JP2844305B2 - Artificial root - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an artificial dental root having a screw portion to be implanted in a jaw bone, and more particularly to a technique for distributing an occlusal force to the jaw bone to reduce the load on the jaw bone.

[0002]

2. Description of the Related Art Conventionally, a dental implant having a screw portion implanted in a jaw bone is widely known as a spiral implant among screw implants. However, the present inventor has found that this spiral implant is effective as an earthquake-resistant structure. He noticed that it was very similar to the “top-type foundation” of civil engineering and architectural engineering, and tried to improve the spiral implant by focusing on the theory of this “top-type foundation”.

[0003] This spiral implant differs from other screw implants in the following respects.

[0004] Conventional screw implants are unaware of the "top-of-the-law foundation" theory and have not responded at all.

[0005] In other words, depending on whether the screw is in the form of ripples or a continuous sine curve, no consideration is given to the "top foundation".

In other screws, the depths of the ridges and valleys of the screw are shallow and small, and are merely considered to be intended for vertical fixing.

[0007] The surface structure of the implant itself is intended to have a surface area several times larger than that of a smooth surface by a plasma coating method or the like. The method of augmentation is that when an occlusal force of about 50 [kg] is applied to a single implant in an actual clinic, a micro crack (Micr
o-crack) is a theory that alveolar bone microfractures occur and are not effective, and this manifests as a subsidence phenomenon of implants in the alveolar bone over time, and as a result, It is believed that the surrounding bone has lost its absorption and its durability has been shortened.

[0008] As is well known, the "top type foundation" has a top shape in which a mandrel is inserted into the center of a block body having a triangular cross section, and its effectiveness has been recognized as a foundation material for soft ground. That is, the load is distributed over the entire surrounding ground by the conical inclined surface of the block body, and the supporting force on the soft ground is increased.

On the other hand, the spiral implant has a helical thread protruding around a shaft body, and this thread corresponds to a block body of a top type foundation, and compresses a load on bone through a slope of the thread. Distributed.

As an improvement of such a spiral implant, the present inventor has already proposed an artificial dental root described in Japanese Utility Model Publication No. 4-31048.

[0011]

However, in the above-mentioned conventional spiral implant, the degree of stress dispersion is insufficient, and the alveolar bone and the jaw bone are absorbed to reduce the remaining bone mass, It was not possible to respond to soft cases with a small amount of bone due to the lack of time immediately after tooth extraction or no time after tooth extraction, and to elderly patients with osteoporosis.

[0012] However, such a case is also a non-indication of a removable denture which is commonly used today, and a case where it is desirable to restore the function by a fixed intraosseous implant for the purpose of effective function restoration. It is. There is a strong need and demand for intraosseous implants in cases with reduced alveolar bone and immediately after tooth extraction, with the aim of enabling intraosseous implants to be applied to soft residual jawbones of limited volume and depth. Therefore, how to expand the scope of application remains as a major issue.

[0013] The present inventor has proposed, under the proposition "how to use a small number of jawbones or soft jawbones to better distribute the occlusal force to the jawbones immediately after implantation," the hardness of the jawbones of the human body. Using bovine ribs that are similar to the above, we conducted a detailed study of the physical properties of raw bone and the mechanical interface characteristics between the implant and raw bone, and found that even if the mechanical strength of the spiral implant itself was sufficiently strong, If it is far from the strength of the surrounding jawbone that supports it,
It does not directly contribute to the effective distribution of stress into the bone, "rather it was found that the shape of the implant, especially the angle of the thread of the thread, had a significant effect on the stress distribution.

Further, as a result of the occlusal force being applied to the implant, the implant body may be broken several years later due to metal fatigue with the passage of time, and it is necessary to improve the strength as well as the stress dispersion.

The present invention has been made to solve the above-mentioned problems of the prior art.
Focusing on the fact that the thread angle has a significant effect on the effect of dispersing stress on the jawbone, spiral spirals with optimal thread angles
It is to provide a type of artificial root.

[0016]

In order to achieve the above object, according to the present invention, in an artificial tooth root having a screw portion to be implanted in a jaw bone, the angle of the thread of the screw portion is set to 6 degrees.
It is characterized in that it is set in the range of 0 ° to 70 °.

It is effective that the screw portion is formed around a shaft having a central hole.

Further, the diameter of the center hole of the screw portion is set to 1.
By reducing the value from 8 [mm] to 1.6 [mm], the thread portion was strengthened against fracture of the thread portion due to metal fatigue over time.

The screw portion is formed around a hollow shaft having a central hole.

The shaft is provided with a window communicating with the central hole.

The thickness of the neck from the screw to the head is
Make the artificial tooth root smaller than the outer diameter of the screw part so that the artificial tooth root does not come into contact with cortical bone and compact bone in the early stage of implantation, and distribute the load only to the cancellous bone of the bone marrow where the screw part is embedded It is characterized by doing.

It is characterized in that the thickness of the neck is set in a range up to about 2 [mm].

It is characterized in that the head shape is made into a modified cross-sectional shape that becomes thinner toward the front end, so that the direction can be identified and the implant can be performed by rotation.

The present invention is characterized in that the head has a conical shape having one plane having a D-cut cross section.

The present invention is characterized in that it has a structure in which a groove for a driver is formed in the stump of the head.

[0026]

The angle of the thread of a conventional artificial tooth with a thread portion is set at approximately 77 °, while the angle of inclination of the block body in civil engineering construction is 4 from the theory of the “top type foundation”.
It has been clarified that it is preferable to set the angle to 5 °, and if corresponding to the screw thread, it is preferable to set the screw thread angle to about 90 ° at approximately 45 ° up and down.

However, when an actual test was conducted, it was found that, in the case of the artificial tooth root, the stress dispersing effect was the highest in the range of 60 ° to 70 °, not in any of the above angles.

The reason is considered to be that the jawbone in which the screw portion is implanted has elasticity different from the ground on which the building is based, and is elastically deformed by a load. That is, if the screw portion implanted in the jaw bone does not deform to follow the deformation of the jaw bone to some extent, the contact portion becomes partially in contact and stress concentration occurs, and the bone tissue is destroyed at a small load stage.

That is, when the thread angle is large, the thickness of the thread becomes large, so that the rigidity of the thread part becomes large, and the occlusal force is applied to the bone tissue without being buffered at the thread part, and the stress is locally applied. Will be expensive.

On the other hand, when the thread angle is small, the thickness of the thread becomes small, so that the rigidity of the thread part becomes small, and even if an occlusal force is applied, the thread part is elastically deformed and the load acting on the bone tissue is reduced. It can buffer and distribute the stress. However, if the thread angle is too small, a buffering effect can be obtained, but the tip of the thread bites into the bone tissue and stress concentration occurs at the tip.

