JPH0542168A - Cap for osteocavity - Google Patents

Abstract

PURPOSE:To surely seal the osteocavity and to assure the space sufficient for the growth of the original tissue of the bone in the osteocavity as well as to prevent the infiltration and growth of the non-calcification tissue therein by forming the cap for sealing the osteocavity of calcium phosphate compds. and providing at least the fine pores in which the bodily fluid flows. CONSTITUTION:Powders of the calcium phosphate compds., such as hydroxyapatite, calcium triphosphate and calcium tetraphosphate, alone or the calcium phosphate compds. and high-polymer combustible fibers are sufficiently mixed at the ratio at which the porosity of the open cellular pores of about <=1mum attains about 20 to 80vol% of the entire part of the cap for the osteocavity after calcination. The mixture is then molded to a desired shape. The molding is calcined at about >=700 deg.C. The bioaffinity is improved in this way and the advance of the epithelium, etc., into the osteocavity and the infection with bacteria are prevented. The environment where the neobone is rapidly grown in the osteocavity is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cover for a cavities for sealing cavities in the medical fields such as orthopedics, plastic surgery and dentistry.

[0002]

2. Description of the Related Art Conventionally, in medical care such as orthopedic surgery, plastic surgery and dentistry, tumors and inflammations in bones near the bone surface, fractures,
The ostium of the bone cavity caused by treatment such as bone atrophy or tooth extraction is often left as it is, and this causes aesthetic and functional problems such as deformed and atrophied bone outline and reduced bone strength. ing. Therefore, recently, a treatment of filling the bone cavity with apatite granules to maintain the outer shape of the bone has been performed. However, in the procedure, in order to prevent leakage of the filled apatite granules, it is necessary to suture the periosteum and epithelium of the fossa cavities sufficiently tightly, but such a method is extremely difficult and cannot be sutured. The actual situation is that infection occurs and the filled granules leak out from the part that was opened. Further, in order to prevent the leakage of the granules, it has been proposed to cover the upper part of the bone cavity with an absorbable hemostatic agent, but the absorbable hemostatic agent used for the treatment has low strength after absorption of the hemostatic agent, and There is a problem that the leakage of the granules cannot be completely prevented because it is absorbed in 1 to 2 weeks.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to effectively seal the fossa cavities, to secure a sufficient space for the growth of osteogenic tissues in the cavities, and to prevent non-calcium such as muscle, epithelium and connective tissue. Prevents the invasion and growth of chemical tissues and promotes the formation of new bone,
In addition, when apatite granules etc. are filled in the bone cavity,
It is an object of the present invention to provide a cover for a cavities that can completely prevent leakage of the granules and can promptly promote adhesion of the epithelium of cavities.

[0004]

According to the present invention, there is provided a lid for closing a bone cavity, the lid being made of a calcium phosphate compound and having at least pores through which body fluids flow. A clavicle lid is provided.

The present invention will be described in more detail below.

[0006] As the calcium phosphate compound constituting the cover for the cavities of the present invention, hydroxyapatite, tricalcium phosphate, tetracalcium phosphate and the like, which are particularly excellent in biocompatibility, are preferable, and particularly, in terms of strength, the firing temperature is 500.
A calcium phosphate compound calcined at a temperature of not less than 0 ° C, particularly 700 ° C or more can be preferably mentioned. If the firing temperature is lower than 500 ° C., the strength is lowered, which is not preferable.

[0007] The cover for the cavities of the present invention is required to have at least pores through which body fluid passes in order to promptly form new bone in the blocked cavities. The average diameter of the pores is preferably 5 μm or less, and particularly preferably 1 μm or less, which is a continuous hole. When the diameter of the pores exceeds 5 μm, muscles, epithelium, etc. invade and grow in the fossa cavities in addition to body fluids, bone formation is inhibited, and infection with bacteria etc. occurs, which is not preferable.

The occupancy ratio of the pores, that is, the porosity is
It is preferably in the range of 20 to 80% by volume with respect to the entire cover of the cavities. If the amount is less than 20% by volume, the bodily fluid component cannot sufficiently pass through the lid to invade the cavities, and the epithelial cleavage is likely to occur.
If it exceeds, the strength will be reduced, which is not preferable.

