US3983712A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preserving teeth with attached live root membrane
Assignee: Individual
•
Filing: 1975-03-25
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Granted: 1976-10-05
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Expires: 1995-03-25
Abstract
Abstract The invention is concerned with a method of preserving extracted teeth with attached live root membrane. After treating the teeth in order to eliminate bacteria and fungi in a nutrient solution to preserve the viability of the root membrane cells the teeth are subjected to a freezing process in two stages and in the presence of a similar nutrient fluid, the temperature being lowered slowly in the first stage to a value between -20° and -50°C and rapidly in the second stage to a value below -50°C, preferably below -150°C.
Inventors
- 👤 Per-Osten Soder
- 👤 Lennart A. T. Wieslander
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 06:59
CPC Classifications
A; A01; A01N; A01N1/00; A01N1/10; A01N1/16; A01N1/162; A01N1/12; A01N1/122; A01N1/124
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
166 words
A method for preserving a tooth having attached live root membrane which comprises the steps of 1. immersing said tooth in a liquid containing known tooth nutrients and antibiotics which will eliminate bacteria and fungi that might result from the tooth being in a nutrient solution, 2. transporting the tooth while it is immersed in said nutrient liquid containing antibiotics to a tooth bank, 3. upon arrival at the tooth bank replacing said nutrient liquid containing antibiotics with a nutrient liquid that does not contain antibiotics, 4. in a first cooling stage cooling the tooth and surrounding nutrient material at a rate of 0.5°-3° Celcius per minute until a first temperature within the range of between -20° and -50° C is attained. 5. in a second cooling stage rapidly cooling said tooth and surrounding nutrient material below said first temperature to a second temperature that is below -50° C but not below -250° C, 6. storing said tooth at said second temperature in said tooth bank.
Claim 2
Independent Claim
166 words
A method for preserving a tooth having attached live root membrane which comprises the steps of 1. immersing said tooth in a liquid containing known tooth nutrients and antibiotics which will eliminate bacteria and fungi that might result from the tooth being in a nutrient solution, 2. transporting the tooth while it is immersed in said nutrient liquid containing antibiotics to a tooth bank, 3. upon arrival at the tooth bank replacing said nutrient liquid containing antibiotics with a nutrient liquid that does not contain antibiotics, 4. in a first cooling stage cooling the tooth and surrounding nutrient material at a rate of 0.5°-3° Celcius per minute until a first temperature within the range of between -20° and -50° C is attained. 5. in a second cooling stage rapidly cooling said tooth and surrounding nutrient material below said first temperature to a second temperature that is below -50° C but not below -250° C, 6. storing said tooth at said second temperature in said tooth bank.
Claim 3
Dependent Claim
17 words
A method according to claim 1 wherein said second temperature is between -150° C and -200° C.
Claim 4
Dependent Claim
48 words
A method in accordance with claim 1, wherein the temperature in the first freezing stage is lowered gradually at a rate of approximately 1° C/minute down to a value of approximately -30° C, after which the temperature in the second stage is rapidly reduced to approximately -195° C.
Claim 5
Dependent Claim
28 words
A method in accordance with claim 1 wherein freezing is allowed to occur in the presence of a fluid containing a substance which prevents the formation of crystals.
Claim 6
Dependent Claim
20 words
A method in accordance with claim 3 characterized in that the substance preventing the formation of crystals is dimethyl sulphoxide.
Claim 7
Dependent Claim
13 words
A method according to claim 1 wherein said nutrient liquid comprises Eagle's medium.
References Cited (Backward Citations)
US3303662A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-10-05 | 1980-04-05 | 1980-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-05 | 1984-04-05 | 1984-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-05 | 1988-04-05 | 1988-10-05 | $7700.00 | Window Closed / Lapsed |