resin solidifies and shrinks, which is prone to microleakage and reduces the retention force of the post and core.

[0004] With the widespread application of digital technology in the field of dentistry, CAD / CAM integrated fiber post and core has been widely used in the field of dentistry. It takes into account the excellent suitability of cast metal post and core and the appropriate elastic modulus and aesthetics of prefabricated fiber post, which is conducive to the preservation of residual root and crown. In the process of making CAD / CAM integrated fiber post and core, the accurate preparation of the digital post and core model of the affected tooth is the basis and key to its success. At present, the acquisition of digital post and core model is mainly through the following methods: (1) CBCT method: take CBCT and extract root canal morphology data from it; (2) scanning rod method: use scanning rod to obtain post and core data through intraoral scanning; (3) silicone rubber impression method: make silicone rubber impression of post and core and perform digital scanning to obtain post and core data. The steps of extracting root canal morphology by CBCT method are complicated, there may be artifacts, and the accuracy is low. At the same time, it will increase the patient's medical expenses and radiation. The scanning rod method requires a special scanning rod, which increases the complexity of clinical operation and is not applicable to root canals with irregular morphology. The silicone rubber impression method is simple and easy to use, does not increase the cost and radiation of CBCT, is suitable for irregular root canals, and has the widest application range. In clinical practice, a local tray is usually used to make a silicone rubber impression of at least three teeth including the affected tooth, but in a few cases, the post and core model is deformed, resulting in poor positioning of the post and core, requiring re-impression and rework, which increases the number and time of patient visits. Summary of the invention

[0005] Based on this, it is necessary to provide a method for making an integrated post and core based on a single tooth impression, an integrated post and core, and a post and core system in order to address the above technical problems.

[0006] In a first aspect, the present application provides a method for manufacturing an integrated post and core based on a single tooth impression, comprising:

[0007] Prepare the affected tooth according to the requirements of full crown restoration, and prepare the root canal post of the affected tooth using a reamer;

[0008] Taking a single tooth impression of the affected tooth, obtaining a post and core impression of the affected tooth, scanning the post and core impression of the affected tooth to obtain a digital single tooth impression, and then performing an intraoral dentition scan on the patient;

[0009] According to the digital single tooth impression and the intraoral dentition scanning result, the integrated post and core are digitally designed and processed to obtain an initial integrated post and core;

[0010] The initial integrated post and core are subjected to model fitting and adjustment to obtain a target integrated post and core, and the target integrated post and core are subjected to clinical fitting and bonding. In one embodiment, the tooth preparation according to the requirements of full crown restoration includes:

[0011] For the affected tooth that meets the indications for post and core crown and excludes contraindications, the apical filling is removed to expose the root canal opening according to the pulp cavity and root canal morphology of the affected tooth X-ray; the tooth is prepared according to the requirements of full crown restoration, the thin-walled weak tip and undercut tissue in the pulp cavity are removed, the gap between the apical surface and the adjacent surface is at least 0.8mm, the axial convergence degree is 2°-5°, and the thickness of the remaining tooth tissue is at least 0.6mm.

[0012] In one embodiment, the step of preparing the root canal post of the affected tooth using a reamer comprises:

[0013] The root canal post channel of the affected tooth is prepared using a reamer, requiring 4-5 mm of root filling material to be retained at the root apex, the length of the post to be greater than the clinical crown height, the length of the intrabone post to be greater than 1 / 2 of the intrabone root length, and the diameter of the post to be 1 / 4-1 / 3 of the root diameter.

[0014] In one embodiment, before taking a single tooth impression and digital scanning of the affected tooth, the method further comprises:

[0015] Use a K file wrapped with an alcohol cotton ball to clean the post channel, and use a moisture-absorbing paper tip to remove the residual liquid in the post channel. Adjust the length of the prefabricated reinforcement nail used for molding to match the length of the root canal, take out the reinforcement nail, and place it next to the chair for use.

[0016] In one embodiment, taking a single tooth impression and digital scanning of the affected tooth comprises:

[0017] Prepare the silicone rubber weight, and use the silicone rubber light gun + fine gun head to inject the silicone rubber light into the post channel to completely cover the post channel, pulp cavity and side wall edge; place the screw conveyor on the low-speed mobile phone, insert it into the post channel and rotate it at a low speed to empty the gas in the post channel, place the reinforcement nail in the post channel, and place one reinforcement nail in each post channel, and inject the silicone rubber light again to completely cover the reinforcement nail and the edge of the affected tooth; take the prepared silicone rubber weight and place it on the silicone rubber light, completely surround the affected tooth in the buccal and lingual direction and have a thickness of at least 3mm, extend to the adjacent tooth in the mesiodistal direction, and do not exceed 1 / 2 of the mesiodistal length of the adjacent tooth at most, and take out the silicone rubber impression after 5 minutes; the silicone rubber impression can be dislocated from the buccal root direction, or from the buccal root direction to the buccal and lingual directions; use an intraoral scanner to scan the silicone rubber impression, and export the scanned copy data as PLY (Polygon File Format, a data format for storing three-dimensional graphic objects) format, named "Data 1-Single Tooth Impression".

