Ultrathin Ceramic Veneer Machining via Cushioned Green State Support
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Solution Overview
Problem
Existing methods for manufacturing ultrathin dental ceramic veneers are invasive and time-consuming, as they require substantial tooth thinning and are prone to fracture during machining due to the mechanical fragility of 'green' ceramic powders, which limits the achievable thickness to around 0.4-0.5 millimeters.
Innovation Solution
A CNC machining process that supports the ceramic block with a low modulus of elasticity material on the opposite face during machining, allowing for the use of pre-sintered or unsintered ceramic powders, which cushions impacts and prevents fracture, enabling the production of veneers with thicknesses between 0.05 and 0.4 millimeters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If CNC machining is performed on green ceramic powders to obtain thin veneers, then manufacturing precision and productivity are improved, but the ceramic compact fractures easily during machining due to its mechanical fragility
Solution Approach 1:
The patent applies beforehand cushioning by placing a resilient support material (such as rubber or foam) between the green ceramic compact and the machining tool or fixture. This cushioning layer absorbs machining forces and prevents the fragile green ceramic from fracturing during CNC machining, enabling the production of ultrathin veneers (0.05-0.4mm) with high reliability.
Solution Approach 2:
The patent introduces an intermediary support material as a mediator between the green ceramic compact and the machining system. This intermediary layer provides mechanical support during machining operations, allowing precise thickness control while preventing fracture of the green ceramic material.
2Object-affected harmful factors
If the veneer thickness is reduced to minimize tooth thinning, then the invasiveness of the procedure is reduced, but the mechanical strength and fracture resistance of the veneer deteriorate
Solution Approach 1:
The patent changes the physical state parameter of the ceramic material by machining in the green (unsintered) state rather than the sintered state. This parameter change allows the creation of ultrathin veneers (0.05-0.4mm) that would be impossible to machine from sintered ceramic, while the subsequent sintering process restores and enhances the mechanical strength of the final product.
Solution Approach 2:
The patent applies preliminary action by performing the machining operation on the green ceramic compact before sintering. This allows precise geometric shaping and thickness control to be established in advance, and the subsequent sintering process consolidates the structure without altering the pre-established geometry, resulting in strong ultrathin veneers.
3Strength
If traditional manual layering processes are used to manufacture dental veneers, then the mechanical strength of the veneer is maintained, but the manufacturing time and complexity increase substantially
Solution Approach 1:
The patent replaces the manual mechanical layering process with automated CNC machining of a green ceramic compact. This substitution eliminates the time-consuming sequential layering and firing operations, achieving veneer production in a single automated machining step followed by one sintering cycle, dramatically reducing manufacturing time while maintaining strength.
Solution Approach 2:
The patent changes the material state parameter to green (unsintered) ceramic compact, which has different mechanical properties that enable rapid CNC machining. This parameter change allows the entire veneer thickness to be created in one machining operation rather than through multiple manual layering cycles, significantly reducing manufacturing time while the final sintering restores full mechanical strength.
4Reliability
If sintered ceramic blocks are machined to obtain thin veneers, then the mechanical strength during machining is sufficient, but the minimum achievable thickness is limited to around 0.4-0.5 millimeters
Solution Approach 1:
The patent applies inversion by reversing the conventional sequence: instead of machining sintered ceramic to achieve thinness, it machines green (unsintered) ceramic to the desired ultrathin dimensions first, then sinteres the finished thin veneer. This inversion allows achievement of thicknesses (0.05-0.4mm) that would be impossible to machine from sintered blocks, while the support material compensates for the low strength during machining.
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 process allows for the efficient and minimally invasive production of ultrathin ceramic veneers with high mechanical strength, reducing tooth thinning and enabling the use of high-strength materials like zirconia and alumina, achieving thicknesses previously difficult to achieve without extensive tooth reduction.
Implementation Method 1
the low modulus of elasticity material... cushions impacts and prevents fracture
Implementation Method 2
pre-sintered or unsintered ceramic powders
Data Source
AI summary
The present disclosure relates to a ceramic structure for dental application, preferably dental restoration, process for obtaining it and its uses. The process now disclosed comprises computer-controlled machining (CNC), particularly by milling, to obtain a ceramic structure, for example dental covers, which reach thicknesses between 0.05 and 0.4 millimeters.