Stemmed Sintered Preforms for Faster Chairside Dental Restorations
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Solution Overview
Problem
The existing methods for creating dental restorations from 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 the milled shape are used, then manufacturing precision is improved, but loss of time increases and productivity decreases
Solution Approach 1:
The preform is prepared in advance with a porous structure that already incorporates the stem and attachment features. This preliminary shaping allows the preform to be directly mounted and milled into the final restoration shape without requiring post-sintering adjustments, thereby reducing total processing time while maintaining precision
Solution Approach 2:
The invention changes the density parameter of the ceramic material by using a porous preform structure that can be milled before sintering. The porous structure allows for easier machining while the subsequent sintering process densifies the material to its final strong state, resolving the contradiction between machinability and final strength
2Manufacturing precision
If separate steps of milling and sintering are used, then manufacturing precision is improved, but productivity decreases
Solution Approach 1:
The preform is pre-shaped with the correct stem and attachment geometry before sintering. This preliminary action ensures that the critical fit features are established early, allowing the final milling step to focus only on aesthetic and surface features, thereby increasing productivity without sacrificing restoration fit
Solution Approach 2:
The manufacturing process is segmented into distinct phases: preform creation, mounting, and final shaping. This segmentation allows each phase to be optimized independently, with the preform phase ensuring structural integrity and the final shaping phase ensuring aesthetic precision, thereby improving both productivity and restoration quality
3Ease of manufacture
If traditional mill blanks with single size and shape are used, then ease of manufacture is improved, but loss of substance increases
Solution Approach 1:
The preform is designed with local variations in density and structure - the porous body for easy machining and the denser stem/attachment regions for structural integrity. This local quality differentiation allows for optimized material usage, reducing waste while maintaining ease of manufacture through standardized preform designs
4Loss of time
If sintered preforms are shaped directly without post-shaping sintering, then loss of time is reduced, but manufacturing precision may worsen
Solution Approach 1:
The preform is pre-shaped with the correct internal structure and external dimensions before sintering. This preliminary shaping ensures that the bulk geometry is accurate, and the final chair-side milling only needs to refine surface features, thereby achieving both time reduction and maintained precision
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 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.