JPS6014860A - Inorganic implant material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a biomaterial made of an inorganic substance, and more particularly to an inorganic implant material that is less likely to react with foreign substances, has excellent biocompatibility, and has a high ability to generate new bone.

BACKGROUND OF THE INVENTION Cases in which a defect or void is created in a bone due to a highly comminuted fracture or resection of a bone MS, and a prosthesis is required for the location, are often encountered in the field of surgery or orthopedics. Conventionally, in such cases, a method has been adopted in which spongy autologous bone is harvested from the patient's own iliac bone and filled into the bone defect site, etc., to accelerate the recovery and healing of the bone tissue. However, since bone tissue other than the damaged area is removed, the patient suffers a great deal of pain and the surgery requires a great deal of effort. Furthermore, it is not always possible to harvest a sufficient amount of autologous bone to fill a wide range of bone defects, and it becomes necessary to use some kind of substitute to cover the shortage. Methods for filling with bone other than autologous bone include allogeneic bone grafting and xenogeneic bone grafting. Regarding allogeneic bone transplantation, the use of cryopreserved bone, demineralized bone, etc. is being studied, but it has not yet reached the stage of practical use. There are also methods such as using materials that contain the same material, but all of them have problems such as rejection reactions, and they have almost no bone formation ability, so the postoperative course is not necessarily good. Therefore, when filled into bone defects and cavities, artificial materials have excellent biocompatibility, promote pre-stone formation in the affected areas and surrounding areas, and repair and restore the structure and function of damaged bone tissue. Development is eagerly awaited. Furthermore, in order to shorten the recovery period when treating a fracture, internal placement methods are sometimes used to directly fix the fracture, and metal plates, nails, screws, etc. are used for fixation. However, even with such methods, healing often takes a long time, from six months to a year or more, and the material used for internal fixation must be surgically removed from the body after the fracture site has healed. The physical, mental, and financial burden on patients is enormous.

On the other hand, various metals and plastic materials have traditionally been used as substitute materials for the hard tissues of living organisms, but these materials tend to undergo changes such as dissolution and deterioration in the harsh environment of living organisms, and are also susceptible to toxicity and foreign body reactions. As a result, ceramic materials with good compatibility with living organisms have been attracting attention.

Recently, artificial bones, artificial joints, and artificial tooth roots made of single crystal or polycrystalline alumina Al2O3, and artificial tooth roots made of sintered bodies of tricalcium phosphate Ca3 (PO4) 2 and hydroxyapatite Ca3 (PO4) 30H have been developed. Proposed. All of these are said to have excellent biocompatibility. For example, when a sintered hydroxyapatite body is implanted into the bone of a living body, no foreign substance film is observed, and the sintered body and bone tissue are directly connected. Results have been reported that show strong binding.

However, it is not clear what kind of material properties a ceramic implant material has that will cause particularly little foreign body reaction, be excellent in biocompatibility, and produce new bone quickly.

Therefore, one object of the present invention is to provide particularly excellent biocompatibility,
Moreover, it is an object of the present invention to provide an inorganic implant material that causes very little foreign body reaction and forms bone tissue in a particularly short period of time.

Another object of the present invention is to provide an inorganic implant material that promotes masonry preparation in the filled part and can particularly quickly repair and restore the structure and function of the bone tissue defect and the surrounding area of the bone tissue fixation site. It is in.

Still another object of the present invention is to provide an inorganic implant material in which new bone is generated particularly quickly.

The above and other objects of the present invention will become more apparent from the following description.

According to the present invention, there is provided an inorganic implant material characterized in that the implant material is made of an inorganic material having a negative zeta potential.

The present invention will be explained in more detail below.

The zeta potential as used in the present invention is measured by a streaming potential method. In other words, the sample to be measured is thoroughly ground,
This is filled into a measuring cell in the form of a diaphragm, and the liquid is forced to pass through the dazzling part using an inert gas such as nitrogen as a pressure source. The value of is expressed by the following formula (Hel+mholtz-Smol
uehowski's equation).

Here, l: viscosity coefficient [poise] of the liquid, λ: specific conductivity of the liquid [Ω-'cm-'), ε: dielectric constant of the liquid with respect to air [-), Ei measurement measured potential difference [mV] , P
; Gas pressure [Yen I20] The inorganic material used in the present invention is not particularly limited as long as it has a negative zeta potential determined by the streaming potential method and is not toxic to living organisms. From the viewpoint of biocompatibility, calcium phosphate compounds or calcium phosphate-based glasses are preferred, and among them, glasses whose main components are tricalcium phosphate, tetracalcium phosphate, hydroxyapatite, fluoroapatite, and calcium phosphate are preferred. The use of a species or a mixture of two or more species is particularly preferable because it is the same as or similar to the inorganic components of biological hard tissue, and has better biocompatibility. Among these, hydroxyapatite is an inorganic component constituting the hard tissues of living organisms, and among these compounds, it can be said to be a more preferable compound.

Inorganic materials that can be used in the present invention include those synthesized by known manufacturing methods, such as bones,
Even materials obtained from naturally occurring materials such as phosphate rock can be used as long as the zeta potential is negative.