[0018] In one embodiment, the intraoral dentition scanning of the patient comprises:

[0019] The intraoral scanner is used to scan the upper and lower dentition and the occlusal relationship of the patient, and the scanned data is exported into the PLY format and named "Data 2 - Dentition".

[0020] In one embodiment, the integrated post and core are digitally designed and processed according to the single tooth impression result, the digital scanning result and the intraoral dentition scanning result, including:

[0021] Select the affected tooth position, select "onlay" as the design type, mark the opposing teeth, and reverse the post-core impression to a positive post-core mold; select 1-3 reference points on the crown of the affected tooth to match and merge the "Data 1-single tooth impression" and the "Data 2-dentition", draw the edge line of the restoration on the merged model, and make fine adjustments; design the direction of the placement channel of the restoration. If it is a single post channel or a double post channel parallel to each other, the placement channel is parallel to the post channel direction; if there are two or more post channels and they are not parallel to each other, select the post channel closest to the long axis of the root of the affected tooth as the main one The post channel and the other post channels that deviate from the long axis of the tooth root are pin posts. At this time, the direction of the placement channel is parallel to the main post channel. According to the undercut information prompted by the placement channel direction, the design model is trimmed and the undercut is manually filled to make it less than 0.15mm. The bottom of the inlay is generated, and the bonding gap is designed to be 0.04-0.05mm. The teeth are arranged and the tooth position is adjusted to coordinate with the adjacent teeth and the opposing teeth. The crown is generated, and the post and core edge, adjacent and occlusal space are adjusted through the "free shaping" operation. For single post channels or double post channels parallel to each other, the restoration is merged and saved. Use the "free shaping" operation to level the surface of the post and core, remove the thin-walled weak tip, select "free shaping of restoration", select the attachment, add the handle, complete the design, and export the data to STL format; for posts with two or more that are not parallel to each other, it is necessary to design a pin post, export the design to STL format, load it into Magics software (version 20 and above), click the "cut or punch" option, select the "circle" option, and set the parameters as follows: the center of the circle is the center of the root apex of the post, and the cutting radius is 0.1-0.2mm larger than the radius of the pin post. The tolerance is designed to be 0.04-0.050mm, no notch is designed, the gap is 0.04-0.05mm, the cutting of the pin post is completed, the data is saved as an STL file, and re-imported into the exocad software. The surface of the post and core is smoothed through the "free shaping" operation, and the thin-walled weak tip is removed. The handle of the pin post is added through the "add accessories" function to complete the design and export the data in STL format; the designed file is transferred to a digital cutting device or a 3D printing device, and the integrated post and core is made using a glass fiber reinforced resin block as a raw material.

[0022] In one embodiment, the target integrated post and core are subjected to clinical trial fitting and bonding, including:

[0023] Clinically, the target integrated post and core are disinfected with alcohol, tried on, and the positioning, fit and retention of the target integrated post and core are checked; the post channel, the affected tooth and the target integrated post and core are disinfected, the crown of the affected tooth and the target integrated post and core are blown dry, the liquid in the post channel is absorbed by moisture-absorbing paper points, the target integrated post and core are bonded with resin cement, the resin is completely light-cured, the excess adhesive is removed, the tooth is re-prepared, and the crown restoration is performed.

[0024] In a second aspect, the present application further provides an integrated post and core, which is prepared according to the method for preparing an integrated post and core based on a single tooth impression as described in the aforementioned embodiment.

[0025] In a third aspect, the present application also provides a post and core system, including the above-mentioned integrated post and core.

[0026] The above-mentioned integrated post and core production method based on a single tooth impression, the integrated post and core and the post and core system are used to make a post and core impression by developing the concept and technology of a single tooth impression. The impression range includes the affected tooth and a small number of adjacent teeth. When the impression is dislocated, the resistance of the adjacent teeth is small. It can not only be dislocated in the buccal direction, but also in the buccal and lingual direction, ensuring that the impression is not deformed and improving the suitability of the post and core; at the same time, this impression technology not only does not require the use of a tray, saving materials, but also significantly reduces the silicone rubber impression material used, reducing costs. In addition, based on the accuracy of the single tooth impression, the present application provides a digital design method for an integrated post and core, which is suitable for single post channels and two or more post channels, etc., and solves the problems of poor positioning and poor suitability of the integrated post and core. In summary, the present application can not only be used for secondary post and core restoration with poor post and core positioning, but also through digital means, the location and degree of post and core deformation can be found, improving the clinician's ability to identify the deformation of the post and core impression, reducing or even avoiding the probability of deformation of the post and core impression, reducing the rework rate, and saving medical and patient diagnosis and treatment time. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments of the present application or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 It is a schematic diagram of a process of manufacturing an integrated post and core based on a single tooth impression in one embodiment;

