Sintered Dental Preform Machining With Stem-Based Nesting
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Solution Overview
Problem
The existing methods for creating dental restorations using ceramic materials require separate steps of milling and sintering, which are time-consuming and limit the ability to produce chair-side restorations, increasing patient wait times and material waste.
Innovation Solution
A method and apparatus for making custom dental restorations using a sintered preform with a stem, allowing direct shaping and machining into a final restoration without additional sintering, utilizing unique nesting methods and machining strategies to reduce material removal and processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate steps of milling porous ceramic and sintering are used, then manufacturing precision is achieved, but loss of time increases and productivity decreases
Solution Approach 1:
The preform is prepared in advance with a porous structure that already contains the restoration geometry, including the stem and crown portions. This preliminary shaping allows the preform to be directly inserted into the restoration device without requiring subsequent sintering steps, thereby reducing processing time while maintaining manufacturing precision through the pre-configured geometry
Solution Approach 2:
The restoration is divided into two functional parts: a porous preform body that provides the structural framework and geometry, and a separate stem component that can be inserted into the preform. This segmentation allows the preform to be prepared independently in advance, enabling chair-side applications without requiring time-consuming sintering of the entire restoration
2Ease of manufacture
If traditional mill blanks with single size and shape are used, then ease of manufacture is maintained, but loss of substance increases
Solution Approach 1:
The preform is designed with non-uniform geometry that matches the specific requirements of the dental restoration, with varying porosity and density distributions in different regions. The preform body has a shape that closely resembles the final restoration geometry, allowing material to be placed only where needed rather than removing excess material from a standardized blank
3Strength
If sintered materials are shaped after sintering, then strength is maintained, but loss of time increases due to post-shaping sintering requirements
Solution Approach 1:
The preform is shaped in advance with the complete restoration geometry including the stem and crown portions before insertion into the restoration device. This preliminary shaping eliminates the need for post-insertion sintering and shaping operations, reducing treatment time while the preform's porous structure maintains sufficient strength for chair-side application
Solution Approach 2:
The preform utilizes a porous material structure with controlled density and porosity parameters that provide adequate strength for immediate chair-side use without requiring full densification through sintering. The porosity parameter is optimized to balance strength requirements with the ability to be shaped and inserted without subsequent thermal processing
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces the time required to prepare a finished dental restoration, allowing for chair-side applications and minimizing material waste by enabling direct insertion of the shaped restoration into the mouth without post-shaping sintering processes.
Implementation Method 1
After milling, the porous restoration design is sintered to full density to produce a final restoration
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.