Then, as a result of intensive research, it was found that the temperature was 60 ° -70 °.
By setting the angle in the range of °, the load such as the occlusal force could be moderately buffered, and the stress concentration at the tip of the screw thread could be reduced as much as possible, and a uniform stress dispersion effect could be obtained.

Further, by lowering the rigidity by hollowing out the shaft of the screw portion, it is possible to enhance the buffering effect of loads such as occlusal force, in combination with the setting of the range of 60 ° to 70 °. In addition, the burden on bone tissue can be reduced as much as possible.

In particular, a window opening structure provided with a window portion is effective for this effect.

A hard titanium material having good biocompatibility is preferable, but the correlation between the flexibility and Young's modulus of the titanium material and the Young's modulus of cancellous bone is effective in dispersing the load stress. This is an important condition to achieve. If the titanium material is hard, it is not enough, and the crystal structure is important.

The windowing structure is effective in relation to the Young's modulus of the cancellous bone around the implant (artificial root) due to the “soft structure”. Other screw-type implants have no windows or do not have a "soft structure".

On the other hand, if the shaft of the threaded portion has a hollow structure, the effect of dispersing stress is enhanced, but problems occur in strength and durability.

At this point, the outer diameter of the thread is φ4.0 [mm].
When the valley diameter (shaft diameter) is 2.4 [mm], the stress dispersion effect is maintained by changing the diameter of the central hole from the conventional φ1.8 [mm] to φ1.6 [mm]. An artificial tooth root excellent in strength, durability and durability could be realized.

Further, the thickness of the neck portion from the screw portion to the head is made smaller than the outer diameter of the screw portion so that the implant (artificial dental root) body does not come into contact with cortical bone or compact bone in the early stage of implantation. By distributing and applying the load only to the cancellous bone of the bone marrow in which the screw portion is embedded, an appropriate stress is applied to the bone tissue, and the functional healing of the bone tissue is promoted.

Common sense Generally, when seeking to maintain and stabilize an artificial tooth root in the early stage of implantation, the head of an artificial tooth root () is inserted into the dense bone for the purpose of applying external force to hard and durable cortical bone and dense bone. (Head) A method is employed in which the base and neck are brought into close contact and fixed.

However, the present invention is based on the premise that no fixation by maintaining contact with the dense bone is expected at all, and the maintenance and fixation at the initial stage of planting are all required for the soft bone marrow and cancellous bone inside. .

The stable healing of the interface between the living body and the implant (artificial root) body is an important problem. As a result, stress concentration occurs around the neck of the implant (artificial dental root), which has a negative effect on the regeneration and healing of the surrounding tissue, and causes bone resorption over time and the accompanying downward growth of epithelial soft tissue. Microbial infection of soft tissues is a major problem in long-term prognostic management.

On the other hand, when the maintenance and fixation in the early stage of planting are all required for the soft bone marrow and cancellous bone inside, the growth and addition of bone at the neck is conversely recognized even in an unclean environment ( Photo 7 of Case 2 of P.4 and Photo 1 of Case 5 of P7 in the attached document “Clinic of Shell Chev Implant”
0, p. 8 and P.E. 9 (compare pictures 7 and 14). The present invention has found a thread size that most effectively distributes stress into such soft bone marrow tissue.

The fact that the thickness of the neck is about 2 [mm] is a thickness that is not seen in other general artificial dental roots.
Unlike the other artificial roots, it does not require nervous cleaning management in the long-term prognosis management after the operation of the artificial root. This is the "OGA-BAR" which has been proposed by the inventor for some time.
It is based on theory.

The "OGA-BAR" theory states that "prosthetically, if the width of the upper structure in contact with the attached gingiva is in the range of 2.0 [mm], the periodontal tissue is self-cleaning. You can automatically maintain permanent health. " This has greatly improved the way temporary dental restorations and final prostheses interact with soft tissue.

In terms of periodontology, when the diameter of the implant (artificial root) body greatly exceeds 2 [mm] and becomes 4 [mm], the natural epithelium accompanying the metabolism of the epithelium near the adhesive interface with the epithelium is obtained. It has been found that as a result of the inability to shed (self-cleansing), it accumulates as old grime, which creates a source of soil near the interface, causes inflammation and infection, and triggers periodontal disease. Therefore, the neck thickness 2 [mm],
It has significant periodontological significance and value.

For the same reason of the self-cleaning action, the thickness of the head (head) is limited to about 3 [mm]. In addition, the thickness of the implant (artificial root) and neck (neck) is appropriately set at 2 [mm] in consideration of the relationship with the strength of bending stress.

In the present invention, the shape of the head is set to a conical shape having one plane of a D-cut cross section, so that it is easy to determine the direction of the front and rear sides.

Also, a torque may be applied at the time of artificial root implantation using a hand key or the like using a deformed cross section of the artificial root head. May bite. Therefore, it is preferable to provide a groove for receiving a driver's bit at the stump of the head and apply a screwing torque to the head. Thus, there is no fear that the hand key will not be cut off by digging into the side of the head.

[0049]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. In FIG. 1 showing an artificial tooth root according to one embodiment of the present invention, reference numeral 1 denotes an entire artificial tooth root, and a root 3 having a screw portion 2 to be implanted in a jaw bone and a technical object are generally attached. A head 4 and a neck 5 connecting the root 3 and the head 4 are provided. In this embodiment, the root 3 and the head 4 are integrally formed as one shaft.

The root 3 comprises a hollow shaft 6 and the above-mentioned helical screw portions 2 and 2 projecting from the outer periphery of the shaft 6. The shaft body 6 has a central hole 7, and windows 8 are formed on the left and right side surfaces.

The base of the neck 5 and the head 4 and the root 3 is a tapered portion 9 which gradually expands toward the head 4 and the root 3. Head 4
Has a D-shape having a flat portion 41 on one side,
Both sides can be identified.

In this manner, the use of the technical dowel post can be accurately positioned in accordance with the direction of the flat portion 41 of the head 4 of the artificial dental root, and the efficiency of the technical work is significantly improved. Help.

Originally, the head shape of the artificial tooth root was generally a cylindrical shape with two parallel cuts, but a conical shape with two parallel cuts has already been proposed. 2 (a) and 2 (b) show a cylindrical form with two parallel plane cuts, and FIGS. 2 (c) and 2 (d) show a conical form with two parallel plane cuts.

