Sintered Dental Preform Nesting for Chair-Side Milling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing methods for creating dental restorations from ceramic materials require separate steps of milling porous ceramic designs and sintering them to full density, which limits the ability to produce chair-side ceramic restorations and increases patient wait times.
Innovation Solution
A method for making custom dental restorations using a machinable sintered preform that can be directly shaped into final form without additional sintering, utilizing unique preform designs, nesting strategies, and machining techniques to reduce processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate steps of milling porous ceramic designs and sintering them are used, then manufacturing precision and material strength are improved, but processing time and device complexity increase
Solution Approach 1:
The preform is pre-sintered to a partially dense state with controlled porosity before the final machining step. This preliminary sintering action creates a material that can be efficiently milled while minimizing post-processing time, as the preform already has sufficient structural integrity to hold its shape during machining without requiring full densification afterward.
Solution Approach 2:
The invention combines the sintering and machining operations into a more integrated process flow. By controlling the sintering degree during preform creation and then performing precision machining on this pre-sintered material, the separate steps of full sintering then machining are merged into a coordinated sequence that reduces total processing time while maintaining both precision and strength.
2Strength
If separate steps of milling porous ceramic designs and sintering them are used, then material strength is improved, but device complexity and process steps increase
Solution Approach 1:
The preform undergoes preliminary sintering to achieve a controlled degree of densification before final machining. This preliminary action creates a material structure that balances machinability with final strength requirements, eliminating the need for complex multi-stage sintering processes after machining.
Solution Approach 2:
The invention changes the density parameter of the ceramic material during the preforming stage, creating a preform with intermediate density that is easier to machine than fully dense ceramic but still maintains sufficient strength. This parameter change allows simplification of the overall process by eliminating the need for post-machining sintering.
3Ease of manufacture
If traditional mill blanks with single size and shape are used, then ease of manufacture is improved, but material waste increases
Solution Approach 1:
The preform is created with a density distribution that varies locally - the regions that will become the final restoration have higher density and less porosity, while surrounding areas maintain lower density for easier machining. This local quality variation allows the preform to be tailored to the specific restoration geometry, minimizing material waste while maintaining ease of manufacture.
Solution Approach 2:
The invention changes the density parameter of the preform material to create a gradient structure that optimizes both manufacturability and material efficiency. By controlling the degree of sintering locally in different regions of the preform, the process achieves near-net-shape manufacturing that significantly reduces material waste compared to traditional uniform blanks.
4Loss of time
If fully sintered materials are shaped directly without post-shaping sintering, then processing time is reduced, but manufacturing precision may worsen
Solution Approach 1:
The preform undergoes preliminary sintering to achieve a controlled intermediate density state before final machining. This preliminary action creates a material that is easier to machine with higher precision than fully dense ceramic, while the controlled porosity allows for tighter dimensional tolerances during the machining process.
Solution Approach 2:
The invention optimizes the density parameter of the preform material to fall within a specific range that balances machinability and dimensional accuracy. By controlling the sintering degree to create a preform with 30-70% theoretical density, the material achieves optimal properties for precision machining without requiring post-shaping sintering, thus maintaining manufacturing precision while reducing processing time.
Data Source
AI summary
A method is provided for shaping a custom dental restoration from a preform, wherein the preform comprises a preform body and a preform stem. A method is further disclosed for generating one or more nesting positions for the restoration design within the geometry of the preform body relative to the position of the preform stem. A method is further disclosed for generating machining instructions based on the selected nesting position to optimize machining for chair-side applications.