[0029] Figure 2 Schematic diagram of a single tooth impression in one embodiment; wherein A is a root view, B is a buccal and lingual view, and C is a mesiodistal view;

[0030] Figure 3 The figure is a flowchart of the CAD / CAM integrated post and core production process based on a single tooth impression in one embodiment; wherein, (A) a new project is created with Exocad software (version 3.0), the design type is selected as "onlay", and an integrated post and core is produced; (B) intraoral dentition scan data is imported; (C) single tooth impression scan data is added; (D) single tooth impression scan data is reversed into a post and core positive mold; (E) dentition data and single tooth positive mold data are matched and replaced and merged; (F) the design data after replacement and merging; (G) the post and core edge line is drawn; (H) the positioning path is set and the undercut information is displayed; (I) the crown is placed; (J) the post and core shape is designed; (K) the occlusion of the post and core; (L) the handle is added; (M) the designed post and core; (N) the integrated post and core after digital cutting; (O) the integrated post and core crown is tried on the model, and the positioning is smooth and the edge is tight;

[0031] Figure 4 The present invention is a flow chart of the secondary post and core design and processing steps based on a single tooth impression in one embodiment; wherein, (A) a silicone rubber impression of the lower left dentition is made using a partial tray, a digital impression is obtained by intraoral scanning, and an integrated post and core is made using CAD / CAM. The post and core of the lower left second molar can be fully seated, but the post and core of the lower left first molar is poorly seated; (B) a single tooth impression of the lower left first molar is made using silicone rubber material; (C) a digital scan of the single tooth impression; (D) the partial impression and the single tooth impression are matched using exocad software, and the post channels of the two cannot match, indicating that the partial tray has an impression deformation; (E) a post and core are designed using the patented technology. The shape of the integrated post and core designed; (F) Magics software circularly cuts the distal post channel, apical view; (G) Magics software circularly cuts the distal post channel, apical view; (H) The pin post after cutting; (I) The main post and core after cutting; (J) The designed main post and core and pin post; (K) The main post and core designed based on the local impression (right) and the main post and core designed based on the single tooth impression (left), the two have different post and core angles; (L) The main post and core designed based on the local impression is not well positioned; (M) The main post and core designed based on the single tooth impression is well positioned and the edges are tightly fitted; (N) The pin post designed based on the single tooth impression is smoothly positioned and tightly fitted. DETAILED DESCRIPTION

[0032] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present application are given in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0034] In one embodiment, Figure 1 As shown, a method for making an integrated post and core based on a single tooth impression is provided, comprising the following steps:

[0035] Step 1: Tooth preparation for the crown and root canal preparation:

[0036] For teeth that meet the indications for post-core crowns and exclude contraindications, remove the fillings on the apical surface according to the pulp cavity and root canal morphology of the X-ray film of the tooth, expose the root canal orifice, and prepare the tooth according to the requirements of full crown restoration, remove the thin-walled weak tip and the concave tissue in the pulp cavity, the gap between the apical surface and the adjacent surface is at least 0.8mm, the axial plane convergence is 2°-5°, and the thickness of the remaining tooth tissue is at least 0.6mm. Use a reamer to prepare the root canal post channel, requiring 4-5mm of root filling material to be retained at the root apex, the length of the post is greater than the clinical crown height, the length of the intraosseous post is greater than 1 / 2 of the intraosseous root length, and the diameter of the post is 1 / 4-1 / 3 of the root diameter.

[0037] Step 2: Single tooth impression and digital scan, intraoral dentition scan:

[0038] Use K file to wrap alcohol cotton ball to clean the post channel, remove residual liquid in the post channel with moisture-absorbing paper tip, adjust the length of prefabricated reinforcement nail for molding to match the length of root canal, take out the reinforcement nail and put it beside the chair for use; prepare silicone rubber heavy body, and use silicone rubber light body gun + fine gun head to inject silicone rubber light body into the post channel to completely cover the post channel, pulp cavity and side wall edge; place the screw conveyor on the low-speed mobile phone, insert it into the post channel and rotate it at low speed to empty the gas in the post channel, place the reinforcement nail in the post channel, place 1 reinforcement nail in each post channel, and inject silicone rubber light body again to completely cover the reinforcement nail The silicone rubber impression is taken out after 5 minutes. The impression can be dislocated from the buccal root direction or from the buccal root direction to the lingual direction. The silicone rubber impression is scanned with an intraoral scanner. The scanned copy is required to be clear, continuous and complete, and the scanned copy data is exported in PLY format and named "Data 1-Single Tooth Impression". The patient's upper and lower dentition and occlusal relationship are scanned with an intraoral scanner. The scanned copy data is exported in PLY format and named "Data 2-Dentition".

