JPH05309103A - Artificial tooth-root incorporation type web tray for lower jaw repair - Google Patents

Abstract

PURPOSE:To carry out the proper recovery of the figure and the function of a lost teeth and jaw bone organization by installing an artificial tooth-root fixing device integrally on a web tray which is for cancellous bone comminuted bone marrow transplantation and consists of a resolvable and absorbable by a living body material. CONSTITUTION:A web tray 1 is formed of a plain weave fabric made by weaving a monofilament thread of a molten spun poly L-latic acid in a coarse grid form, it is hydrolyzed by a latic acid in vivo, and provided to be metabolized up to the water and the carbon dioxide finally (in about two years). When this web tray 1 is composed, an artificial tooth-root fixing device 2 is fixed by inserting a woven thread in a hole provided to the plate 3 of the artificial tooth-root fixing device 2, and fixed to a lower tooth-root 5 made of a pure titanium or the like with a screw 4 screwed to the fixing device 2. An upper gum 6 is screwed up to the lower tooth-root 5 with a screw formed at the lower side of the upper side tooth-root 6. The web tray 1 composed in such way is prepared to fit to the defected part of the teeth and the jaw bone organization between mother bones 7 and 8, and it is fixed to the mother bones 7 and 8 with metallic wires 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the provision of an artificial dental root / jaw bone reconstruction material for restoring the morphology / function of lost tooth / jaw bone tissue.

[0002]

2. Description of the Related Art Jaw bone defects are frequently caused by various causes such as tumors, cysts, inflammation and trauma, and there is a demand for establishment of a more reliable jaw bone reconstruction method. However, the jawbone is close to the source of infection in the oral cavity, and the amount of covering tissue is poor.
When radiation or chemotherapy is applied to a malignant tumor, the condition as a transplant bed is poor and the success rate is low. In recent years, bone marrow cancellous bone graft transplantation, which is superior in infection resistance and engraftment rate and has a high bone formation ability, has been attracting attention as compared with conventional block bone transplantation.

This method uses a transplantation tray for maintaining the shape of the defect and fills the bone marrow cancellous bone fragments into the bone to regenerate the bone. Since there are many postoperative complications such as infection, recently, Leake, Schwarts, Albert et al. Have devised a mesh tray in which Dacron fibers are coated with a more flexible and highly shaped polyether polyurethane. According to this, the operation during the operation becomes easy,
There are few postoperative complications and excellent reproducibility of the jaw bone morphology is obtained.

[0004]

However, even with the method described above, since the material is non-absorbent,
Secondary surgery for removal is often necessary because it remains in the body for a long period of time and a semi-permanent foreign body reaction continues. In addition, it is difficult to implant an alveolar ridge for artificial teeth or an artificial root, and with some exceptions, satisfactory gall bile function has not been restored. The present invention provides a jawbone reconstruction tool that avoids the semi-permanent foreign body reaction due to the residue described above and is also excellent in the recovery of masticatory function.

[0005]

DISCLOSURE OF THE INVENTION The present invention relates to a mandibular bone reconstruction tray in which a net tray that is decomposed and absorbed in a living body after a predetermined period of time has a structure for a mandibular bone reconstruction tray for recovering the masticatory function. The present invention relates to the provision of an artificial tooth root-incorporated mesh tray characterized by being integrally assembled.

[0006]

[Function] The biodegradable and absorbent mesh tray constituting the present invention is
Poly-L-lactic acid, poly-D-lactic acid, polyglycolic acid,
A biodegradable and absorbable polymer such as polycaprolactone, or a copolymer thereof, or a stereocomplex of L-lactic acid and D-lactic acid, etc. is used as a material to make it non-stretchable and porous. Woven or molded into a punching sheet.

On the other hand, the artificial root fixing device to be assembled to this is composed of a screw and a plate for screwing and fixing the screw, and the plate is bonded by an adhesive or by heat sealing or the like, and further by a thread. Pass it through and integrate it with the mesh tray. The artificial root fixing device is provided in an appropriate number in the approximate center of the mesh tray according to the distance between the teeth of the patient. In application, after cutting the mesh tray to the required width, the tray is kept at its plastic temperature. U in hot water at ~ 70 ℃
It is shaped into an arbitrary shape such as a letter shape or a bowl shape, and is fixed with the lower root attached to the above-mentioned screw. At the time of fixation, cancellous bone fragment bone marrow is transplanted into such a mesh tray,
Measures bone regeneration.