However, in actual use, the head is used for maintaining the crown restoration, but its positional relationship with the occlusal plane in the oral cavity is almost always used in an inclined state. Can be Therefore, if the front and back sides are not in a form that can be distinguished, the transfer of the model as shown in FIG. 3 is performed in order to prevent the model from being broken and to manufacture a dental technique model for manufacturing an accurate crown restoration. Using a coping (TransferCoping) 71, a dowel of the same shape corresponding to an implant (artificial root) head
When devising and using a post (Dowel Post) 72, a conventional parallel two-planar implant (artificial root) head configuration as shown in FIGS. The Dowel Post proved impossible to distinguish between front, back and front.

The front / back and front / back are front and rear of the face. When the implant head is a parallel two-sided cut, the tooth or implant (artificial root) is usually at an acute angle, not at a right angle, to the plane where it engages when it functions as a tooth (occlusal plane). As a result of the pairing, taking an impression, when inserting the dowel post inside the coping, the tip of the post is small and it is difficult to distinguish the front and rear direction, so it was mistakenly rotated by 180 degrees. Since it is not possible to identify whether or not it is correct even if inserted, it is not possible to judge that the direction of the stump of the implant head (head) has been rotated by 180 degrees from the impression surface until the model is released from the impression surface. There are drawbacks.

On the other hand, since the D-cut head (head) is a single plane, there is no possibility that an error will occur.

Therefore, according to the present invention, the shape of the head is changed
As a conical shape having one plane 4a of the cut, the directivity of the front and rear and front and back is easily discriminated. The head of the dowel post has the same form as the implant head 4.

It has been found that when six parallel two plane portions are planted on one side of the jaw, it is inappropriate and impossible to visually establish a parallel relationship without undercuts.

FIG. 4 shows a two-plane cut head (head) 4 '.
FIG. 4 is a comparative explanatory diagram of a case of a head (head) 4 with a single plane D cut.

As shown in FIG. 4, when implanting an implant (artificial tooth root) inside the jaw bone, a wider contact area with the jaw bone is obtained, and a direction that can cope with the load of the occlusal force is taken into consideration. When multiple plants are planted, they are planted in each direction in consideration of aesthetics and mating relationship, but at the end of planting, the implant head (head) is used for the purpose of manufacturing a prosthesis. It is necessary to adjust the bending so that they are parallel to each other.

Undercut (undercut) means that when an implant (artificial root) is looked down from above, no shadow is formed below the upper part of the head (head). In other words, unless you aim for a shape that does not leave a shadow with a cone or trapezoid, you will not be able to obtain an accurate impression, and the prosthesis manufactured on the model you make will be like a skirt that does not fit perfectly with the neck below the model It has a transparent shape, and in this case, even if cemented, it becomes unclean or desorbs with time, and a good prognosis cannot be expected (see FIG. 4 (a)).

It is an important condition that the implant heads (heads) 4 like elongated bamboo shoots are parallel to each other and are not trapped in front, rear, left and right. Immediately after planting for the purpose of finishing the form into such a state, immediately after planting, the side and shaft wall of the implant head (head) are made into a tapered form by a high-speed air turbine (600,000 revolutions per minute) and tungsten carbide steel.・ The implant (artificial root) body made of titanium material was cut with a bar to correct the shape, and was polished with alumina oxide points.

In this operation, a strong vibration is applied to the implant (artificial root) immediately after planting, and the implant (artificial root) is loosened by the vibration, which adversely affects the surrounding bones, thus causing failure. At the same time, the surroundings are contaminated by the scattering of cutting dust, and cutting has a high risk of damaging the tongue and oral soft tissues, and at the same time, cutting and polishing take time and labor costs,
This has led to a decline in labor productivity, which has led directly to a rise in medical costs for implants (artificial roots).

Therefore, the D-cut flat surface 4a is also tapered with respect to the long axis of the implant (artificial tooth root), so that the implant head (head) 4 has a truncated cone shape. Improved parallelism can be obtained with each other (Fig. 4
( c )). As a result, the implant head
There is no longer any need to adjust the sides of the head, so the head remains the same as the standard head, and only the length has to be adjusted.

The lengths of the individually cut and adjusted heads (heads) are copied on the dowel posts using a plastic coping, and the lengths of the cut ends are adjusted to adjust the tips of the posts. This allows the adjusted post to be used for individual implants (artificial roots) when taking impressions.
The Accupost system, which can easily produce an accurate model that does not break, was completed by inserting it into the impression site and injecting the model material into it.

Nowadays, by using the implant head (head) cutter already devised by the present inventor, the implant head (head) can be cut to a desired length in an instant. . As a result, cutting by a turbine was unnecessary except for adjusting the stump to be slightly flat, which contributed to shortening the time and improving the resting and healing effect of the implant (artificial dental root).

Therefore, the implant (artificial root) is also erected because the implant head (head) has a frustoconical shape by giving a taper (Taper) to the long axis of the implant (artificial dental root) also on the flat part. Therefore, if the parallel relationship is visually adjusted for the purpose of obtaining the parallelism between the adjacent teeth and the implant (artificial root), the parallelism without undercut can be easily obtained.

As a result, the necessity of cutting, adjusting and polishing the side surface to eliminate the undercut of the head (head) as in the prior art is completely eliminated, and the length of the head is adjusted according to the bite height. The cutting time and dangerous labor were greatly reduced.

At the same time, the form of the head manufactured according to the standard was maintained as it was, and a way was opened for applying a dowel post manufactured according to the same standard to the production of an accurate and robust model.

Conventionally, the shape of the implant head (head) was two parallel surfaces.
(Refer to FIG. 4 (a)), and it was necessary to remove the undercut Uc. Therefore, the cutting vibration of the tungsten carbide bar by the high-speed air turbine and the breakage of the bar were required for cutting the side surface of the head 4 '. Danger such as scattering of folded / cut pieces and damage to oral soft tissues, and labor and time such as vacuum suction operation were required.

[0071] In addition, the earlier application the things original head form is a cylindrical form two parallel planes cutting Hei 5 over 28 5 9
In No. 59, efforts were made to eliminate the trouble of improving the conical shape and correcting the side surface of the head to taper after implanting the artificial root, but as a result of changing from the cylindrical shape to the conical shape,
Immediately after the artificial root was implanted into the bone hole with the special hand key, the phenomenon that the hand key was difficult to remove from the head occurred.

FIG. 5 shows an example of the hand key.

