JPH03294209A - Collagen treatment material for dental and oral surgery - Google Patents

Abstract

PURPOSE:To obtain the subject collagen treatment material formable e.g. in the form of a collagen sheet having improved strength and absorption rate to living body and useful for promoting the remedy of wound caused by periodontal treatment by compounding a soluble collagen and a fibrous collagen at a specific ratio and crosslinking the mixture. CONSTITUTION:The objective collagen material for dental and oral surgery can be produced by mixing 95-40wt.% of a soluble collagen such as atherocollagen with 5-60wt.% of a fibrous collagen originated from tendon and crosslinking the collagen mixture with a crosslinking agent such as hexamethylene diisocyanate. The material has improved strength and absorption rate to living body and is formable in the form of collagen sheet or sponge. It is useful as a collagen treatment material for dental and oral surgery for the promotion of the remedy of wound in periodontal treatment, prevention of downward growth of gingival epithelium (down growth), prevention of the leakage of filled material after sealing the extraction cavity, etc.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to periodontal disease treatment in the field of dentistry and oral surgery;
The present invention relates to a therapeutic collagen composition used to prevent the growth of gingival epithelium in the apical direction of teeth, that is, downgrowth, and to fill tooth extraction sockets.

(Prior Art and Problems to Be Solved) The ultimate purpose of periodontal treatment is to regenerate periodontal tissue destroyed by periodontitis or the like. When only normal surgical treatment is performed, the healing process is such that the cells that produce cementum and periodontal ligament do not specifically reach the tooth root surface before the epithelium; and become embedded in the tooth root surface, resulting in the formation of a long junctional epithelium. The second fibrous attachment, which lacks cementum and periodontal ligament, is weak and does not completely restore the tooth's occlusal function. Furthermore, this direct attachment of the tooth root epithelium to the tooth root leads to resorption of the tooth root.

Therefore, attempts have been made to insert various membranes between the tooth root and the gingiva, based on the idea of isolating the tooth root from other tissues and selectively assembling cells that produce cementum and periodontal ligament on the tooth root surface. It has been done.

For example, MllllpOer Falter and Gore-
When using a Tex membrane, it is true that cementum and periodontal ligament are regenerated around the tooth root, but since the membrane itself is non-absorbable in the body, it is necessary to regenerate the gingival connective tissue and epithelium at some point after membrane transplantation. The surgical procedure for removing the membrane had to be performed again, making the operation complicated and not very practical. In addition, as an example of a collagen membrane, there is a report using a sheet of atelocollagen (Hisashi Kamoi et al., Journal of the Tokyo Dental Association: Vol. 36, No. 4, April 1988). This study demonstrated an ideal form of healing in which reoperation for extraction was not necessary, and cementum and periodontal ligament existed around the tooth root, to which connective tissue was attached. In some cases, the membrane decomposes in the body before it can be regenerated, or even if it is not decomposed, the membrane loses its shape due to expansion by body fluids.Furthermore, the membrane itself is insufficiently strong, so it takes a lot of skill to push it in. It required extreme care and was difficult to handle.

By the way, collagen is a major protein that constitutes the connective tissue of animals, and its structure is almost the same regardless of animal species. Therefore, unlike other proteins, even collagen derived from a different species of animal has extremely low antigenicity and excellent tissue compatibility. Collagen, which normally constitutes tissue, has crosslinks between its molecules and maintains its tissue form. Atelocollagen is produced by treating with an enzyme or the like to cleave the intermolecular crosslinks and further remove telopeptide, which is the antigen expression site.

As shown above, collagen, especially atelocollagen, has extremely excellent tissue compatibility, but it has the disadvantage that it is rapidly degraded and absorbed in the living body and is degraded and absorbed before it can fully fulfill its therapeutic purpose. . In order to control the rate of decomposition and absorption in vivo, various methods have been used to introduce crosslinks. However, although it was possible to control biodegradability and absorption by introducing crosslinking, it was not possible to sufficiently improve the strength of the composition to the desired level.

The present invention aims to provide a collagen composition for treatment in the field of dentistry and oral surgery, which has a sponge or sheet-like structure composed of collagen, has sufficient strength, and has controlled decomposition and absorption in vivo. purpose.

