Compositions: coating or plastic – Coating or plastic compositions – Dental
Patent
1990-03-21
1993-08-24
Bell, Mark L.
Compositions: coating or plastic
Coating or plastic compositions
Dental
106161, C09K 300
Patent
active
052384918
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
This invention relates to hardening materials for medical and dental use which are used as materials for medical or dental treatment of periodontal diseases, root canal sealing, broken bone filling, hard tissue adhesion and so on.
2. Background Art
As a therapeutic material for periodontal diseases, for example, a mixture of particles of hydroxyapatite (hereinafter referred to as HAp ) or .beta.-tricalcium phosphate [.beta.-Ca.sub.3 (PO.sub.4).sub.2 ] (hereinafter referred to as .beta.-TCP ) and a collagen solution was proposed (the Quintessense, 6(12), 1987).
On the other hand, as root canal sealing materials, for examples, a point such as a guttapercha point or a silver point has been used in combination with a paste agent such as calcium hydroxide or with a cement such as zinc oxide eugenol. A self-setting type apatite cement has also been proposed, which is obtained by mixing tetracalcium phosphate [Ca.sub.4 (PO.sub.4).sub.2 O] (generally referred to as 4CP or TeCP and hereinafter as 4CP ) containing barium apatite with a diluted phosphoric acid solution. The mixture is hardened at a neutral region, and the hardened substance has X-ray opaque character (a contrast character) (YUTAKA DOI et al., "J. J. Dent. Mat.", Special 11, 1988).
Regarding the above-described materials for medical treatment of periodontal diseases, its leakage can be prevented to a certain degree by adhesiveness of collagen to HAp or .beta.-TCP but a chemical binding with tooth cementum can not be expected.
On the other hand, although a guttapercha point, which has been used in combination as a filling material for root canal, shows almost no cytotoxicity and no facile transformation in a body, it is not expected to have osteoconduction because it is a natural resin like gum.
Furthermore, with the above-described self-setting type apatite cement it is possible to form a calcified hard tissue and so hopeful as a filling material for root canal, but it is not possible to make a chemically sufficient binding with hard tissue. Therefore, the filling and bonding are not enough, so that there exists a problem that a gap is formed between the apatite cement and hard tissue.
Thus, a subject of the present invention is to provide a hardening material for medical and dental use wherein a calcified hard tissue analogous to body hard tissue capable of making a chemically sufficient bond with body hard tissue is formed in a body within relatively short time passage.
Disclosure of Invention
To attain the above-described subject, the hardening materials for medical and dental, use relating to the present invention are composed of a calcium phosphate powder and a hardening liquid and also of at least either one of collagen and/or collagen derivatives (hereinafter referred to as collagen ) in a state of powder or solution; the calcium phosphate powder contains a powder of .alpha.-tricalcium phosphate (.alpha.-Ca.sub.3 (PO.sub.4).sub.2) (hereinafter referred as to .alpha.-TCP ) and/or 4CP as an essential component and the hardening liquid comprises at least one acid selected from inorganic acids and acetic acid.
The hardening materials for medical and dental use relating to the present invention, in addition to the above description, further comprises that collagen requires for fibrillation a time longer than 8 minutes under physiological conditions.
In the hardening materials related to the invention when the powder and liquid are mixed, the .alpha.-TCP and 4CP in the powder are hydrated to form amorphous calcium phosphate [Ca.sub.3 (PO.sub.4).sub.2. nH.sub.2 O] (hereinafter referred to as ACP ) and octacalcium phosphate [Ca.sub.8 H.sub.2 (PO.sub.4).sub.6. 5H.sub.2 O] (hereinafter referred to as OCP ), respectively. Accompanied with this, pH of the mixture becomes to a neutral region and hence the collagen dissolved in the liquid forms fibrils. Then, the ACP and OCP cohere to the collagen fibrils under this condition and then transform into HAp and/or apatite with progression of hardening. The .alpha.-TCP and 4CP m
REFERENCES:
patent: 4677140 (1987-06-01), Shiotsu
patent: 4776890 (1988-10-01), Chu
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Patent Abstracts of Japan, vol. 12, No. 297 (C-519) (3144), Aug. 12, 1988, & JP, A, 63-66106 (Advance Co., Ltd.) Mar. 24, 1988.
Patent Abstracts of Japan, vol. 11, No. 96 (C-412) (2543), Mar. 26, 1987, & JP, A. 61-246107 (Sankin Kogyo K.K.) Nov. 1, 1986.
The Quintessence, vol. 6,No. 12, Dec. 1987.
Ishii Takashi
Kurihara Tooru
Sugihara Fumihito
Bell Mark L.
Einsmann Margaret
Nitta Gelatin Inc.
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