CN111821044B

CN111821044B - Integrative hat of bolt formula stake core suitable for back tooth gum repair space is less than 3mm

Info

Publication number: CN111821044B
Application number: CN202010267209.XA
Authority: CN
Inventors: 谢海峰; 陈晨; 李林; 杨家雪; 徐晶
Original assignee: Affiliated Stomatological Hospital of Nanjing Medical University
Current assignee: Affiliated Stomatological Hospital of Nanjing Medical University
Priority date: 2020-04-07
Filing date: 2020-04-07
Publication date: 2021-02-05
Anticipated expiration: 2040-04-07
Also published as: CN111821044A

Abstract

The invention provides a plug pin type pile-core integrated crown with a repairing space less than 3mm for a posterior gingival retraction, which comprises a main body, a plug pin channel and a plug pin, wherein the main body comprises a crown part and a medullary cavity part, the crown part restores the form and the occlusion relation of an affected tooth, and covers and wraps a preparation body of the affected tooth; the pulp cavity is positioned in the pulp cavity and is matched with the pulp cavity to obtain the retention force, and the bolt extends out of the prepared pile channel in the root canal through the bolt channel of the main body to obtain the retention. This kind of be applicable to back tooth and close integrative hat of bolt formula stake nuclear that the gum restoration space is less than 3mm, it is good to have the maintenance, need not to transfer to grind to the jaw tooth, and the damage is little, and the advantage that aesthetic property is good provides a good novel restoration for this kind of patient and is used for the defective restoration of tooth body, is particularly useful for back tooth restoration gum space undersize, can't use the conventional circumstances of covering up with stake nuclear + hat restoration.

Description

Integrative hat of bolt formula stake core suitable for back tooth gum repair space is less than 3mm

Technical Field

The invention relates to the field of tooth defect repair in oral prosthetics, in particular to a tooth prosthesis suitable for posterior teeth repair

A plug pin type pile-core integrated crown with a gum space less than 3mm and a manufacturing method thereof.

Background

Dental defects caused by caries, trauma and the like are common diseases and frequently encountered diseases in an oral repair clinic. The residual root and crown belong to the category of severe tooth defect, and the pile core needs to restore the appearance of the abutment to provide sufficient retention force due to the lack of retention shape required by crown restoration, namely the restoration mode of the pile core crown.

Compared with the full crown, the pile-core and crown repairing mode improves the retention rate of residual roots and residual crowns. However, there are clinical cases in which the post-dental defect belongs to the indication of post-coronal restoration, but the tooth is affected

The gingival repairing space is less than 3mm, and the posterior dental area is tightly occluded. At least 3mm is ensured due to the shape of the pile core restoring preparation body

The gingival height can provide sufficient retention for the crown, an

The sides should have at least a 1-2mm gap to provide a crown

The containing space of the surface repair material obviously cannot be used for directly repairing the pile core crown in the cases because enough repairing space cannot be obtained. Currently, such cases are not rare clinically, and the treatment options include the following:

i. and (4) filling, wherein the filling material obtains certain retention by virtue of the medullary cavity. Although the method is simple, the tooth can not restore good tooth appearance, the occlusion function is poor, the filling lacks protection on the abutment, the filling falls off at the later stage, the probability of tooth fracture is high, and the prognosis is poor.

Coronal lengthening, or conditioning, of the affected teeth is also one of the ways of treatment for the jaw teeth (even conditioning in large quantities after root canal treatment), with the aim of obtaining a repair space. However, the treatment mode has large trauma, high cost and more times of treatment, particularly, the reduction of the length of the root in the actual bone caused by the crown lengthening operation and the long-term complication caused by the problems of the reduction of the tooth strength caused by the root canal treatment and the like are high in probability, and the treatment mode is generally unacceptable for patients.

iii that the affected tooth should be restored to its shape

Although the height of the gum is less than 3mm, the difference is not great, and the patient can adopt auxiliary position-fixing shape design and other modes to repair the post-nuclear crown, usually only metal casting repair bodies can be adopted, and the method cannot be applied to the patient with high requirement on beauty and needing to carry out special inspection on nearby tissues.