A "hand key" 50, referred to as a knurl, holds the implant head with a mere cylindrical portion 51 and rotates it into a bone hole tapped to a predetermined depth. As a result, the head (head) form of the conventional parallel two-plane cut was good, but as a result of the head (head) changing to the taper form, contact between the hand key 50 and the head (head) 4 was made. Was limited to a slight contact between the thick part of the base of the head (head) 4 and the entrance of the hand key 50, so that a strong force was applied to a narrow area and applied to the implant (artificial root) body. A phenomenon occurred in which the hand key digged in and did not come off.

Therefore, as shown in FIGS. 1, 2 (e) and 2 (f), a single groove 4c for receiving a bit of a flathead screwdriver is provided in the stump 4b of the head 4. As a result, it became possible to securely screw into the bone hole with confidence. In the example shown, it is configured to accept the bit of a flathead screwdriver.
You may be a driver. However, since the stump is a D-cut flat surface, a flat-blade screwdriver is preferable.

As a result, as a result of the rotation planting operation, the hand
The artificial tooth root head 4 bites into the key 50 and comes into close contact therewith.
The inconvenience that the hand key 50 does not come off from the device can be completely avoided. Accordingly, the hand key 50 has been changed from a conventional cylindrical shape to a shape in which a flat screwdriver bit 52 is housed inside.

As a result of the tapered configuration, the contact portion where the artificial tooth root head can be rotated with the hand key 50 is only the base portion from the neck portion of the head, and the short size hand key does not reach the base portion. -Use of a hand key of a size is required, and operation may be hindered when there are neighboring teeth or when the opening is not sufficiently large.

Therefore, as described above, a single groove 4c for receiving a flathead screwdriver is formed in the stump of the head 4, and as a result, the hand key 50 is changed to a long size and a short Both sizes can be easily used and the inconvenience has been resolved.

Groove 4c of implant head (head) 4
Makes a cut in the last step of making an implant (artificial root) at the factory.

The screw portion 2 is a double thread in this embodiment.
The pitch is reduced while the lead is small.

The cross-sectional shape of the thread portion 2 is substantially triangular, and the angle α of the thread 10 is set in the range of 60 ° to 70 °. Both inclined surfaces of the thread 10 are symmetrical, and in this embodiment, are formed into an equilateral triangle having approximately 30 degrees in the vertical direction.

FIGS. 7 to 12 show stress states applied to the inside of the bone 11 around the screw portion 2 when the thread angle α is 56 °, 60 °, 64 °, 70 °, 75 °, and 82 °, respectively. It is a thing. In the figures, E1 denotes the Young's modulus of titanium, which is the material of the artificial tooth root, and E2 denotes the Young's modulus of the cancellous bone of the bone marrow. In each figure, the thread angle is described at the same angle in order to compare stress states. Incidentally, the Young's modulus E1 of titanium is 10.19 × 10 ³ [kgf / cm ² ] on average, and the proportional limit is 9.5.
49 × 10 ³ [kgf / cm ² ], Young's modulus of cancellous bone is 0.2
27 [kgf / cm ² ] with a proportional limit of 0.1082 × 10 ³ [k
gf / cm ² ]. In the figure, the area I is a safe area where the stress is small, the area II is a safe area where the stress is medium and the area I is safe.
In the area II, the stress is large, and is a range where the load is sometimes large. Accordingly, the larger the area of the region I is, the smaller the load on the jaw bone is.
This indicates that the larger the area, the greater the load on the jawbone.

When the thread angle α is large, the thickness of the thread 10 increases, so that the rigidity of the thread 10 increases, and the occlusal force is applied to the bone tissue without being buffered at the thread 10 portion.
The stress is locally increased.

On the other hand, if the thread angle α is small, the thread 10
Since the thickness of the thread 10 is reduced, the rigidity of the screw thread 10 is reduced, and even if an occlusal force is applied, the screw thread 10 is elastically deformed, so that the load acting on the bone tissue is buffered and the stress can be dispersed. However, if the thread angle α is too small, a buffering effect can be obtained, but the tip of the thread 10 bites into the bone tissue and stress concentration occurs at the tip.

Referring to the drawings, 60 °, 64 °, 70 °
In °, the range of I (small stress) is relatively wide (FIGS. 8, 9,
10), 75 ° (see FIG. 11), 82 ° (see FIG. 12).
), The range of I is narrowed (especially the thread 10
Bottom side).

From this data, it can be seen that the stress dispersion effect is high up to 70 °.

On the other hand, at 56 °, the thread 10 and the thread 10
Although the range of I (small stress) is wide, a portion of III (high stress) is formed near the tip of the thread 10 (see FIG. 2).

As for the data at the portion of 56 ° or less, it is obvious from the common sense of physics that the stress increases.

From these data, it was found that almost 60 ° to 70 °
When set within such a range, a load such as an occlusal force can be moderately buffered, and the stress concentration at the tip of the screw thread can be reduced as much as possible, so that a uniform stress dispersion effect can be obtained.

Further, a normal endosseous implant (artificial dental root) is usually implanted in the bone marrow. However, even if the bone tissue around the titanium spiral implant is trabecular bone of the bone marrow, the cortical bone There was no change in the stress distribution diagram even with a compact bone.

Therefore, the stress inside the jaw bone can be evenly dispersed and reduced, so that it is possible to cope with a case where the amount of remaining bone is small or softened bone.

Further, in the artificial tooth root of the present invention, the shaft 6 is hollowed to reduce rigidity, so that the shaft 6
In combination with the setting in the range of °, the buffering action of loads such as occlusal force can be enhanced, and the burden on bone tissue can be reduced as much as possible.

On the other hand, in order to effectively disperse the external force applied to the artificial tooth root 1 and transmit it as a small stress to the surrounding jaw bone, it is more advantageous that the surface area of the screw part 2 of the artificial tooth root 1 that bears the vertical load is larger. . Here, the length of the screw portion 2 is determined by the depth of the jaw bone 11 to be implanted, and the length of the screw portion 2 can be increased by the shorter pitch p than before.
The contact area is increased by the length of the screw portion 2, and the magnitude of the dispersed stress itself can be reduced.

In this embodiment, the pitch of the threaded portion 2 is changed from 1.76 [mm] to 1.50 [mm]. As a result, an effective area of 1.76 ÷ 1.50 = 1.173 times was obtained. The conventional thread angle is 77 °
It has no special mechanical advantage. In contrast, in the present invention, a general 60
It has been found that by setting the angle to °, the stress dispersing effect is improved by 30% or more, and the synergistic effect with the change in the pitch dimension increases the stress dispersing effect by 50% or more as compared with the conventional product.

