Method for producing a ceramic fixed partial denture
View Patent ↗A method for making ceramic fixed partial dentures comprising separating the as-sintered partial denture structure, rejoining the retainers and pontic with glass, which forms a strong joint between the retainers and pontic after sintering. This method may produce ceramic long-span fixed partial dentures with a better fit.
1. A method for forming a fixed partial denture, comprising:
milling a porous ceramic block into a shape of a series of teeth thereby forming a pre-sintered framework structure comprising:
a plurality of retainers; and
a pontic located between and connected to adjacent retainers via a connector;
sintering the pre-sintered framework structure thereby forming an initial sintered framework structure;
separating the initial sintered framework structure at the connector thereby providing a plurality of sintered retainers and a sintered pontic;
seating each sintered retainer and aligning the sintered pontic on a respective tooth abutment within a patient's mouth or on a dental model so as to provide an accurate fit; and
rejoining each sintered retainer to the sintered pontic thereby forming a final framework structure and sintering to form the fixed partial denture,
wherein the fixed partial denture comprises:
at least 90% ZrO 2 by weight;
at least 3% Y 2 O 3 by weight;
at least 1% HfO 2 by weight;
no more than 0.1% Al 2 O 3 by weight;
no more than 0.1% SiO 2 by weight; and
no more than 0.1% Na 2 O by weight of the fixed partial denture.
2. The method of claim 1 , wherein the porous ceramic block comprises porous pre-sintered zirconia.
3. The method of claim 2 , wherein the porous ceramic block further comprises yttrium oxide.
4. The method of claim 1 , wherein at least one of the pre-sintered framework structure and the final framework structure is sintered in a pressure ranging from 1-50 mbar.
5. The method of claim 1 , wherein at least one of the pre-sintered framework structure and the final framework structure is sintered at a temperature ranging from 900° C. to 1500° C.
6. The method of claim 5 , wherein at least one of the pre-sintered framework structure and the final framework structure is sintered at a temperature ranging from 1000° C. to 1200° C.
7. The method of claim 1 , wherein at least one of the pre-sintered framework structure and the final framework structure is sintered for a period ranging from 1-60 minutes.
8. The method of claim 7 , wherein at least one of the pre-sintered framework structure and the final framework structure is sintered for a period ranging from 5-10 minutes.
9. The method of claim 1 , wherein the initial sintered framework structure is separated by ultrasonic vibration-assisted machining, laser-assisted machining, or thermal-assisted machining.
10. The method of claim 9 , wherein the initial sintered framework structure is separated by laser-assisted machining.
11. The method of claim 1 , wherein the initial sintered framework structure is separated by ultrasonic vibration-assisted machining, laser-assisted machining, or thermal-assisted machining, and the method further comprises separating the initial sintered framework structure with a machining tool heated to a temperature up to 500° C.
12. The method of claim 1 , wherein the accurate fit is provided by seating each sintered retainer and aligning the sintered pontic on the respective tooth abutment within the patient's mouth.
13. The method of claim 1 , wherein the accurate fit is provided by seating each sintered retainer and aligning the sintered pontic on the respective tooth abutment of the dental model.
14. The method of claim 1 , wherein each sintered retainer is rejoined to the sintered pontic by applying a glass therebetween.
15. The method of claim 14 , wherein the glass is in the form of a paste.
16. A fixed partial denture, comprising:
at least 90% ZrO 2 by weight;
at least 3% Y 2 O 3 by weight;
at least 1% HfO 2 by weight;
no more than 0.1% Al 2 O 3 by weight;
no more than 0.1% SiO 2 by weight; and
no more than 0.1% Na 2 O by weight of the fixed partial denture;
wherein the fixed partial denture is in the form of a plurality of retainers and a pontic located between and connected to adjacent retainers via a connector and which does not have a porcelain veneer.
17. The fixed partial denture of claim 16 , comprising:
91-94% ZrO 2 by weight;
4-6% Y 2 O 3 by weight;
2-4% HfO 2 by weight;
no more than 0.1% Al 2 O 3 by weight;
no more than 0.1% SiO 2 by weight; and
no more than 0.1% Na 2 O by weight of the fixed partial denture.
18. The fixed partial denture of claim 16 , which has a failure load in a range of 200-700 N.