(Means for Solving the Problems) As a result of various studies on the strength and bioabsorption rate of collagen membranes, the present inventor found that by blending fibrous collagen into soluble collagen in an appropriate ratio and crosslinking it with a crosslinking agent. The present invention was completed based on the discovery that the strength and rate of bioabsorption are significantly improved.

That is, the present invention is a collagen treatment material for dentistry and oral surgery in which a collagen composition comprising 95 to 40% by weight of soluble collagen and 5 to 60% by weight of fibrous collagen is crosslinked.

The soluble collagen used in the present invention includes bovine, rat,
Collagen extracted with acid from mammals such as mice, as well as various animals such as birds and fish, or atelocollagen dissolved and extracted using enzymes from the connective tissues of these animals, or collagen extracted by alkali treatment. These are chemically modified collagen derivatives that can be dissolved in water to form a uniform aqueous solution. Particularly desirable is atelocollagen made from bovine dermis solubilized using pepsin.

Further, as the fibrous collagen used in the present invention, key-derived collagen isolated from keys, crosslinked collagen obtained from the dermal layer of animal skin, etc. can be used. In particular, it is desirable to use collagen derived from tendons. Collagen derived from keys has long fibers, and when used in combination with soluble collagen, the mechanical properties of molded products can be greatly improved.

Furthermore, the key is that compared to other organs, there are fewer proteins other than collagen and it is easy to purify. It has been shown that key-derived collagen can be purified by dissolving and separating fat using an organic solvent, and then washing with a protein denaturing agent under conditions that prevent collagen from being denatured and that allow other proteins to denature and elute. I found it. This has made it possible to safely apply fibrillar collagen ecologically.

As mentioned above, a collagen composition consisting of soluble collagen and fibrous collagen can be mixed and used in any proportion depending on the desired mechanical properties such as strength and flexibility, as well as the rate of biodegradation and absorption. , 95-40% by weight of soluble collagen and 5-60% by weight of fibrous collagen are desirable. In particular, a desirable mixing ratio is 90-70% by weight of soluble collagen and 10-30% by weight of fibrous collagen.
The amount is 2.

This mixing operation is carried out by adding and dispersing an acidic suspension of fibrous collagen at a concentration of 2z or less to an acidic aqueous solution of soluble collagen at a concentration of 5% or less.

At this time, the concentration of total collagen is preferably 3% or less. This operation is performed by stirring with a homogenizer or the like while paying attention to temperature rise so that the solution temperature does not exceed 20°C. This homogeneous acidic dispersion may be molded into a sponge or sheet by being lyophilized or freeze-dried or air-dried as it is or after neutralization. After that, it is pressed to a thickness of 500 μm when swollen.
Make it as follows.

When an uncrosslinked collagen membrane is directly applied to a living body,
It may become difficult to handle due to swelling due to body fluids, etc.
In addition, it will be degraded and absorbed about a week after transplantation. For this purpose, collagen sponges are cross-linked. Conventionally well-known crosslinking agents include formaldehyde,
Aldehyde compounds such as geltaraldehyde, isocyanate compounds such as hexamethylene diisocyanate, or polyepoxy compounds can be used.

Particularly preferred is hexamethylene diisoanate, which does not cause irritation such as cytotoxicity. The degree of crosslinking is such that it is desirable that the membrane maintains its shape for three weeks or more after transplantation.

Example (1) Preparation of atelocollagen Fresh calf skin was thoroughly washed with purified water to remove adhering dirt. After disinfection with 70% ethyl alcohol, the hair was removed and the surface of the skin was scraped off with a razor so as not to leave any hair roots.Furthermore, the same operation was performed on the back side to remove the fat layer and the like to obtain the dermal layer. This was shredded and washed with 5% NaCl water, then 4Q distilled water was added to 100 g of dermis, and IN H
The pH was adjusted to 3.0 with cI, 0.2 g of pepsin was added, and the mixture was kept at 20° C. for 5 days with intermittent stirring.

The pH of the soluble collagen aqueous solution obtained by this treatment was adjusted to 10 to inactivate pepsin.
a0H) It was kept at 4°C for 24 hours.

After that, by repeating the isoelectric precipitation method and filtration,
``Collagen was purified to obtain sterile and pyrogen-free atelocollagen.