In addition, if the angle is 60 °, a general ISO standard product can be used as a set of three dedicated bone taps, and a special 77 ° expensive custom-made product which has been conventionally used can be used. The cost can be greatly reduced.

As is well known, the artificial root can be categorized into a one-time method and a two-time method. In the one-time method, an artificial tooth root is implanted and implanted inside the jaw bone in one operation, the head is raised, and temporary crown restoration is performed there. In the second method, the gingival soft tissue is incised and exfoliated in the first operation, an intraosseous implant (artificial root) is implanted in the bone, the gingival soft tissue is put back on the suture, and the suture is rested for 3 to 6 months. After waiting for the bone to heal while maintaining the condition, the second operation is started, and the implanted implant (artificial dental root) is started. That is, the soft tissue covering the top of the implant (artificial root) is removed, the screw cover of the intraosseous implant (artificial root) is removed, and the head is screwed to the endosseous implant (artificial root). This is a method of starting up twice by connecting.

The phenomenon that an electromotive force is generated when a stress is applied to the collagen (Collagen) constituting bone is a physical common sense, but the current generated by the electromotive force is a piezo (Pies).
o) It is called current. Piezoelectric current is used to accelerate the treatment of epiphyses such as broken limbs, and today, in the field of plastic surgery, a weak electric current is applied to the fracture line to promote healing.

A similar phenomenon occurs in the case of a single-method implant (artificial dental root). A proper function is restored immediately after the implant (artificial dental root) is planted, and stress is applied to the two-method implant (artificial dental root). It is empirical that applying moderate stress promotes rapid functional healing of bone tissue rather than isolating the implant (artificial root) from external forces and blocking the external force from spreading to the surrounding bone I know. See “Practice of Shell Chev Implants” on P. Photographs of Case 2 of Case 4 Photographs of Case 4 of Case 5 Photographs of Case 5, Case 7, P.7. 8 and P.8. This is clear from the comparison of the photograph 14 of FIG. For this purpose, the effect of dispersing the stress on the bone tissue around the implant (artificial root) body is a particularly important factor. It can be compared to the "rigid structure" and "flexible structure" of architectural engineering.

[0098] The stress distribution on bone made of Collagen has an important implication on the consequences of producing a piezocurrent effect, which promotes the healing of bone trauma.

Other implants of today (artificial roots)
The body is contrary to the "top-of-the-line theory", and does not apply the mechanical significance of the "flexible structure" and the Piezo current effect to the "rigid structure".

Other implants (artificial dental roots) that do not know the “rigorous basic theory” in “rigid structure” are, without exception, cortical bones existing in the jaw bone surface layer with a thickness of 1 to 2 [mm] by the single method. We are seeking to maintain and fix the dense bone in the early stage of planting, and we are seeking the stress burden. As a result, bone resorption occurs around the neck of the implant (artificial root) without exception, and inflammation of the soft tissue occurs in that area, which is one of the causes of trouble and failure.

On the other hand, both the spiral implant and the sinkrest implant have morphological features based on the “top-of-the-line basic theory”, and the neck is φ2.0 [mm]. Hole diameter is 2.4
[Mm] and the tap diameter is 4.0 [mm]
From the early stage of planting, there is a peculiar morphological feature that requires no stress and no stress burden on the dense bone, but only the cancellous bone of the bone marrow.

[0102] As a result, since it is possible to perform single planting and immediate temporary crown restoration, there is no need to cut and cover both adjacent teeth, which is common general knowledge of an implant (artificial dental root), and connect and fix it with it. In addition, as a result of avoiding the sacrifice of both adjacent teeth, safe, quick and inexpensive treatment became possible.

The features are: a. Large thread; b. A hollow structure, c. Large pitch, d. Opening the window to increase the elasticity of the crest, thereby e. The crystal grains of the titanium material are treated in consideration of the elastic modulus. That is, the size of the crystal grains is adjusted so that the elastic modulus of titanium approaches that of cancellous bone.

For the above reasons, this implant (artificial dental root) is a one-time method, but provides epoch-making clinical results, and has been given "origami" many times by professional societies in the past.

As in the present invention, the effect of dispersing stress can be further improved by 50% or more by setting the angle of the thread effective for dispersing the stress (approximately 60 ° to 70 °). This is a breakthrough in the implantation of artificial roots. Many conventional dental implants keep their rest without any load for 3 to 6 months after planting, and they can spend their time in the initial healing period indefinitely. Improving the initial stress-dispersing effect is an essential condition for expanding the range of indications and achieving safe and reliable healing.

As described above, if the shaft 6 of the screw portion 2 is hollow, the effect of dispersing stress is enhanced, but problems occur in strength and durability.

At this point, the outer diameter of the thread is φ4.0 [mm].
In the case where the diameter of the valley (shaft diameter) is 2.4 [mm] and the hole diameter of the center hole 7 is 1.6 [mm], the strength and durability are excellent while maintaining the stress dispersion effect. An artificial tooth root could be provided.

The hole diameter was changed from 1.6 [mm] in the past to 1.6 [mm] and 0.3 [m].
m] was merely changed to 0.4 [mm], whereby the mechanical strength against bending stress could be enhanced by up to 50%. In this embodiment, the height H of the thread 10 is 0.8 [mm], the width a of the thread crest is 0.2 [mm],
The width b of the valley is set to 0.5 [mm].

The height H of the thread 10 is important in terms of securing a contact area for dispersing stress. If the height H is too low, the dispersing effect is reduced. If the height H is too high, the outer diameter becomes large, and the artificial root itself becomes thick. In addition, it is unsuitable because excessive torque is required for cutting the tap, and when planting in a thin jawbone, there is a disadvantage that the indication is limited, so that 0.8 to 2.3 [m
m] is preferable, and the width b of the valley defines the thickness of the portion receiving the load. Therefore, if the width b is too small, the strength becomes weak, and if the width b is too large, the pitch becomes large and the surface area decreases. Therefore, about 0.4 to 0.7 [mm] is preferable.

The thread crest a is a portion that cuts into the bone, and the smaller the width a, the smaller the sharpness and the sharper the stress concentration becomes. Therefore, the thread crest a is preferably about 0.15 to 0.4 [mm].

FIG. 13 shows a case where 0 °, 45 °
3 shows the results of bending tests on the artificial roots of the conventional example and the present example when loads are applied from three directions of 90 ° and 90 °.
As is clear from FIG. 13, it can be seen that the strength against the load from the direction 90 ° with respect to the window direction is 50% higher than that of the conventional example.

FIG. 14 shows the results of the compression test. The results show that the artificial tooth root of the present invention has a higher mechanical strength than the conventional example against this compressive load.