As described above, after a certain period of time, the bone in the defective portion is regenerated, and the mesh tray itself is decomposed and absorbed in the living body and disappears. On the other hand, the screw screwed to the lower tooth root is removed, and instead the upper tooth root is screwed to this to provide a root for attaching a denture.

Since the material of the present invention is biodegradable and absorbable, reoperation for removal is not required. Further, it is also possible to attach a tooth root, which makes it possible to attach a denture. Further, when this is applied, its shape can be easily adjusted in warm water, and it is not necessary to prepare a multi-sized tray according to the patient as in the conventional case. In addition, if the mesh tray itself is porous, it is easy for the external tissue to penetrate into the tray. Therefore, a plain weave fabric made of thick monofilament yarn is used in consideration of morphological stabilization, or punching with holes. Used for this as a sheet.

[0010]

1 is a perspective view showing the structure of the present invention.
The mesh tray 1 is a plain woven fabric in which melt-spun poly-L-lactic acid monofilament yarn (diameter 1 mm, average molecular weight 50,000) is roughly woven in a lattice pattern, and is hydrolyzed to lactic acid in the living body and finally. It is metabolized to water and carbon dioxide. The decomposition / absorption rate maintains about 75% or more of the initial strength up to 3 months after implantation in the living body, and thereafter it is gradually decomposed and almost disappears 2 years after implantation.

When the mesh tray is woven, the artificial tooth root fixing device 2 has a structure in which a woven thread is fixed through a hole provided in the plate portion 3 and a screw 4 is screwed into the woven thread. The plate 3 has a diameter of 5 mm and a thickness of 2 mm formed of poly-L-lactic acid, and the screw 4 has a diameter of 1.5 formed of polyethylene.
An example is one having a size of mm and a length of 5 mm. In FIG. 1, this is placed about 10 mm in the center of the three-mesh tray 1.
An example of attachment at intervals is shown.

In the artificial tooth root fixing device 2, usually, a lower tooth root 5 as shown in FIG. 2 is first screwed and fixed by the screw 4. The lower tooth root 5 is pure titanium,
Alternatively, a titanium alloy (AL6%, V4%, Ti90%) is flatly formed and has a flattened upper end with a screw receiver having the same size as the screw 4 in the center portion of the upper end, and fixed to the artificial root fixing device 2 without a gap. It is like this. Further, the surface other than the upper end, which is in contact with the bone tissue, may be coated with a bioactive substance such as hydroxyapatite (HAP). As the shape and size, a cylindrical shape having a hemispherical tip and a diameter of 4 to 5 mm and a length of 8 to 12 mm can be exemplified, but this can be selected according to the case and site. However, unlike conventional artificial tooth roots, there is no need for implanting operation,
A considerable degree of freedom is allowed in its shape.

On the other hand, the upper tooth root 6 is made of pure titanium and is composed of a mucous membrane penetrating portion for the purpose of gingival attachment and an abutment portion for the prosthesis of the crown. It is screwed to 5 and can be connected and fixed without a gap. The surface of the viscous penetrating portion is mirror-polished in consideration of the adhesiveness and cleanability of the gingival epithelium, and the length of 3 to 6 mm can be selected according to the thickness of the gingiva.

FIG. 3 shows the actual use of the invention.
First, the tray is shaped into an inverted U shape in warm water according to the size and shape of the bone defect while cutting off the excess portion at the end of the mesh tray 1 with scissors. At this time, it is important to adjust the excision range so that the artificial tooth root fixing device 2 comes to a predetermined upper position. The length of the tray needs to be set to be 2 to 3 cm longer than the bone defect so that both ends of the tray overlap with the mother bone with a width of 1 to 1.5 cm in consideration of fixation to the mother bones 7 and 8. In addition, the depth of the mesh tray is adjusted to about ⅔ of the vertical width of the osteotomy in the case of segmental resection, and in the case of marginal resection, it is adjusted so as to overlap the defect margin with a width of 5 to 6 mm. Then, a red-hot metal spatula is applied so that the ends of the mesh tray are not frayed, and the fibers of the ends are welded to each other. In addition, the unnecessary artificial tooth fixing device is similarly removed by melting and cutting the joint part with the tray with a red-hot metal spatula. Finally, heat the tray with flame or a metal trowel to make fine adjustments according to the curvature of the mother bone.