The intramedullary canal retaining crown is a method proposed in recent years, belongs to a variant onlay type and has certain advantages in the aspects of tooth preservation, low technical sensitivity and the like. However, the research also finds that the retaining crown of the pulp cavity provides a retaining shape depending on the pulp cavity and a part extending to the root canal orifice, and the retaining crown is easy to be folded in the case of weak tooth tissues or uneven stress because the retaining crown is not connected with the root into a whole.

Thus, for affected teeth

The gum repair space is less than 3mm, and the case that the back tooth area is tightly occluded provides a tooth repair which has good retention, does not need to adjust and grind jaw teeth, has small damage and can realize good tooth repair, which is a problem to be solved urgently in clinic at present.

Disclosure of Invention

The invention aims to provide a tooth repairing device suitable for posterior tooth repair

Plug pin type pile-core integrated crown for case with gum space less than 3mm

The case that the gum repairing space is too small and the back tooth area is tightly occluded provides a type of tooth defect restoration which has good retention, does not need to adjust and grind jaw teeth, has small damage and can realize good treatment.

The technical solution of the invention is as follows:

is suitable for posterior teeth

The integrative hat of bolt formula stake core that the gum restores space and is less than 3mm, including main part, bolt passageway and bolt, the main part includesThe crown part is arranged at the end part of the medullary cavity part and restores the form and the occlusion relation of the affected tooth, and covers and surrounds the affected tooth preparation body; the pulp cavity is positioned in the pulp cavity and matched with the pulp cavity to obtain retention force, the main body is internally provided with a plug pin channel, the plug pin channel comprises an upper placing opening, a channel and a lower opening, and the upper placing opening is arranged on the main body

In the non-occlusion contact area of the surface, the lower opening is arranged at the parallel and level position of the root canal mouth, the bolt channel penetrates through the crown part and the marrow cavity part, the bolt channel is respectively communicated with the upper opening and the lower opening, the bolt comprises an upper part of a pile core, a middle part of a slope and a lower part of a root pile, and the top end of the upper part of the pile core is used as the bolt

The upper placing opening of the main body channel is exposed on the surface and closed, the lower end of the upper part of the pile core is connected with the end part of the lower part of the root pile through the middle part of the slope, the upper part of the pile core is embedded into the channel of the main body, the middle part of the slope and the lower part of the root pile extend out of the lower opening of the plug pin channel, the lower part of the root pile is matched with the preparation form of the root canal orifice and the prepared pile channel in the root canal, the diameter of the upper part of the pile core is larger than that of the lower part of the root pile, the difference is as close as possible to 1.

Further, when a certain root canal of the affected tooth and the pulp cavity can obtain the same common in-place channel, the pulp cavity of the main body is extended into the root canal to be made into a root-pile shape to obtain a retention force, and 1 channel and a lower opening are designed to correspond to the pile channels in other root canals; when the affected tooth root canal and the medullary cavity can not obtain a common positioning channel, the medullary cavity part of the main body is provided with lower opening openings at all root canal openings needing to be prepared, a plurality of bolt channels are designed to be communicated with the lower opening openings, the bolt channels are not mutually contacted and communicated, and locking angles are formed among the bolt channels.

Furthermore, the upper part of the core of the bolt and the lower part of the root pile are respectively filled with the channel of the main body and the canal in the root canal, and a gap of 30-50 μm is reserved as a containing space of the adhesive.

Furthermore, the joint of the upper part of the core of the bolt and the lower part of the root pile is the middle part of a slope, and the middle part of the slope is matched with the prepared slope form in the depth range of 0-1.5mm at the position of the affected root canal.

Furthermore, the angle formed by the middle part of the slope of the bolt and the lower part of the root pile is close to 120 degrees, and if the angle cannot be reached, an angle which is as large as possible between 90 degrees and 120 degrees needs to be formed.

Furthermore, the upper part of the core of the bolt is of a cylindrical structure, and the lower part of the root pile is of a conical structure which is in accordance with the taper of the root pipe.