[0113] The utility model registration No. 1
The artificial tooth root commercialized in No. 962419 standardized a certain relationship between the head (head) and the spiral connection part. As a result, the structure of the spiral connection part can be confirmed by looking at the direction of the head (head). However, if the window of the spiral is always positioned in the direction of the bone marrow when implanted in thin bone, there is no danger that connective tissue will enter the hollow part of the spiral and hinder the regeneration of bone tissue. Since it has been found that regeneration of bone tissue occurs, conventionally, an artificial dental root having a diameter of 4 [mm] has been applied to a portion having a bone width of 6 [mm] or more in principle. mm], it was confirmed that it could sufficiently cope with such a thin part, and it was possible to significantly expand the indications.

Here, a method and concept of implanting an artificial tooth root having a diameter of 4.0 [mm] in the bone width of 3.0 [mm] will be described with reference to FIG. In the example shown, the width is 3 mm
4 [mm] diameter threaded part is applied to the bone. That is, a diameter of 4.0 [mm] and a bone width of 3.0 [m]
m], the hole diameter d of the central hole 7 is 1.6 [mm] and the wall thickness t is 0.4 [mm]. In this case, the window 8,
It is important that 8 goes into the bone.

The right half of the figure is a cutaway view of the alveolar bone 11 having a width of 3.0 [mm]. The bone marrow tissue of the cancellous bone 13 in which the surface layer is about 1 [mm] is the compact bone 12 and the inside is soft. is there. The left half in the figure is a sectional view of the spiral, and it is important that the two-walled portion connected in the axial direction is located outside the dense bone 12. That is, if the window communicates with the outside, soft tissue enters and hinders bone formation.

First, as a procedure for implanting an artificial tooth root, a guide hole was drilled at the center with a thin drill having a diameter of 1.2 [mm], and this was gradually drilled to a diameter of 1.5 [mm], 1.8.
[Mm] and 2.4 [mm] drill to enlarge thickly, and then tap with a diameter of 3.0 [mm], the same as the bone width, and a tap of 4.0 [mm] thicker than the bone width. It is relatively easy to hold the center line by supporting the hard dense bone on the surface layer, and it is possible to form a 4.0 [mm] tap hole in a 3.0 [mm] bone width portion. Since the D-cut flat part 41 of the head 4 of the artificial tooth root 1 and the shaft body 6 serving as the support of the root part 3 are on the same axial plane, the directionality of the window can be clearly determined from the outside. The plant can be safely planted while taking into account the direction that can be used effectively mechanically.

The material of the artificial root is not limited to titanium, and various materials having predetermined strength, biocompatibility and the like can be used.

The shape of the screw thread is not limited to a triangular screw as shown, and various shapes such as a trapezoidal shape and a corrugated shape can be selected.

The screw portion 2 is a double thread in this embodiment.
The pitch is reduced while the lead is small. However, the number of threads of the screw portion 2 is not limited to two, but may be one or three or more.

FIG. 16 shows a single-thread type artificial tooth root.

The components shown in FIGS. 16 (a) to 16 (c) are exactly the same as those of the above-described two-thread type except that the screw portion 201 is a single thread, and the same reference numerals are used for the same components. And its explanation is omitted.

FIGS. 16 (d) to 16 (f) show a solid sinkrest type in which the head 4 and the neck 9 are exactly the same. The external force is supported only by the screw portion 202 buried in the soft cancellous bone without interfering with the dense bone, and the same components are denoted by the same reference numerals. The shape of the sink portion type screw portion 202 is a tapered shape that gradually tapers toward the lower end, and the threads 210 are formed in a spiral strip at a predetermined pitch. The diameter of the thread 210 is gradually reduced so as to be tapered.

In the case of this syncrest type, it is preferable to set the thread angle β to about 90 to 120 degrees.

In consideration of the effect of mechanical dispersion, the lead angle of the one-wire to one-wire is reduced by half, so that the slip on the thread side corresponding to the “top type” is reduced. It is about 20% better than Article 2.

Conventionally, bones for artificial dental roots have been formed by tapping the bones by hand. However, this operation requires great care and force, and it is difficult to prevent the fracture of the bone grooves due to camera shake. , Needed time and skilled labor. In the case of the single-row type, since it is necessary to form a tap by rotating twice as much as the double-row type, the double-row type which requires less labor is generally used.

However, a motor having a high torque has been developed due to recent technological innovation, and the present inventors have already experienced that a tap can be formed electrically. As a result, no troublesome tap formation by hand is required, and a sharp bone groove with no camera shake can be formed in a short time of about 1/10. It turned out that the need to tap was not a problem for motors.

[0127] Further, the sharpness of the tap is improved, and the tap can be easily formed even on hard bone, and an implant (artificial root) can be formed.
In the case where the taps come close to each other and the taps collide with each other, there is a limit in the two-row type in order to perform a smooth tap operation.

That is, conventionally, even if the bone has a sufficient depth, the upper two-thirds are soft, and the lower one-third are markedly hard. Drilling was possible, but tapping was not possible at all.

The reason is that if an attempt is made to cut a tap on a hard part, the tap part of the upper soft part is crushed and destroyed.

In the conventional double thread, the notch groove 2 of the tap is used.
As shown in FIGS. 17E to 17F, the structure of the tap 2
The three ridges 22 of the three-ridge structure that are parallel to the long axis 21 of the zero and that are the cutting edges of the tap 20 are arranged in three rows in the long axis direction. As a result of the blades 22a of the three rows of ridges 22 simultaneously synchronizing and biting into the surroundings, inside the jaw bone in which the hardness of the bone around the tap 20 varies depending on the direction, in the hard direction one of three rows at a time. In order for one row to bite, an excessively large torque is required temporarily. In addition, it is extremely difficult to form a smooth tap due to a reaction due to a change in axiality in a region where there is a difference in hardness between soft and soft bones.

In addition, since the jawbone is narrow and there is not enough space for planting an artificial tooth root, it is necessary that the artificial tooth roots come close to each other and sometimes come in contact with each other. In screw tap 20, blade 2 of tap 20
Since 2a is arranged on the same axis surface, there is a disadvantage that smooth bite cutting cannot be performed for the same reason.

In the case of the double thread, the notch groove 23 of the tap 20 is used.
Giving the groove a receding lead angle causes the tip of the cutting blade 22a to be too sharp, so that the blade is liable to be damaged and practicality cannot be expected.

As a solution to this problem, it has been a common sense in the past to cut the tap by hand. However, even with a single-thread screw, a sharp tap without hand shake can be achieved with an electric motor in a time of 1/10 or less. Since it was found to be cut, it was found that the use of a single thread was more appropriate.