[0039] Step 3: Digital design and processing of integrated post and core:

[0040] Open exocad software (version 3.0 and above), create a new project, select the affected tooth, select "onlay" as the design type, and mark the opposing teeth. Click the "Design" option in the operation bar, import "Data 2-Dentition", click "Tools", select "Add / Remove Mesh", select the mesh type as "Additional Scan Model", and load "Data 1-Single Tooth Impression". Select "Data 1-Single Tooth Impression", right-click, and select the "Edit Mesh" option; right-click, select "Show Triangular Mesh Positioning"; right-click, select "Invert Triangular Mesh Positioning", and click "OK". This step will invert the post and core impression into a positive post and core mold for subsequent post and core design. Right-click, select "Match Scan", select 1-3 reference points on the crown of the affected tooth to match "Data 1-Single Tooth Impression" and "Data 2-Dentition", click "OK", and select "Replace All Scan Data" to complete data matching and merging. Draw the margin line of the restoration on the merged model and make fine adjustments, requiring a smooth transition between the margin line and the remaining tooth tissue. Design the direction of the placement path of the restoration. If it is a single post path or two parallel post paths, the placement path is parallel to the post path direction; if there are two or more post paths and they are not parallel to each other, the post path closest to the long axis of the root of the affected tooth is selected as the main post path, and the other post paths that deviate from the long axis of the root are pin posts. At this time, the placement path direction is parallel to the main post path. According to the undercut information prompted by the placement path direction, trim the design model and manually fill the undercut to make it less than 0.15mm. Generate the bottom of the inlay and design the bonding gap to be 0.04-0.05mm. Arrange the teeth and adjust the tooth position to coordinate with the adjacent teeth and the opposing teeth. Generate the crown and adjust the post and core edge, adjacent and occlusal space through the "free shaping" operation. For single pile channel or double pile channels parallel to each other, merge and save the restoration, use the "free shaping" operation to smooth the surface of the post and core, remove the thin-walled weak tip, select "free shaping of restoration", select the attachment, add the handle, complete the design, and export the data to STL format; for pile channels with two or more that are not parallel to each other, it is necessary to design a pin pile, export the design to STL format, load it into Magics software (version 20 and above), click the "cut or punch" option, select the "circular" option, and refer to the STL format. The data are set as follows: the center of the circle is the center of the apical area of ​​the post channel, the cutting radius is 0.1-0.2mm larger than the radius of the post channel of the plug post, the tolerance is designed to be 0.04-0.050mm, no notch is designed, the gap is 0.04-0.05mm, the cutting of the plug post is completed, the data is saved as an STL file, and re-imported into the exocad software. The surface of the post and core is smoothed through the "free shaping" operation, and the thin-walled weak tip is removed. The handle of the plug post is added through the "add accessory" function to complete the design, and the data is exported to the STL format.The designed files are transferred to digital cutting equipment or 3D printing equipment, and glass fiber reinforced resin blocks are used as raw materials to produce CAD (Computer-aided design) / CAM (Computer-aided manufacturing) integrated fiber posts and cores.

[0041] Step 4: Try out the model of the integrated post and core:

[0042] There are certain errors in the digital processing process, which leads to slight deformation of the post and core, so the post and core need to be adjusted on the plaster model. The silicone rubber impression of the single tooth is disinfected and the plaster model is cast. The integrated post and core are tried on the plaster model, the concave surface of the post and core is removed, the surface of the post and core is cleaned by sandblasting, the post and core are disinfected with alcohol, and then sent to the clinic.

[0043] Step 5: Clinical trial fitting and bonding of integrated post and core:

[0044] In clinical practice, the integrated post and core are disinfected again with alcohol, and the post and core are tried on to check the position, tightness and retention of the post and core. The post channel, the affected tooth and the post and core are disinfected, the crown and the post and core of the affected tooth are blown dry, the liquid in the post channel is absorbed by a moisture-absorbing paper tip, the post and core are bonded with resin cement, the resin is completely light-cured, the excess adhesive is removed, the tooth is re-prepared, and the crown restoration is performed.

[0045] In the above-mentioned method for making an integrated post and core based on a single tooth impression, the concept and technology of a single tooth impression are developed to make a post and core impression. The impression range includes the affected tooth and a small number of adjacent teeth. When the impression is dislocated, the resistance of the adjacent teeth is small. It can not only be dislocated in the buccal direction, but also in the buccal and lingual direction, ensuring that the impression is not deformed and improving the suitability of the post and core; at the same time, this impression technology not only does not require the use of a tray, saving materials, but also significantly reduces the silicone rubber impression material used, reducing costs. In addition, based on the accuracy of the single tooth impression, the present application provides a digital design method for an integrated post and core, which is suitable for single post channels and two or more post channels, etc., and solves the problems of poor positioning and poor suitability of the integrated post and core. In summary, the present application can not only be used for secondary post and core restoration with poor post and core positioning, but also through digital means, the location and degree of post and core deformation can be found, improving the clinician's ability to identify the deformation of the post and core impression, reducing or even avoiding the probability of deformation of the post and core impression, reducing the rework rate, and saving medical and patient diagnosis and treatment time.