After the adjustment of the mesh tray 1 is completed as described above, the operation for fitting and fixing the tray to the bone defect portion is started. This method is different from the conventional method of applying from the lower edge of the mandible, and is characterized in that the tray can be fitted and fixed from the alveolar apex edge. At this time, in order to prevent the tray from protruding below the mucous membrane, one layer (thickness of 2 to 3 mm) of bone is removed in advance from the upper edge of the stump of the main bone in the range where the mesh tray overlaps. Once the tray is fitted in place, drill the buccolingual bone from above the tray, pass it through the metal wires 9, 10 to the upper and lower edges of the tray, and tie it around to secure the mesh tray. .. Finally, the lower root 5 is firmly screwed and fixed to the screw 4 of the artificial root fixing device 2 at a predetermined position, and the tray is filled with iliac cancellous bone marrow (PCBM) or an equal amount mixture of PCBM and HAP granules. Then, the surrounding tissue is tightly sutured to complete the surgical procedure. If the same bio-absorbable material as the mesh tray is used instead of the suture and the above-mentioned metal wire for surrounding ligation, there is an advantage that no removal is required. In addition, postoperative 3
~ 4th month, the gingiva on the artificial tooth root is opened, the polyethylene screw 3 at the upper end of the artificial tooth is removed, and the upper tooth root 6 is placed on the same portion.
Is screwed in and integrated with the lower tooth root 5. After 1 to 2 weeks, normal crown prosthesis is performed after the establishment of gingival attachment.

In the course of an experiment using the product of the present invention in an adult dog, a bone defect of 2.5 cm in length formed in the mandibular molar tooth part was partially restored by one month after the operation. Seen 3
At the end of the month, good alveolar morphology recovery and strong osteointegration of the artificial tooth root were obtained by vigorous bone formation along the mesh tray and the artificial tooth bone. At this point, the upper root was attached, and two weeks later, crown restoration was possible. Even 6 months after the operation, there was no funnel-shaped bone resorption of the artificial root-neck which was frequently observed by the conventional method.
The bone cortex was formed by the mature lamellar bone and the functional arrangement of trabecular bone was found around the artificial root. Moreover, the same findings were maintained one year after the operation. On the other hand, net tray 1
Maintained 70% of initial strength for about 3 months after surgery, but had no effect on bone formation. After that, it gradually decomposed and almost disappeared after about 2 years.

[0017]

As described above in detail, according to the present invention, since the artificial dental root device can be mounted in advance, the intraoperative operation becomes extremely easy. In addition, the jaw bone can be reliably reconstructed without inhibiting the active bone formation of PCBM. In addition, the reconstruction net tray is decomposed and absorbed in the living body, so that semi-permanent foreign body reaction, exposure, and infection can occur. Postoperative complications such as can be reduced. Further, the alveolar morphology can be recovered, and the masticatory function can be recovered early after the operation. Further, it has many features that can solve many problems at present, such as the need for complicated implanting operations of conventional artificial tooth roots.

[Brief description of drawings]

FIG. 1 is a perspective view illustrating the configuration of the present invention.

FIG. 2 is a sectional view of the present invention.

FIG. 3 is a side view illustrating a usage state of the present invention.

[Explanation of symbols]

 1 mesh tray 2 artificial tooth root fixing device 5 lower tooth root 6 upper tooth root

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masakazu Suzuki 19 Kita-Otsubo, 3-chome, Nishimachi, Ayabe City, Kyoto Prefecture (72) Inventor, Koji Nishitani, No. 1, Ishiburo, Shinmachi Ikura, Ayabe City, Kyoto Prefecture Gunze Co., Ltd. Kyoto Research Laboratory

Claims (1)

[Claims] 1. A structure for a trabecular bone marrow transplant tray, wherein an artificial root fixing device is integrally attached to a mesh tray made of a biodegradable and absorbable material, for artificial root embedded mandibular reconstruction. Net tray.