FIG. 17 shows that the artificial root is formed with a single thread.
As shown in (a) to (c), it is possible to provide the tap 30 with a groove 33 having a larger retreat lead angle, and as a result, the peak 32 serving as the blade 32a of the tap 30 is different from the conventional one. As a result of the spiral arrangement instead of the structure arranged in parallel with the long axis 31, the cutting edge of the tap 30 comes into contact with the cutting surface continuously at different points in time. It was found that the tap could be cut with a small torque. Tap 30 from 2 to 1
Is half , and even if the same retraction lead angle is applied to the tap 30, the tip of the blade is twice as thick and durable as compared to the case where the retraction lead angle is applied to the double thread.

As a result, even when the tap 30 comes into contact with the previously implanted artificial tooth root, no run-out occurs and a smooth tap formation can be performed, as shown in FIG. Dense planting becomes possible. In the figure, A is a soft tissue surface, and B is a bone tissue surface.

This is similar to the fact that a two-cylinder engine is easy to knock, but a sixteen-cylinder engine can smoothly rotate without knocking.

As a result, the torque of the electric motor is reduced to １ ／ of the conventional torque, which directly affects the structure of the hand piece that transmits the torque, and is directly related to cost reduction and improvement in durability. It is also directly linked to the safety and ease of operation.

As a result, the operation of the artificial root can be performed by the motor incorporated in the conventional dental unit.
That is, an expensive motor costing 400,000 to 600,000 yen, and sometimes 1.5 million yen is no longer necessary.

[0139] The present applicant has previously noted that incision, peeling and suturing of the gingival periosteum specific to implant (artificial root) surgery are harmful.
It proved to be useless and unnecessary, and furthermore, the water injection cooling operation was expensive, and it was difficult and painful for water injection to both the patient and the operator. The operator and the patient are obliged to maintain a certain posture, restricting free operation, and impeding the surgical field with irrigation, making it difficult to see the local area clearly and the depth of the drill Is extremely difficult to confirm, and there is a disadvantage that the risk of damaging the inferior alveolar artery and nerves is likely to be increased.

[0140] Also, since saline is applied to the mucous membrane of the throat near the patient's soft palate and it is dried by suction, the patient is salty, painful, coughs, and breaks the drill due to its unexpected upset. There is a danger of saliva contamination of the folds and taps.

These dangers and difficulties have been resolved as a result of the necessity of the injection cooling operation. In addition, although an assistant is required depending on the part, it is not necessary in many cases, and the operator (self-prosthesis) can perform an implant (artificial dental root) alone.

Since the osmotic pressure of the physiological saline is not equal to the osmotic pressure of the tissue, the cells on the tissue surface are damaged by the water injection cooling operation with the physiological saline and lose the regenerative healing ability. Research reports have stated that there is no benefit other than to cause pain. Also, since all water injection and cooling systems today do not have a mechanism to replace the water delivery tube with fresh, sterile tubes every time, in occasional clinical settings, the inside of the tubes becomes contaminated and becomes a source of infection. I have. As an alternative, a method using a high-torque, low-speed motor has been proposed.

The rise in medical costs is a major problem that cannot be ignored by both patients and operators.

Reducing the price of an implant (artificial root) tool is an important condition in promoting the spread and implementation of implants (artificial roots).

By adopting the single-row type as shown in FIG. 16, the form becomes closer to the "top-of-the-basis theory", and the lead angle of the screw is reduced by half, so that the sliding stress is reduced.

FIG. 18 shows a tool set.

In the case of electric power, the drill 60
If the tap can be used, tap 6 of the same length
1 can be used and the implant holder (artificial root) 63 can be held at the same length with the handpiece 64 of the motor drive. Can be completed.

FIG. 19 shows the shape of the cutting edge of the tap.

As shown in FIG. 19, the groove 33 'of the conventional bone tap has a conventional V-shape, so that the bone cutting piece is clogged, the cutting resistance is increased and the biting stops, and the operation is stopped. Since it took time and time to remove the clogging of the cutting pieces, the V-shape was improved to a U-shape, and the straight groove 33 'was replaced with the spiral groove 33'.
As a result, clogging of the groove was eliminated, and continuous tap cutting became possible. As a result, the operation was not interrupted, and the speed was improved by a factor of 10 or more. At the same time, contamination of the tap could be prevented.

It has been found that with a single thread it is possible to form the start of the tooth edge of the tap 30 at the same time as a groove with a lead angle that recedes to a moderately sharp and moderately strong angle. . As a result, it has become possible to effectively cut even hard bones in which teeth have not been formed in the past by changing the shape of the cutting edge.

As shown in FIG. 19E, the tap groove 33 is formed.
The straight one cuts the cutting surface at 90 degrees while the spiral one cuts at an acute angle when the edge of the tip is viewed from the side as shown in FIG. Sharpen the surface. In FIG. 5F, the angle γ is a rake angle for improving the bite, and the angle δ is a clearance angle for reducing the cutting resistance to prevent heat generation.

As a result, a path has been opened that allows the use of significantly harder bone tissue which could not be used effectively in the past. As a result, the indications can be further expanded.

[0153]

The present invention has the above configuration and operation, and has the following effects. [Claim 1] The screw portion has a hollow flexible structure and the screw angle is optimized.
By setting the angle in the range of 60 to 70 ° , the stress can be distributed most efficiently and evenly to the cancellous bone, and the burden on the jaw bone can be reduced. Therefore, the artificial bone can be applied to many parts and patients which have been conventionally excluded from the indications of the artificial dental root because the amount of the remaining bone is small, and the bone quality is soft due to osteoporosis of the elderly and the like, and the bone is soft. Further, the failure immediately after planting can be largely solved by a large increase in the initial stress dispersion effect. On the other hand, since the load applied to the cancellous bone is appropriately dispersed, occlusal pressure can be applied immediately after implantation by performing provisional crown restoration, and the conventionally required rest period after implantation Becomes unnecessary. Also, when the neck is in contact with the cortical bone, when external force acts, stress concentration occurs at the contact part, which affects the regeneration and treatment of surrounding tissues,
In the present invention, since the neck is made thin and does not come into contact with cortical bone,
Adverse effects on surrounding tissues can be minimized.
Furthermore, since the load is applied to the cancellous bone immediately after planting,
Appropriate stress acts on cancellous bone, and a piezocurrent effect is exerted to promote regeneration of bone tissue. [Claim 2] When the shaft of the screw portion has a hollow structure, the stress dispersion effect is enhanced, but the strength and durability are reduced. In this regard, when the valley diameter (shaft diameter) is 2.4 [mm] and the hole diameter of the central hole is 1.6 [mm ] , the strength and durability are maintained while maintaining the stress dispersion effect. An excellent artificial tooth root was realized. [Claim 3] If the thickness of the neck is in the range of 2 [mm 2 ] , the epithelium near the adhesive interface with the epithelium falls off spontaneously with metabolism.
Permanent health can be maintained. On the other hand, if the thickness is too small, the strength becomes weak. Therefore, the thickness is set to 2 [mm 2 ] which can maintain the strength and maintain the function of the self-cleaning action. In addition, the diameter 2.4 [mm] of the shaft body corresponds to the hole diameter formed in the dense bone of the cortex, and if set to such a hole diameter, there is no possibility that the neck portion comes into contact with the cortical bone. Therefore, it is possible to demand the stress burden and maintenance only for the cancellous bone. [Claim 4] The height of the thread is important in terms of securing a contact area for stress dispersion. If it is too low, the dispersion effect is reduced, and if it is too high, the outer diameter becomes large and the artificial tooth root itself becomes thick. 0.8 to 2.3 [mm 2 ] is preferable because it is inappropriate because the cutting of the tap requires an excessive torque and the indication may be limited when implanted in a thin jaw bone. .

