Method for planning a sintering of a dental prosthesis part

Patent metadata

Field	Value
Publication number	US-10939980-B2
Application number	US-201415105530-A
Country	US
Kind code	B2
Filing date	Dec 18, 2014
Priority date	Dec 18, 2013
Publication date	Mar 9, 2021
Grant date	Mar 9, 2021

Abstract

The invention relates to a method for planning a heat treatment of a dental prosthesis part (1), in which a 3D model (9) of the dental prosthesis part to be produced (1) already exists. A temperature profile (16) for the heat treatment of the dental prosthesis part (1) is automatically determined by a computer (17) as a function of determined geometric parameters (10, 11, 12, 13) of the dental prosthesis part to be produced (1) and/or of determined material parameters of the dental prosthesis part to be produced (1).

First claim

The invention claimed is:

1. A method for planning a heat treatment of a dental prosthesis part comprising the steps of:
providing a virtual 3D model of the dental prosthesis part;
automatically computing a temperature profile for the heat treatment of the dental prosthesis, the temperature profile includes an automatically computed heating rate, an automatically computed holding temperature and an automatically computed holding time;
heat treating the dental prosthesis part according to the temperature profile using a sintering furnace adapted with the computed temperature profile
wherein the temperature profile is automatically computed based on one or more geometrical parameters of the virtual 3D model and material parameters of the dental prosthesis part,
wherein the one or more material parameters of a material of the dental prosthesis part are selected from the group consisting of a heat conductivity, a thermal shock resistance, a maximum heat-up rate and a temperature limit value for a phase transformation of the material, and
wherein the one or more geometrical parameters are determined by measuring dimensions of the virtual 3D model of the dental prosthesis part.

2. The method according to claim 1 , further comprising automatically determining the temperature profile such that with an increasing maximum lateral wall thickness, an increasing maximum occlusal wall thickness, an increasing maximal cross section and/or an increasing total volume of the dental prosthesis part, (i) the heating rate of the temperature profile decreases, (ii) the holding time of the temperature profile increases and/or (iii) the holding temperature of the temperature profile decreases.

3. The method according to claim 1 , wherein the temperature profile is automatically computed such that with an increasing heat-conductivity and/or thermal shock resistance of the material, the heating rate of the temperature profile increases.

4. The method according to claim 1 , wherein the heat treatment includes sintering, crystallization, a combination of sintering and glazing or a combination of crystallization and glazing.

5. The method according to claim 1 , wherein the selected material for production of the dental prosthesis part is zirconium dioxide (ZrO2), wherein the dental prosthesis part is an individual tooth, a full crown, a partial crown or an inlay, wherein the total volume of the dental prosthesis part does not exceed a volume of a standard molar, wherein the maximum lateral wall thickness and/or the maximum occlusal wall thickness fall below a limit value of 6 mm, wherein a first temperature profile is established for sintering at a heating rate between 100° C./minute and 400° C./minute, with a holding temperature between 1500° C. and 1600° C. and a holding time between 5 minutes and 10 minutes.

6. The method according to claim 5 , wherein the material selected is zirconium dioxide (ZrO2), wherein the dental prosthesis part is a bridge consisting of no more than 6 connected teeth or no more than 6 individual teeth or partial crowns, wherein a second temperature profile is established for a sintering with a heating rate between 70° C./minute and 200° C./minute, with a holding temperature between 1450° C. and 1550° C. and a holding time between 20 minutes and 40 minutes.

7. The method according to one of the claim 1 , wherein the selected material is zirconium dioxide (ZrO2), wherein the dental prosthesis part is a bridge consisting of more than 6 individual teeth, wherein a third temperature profile is established for a sintering with a heating rate between 10° C./minute and 70° C./minute, with a holding temperature between 1500° C. and 1600° C. and a holding time between 100 minutes and 140 minutes.

8. The method according to claim 1 , wherein the selected material is aluminum oxide (Al 2 O 3 ), wherein a fourth temperature profile is established for a sintering with a heating rate between 10° C./minute and 70° C./minute, with a holding temperature between 1500° C. and 1600° C. and a holding time between 100 minutes and 140 minutes.

9. The method according to claim 6 , further comprising graphically displaying the virtual 3D model of the dental prosthesis part using a display unit wherein one or more sections of the virtual 3D model are graphically highlighted when the one or more sections exceed a predefined limit value concerning labial or occlusal wall thickness.

10. The method according to claim 9 , wherein a user adjusts the highlighted one or more sections manually using virtual tools, or that the highlighted one or more sections are automatically adjusted by the computer such that that they fall below the predefined limit value for labial wall thickness or occlusal wall thickness so that for the dental prosthesis part according to this adjusted virtual 3D model the sintering can be performed using a first temperature profile instead of a second temperature profile.

11. The method according to claim 1 wherein the step of determining the temperature profile is performed by selecting from a number of temperature profiles that are stored in a memory.

12. The method according to claim 1 , wherein said dimensions are selected from the group consisting of a maximum lateral wall thickness, a maximum occlusal wall thickness, a ratio of the maximum occlusal wall thickness and the maximum lateral wall thickness, a maximum cross section, a total volume, a maximum total length and a maximum change in a cross section.

13. A system for planning the heat treatment of a dental prosthesis part comprising a processor configured to:
provide a virtual 3D model of the dental prosthesis part;
automatically compute a temperature profile for the heat treatment of the dental prosthesis, the temperature profile includes an automatically computed heating rate, an automatically computed holding temperature and an automatically computed holding time;
heat treat the dental prosthesis part according to the temperature profile using a sintering furnace adapted with the computed temperature profile
wherein the temperature profile is automatically computed based on one or more geometrical parameters of the virtual 3D model and material parameters of the dental prosthesis part,
wherein the one or more material parameters of a material of the dental prosthesis part are selected from the group consisting of a heat conductivity, a thermal shock resistance, a maximum heat-up rate and a temperature limit value for a phase transformation of the material, and
wherein the one or more geometrical parameters are determined by measuring dimensions of the virtual 3D model of the dental prosthesis part.

14. The system according to claim 13 , wherein the processor is further configured to automatically determine the temperature profile such that with an increasing maximum lateral wall thickness, an increasing maximum occlusal wall thickness, an increasing maximal cross section and/or an increasing total volume of the dental prosthesis part, (i) the heating rate of the temperature profile decreases, (ii) the holding time of the temperature profile increases and/or (iii) the holding temperature of the temperature profile decreases.

15. The system according to claim 13 , wherein the processor is further configured to automatically compute the temperature profile such that with an increasing heat-conductivity and/or thermal shock resistance of the material, the heating rate of the temperature profile increases.

16. The system according to claim 13 , wherein the processor is further configured to perform a heat treatment that includes sintering, crystallizatio

Assignees

• Sirona Dental Systems Gmbh
• Dentsply Sirona Inc

Inventors

• Fornoff Peter
• Schmidt Christian

Classifications

• C04B2235/6567

  Treatment time · CPC title

• C04B2235/6562

  Heating rate · CPC title

• C04B35/64

  Burning or sintering processes (C04B33/32 takes precedence {; powder metallurgy B22F}) · CPC title

• C04B35/486

  Fine ceramics · CPC title

• C04B35/111

  Fine ceramics · CPC title