[0046] In one embodiment, the digital design and processing of the integrated post and core are performed based on a single tooth impression (the residual root of the upper right second molar, after more than one week of complete root canal treatment, there is no discomfort on percussion and no looseness. After examination, it meets the indications of the post and core crown. The tooth preparation and post channel preparation are performed, and the thin-walled weak tip and the concave tissue in the pulp cavity are removed. The interproximal gap is about 0.8 mm, and the thickness of the remaining tooth tissue is at least 0.6 mm. The root canal post channel is prepared using a reamer, and 5 mm of root filling material is retained at the root apex), which specifically includes the following steps:

[0047] 1) Single tooth impression:

[0048] Use K-file to wrap alcohol cotton balls to clean the post channel, use moisture-absorbing paper tips to remove residual liquid in the post channel, adjust the length of the reinforcement nail to match the length of the root canal, remove the reinforcement nail, and place it next to the chair for use. Prepare the silicone rubber weight, and use the silicone rubber light gun + fine gun head to inject the silicone rubber light body into the post channel so that it completely covers the post channel, pulp cavity and side wall edges. Place the spiral conveyor on a low-speed handpiece, insert it into the post channel and rotate it at a low speed to empty the gas in the post channel, place the reinforcement nail in the post channel, and inject the silicone rubber light body again to completely cover the reinforcement nail and the edge of the affected tooth. Take the prepared silicone rubber weight and place it on the silicone rubber light body, completely surrounding the affected tooth in the buccal and lingual directions with a thickness of about 4 mm, extending to the adjacent teeth in the mesiodistal direction, and not exceeding 1 / 2 of the mesiodistal length of the adjacent teeth. Take out the silicone rubber impression after 5 minutes, dislocate it in the ulnar direction, and obtain a single-tooth silicone rubber impression ( Figure 2 AC). The silicone rubber impression was scanned by an intraoral scanner, and the scanned data was exported in PLY format and named "Data 1 - Single Tooth Impression".

[0049] 2) Intraoral dentition scan:

[0050] Use an intraoral scanner to scan the patient's upper and lower dentition and occlusal relationship, and export the scanned data in PLY format and name it "Data 2-Dentition".

[0051] 3) Digital design and processing of integrated post and core:

[0052] Open exocad software (version 3.0), create a new project, select the affected tooth, select "onlay" as the design type, and mark the opposing teeth ( Figure 3 A). Click the "Design" option in the operation bar, import "Data 2-Dentition", click "Tools", select "Add / Remove Mesh", select the mesh type as "Additional Scan Model", and load "Data 1-Single Tooth Impression" ( Figure 3 C). Select "Data 1-Single Tooth Impression", right-click, and select the "Edit Mesh" option; right-click, and select "Show Triangular Mesh Positioning"; right-click, and select "Invert Triangular Mesh Positioning", and click "OK" to invert the post and core impression into a positive post and core mold ( Figure 3D). Right-click and select "Match Scan", select a reference point on the crown of the affected tooth to match "Data 1 - Single Tooth Impression" and "Data 2 - Dentition" ( Figure 3 E), click "OK", select "Replace all scan data", and complete the data matching and merging ( Figure 3 F). Draw the margin line of the restoration on the combined model and make fine adjustments to ensure a smooth transition between the margin line and the remaining tooth tissue ( Figure 3 G). Design the placement direction of the restoration to be parallel to the post direction. According to the undercut information indicated by the placement direction, trim the design model and manually fill the undercut to make it less than 0.15mm ( Figure 3 H). Generate the bottom of the inlay and design the bonding gap to be 0.05mm. Arrange the teeth and adjust the tooth position to coordinate with the adjacent teeth and the opposing teeth ( Figure 3 I). Generate the crown and adjust the post and core margins, proximal connections and occlusal space using the "Free Forming" operation ( Figure 3 J, K). Merge and save the restoration, use the "free shaping" operation to smooth the surface, remove the thin wall and weak tip, select "free shaping of restoration", select the attachment, add the handle, complete the design, and export the data to STL format ( Figure 3 L, M). The designed file is transferred to the digital cutting equipment, and the fiber post and core integrated with CAD / CAM is made using the glass fiber reinforced resin block as the raw material ( Figure 3 N).

[0053] 4) Model trial wearing of integrated post and core:

[0054] The silicone rubber impression of the single tooth was disinfected and a plaster model was cast. The integrated post and core were tried on the plaster model. The inspection found that the integrated post and core were smoothly positioned, the edges were close, and the retention force was good ( Figure 3 O). The surface of the post and core was cleaned by sandblasting, and the post and core were disinfected with alcohol before being sent to the clinic.