[Claim 5] If a single thread is used, the lead angle is smaller than that of the double thread, slip on the thread side surface is reduced, and the stress dispersion effect can be enhanced. As a result, the tap can have a sharp cutting edge because the lead angle can be reduced, and the rake angle and clearance angle can be appropriately given to reduce the cutting resistance, so that the tapping is easy And the resistance required for tap formation was reduced. In addition, from the viewpoint of dispersing the load, the larger the surface area of the thread is, the more effective it is.
It was preferable to set it to 5 [mm ] . [Claim 6] The thread crest is a portion that cuts into the bone, and in order to counter lateral stress applied to the artificial tooth root, since the width is small and the sharpness increases, the stress concentration increases. ] Is preferred. [Claim 7] The width of the valley of the threaded portion defines the thickness of the portion that receives the load. If the width is too small, the strength becomes weak. If the width is too large, the pitch becomes large and the surface area decreases. 4 ~
It is preferable to set it to 0.7 [mm ] . [Claim 8] By making the head shape a conical shape with a D-cut cross section, it is possible to determine the directionality of the front and back and front and back. In particular, since the flat portion is also tapered, when the artificial tooth is viewed from above, the flat portion is not undercut.

[Brief description of the drawings]

1A and 1B show an artificial tooth root according to an embodiment of the present invention. FIG. 1A is a front view, FIG. 1B is a plan view, and FIG.
(c) is a partially omitted cutaway perspective view, and (d) is an enlarged view of a thread portion.

FIG. 2 is a view showing a head form of an artificial dental root having a parallel two-plane cut cylindrical shape, a parallel two-plane cut cone shape, and a one-plane D-cut cone shape.

FIG. 3 is a diagram showing a coping and a dowel post.

FIG. 4 is an explanatory diagram for comparing a head (head) of a parallel two-plane cut with a head (head) of a one-plane taper cut.

FIG. 5 is a diagram showing a hand key.

FIG. 6 is a diagram showing a configuration example in which a groove for driver engagement is formed in an artificial tooth root head.

FIG. 7 is a diagram showing a stress state near a thread portion when the thread angle is 56 °.

FIG. 8 is a diagram illustrating a stress state near a thread portion when the thread angle is 60 °.

FIG. 9 is a diagram illustrating a stress state near a thread portion when the thread angle is 64 °.

FIG. 10 is a diagram illustrating a stress state near a thread portion when the thread angle is 70 °.

FIG. 11 is a diagram illustrating a stress state near a thread portion when the thread angle is 75 °;

FIG. 12 is a diagram illustrating a stress state near a thread portion when a thread angle is 82 °.

FIG. 13 (a) is a graph showing bending test results of the present invention and a conventional artificial tooth root, and FIG. 13 (b) is a diagram showing a load acting direction in the bending test.

FIG. 14 is a graph showing compression test results of the present invention and a conventional artificial tooth root.

FIG. 15 is an explanatory view of a case where an artificial root having a diameter larger than the bone width according to the present invention is implanted.

FIGS. 16 (a) to (f) are diagrams showing a single-row type artificial tooth root.

FIG. 17 is a diagram illustrating a configuration example of a tap.

FIG. 18 is a view showing a tool set used for implanting an artificial tooth root according to the present invention.

FIG. 19 is a diagram showing the shape of a blade edge of a tap.

FIG. 20 is a view showing a state in which artificial roots are densely erected.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Artificial root (implant) 2 Screw part 3 Root part 4 Head part (head) 5 Neck part (neck) 6 Shaft 7 Central hole 8 Window part 10 Thread 11 Bone α Thread angle

Claims (8)

(57) [Claims] 1. An artificial tooth root having a screw portion to be implanted in a jaw bone, wherein the screw portion is formed around a hollow shaft provided with a central hole, and the shaft body is provided with a window communicating with the central hole. The thickness of the neck portion from the screw portion to the head is set to a size that does not make contact with cortical bone and compact bone in the early stage of implantation,
An artificial tooth root, wherein a load is supported only by a screw portion embedded in cancellous bone of bone marrow, and the angle of the thread of the screw portion is set in a range of 60 ° to 70 ° . 2. The artificial tooth root according to claim 1, wherein the diameter of the shaft body is set to 2.4 [mm] and the diameter of the central hole is set to 1.6 [mm ] . 3. The artificial tooth root according to claim 1, wherein the thickness of the neck is set to 2 [mm ] . 4. The height of the thread is 0.8 to 2.3 [mm ].
Artificial tooth root according to claim 1, 2 or 3, characterized in that set. 5. The thread portion is a single thread and the pitch is 1.5.
4. The method according to claim 1, wherein the distance is set to [mm 2 ].
Or the artificial dental root according to 4. 6. The flat thread crest has a width of 0.15-0.
4 [mm ] .
6. The artificial dental root according to 3, 4, or 5. 7. The width of the valley of the threaded portion is 0.4 to 0.7 [m
m ] . The artificial dental root according to any one of claims 1 to 6, wherein 8. A conical shape having a flat surface with a cross section D-cut so that the head shape becomes thinner toward the tip, and a flat portion is also provided with a taper so as to enable discrimination of direction and rotational implantation. 8. The method according to claim 1, wherein
The artificial dental root according to any one of the above items.