Further, the width of the upper part of the pile core of the bolt is larger than the width of the top end of the lower part of the root pile, the difference is 2mm, and the difference is realized by increasing the width of the upper part of the pile core of the bolt.

Further, of the bolt

The top end of the face is provided with a clamping handle, so that the clinical trial wearing and cementation operation is convenient, and the cutting or grinding is finished.

Furthermore, the main body and the plug are both made of zirconia ceramic materials and are respectively formed by 3D printing or CAM processing.

Any one of the above suitable for posterior tooth restoration

The manufacturing method of the plug pin type pile-core integrated crown for the case with the gum space less than 3mm comprises the following repairing steps:

s1, preparing an intra-root canal: the diameter of the pile channel in the root canal is 1/4-1/3 of the diameter of the root canal, the length of the pile channel is as deep as 4-5mm from the tail end of the root apex, the original root canal filling material at the far end of the affected tooth is reserved to be used as the root apex closure, the pile channel is prepared in 1-3 root canals according to the degree of tooth defect and the retention force provided by the retention shape of the pulp cavity, and when the number exceeds 1, the pile channel obtains a locking angle according to the original direction of the root canal; according to the limitation of the diameter and the length of the root of the tooth, a slope form with a certain shape can be prepared at the root canal opening within the depth range of 0-1.5mm to accommodate the middle part of a slope of a later-stage bolt;

s2, impression preparation: preparing an impression of an affected tooth, pouring a plaster model, scanning the model in a box-type optical scanner, and acquiring digital information of the form and occlusion relation of the affected tooth and a post path;

s3, computer aided design prosthesis form: based on the digital model, the pile-core integrated crown is designed by using computer software in an auxiliary way, and the axial surface and the sum of the main body and the affected crown part need to be recovered

The facial form and the occlusion relation and the realization of the inosculation with the position retention of the pulp cavity of the affected tooth; 1-3 passages are correspondingly determined in the main body according to the number of the root canal preparation pile paths and are positioned

An upper placing opening is designed in a non-occlusion contact area in the surface central pit and connected with a channel, and the lower end of the channel is simultaneously connected with a lower placing opening and arranged at a root canal opening; the upper part of a pile core and the lower part of a root pile of the bolt are designed to be respectively filled with a channel of the main body and a pile channel in a root canal, and a gap of 30-50 mu m is reserved as an accommodating space of the adhesive; the slope of the bolt is positioned in a preparation range with the depth of 0-1.5mm of the root canal orifice;

s4, digital processing: and respectively processing the main body and the bolt pile core by using the zirconia ceramic primary blank product by using a CAM (computer aided manufacturing) device or a 3D (three-dimensional) printing device, and performing crystallization sintering according to the instruction of a ceramic manufacturer to finish the manufacture of the prosthesis.

The invention has the beneficial effects that:

one, this kind is applicable to the back tooth and restores

The integrative crown of bolt formula stake nuclear of the case that the gum space is less than 3mm need not to carry out the crown extension art of suffering from the tooth, also need not to carry out the adjustment and grinding to the jaw tooth, and the wound is little. Compared with the traditional pile core crown repair, the method has less times of treatment.

Secondly, the invention aims at the large-area defect of the post-dental body and the external shape of the original dental crown in clinic

The gingival height is less than 3mm, the occlusion is tight, and the repairing space is insufficient, so that a new repairing body type is provided, the residual tooth tissues can be stored as much as possible, the retaining force is obtained by the retaining force of the bolt for retaining the medullary cavity and extending into the root canal and the locking angle among different bolts, the separation is not easy, the retention is good, the preservation rate of the affected tooth can be improved, and good preservation and treatment are provided for the affected tooth which can not be repaired and can be seriously damaged.

