Calcium phosphate hydroxyapatite precursor and methods for making and using the same

• US 5,542,973 A
• Filed: 12/09/1994
• Issued: 08/06/1996
• Est. Priority Date: 03/12/1993
• Status: Expired due to Term

• Current Assignee: ADA Foundation
• Original Assignee: American Dental Association Health Foundation
• Inventors: Takagi, Shozo, Chow, Laurence C.
• Primary Examiner(s): LANGEL, WAYNE A
• Application Number:
  US08/353,075
• Time in Patent Office: 606 Days
• Field of Search: 423/305, 423/311, 423/308, 623/16, 623/11, 433/199.1, 433/201.1, 433/228.1, 106/35, 106/690, 424/57, 424/602, 424/440
• US Class Current: 106/35
• CPC Class Codes: A61F 2310/00293 containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61K 6/54 Filling; Sealing
• CPC Class Codes: A61K 6/838 Phosphorus compounds, e.g. apatite
• CPC Class Codes: A61K 6/864 Phosphate cements apatite A61K6/838
• CPC Class Codes: A61K 6/876 Calcium oxide
• CPC Class Codes: A61K 8/19 containing inorganic ingredients
• CPC Class Codes: A61K 8/24 Phosphorous; Compounds thereof
• CPC Class Codes: A61L 24/02 containing inorganic materials
• CPC Class Codes: A61L 27/12 Phosphorus-containing materials, e.g. apatite
• CPC Class Codes: A61Q 11/00 Preparations for care of the teeth, of the oral cavity or of dentures; Dentifrices, e.g. toothpastes; Mouth rinses

Abstract

Calcium phosphate compositions that are particularly useful and unique as orthopedic and dental cements and remineralizers, as well as methods and kits for their use, and the resulting products are disclosed. The compositions comprise tetracalcium phosphate which has been prepared from a mixture with a calcium to phosphorous ratio of less than 2, or prepared and maintained under substantially anhydrous conditions prior to use or, preferably, both. The novel compositions are converted substantially to hydroxyapatite upon setting, are substantially gradually resorbable and replaced by bone when implanted in contact with living bony tissue, and offer distinct advantages in terms of cement strength, setting time and reliability and other properties.

Claims

1. A kit of calcium phosphate-containing cement precursor materials comprising (1) tetracalcium phosphate prepared from a mixture of one or more sources of calcium, phosphorous and oxygen which has a calcium to phosphorous ratio of less than 2 and (2) at least one other sparingly soluble calcium phosphate compound.

2. A kit as in claim 1 including a delivery device for application of the cement precursor materials.

3. A kit of calcium phosphate-containing cement precursor materials comprising (1) tetracalcium phosphate prepared and maintained under substantially anhydrous conditions prior to and during its storage in the kit, and (2) at least one other sparingly soluble calcium phosphate compound.

4. A kit as in claim 3 including a delivery device for application of the cement precursor materials.