[0055] 5) Clinical trial fitting and bonding of integrated post and core:

[0056] In clinical practice, the integrated post and core are disinfected again with alcohol, and the post and core are tried on to check the position, tightness and retention of the post and core. The post channel, the affected tooth and the post and core are disinfected, the crown and the post and core of the affected tooth are blown dry, the liquid in the post channel is absorbed by a moisture-absorbing paper tip, the post and core are bonded with resin cement, the resin is completely light-cured, the excess adhesive is removed, the tooth is re-prepared, and the crown restoration is performed.

[0057] In this embodiment, based on the single tooth impression technology, the integrated fiber post and core are digitally designed and produced, which can effectively avoid the deformation of the post and core during the process of taking multiple tooth impressions and improve the suitability of the integrated post and core. It is especially suitable for post and core restorations with irregular root canal morphology and secondary post and core restorations with poor post and core seating.

[0058] In one embodiment, a single tooth impression is combined with digital technology to identify the deformation of the local tray impression, and to design and process the secondary post and core for poor positioning (the first and second molars on the lower left have large tooth defects, and after the root canal treatment, they meet the indications for the post and core crown. The tooth preparation and post channel preparation are performed, and the silicone rubber impression is made with the local tray and digitally scanned to obtain the digital impression ( Figure 4 A), export the scanned data into PLY format and name it "Data 0-Partial tray impression" to make a CAD / CAM integrated post and core. Clinical trial wear found that the lower left second molar was poorly seated, and there was a gap of about 2-3mm between the post and core and the abutment tooth). In order to find out the deformed part of the impression and remake the post and core, the subsequent operations in this embodiment are performed:

[0059] 1) Single tooth impression:

[0060] Use K-file to wrap alcohol cotton balls to clean the post channel, use moisture-absorbing paper tips to remove residual liquid in the post channel, adjust the length of the reinforcement nail to match the length of the root canal, remove the reinforcement nail, and place it next to the chair for use. Prepare the silicone rubber weight, and use the silicone rubber light gun + fine gun head to inject the silicone rubber light body into the post channel to completely cover the post channel, pulp cavity and side wall edges. Place the spiral conveyor on a low-speed handpiece, insert it into the post channel and rotate it at a low speed to empty the gas in the post channel, place the reinforcement nail in the post channel, place 1 impression post each in the mesial and distal roots, and inject the silicone rubber light body again to completely cover the reinforcement nail and the edge of the affected tooth. Take the prepared silicone rubber weight and place it on the silicone rubber light body, completely surrounding the affected tooth in the buccal and lingual directions and having a thickness of about 4mm, extending mesiodistal to the adjacent teeth, and not exceeding 1 / 2 of the mesiodistal length of the adjacent teeth. Take out the silicone rubber impression after 5 minutes, and dislocate it from the buccal and lingual directions to obtain a single-tooth silicone rubber impression ( Figure 4 B). Scan the silicone rubber impression with an intraoral scanner to obtain a digital single tooth impression ( Figure 4 C), export the scanned data into PLY format and name it "Data 1-Single Tooth Impression". Open exocad software (version 3.0), import "Data 0-Partial Tray Impression" and "Data 1-Single Tooth Impression", and perform data matching. The results show that the posts of the two cannot be matched, and the mesial root post has obvious deviation, while the distal root post has a smaller deviation ( Figure 4 D).

[0061] 2) Intraoral dentition scan:

[0062] Use an intraoral scanner to scan the patient's upper and lower dentition and occlusal relationship, and export the scanned data in PLY format and name it "Data 2-Dentition".

[0063] 3) Digital design and processing of integrated post and core:

[0064] Open exocad software (version 3.0), create a new project, select the affected tooth, select "onlay" as the design type, and mark the opposing teeth. Click the "Design" option in the operation bar, import "Data 2-Dentition", click "Tools", select "Add / Remove Mesh", select the mesh type as "Additional Scan Model", and load "Data 1-Single Tooth Impression". Select "Data 1-Single Tooth Impression", right-click, and select the "Edit Mesh" option; right-click, select "Show Triangular Mesh Positioning"; right-click, select "Invert Triangular Mesh Positioning", click "OK" to invert the post and core impression into a positive post and core mold. Right-click, select "Match Scan", select 3 reference points of the crown part of the affected tooth to match "Data 1-Single Tooth Impression" and "Data 2-Dentition", click "OK", select "Replace All Scan Data", and complete the data matching and merging. Draw the margin line of the restoration on the merged model and make fine adjustments, requiring a smooth transition between the margin line and the remaining tooth tissue. Design the placement direction of the restoration, select the mesial root as the main post, design the distal root as a pin post, and place the placement direction parallel to the mesial root. According to the undercut information prompted by the placement path, manually fill the undercut to make it less than 0.15mm, generate the bottom of the inlay, and design the bonding gap to be 0.05mm. Arrange the teeth and adjust the tooth position to coordinate with the adjacent teeth and the opposing teeth. Generate the crown, adjust the post and core edge, adjacent and occlusal space through the "free shaping" operation, and generate an integrated post and core ( Figure 4 E). Export the design to STL format, load it into Magics software (version 20), click the "cut or punch" option, select the "circle" option, and set the parameters as follows: the center of the circle is the center of the apical area of ​​the distal post channel, the cutting radius is 0.1mm larger than the radius of the plug post channel, the tolerance is designed to be 0.050mm, no notch is designed, the gap is 0.05mm, and the cutting of the distal plug post is completed ( Figure 4 FI), the data was saved as an STL file and re-imported into exocad software. The surface of the post and core was smoothed through the "free shaping" operation, and the thin-walled weak tip was removed. The handle of the pin pile was added through the "add accessories" function to complete the design ( Figure 4 J), the data was exported to STL format. The designed file was transferred to the digital cutting equipment, and the glass fiber reinforced resin block was used as the raw material to make the CAD / CAM integrated fiber post core. Comparing the appearance of the new and old main posts, it was found that the curvature of the old post was larger than that of the new post, and the two were not consistent ( Figure 4 K).