Thirdly, the method is suitable for posterior tooth repair

The plug type pile-core integrated crown for the case that the gum space is less than 3mm is made of zirconia ceramic materials, color matching or dyeing is facilitated, the boundary of the plug cemented with a tooth body is not obvious visually, the aesthetic performance is good, the manufacturing material of the restoration is good in biocompatibility, corrosion and abrasion are resistant, the patient satisfaction is high, the color problem of a metal restoration and the serious influence on some special inspections are avoided, compared with the traditional metal casting pile-core crown process, the processing precision is high, and the possibility that metal shrinkage, air holes, sand holes and the like have influence on the precision and the quality of the restoration does not exist.

Drawings

FIG. 1 is a schematic structural diagram of a bolt type pile-core integrated crown provided with 1 bolt according to the present invention;

FIG. 2 is a schematic structural diagram of the bolt type pile-core integrated crown provided with 2 bolts according to the present invention;

FIG. 3 is a schematic structural diagram of a main body crown part and a medullary cavity part in the bolt type core-pile integrated crown provided by the invention;

FIG. 4 is a schematic structural view of the plug pin channel and the upper and lower openings of the channel inside the main body of the plug pin type pile-core integrated crown according to the present invention; FIG. 4 (a) is a schematic structural diagram of a main body and a plug pin passage in the embodiment; (b) is a schematic view of the structure in the direction A in figure (a); (c) is a schematic view of the structure in the direction B of the figure (a).

FIG. 5 is a schematic view of the middle part and angle of the slope of the bolt in the bolt-type pile-core integrated crown according to the present invention;

fig. 6 is a structural schematic diagram of the bolt type pile-core integrated crown in the invention after a diseased tooth is in place;

FIG. 7 is an example of an embodiment of a posterior tooth restoration

A model diagram of a computer-aided design plug pin type pile-core integrated crown of a case with excessively small gum space;

FIG. 8 is an example of an embodiment of a posterior tooth restoration

Computer aided design plug type pile-core integrated crown for cases with too small gum space

A model diagram of a face opening;

FIG. 9 is the completed prosthesis of plug pin type post-core integrated crown made according to the invention by the patient with defective second molar tooth body in the example;

fig. 10 is a photograph of the plug type stake core integrated crown manufactured according to the present invention in place on a working model of a diseased tooth in the embodiment;

FIG. 11 is a photograph of the inside of the mouth of a patient with a defective tooth body of the second molar tooth in the upper right of the example, after the integrated crown of the pin type post and core made according to the present invention is in place and bonded with the affected tooth;

FIG. 12 is a diagram showing the results of finite element stress analysis of plug-in piles under horizontal stress 225N and vertical stress 600N, in which (a) is a diagram showing the results of finite element stress analysis of plug-in piles under horizontal stress 225N and vertical stress 225N, in which the angles of the middle of the slope are 90 °, 120 °, 135 ° and 160 ° from left to right when the diameter difference is 0.5mm, and (b) is a diagram showing the results of finite element stress analysis of plug-in piles under vertical stress 600N, in which the angles of the middle of the slope are 90 °, 120 °, 135 ° and 160 ° from left to right when the diameter difference is 0.5mm, and (c) is a diagram showing the results of finite element stress analysis of plug-in piles under horizontal stress 225N, in which the angles of the middle of the slope are 90 °, 120 °, 135 ° and 160 ° from left to right when the diameter difference is 1mm, (d) the finite element stress analysis result graph of the inserted pin pile under the vertical stress of 600N is shown, wherein when the diameter difference is 1mm, the angles of the middle part of the slope are 90 degrees, 120 degrees, 135 degrees and 160 degrees from left to right respectively;

FIG. 13 is a diagram showing the results of finite element stress analysis of plug-in piles under horizontal stress 225N and vertical stress 600N, in which (a) is a diagram showing the results of finite element stress analysis of plug-in piles under horizontal stress 225N, in which the angles of the middle of the slope are 90 °, 120 °, 135 ° and 160 ° from left to right when the diameter differences are 1.5mm, respectively, (b) is a diagram showing the results of finite element stress analysis of plug-in piles under vertical stress 600N, in which the angles of the middle of the slope are 90 °, 120 °, 135 ° and 160 ° from left to right when the diameter differences are 1.5mm, respectively, (c) is a diagram showing the results of finite element stress analysis of plug-in piles under horizontal stress 225N, in which the angles of the middle of the slope are 90 °, 120 °, 135 ° and 160 ° from left to right when the diameter differences are 2mm, respectively, (d) the finite element stress analysis result graph is a diagram of the finite element stress analysis result of the inserted pin pile under the vertical stress of 600N, wherein the angles of the middle part of the slope from left to right are respectively 90 degrees, 120 degrees, 135 degrees and 160 degrees when the diameter difference is respectively 2 mm.