Of these inorganic materials, the above-mentioned flow! f [by position,
When the liquid passed through the inorganic material to be measured filled in the measurement cell is distilled water, the zeta potential is -005 to -20,0.
It can be said that a force in the mV range is preferable because it has a force of 1, has excellent biocompatibility, and generates new bone quickly. In particular, those having the above-mentioned zeta potential in the range of -02 to -10.0+ mV are particularly preferable because new bone is generated quickly.

The shape of the inorganic implant material of the present invention is not particularly limited as long as it has a negative zeta potential when the inorganic material constituting the implant material is made into powder. For example, powder, granules, porous bodies, flat plates, cylinders, prisms, truncated cones, truncated pyramids,
Various shapes such as fibers are possible.

In the case of powder, an inorganic material produced by a known manufacturing method may be pulverized and filled as is, or it may be filled in a slurry form with physiological saline, blood, etc. In the case of granules, the inorganic material can be sufficiently crushed and granules can be produced by a method such as bread granulation, and the granules can be filled as is in the same way as powder, or the granules can be moistened with physiological saline, blood, etc. and then filled. is also possible.

The porous body can be produced from the cancellous bone of a living body by baking the cancellous bone, or by attaching an inorganic material in the form of a slurry to an organic porous body and baking it to remove the organic component. Compared to dense implant materials made by sintering, new bone can penetrate into the porous body, allowing the implant material to integrate with living tissue more quickly, making it a filling material for bone defects and voids. This can be said to be a preferable shape.

The flat plate can be made by molding inorganic material powder and firing it, and this shape can be applied to bone fixation plates that require strength.

Cylindrical columns, prismatic columns, truncated cones, and truncated pyramids can also be made by the same manufacturing method as the flat plate, and these can be used for bone fixation nails and the like.

The inorganic implant material according to the present invention is used not only in the orthopedic field but also in the dental field, for example, those having shapes such as powder and porous granules are used for the treatment of alveolar pyorrhea and alveolar periosteal bulge. An implant material having the shape can be used as a point for a tooth root canal, etc.

[Example 1] Calcined beef bone with only inorganic components, tricalcium phosphate, hydroxyapatite and tetracalcium phosphate,
Each titanium oxide powder was measured using a streaming potential measuring device (ZP-10B).
The zeta potential was measured using distilled water and 100 times diluted physiological saline as the liquids passed through the sample to be measured, which was filled in a measuring cell using a sample mold (manufactured by Takasu Seisakusho Co., Ltd.). The results are shown in Table 1.

Table 1 Each of these powders was filled into the femur of a domestic rabbit to create an artificial defect (3 m+sφX 4 a+m L ). As a result, one month after phototherapy, new bone formation was observed in the defect area using either material. Among these, when samples obtained from hydroxyapatite and calcined beef bones were used, a large amount of new bone was generated in the defect area, and the defect area was completely repaired. In the case of tricalcium phosphate and western calcium phosphate, the amount of new bone generated in the defect area was second to that of hydroxyapatite etc., and with titanium oxide, although new bone was observed, the degree of repair of the defect area was lower than these.

[Example 2] Hydroxyapatite has a zeta potential of +02 when measured using distilled water as the liquid using the same device as in Example 1.
-〇〇1, -〇〇5, -02, -30, -10.0, -
Using 200, -30.0 mV theal powder, KotL was made into a slurry, impregnated and adhered to an organic porous body, and then fired to remove the organic porous body to produce a hydroxyapatite porous body. The porous material was filled into a bone defect (3 trunks φX 4 +nm L ) artificially created in the femur of a domestic rabbit, and the state of new bone formation and biocompatibility were observed one month later.

As a result, for biocompatibility, the zeta potential is +0.2
Good results were obtained except for +oV and -30.0 mV.

The state of new bone formation is good with a porous material using powder with a zeta potential of -005 to -20,0+iV, especially -0
Porous bodies using powder having a zeta potential of 2 to -10.0+ aV were good, and these porous bodies were almost completely filled with new bone up to the center.

[Example 3] Using a dog, artificially injecting 0.8++++nφ into the root canal of the tooth.
A hole with a depth of 3+n+a was drilled and a cylinder made of hydroxyapatite (09mmφX10++++nL) (zeta potential -3,4+aV).

Liquid: Distilled water). On the other hand, on the same dog's jugular bone, 5
A bone was cut out with +++m square and height of 3III11, and the skeleton was made of the same hydroxyapatite as above, and an attempt was made to fix it with a truncated pyramid of 2Iw + 11 square and 5 leaps in height.

One month after implantation, the implant site was removed and the tissue surrounding the implant material was observed. As a result, in both cases, the space between the living tissue and the implant material was filled with new bone, there was no finding that appeared to be a foreign body reaction, and the biocompatibility was extremely good.

Procedural amendment (voluntary) 1 Indication of the case Patent Application No. 121645 filed in 1982 2 Name of the invention Inorganic implant material 3 Person making the amendment Relationship to the case Patent applicant Mitsubishi Mining Cement Kayami 2 Company 4 Agent Address: 105 No. 1-20 Toranomon, Minato-ku, Tokyo 5 Section 6 "Detailed Description of the Invention" of the specification subject to the amendment Contents of the amendment As shown in the attached sheet, the following parts of the specification of the present application are corrected.

Claims (1)

[Claims] An inorganic implant material comprising an inorganic material having a negative zeta potential.