[0065] 4) Model trial wearing of integrated post and core:

[0066] The silicone rubber impression of the single tooth was disinfected and a plaster model was cast. The old integrated post and core were tried on the plaster model, and it was found that there was a clear gap between the two, and the post and core could not be fully positioned ( Figure 4L), while the new integrated post and core can be fully positioned, and the two fit tightly and have good retention ( Figure 4 M), the pin pile trial showed that it was fully seated and fit tightly ( Figure 4 N). The surface of the post and core was cleaned by sandblasting, and the post and core were disinfected with alcohol before being sent to the clinic.

[0067] 5) Clinical trial fitting and bonding of integrated post and core:

[0068] In clinical practice, the integrated post and core are disinfected again with alcohol, and the post and core are tried on to check the position, tightness and retention of the post and core. The post channel, the affected tooth and the post and core are disinfected, the crown and the post and core of the affected tooth are blown dry, the liquid in the post channel is absorbed by a moisture-absorbing paper tip, the post and core are bonded with resin cement, the resin is completely light-cured, the excess adhesive is removed, the tooth is re-prepared, and the crown restoration is performed.

[0069] In this embodiment, based on the single tooth impression technology, the integrated fiber post and core are digitally designed and produced, which can effectively avoid the deformation of the post and core during the process of taking multiple tooth impressions and improve the suitability of the integrated post and core. It is especially suitable for post and core restorations with irregular root canal morphology and secondary post and core restorations with poor post and core seating.

[0070] In one embodiment, an integrated post and core is further provided, which is prepared according to the method for preparing an integrated post and core based on a single tooth impression as described in the above embodiment.

[0071] In one embodiment, a post and core system is further provided, comprising the integrated post and core.

[0072] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this application.

[0073] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for making an integrated post and core based on a single tooth impression, characterized in that: The method comprises: Prepare the affected tooth according to the requirements of full crown restoration, and prepare the root canal post of the affected tooth using a reamer; Taking a single tooth impression of the affected tooth, obtaining a post and core impression of the affected tooth, scanning the post and core impression of the affected tooth to obtain a digital single tooth impression, and then performing an intraoral dentition scan on the patient; According to the digital single tooth impression and the intraoral dentition scanning result, the integrated post and core are digitally designed and processed to obtain an initial integrated post and core; The initial integrated post and core are subjected to model trial fitting and adjustment to obtain a target integrated post and core, and the target integrated post and core are subjected to clinical trial fitting and bonding.

2. The method according to claim 1, characterized in that The tooth preparation is carried out according to the requirements of full crown restoration, including: For the teeth that meet the indications for post-core crown and exclude contraindications, remove the root fillings according to the pulp cavity and root canal morphology of the X-ray film of the teeth to expose the root canal opening; The tooth is prepared in accordance with the requirements of full crown restoration, the thin-walled weak cusp and the undercut tissue in the pulp cavity are removed, the gap between the interproximal surface and the proximal surface is at least 0.8mm, the axial convergence degree is 2°-5°, and the thickness of the remaining tooth tissue is at least 0.6mm.

3. The method according to claim 1, characterized in that The step of preparing the root canal post of the affected tooth by using a reamer comprises: The root canal post channel of the affected tooth is prepared using a reamer, requiring 4-5 mm of root filling material to be retained at the root apex, the length of the post to be greater than the clinical crown height, the length of the intrabone post to be greater than 1 / 2 of the intrabone root length, and the diameter of the post to be 1 / 4-1 / 3 of the root diameter.