Wherein: 1-crown part, 2-medullary cavity part, 3-upper placing opening, 4-channel, 5-lower placing opening, 6-upper part of pile core, 7-middle part of slope, 8-lower part of pile, 9-bolt

The surface exposed end, 10-the end clamping handle of the bolt, 11-the meshing contact area, 12-the lock angle.

Detailed Description

In order to prove the reasonableness and effectiveness of the bolt type stake-core integrated crown in clinical application, the embodiment is used for typical posterior tooth restoration

The plug pin type pile-core integrated crown provided by the invention is used for repairing the case that the gum space is less than 3 mm.

In this case, the upper left second molar has large area of defect of tooth tissue near the distal and proximal adjacent surfacesThe middle defect is 0.5mm below the gum, the palatine side defect is about 1mm above the gum, the residual tooth body tissues at the far middle side and the buccal side are weak, the occlusion is tight, and the perfect root canal treatment is performed. The patient does not receive the grinding adjustment and has little residual teeth but has far-middle restoration

The gingival space is only 1mm, the size of the near-middle part is slightly less than 3mm, and the conventional crown repair or the stake nuclear crown repair cannot be carried out. If the intramedullary canal retaining crown is made of metal materials, the possibility that metal shrinkage, air holes, sand holes and the like influence the precision and quality of the prosthesis in the casting process exists, and in addition, the aesthetic effect is greatly reduced due to the existence of metal color. For the cases, the bolt type pile-core integrated crown provided by the invention has unique advantages and conforms to the application range.

Based on the procedure mentioned in the present invention, the following preparation is carried out for the affected tooth in the example:

the diameter of the pile channel in the prepared root canal is 1/4 of the diameter of the root canal, the length of the pile channel is as deep as 5mm from the tail end of the root tip, and the original far-end root canal filling material of the affected tooth is reserved to be used as root tip sealing. The embodiment of the patient has the tooth defect degree and the pulp cavity depth (1.5mm), the pulp cavity is prepared in a pulp cavity preparation box for fixing the position, in addition, the preparation pile channels are designed in 2 root canals, and the locking angle 12 exists among the pile channels according to the original direction of the root canal. The socket of this example can prepare enough room to accommodate the sloped middle portion 7 of the pin, and the embodiment prepares the angle of the socket of the affected tooth to be 120 ° so that the angle of the sloped middle portion 7 of the pin is 120 °.

After the preparation is completed, based on the operation steps mentioned in the present invention, the embodiment takes an impression of the affected tooth from the patient, pours a plaster model, scans the model in a box-type optical scanner, obtains the digital information of the form and occlusion relationship of the affected tooth and the post, and performs computer aided design on the form of the prosthesis by using 3Shape Dental System software (3Shape, denmark), as shown in fig. 7 and fig. 8.

As shown in fig. 1 and 6, the bolt type stake core integral crown comprises a main body, a bolt channel 4 and a bolt. As shown in fig. 3, the body comprises a crown portion 1 and a medullary cavity portion 2; the crown part 1 restores the shape of the affected tooth, the occlusion relation, covers and bagsWinding the affected tooth preparation body; the marrow cavity part 2 is filled with the marrow cavity of the affected tooth, is matched with the shape of the marrow cavity and simultaneously extends to the root canal with thick palate root to form a root-pile shape so as to obtain the retention force; designing 1 far-buccal-root bolt channel 4 in the main body according to the number of root canal preparation pile channels, wherein the bolt channel 4 comprises an upper placing opening 3, a channel 4 and a lower opening 5 as shown in figure 4; with upper port 3 in the body

On the central fossa of the surface, avoiding the occlusion contact area 11, the lower opening 5 is positioned at the root canal opening and is respectively communicated with two ends of the channel 4; the channel 4 runs through the crown 1 and the medullary cavity 2 of the body; in addition, an integrated crown containing two bolt piles can be arranged according to the defect degree of the affected teeth, as shown in figure 2.

