Patent US4149894A successfully refreshed from Google Patents.
US4149894A
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US
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Process for producing an apatite powder having improved sinterability
Assignee: Pentax Corp
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Filing: 1978-03-17
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Granted: 1979-04-17
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Expires: 1998-03-17
Abstract
Abstract A sintered apatite body obtained by molding and sintering an apatite powder, Ca5(PO4)3OH, containing 0.01 to 20% by weight of (Ca,Mg)3(PO4)2. The sintered apatite body has high mechanical strength and good affinity with living tissues and cells, and is suitable as medical implant materials such as prosthetic teeth or bones.
Inventors
- 👤 Masatomi Ebihara
- 👤 Masahide Inoue
- 👤 Tsuneo Hidaka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 10:53
CPC Classifications
A; A61; A61L; A61L27/00; A61L27/02; A61L27/12; C; C01; C01B; C01B25/00; C01B25/16; C01B25/26; C01B25/32; C01B25/322; C04; C04B; C04B35/00; C04B35/01; C04B35/447; A61F; A61F2310/00; A61F2310/00005; A61F2310/00179; A61F2310/00293
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
161 words
A process for producing an apatite powder suitable for sintering and having the formula Ca 5 (PO 4 ) 3 OH, containing 0.01 to 20% by weight of (Ca, Mg) 3 (PO 4 ) 2 which comprises calcining a mixed powder of 0 to 20% by weight of a calcium compound selected from the group consisting of Ca(OH) 2 , CaCO 3 , and CaO, 0.01 to 20% by weight of a magnesium compound selected from the group consisting of (Ca, Mg) 3 (PO 4 ) 2 , Mg 3 (PO 4 ) 2 , MgHPO 4 , Mg(H 2 PO 4 ) 2 , MgSO 4 , MgCO 3 , Mg(OH) 2 , and MgO, and 99.99 to 60% by weight of amorphous apatite of the formula Ca.sub.10-x H.sub.x (PO.sub.4).sub.6 (OH).sub.2-x.yH.sub.2 O wherein O≦x≦1, and y≦x, whereby upon molding and sintering said apatite powder, grain-growth is inhibited thereby contributing to an increase in the mechanical strength of the sintered apatite.
Claim 2
Dependent Claim
161 words
A process for producing an apatite powder suitable for sintering and having the formula Ca 5 (PO 4 ) 3 OH, containing 0.01 to 20% by weight of (Ca, Mg) 3 (PO 4 ) 2 which comprises calcining a mixed powder of 0 to 20% by weight of a calcium compound selected from the group consisting of Ca(OH) 2 , CaCO 3 , and CaO, 0.01 to 20% by weight of a magnesium compound selected from the group consisting of (Ca, Mg) 3 (PO 4 ) 2 , Mg 3 (PO 4 ) 2 , MgHPO 4 , Mg(H 2 PO 4 ) 2 , MgSO 4 , MgCO 3 , Mg(OH) 2 , and MgO, and 99.99 to 60% by weight of amorphous apatite of the formula Ca.sub.10-x H.sub.x (PO.sub.4).sub.6 (OH).sub.2-x.yH.sub.2 O wherein O≦x≦1, and y≦x, whereby upon molding and sintering said apatite powder, grain-growth is inhibited thereby contributing to an increase in the mechanical strength of the sintered apatite.
Claim 3
Dependent Claim
29 words
The process of claim 1, wherein the calcining is carried out in an inert gas or in air at 400° to 1000° C. for about 0.1 to 2 hours.
Claim 4
Dependent Claim
63 words
A process for producing an apatite powder, Ca 5 (PO 4 ) 3 OH, containing 0.01 to 20% by weight of (Ca, Mg) 3 (PO 4 ) 2 which comprises adding H 3 PO 4 incrementally to a mixed suspension of Mg(OH) 2 and Ca(OH) 2 with an Mg(OH) 2 /Ca(OH) 2 weight ratio of 0.0001:1 to 0.2:1, and calcining the resulting powder.
Claim 5
Dependent Claim
63 words
A process for producing an apatite powder, Ca 5 (PO 4 ) 3 OH, containing 0.01 to 20% by weight of (Ca, Mg) 3 (PO 4 ) 2 which comprises adding H 3 PO 4 incrementally to a mixed suspension of Mg(OH) 2 and Ca(OH) 2 with an Mg(OH) 2 /Ca(OH) 2 weight ratio of 0.0001:1 to 0.2:1, and calcining the resulting powder.
Claim 6
Dependent Claim
29 words
The process of claim 3 wherein the calcining is carried out in an inert gas or in air at 400° to 1000° C. for about 0.1 to 2 hours.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-04-16 | 1982-10-16 | 1983-04-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-04-16 | 1986-10-16 | 1987-04-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-04-16 | 1990-10-16 | 1991-04-17 | $7700.00 | Window Closed / Lapsed |