4. The method according to claim 1, characterized in that: Before taking a single tooth impression and digital scanning of the affected tooth, the method further includes: Use a K file wrapped with an alcohol cotton ball to clean the post channel, and use a moisture-absorbing paper tip to remove the residual liquid in the post channel. Adjust the length of the prefabricated reinforcement nail used for molding to match the length of the root canal, take out the reinforcement nail, and place it next to the chair for use.

5. The method according to claim 4, characterized in that A single tooth impression and digital scan are performed on the affected tooth, including: Prepare the silicone rubber heavy body, and use the silicone rubber light body gun + fine gun head to inject the silicone rubber light body into the post channel, so that it completely covers the post channel, medullary cavity and side wall edge; Place a screw conveyor on a low-speed mobile phone, insert it into the post channel and rotate it at a low speed to evacuate the gas in the post channel, place a reinforcement nail in the post channel, place one reinforcement nail in each post channel, and inject the silicone rubber light body again to completely cover the reinforcement nail and the edge of the affected tooth; Place the prepared silicone rubber heavy body on the silicone rubber light body, completely surround the affected tooth in the buccal and lingual direction and have a thickness of at least 3 mm, extend to the adjacent tooth in the mesiodistal direction, and not exceed 1 / 2 of the adjacent tooth's mesiodistal length at most. Take out the silicone rubber impression after 5 minutes; the silicone rubber impression can be dislocated in the buccal root direction, or in the buccal and lingual directions; The silicone rubber impression was scanned using an intraoral scanner, and the scanned data was exported in PLY format and named "Data 1 - Single Tooth Impression".

6. The method according to claim 5, characterized in that The intraoral dentition scanning of the patient comprises: The intraoral scanner is used to scan the upper and lower dentition and the occlusal relationship of the patient, and the scanned data is exported into the PLY format and named "Data 2-Dentition".

7. The method according to claim 6, characterized in that According to the digital single tooth impression and intraoral dentition scanning results, the integrated post and core are digitally designed and processed, including: Select the affected tooth, choose "onlay" as the design type, mark the opposing teeth, and reverse the post and core impression to a positive post and core mold; Select 1-3 reference points on the crown of the affected tooth to match and merge the "Data 1 - Single Tooth Impression" and the "Data 2 - Dentition", draw the margin line of the restoration on the merged model, and make fine adjustments; Design the placement path direction of the restoration. If it is a single post path or two parallel post paths, the placement path is parallel to the post path direction. If there are two or more post paths and they are not parallel to each other, the post path closest to the long axis of the root of the affected tooth is selected as the main post path, and the other post paths that deviate from the long axis of the root are pin posts. In this case, the placement path direction is parallel to the main post path. According to the undercut information prompted by the placement path direction, the design model is trimmed and the undercut is manually filled to make the undercut less than 0.15mm. Generate the inlay bottom, design the bonding gap to be 0.04-0.05mm, arrange the teeth, and adjust the tooth position to coordinate with the adjacent teeth and the opposing teeth; Generate a crown, adjust the post and core margins, adjacencies, and occlusal space through the "free shaping" operation, merge and save the restoration for a single post channel or a double post channel that is parallel to each other, smooth the post and core surface through the "free shaping" operation, remove the thin-walled weak tip, select "free shaping of restoration", select the attachment, add the handle, complete the design, and export the data to STL format; For piles with two or more non-parallel channels, it is necessary to design a pin pile, export the design to STL format, load the design into Magics software (version 20 and above), click the "cut or punch" option, select the "circle" option, and set the parameters as follows: the center of the circle is the center of the root apex of the channel, the cutting radius is 0.1-0.2mm larger than the radius of the plug pile channel, the tolerance is designed to be 0.04-0.050mm, no notch is designed, and the gap is 0.04-0.05mm. The cutting of the pin pile is completed, the data is saved as an STL file, and re-imported into the exocad software. The surface of the post and core is smoothed through the "free shaping" operation, and the thin-walled weak tip is removed. The handle of the pin pile is added through the "add attachment" function. The design is completed and the data is exported to STL format; The designed file is transferred to a digital cutting device or a 3D printing device, and the integrated post and core is manufactured using a glass fiber reinforced resin block as a raw material.

8. The method according to any one of claims 1 to 7, characterized in that: Performing clinical trial fitting and bonding of the target integrated post and core includes: Clinically, the target integrated post and core are disinfected with alcohol, the target integrated post and core are tried on, and the positioning, tightness and retention of the target integrated post and core are checked; Disinfect the post channel, the affected tooth and the target integrated post and core, blow dry the crown of the affected tooth and the target integrated post and core, absorb the liquid in the post channel with a moisture-absorbing paper tip, bond the target integrated post and core with resin cement, completely light-cure the resin, remove excess adhesive, re-prepare the tooth, and perform crown restoration.

9. An integrated post and core, characterized in that: The integrated post and core is prepared according to the method for making an integrated post and core based on a single tooth impression according to any one of claims 1 to 8.

10. A post and core system, characterized in that: It comprises the integrated post and core as claimed in claim 9.

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