Importing design data of the pile-core integrated crown into Magic design software (Materialise, Belgium), independently designing a bolt, wherein the bolt comprises a pile-core upper part 6 and a root pile lower part 8, respectively filling a channel 4 of a main body and a pile channel in a root pipe, and reserving a binder space of 30-50 mu m; the upper part 6 of the pile core is connected with the end part of the lower part 8 of the root pile, the upper part 6 of the pile core and the lower part 8 of the root pile form a T shape together, the upper part 6 of the pile core is embedded into the channel 4 of the main body and is columnar, and the lower part 8 of the root pile extends out of the lower opening 5 of the plug pin channel 4 and is matched with a prepared pile channel of the root canal; the diameter of the upper part 6 of the bolt pile core is preferably 2.78mm, the width is larger than the width of the lower part 8 of the root pile, the diameter difference is designed to be as close to 2mm as possible, but the diameter of the lower part 8 of the root pile is not smaller than 0.8mm, the shortage of excessive thinning resistance of materials is avoided, the joint of the upper part 6 of the bolt pile core and the lower part 8 of the root pile is in a certain slope form and is a slope middle part 7, and as shown in figure 5, the slope middle part 7 is matched with the preparation shape of a corresponding root pipe opening; the plug pin is arranged in the exposed area of the surface of the main body and matched with the placing port

The central fossa of the face and avoiding the bite contact zone 11; when the bolt is designed, can be at

The top end of the face is provided with a clamping handle 10, so that the clinical trial wearing and cementation operation is convenient, and the trial wearing is completedThen cutting and grinding the clamping handle 10 by a turbine to

The faces were flat and polished.

After the design is completed, based on the operation steps mentioned in the present invention, the two independent data of the main body and the plug pin are sent to the computer processing module, 3D printed by using zirconia ceramic material, and dyed after sintering, as shown in fig. 9. The effect of the integral crown of the completed stake core on the model in place is shown in figure 10.

When the patient is in a double-examination, the main body of the post-core integrated crown is tried on, the adhesion with the tooth tissue and the shape, inclination direction, polymerization degree, occlusion space of the core are checked, and the holding handle 10 holding the tip of the plug is inserted from the plug of the main body

The surface exposed end 9 is in place, and the clamping handle 10 is adjusted and ground, cut off and adjusted

Bonding and polishing to finish the repair treatment. As can be seen from the picture of the normal and middle jaw position in the mouth of the patient, although the combined gum height of the upper left second molar is smaller, the restoration of the plug type pile-core integrated crown provided by the invention obtains a satisfactory restoration effect, and the affected teeth which cannot be restored and treated originally are preserved, as shown in fig. 11.

In order to verify the reasonableness of the bolt form design of the bolt type pile-core integrated crown, in another specific example, a three-dimensional finite element analysis is used for carrying out stress analysis on bolts with different structures and forms, and the bending resistance of the bolt under the condition of material fixation is judged, as shown in fig. 12 and 13.

Setting the length of a lower jaw first molar root to be about 12.9mm, keeping the root tip to be 4-5mm closed, and setting the fixed length of a part of a bolt below a root canal orifice to be 8 mm; therefore, the height of the gingival of the similar special case is less than 3mm, the height of the first molar pulp chamber of the lower jaw is about 1mm generally, and in order to simulate the condition that the height of the gingival of the clinical case of the affected tooth is only 2mm, the fixed height of the upper part 6 of the stake core of the bolt is set to be 3 mm; because the clinical root canal is prepared to 04 conicity, the conicity of the lower part 8 of the root pile of the bolt is set to 0.04, and the diameter of the bottom part is set to 0.98 mm.