(2) No! Preparation of Collagen from L. The sheath of a fresh bovine Achilles key was removed with scissors. A Y-shaped key without a sheath was sliced into 1 to 2 thick slices using a meat slicer. It was treated with Micro-Cut 2-3 times to separate it uniformly and into individual fibers. This operation reduced the fiber length to 0.2 mm or less. The finely divided key collagen fibers were washed twice with a fat solvent such as ethyl alcohol-ethyl ether to remove fat components, and recovered by centrifugation. Furthermore, in order to remove impurities such as other proteins, a 1M calcium chloride aqueous solution was used, which was 30 times the amount of collagen.
Washed at °C. By this operation, the content of albumin, for example, in collagen was 1 ppm or less.

Thereafter, washing with distilled water and recovery were repeated to obtain biocompatible tendon-derived fibrous collagen.

(3) Production of collagen sponge Using atelocollagen prepared in (1) above, 2% by weight
An acidic aqueous solution (pH 3; HCI) was prepared. Furthermore, an acidic dispersion (pH 3; HCI) having a collagen concentration of 2% by weight was prepared using the Kagideki collagen prepared in (2) above. The weight ratio of this atelocollagen aqueous solution and tendon-derived collagen dispersion was (a) too:O.

(b) 90: 10. (c) 60:40. (d)4
They were mixed at a ratio of 0:60.

Thereafter, the mixture was stirred with a homogenizer and then neutralized with NaOH to obtain a dispersion having a pH of 7 to 8. This dispersion liquid was dispensed into IM-thickness trays for freeze-drying, and freeze-dried. The obtained sponge was compressed to a thickness of 0.2 mm. Thereafter, 0.05 molar equivalent of hexamethylene diisocyanate was added to methyl alcohol in a 5-fold molar equivalent to ε-Nl (t) of collagen.
The crosslinking reaction was carried out by immersing the sample in a solution containing 100% of the solution and shaking it. After that, the above (a) to (d) are washed with methyl alcohol and water, and dried.
) A collagen sponge sheet with the composition was obtained. The crosslinking rate of ε-NH1 in the collagen sponge sheet thus obtained was about 55 to 60%.

(4) Comparison of physical properties of collagen sponge sheets (3)
The tensile strength and flexibility of the cola-non sponge sheets of each composition (a) to (d) prepared in (a) to (d) were measured. The tensile strength of each trousers: sheet is LC171.
It was cut to a size of 7cm x 7cm and measured using a tensile tester. Flexibility was evaluated based on appearance and texture; (a)
The collagen sponge sheet was set as 100, and this was used as a reference. The results were as shown in Table 1.

(5) Bioabsorbable Wister female rats (200-250 g) were pierced under anesthesia on the back, and after disinfection with isodine, 2 symmetrical hairs were placed on the midline of pressure at 4 locations, approximately 1.5 cm in total. An incision was made at the corner and a subcutaneous pocket was created. The collagen sponge sheets (compositions) of (a) to (d) cut into 1CsrI angles were placed and sutured. In this case, care was taken to ensure that the skin incision line was not located on the implant material. 1 week, 2 weeks, 3 weeks, 4 weeks,
After 5, 6, and 7 weeks, the mice were dissected, and samples including the subcutaneous tissues were taken out, fixed in formalin, embedded in paraffin, and tissue sections were prepared for histological evaluation. For comparison, (b)
The sample (e) which was not subjected to crosslinking treatment was also evaluated. The results were as shown in Table 2.

(Margin below) (Effects of the invention) The collagen therapeutic material of the present invention is a crosslinked product containing soluble collagen and fibrous collagen in a specific ratio, so it is a collagen with improved strength and bioabsorption rate. It can be in the form of a sheet or sponge, and is used for dental and oral surgery, such as promoting wound healing in periodontal treatment, preventing the downward growth of the gingival epithelium, and preventing leakage of filling material after filling a tooth extraction socket. It is extremely useful as a collagen treatment material.

Claims (1)

[Scope of Claims] 1. A collagen treatment material for dentistry and oral surgery, which is obtained by crosslinking a collagen composition consisting of 95 to 40% by weight of soluble collagen and 5 to 60% by weight of fibrous collagen. 2. The collagen treatment material for dental and oral surgery according to claim 1, wherein the soluble collagen is atelocollagen and the fibrous collagen is collagen derived from tendon. 3. The collagen therapeutic material for dental and oral surgery according to claim 1 or 2, wherein the crosslinking is carried out using a crosslinking agent hexamethylene diisocyanate.