The shape of the cover for the cavities of the present invention is not particularly limited as long as it can completely close the cavities. For example, a disc shape or an ellipse larger than the shape of the upper end of the cavities. It is preferable that the shape is a shape. In addition, since the outer shape of the bone is generally rounded, it is preferable to give the lid a curvature along the outer shape of the bone by forming a convex lens shape or a trough shape or the like in order to bring it into close contact with the bone surface. Furthermore, the thickness of the lid is preferably in the range of 0.3 to 2 mm, and it is particularly preferable that the thickness of the central portion is thicker than the thickness of the surroundings from the viewpoint of strength.

In order to manufacture the lid for an osseous cavity of the present invention, the calcium phosphate compound powder alone or the calcium phosphate compound powder and the polymer combustible fiber are sufficiently mixed at a ratio to give a predetermined porosity after firing, and thus the desired shape is obtained. After molding, it can be easily obtained by firing at a temperature of preferably 500 ° C. or higher.

In order to use the cover for the cavities of the present invention, after filling the cavities with a filler such as a known apatite granule, the cavities are placed on the cavities and the periosteum, muscle, Then, it can be used by a method of sewing the epithelial part such as the epithelium, or when the bone cavity itself is small, fixing it on the bone cavity without filling the filler and sewing the epithelium part. At this time, the epithelium does not necessarily need to be airtightly sewn.

Further, in the cover for the cavities of the present invention, in order to accelerate the rate of bone formation, B is provided at the portion where the cavities are in contact with the cavities.
MP (Bone Morphogenetic Protein) or bone cells can also be attached and used.

[0013]

INDUSTRIAL APPLICABILITY The lid for an orbital sinus of the present invention is made of a calcium phosphate compound and has pores through which at least a body fluid flows, so that it has excellent biocompatibility and invades an epithelium or the like into an orbital sinus and bacteria. Therefore, it is extremely useful as a material that provides an environment for promptly producing new bone in the cavities.

[0014]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[0015]

Example 1 Apatite powder (particle size: 88 μm or less) alone or prepared by spraying urethane from apatite powder with a polymer combustible fiber having a diameter shown in Table 1 After pressing the mixture, the mixture was fired at 700 ° C., and the cavities lids 1 to 4 shown in Table 1 were obtained.
(Dimension 10 mmφ × 1.5 mmL) was produced. The average pore diameter and the porosity are shown in Table 1.

[0016]

[Table 1]

Next, the posterior teeth of monkeys are extracted to form a cavities, and the cavities are densely filled with apatite granules (trade name "Bone Tight" manufactured by Mitsubishi Materials Corp.), and then the cavities are closed. After being placed and fixed on the upper part of the cavities, the epithelial part was sutured. When the progress was observed by X-ray,
No leakage of apatite granules was observed. After 12 weeks, the animals were sacrificed, a hard tissue sample was prepared, and the formation state of new bone in the cavities was observed. As a result, when the cavities lid 1 and the cavities lid 2 shown in Table 1 were used, The formation of new bone in the cavities was good, and then the cavities lid 3 was good. Further, when the lid 4 for the cavities was used, some fibrous connective tissue had entered the cavities, and the formation of new bone was slightly small.

[0018]

[Comparative Example 1] Apatite granules were filled into the fossa cavities in the same manner as in Example 1 except that the epithelium was sutured without using the lid for the cavities. When the granules leaked immediately after the filling, 3 after filling. As a result of observation by X-ray at the time of week, apatite granules filled up to the height of the upper part of the bone cavity had leaked out to a height of about ½ of that at the time of filling. In addition, in the observation after 12 weeks, there were many fibrous connective tissues in the cavities and only formation of new bone was observed in a part of the inner circumference of the cavities.

Claims (1)

[Claims] 1. A lid for closing a bone cavity, wherein the lid is made of a calcium phosphate compound and has at least pores through which body fluid flows.