According to the setting parameters of the bolt, a bolt model is established in SolidWorks 2016(Dassault systems, France) software, and 16 models are formed according to the slope angles (90 degrees, 120 degrees, 135 degrees and 160 degrees) and the diameter differences (0.5mm, 1mm, 1.5mm and 2mm) of the upper part and the lower part of the bolt. The file is then imported into finite element analysis software ansys18.1, and the Von Mises stress distribution of the middle part 7 of the bolt slope under horizontal load 225N and vertical load 600N of the 16 models is mainly observed. The prosthesis is provided with a zirconia ceramic material with the elastic modulus of 210GPa and the Poisson ratio of 0.30.

Under the load of horizontal and vertical different directions, when the joint of the upper part and the lower part of the bolt is 90 degrees, the position with the largest stress action is positioned at the joint of the upper part and the lower part, namely the slope middle part 7, and under any diameter difference (0.5mm, 1mm, 1.5mm and 2mm), the maximum value of the Von Mises stress is higher than that of the obtuse angle group (120 degrees, 135 degrees and 160 degrees) (Table 1), which means that the bolt is most easy to break under the same condition.

At 120 ° of the ramp mid-section 7 under load in both the horizontal and vertical directions, the Von Mises stress was lower at any diameter difference (0.5mm, 1mm, 1.5mm and 2mm) than at 135 ° and 160 ° (table 1), meaning the lowest breaking under the same conditions.

When the angle of the middle part 7 of the bolt slope is larger than 90 degrees, the stress borne by the middle part 7 of the slope is reduced along with the increase of the diameter difference, and when the diameter difference between the upper part and the lower part of the bolt is 2.0mm, the Von Mises stress value under horizontal/vertical load is minimum (table 1) no matter what angle (90 degrees, 120 degrees, 135 degrees and 160 degrees) is presented by the middle part 7 of the bolt slope, and the bending resistance is relatively strongest at the moment.

TABLE 1

In table 1, when the diameter differences between the upper part 6 of the pile core and the lower part 8 of the root pile are 0.5mm, 1mm, 1.5mm and 2mm, respectively, the angles of the middle part 7 of the slope are 90 °, 120 °, 135 ° and 160 °, respectively, the plug pile has finite element stress values (MPa) under a horizontal stress of 225N and a vertical stress of 600N.

Based on the above three-dimensional finite element analysis results, the following conclusions can be drawn: (1) when 7 angles in the middle part of the bolt slope are 90 degrees, stress is obviously increased when the root pipe opening can not form the slope in the preparation process of the clinical pile foundation, the diameter of the upper part of the bolt can be increased in the allowable range of the main body at the moment, the diameter difference of the upper part of the bolt and the diameter difference of the lower part of the bolt are more favorable for the dispersion of the stress of the joint of the upper part and the lower part of the bolt, the difference of the diameters of the upper part and the lower part of the bolt is close to 2 mm. (2) When the root canal opening has enough space to prepare the slope form to contain the slope middle part 7 of the bolt when the clinical pile canal is prepared, the angle of the slope middle part 7 of the bolt is 120 degrees, which is more beneficial to stress dispersion and prevention of breakage.

Claims

1. Is suitable for posterior teeth

Integrative hat of bolt formula stake core that the gum restores the space and is less than 3mm, its characterized in that: the tooth preparation device comprises a main body, a pin channel and a pin, wherein the main body comprises a crown part and a medullary cavity part, the crown part is arranged at the end part of the medullary cavity part, and the crown part restores the form and the occlusion relation of an affected tooth and covers and wraps the affected tooth preparation body; the pulp cavity is positioned in the pulp cavity and matched with the pulp cavity to obtain retention force, the main body is internally provided with a plug pin channel, the plug pin channel comprises an upper placing opening, a channel and a lower opening, and the upper placing opening is arranged on the main body

Face exposing end and closing mainThe mouth is placed on the body passageway, the tip of root stake lower part is connected through the slope middle part to the lower extreme on stake core upper portion, in the passageway of stake core upper portion embedding main part, slope middle part and root stake lower part all stretch out in the lower opening of bolt passageway, the root stake lower part and the orificial preparation form of root canal and the interior stake way adaptation of preparing of root canal, the diameter on stake core upper portion is greater than the diameter difference 1-2mm of root stake lower part, the axis of root stake lower part forms 90-120 angle with the terminal surface at slope middle part, specifically does: when the axial line of the lower part of the pile forms 90 degrees with the end face of the middle part of the slope, namely the stress is obviously increased when the mouth of the pile cannot form the slope during the preparation of the clinical pile channel, the diameter of the upper part of the pile core is increased within the allowable range of the main body, the larger the diameter difference with the top of the lower part of the pile is, the more the dispersion of the stress at the joint of the upper part of the pile core and the lower part of the pile is, the difference of 2mm between the diameters of the; when the root pipe opening has enough space to prepare the slope form to contain the slope middle part of the bolt when the clinical pile way is prepared, the axis of the lower part of the root pile and the end surface of the slope middle part form 120 degrees; respectively processing a main body and a bolt pile core by using a zirconium oxide ceramic primary blank product through CAM (computer aided manufacturing) equipment or 3D (three-dimensional) printing equipment by adopting a zirconium oxide ceramic material;

when a certain root canal of the affected tooth and the pulp cavity can obtain the same common in-situ channel, the pulp cavity of the main body is extended into the certain root canal to be made into a root-pile shape, so as to obtain the retention force, and in addition, 1 channel and a lower opening are designed to correspond to the pile channels in other root canals; when the affected tooth root canal and the medullary cavity can not obtain a common positioning channel, the medullary cavity part of the main body is provided with lower opening openings at all root canal openings needing to be prepared, a plurality of bolt channels are designed to be communicated with the lower opening openings, the bolt channels are not mutually contacted and communicated, and locking angles are formed among the bolt channels.

2. The tooth paste as claimed in claim 1, adapted for posterior teeth

Integrative hat of bolt formula stake core that the gum restores the space and is less than 3mm, its characterized in that: the upper part of the core and the lower part of the root pile of the bolt are respectively filled with the channel of the main body and the pile channel in the root canal, and a gap of 30-50 mu m is reserved as the container of the adhesiveA nano-space.

3. The tooth paste as claimed in claim 1, adapted for posterior teeth

Integrative hat of bolt formula stake core that the gum restores the space and is less than 3mm, its characterized in that: the joint of the upper part of the core of the bolt and the lower part of the root pile is the middle part of the slope, and the middle part of the slope is matched with the prepared slope form within the depth range of 0-1.5mm at the position of the affected root canal.

4. The tooth paste as claimed in claim 1, adapted for posterior teeth

Integrative hat of bolt formula stake core that the gum restores the space and is less than 3mm, its characterized in that: the middle part of the slope of the bolt and the lower part of the root pile form an angle of 90-120 degrees.

5. The tooth paste as claimed in claim 4, applied to posterior teeth

Integrative hat of bolt formula stake core that the gum restores the space and is less than 3mm, its characterized in that: the angle formed by the slope middle part of the bolt and the lower part of the root pile is as close as possible to 120 degrees.

6. The tooth paste as claimed in claim 1, adapted for posterior teeth

Integrative hat of bolt formula stake core that the gum restores the space and is less than 3mm, its characterized in that: the upper part of the core of the bolt is of a cylindrical structure, and the lower part of the root pile is of a conical structure which accords with the taper of the root pipe pile channel.

7. The tooth paste as claimed in claim 1, adapted for posterior teeth

Integrative hat of bolt formula stake core that the gum restores the space and is less than 3mm, its characterized in that: the width of the upper part of the pile core of the bolt is larger than the width of the top end of the lower part of the root pile, the difference value is 2mm, and the difference value is realized by increasing the width of the upper part of the pile core of the bolt.

8. The tooth paste as claimed in claim 1, adapted for posterior teeth

Integrative hat of bolt formula stake core that the gum restores the space and is less than 3mm, its characterized in that: of the bolt