Sintered Lithium Disilicate Dental Restoration via Reduced Pressure Sintering
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Solution Overview
Problem
Current processes for producing lithium disilicate glass ceramic dental restorations are limited by the need for wet grinding, restricted productivity, and limited possibilities for individualization, particularly with respect to color and distribution.
Innovation Solution
A process involving the sintering of a porous 3-dim article with a shape resembling a dental restoration, under reduced atmospheric pressure conditions, allowing for dry milling and simplified sintering without the need for a support structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If wet grinding process is used to shape the dental restoration, then the material can be shaped, but productivity is limited and the process is complex
Solution Approach 1:
The patent changes the material parameters by using a porous green body with specific pore structure and composition (lithium disilicate glass ceramic with 60-80 wt% SiO2, 10-20 wt% Li2O, 5-15 wt% Al2O3) that allows dry milling. This parameter change enables the transition from wet to dry grinding, improving productivity while maintaining ease of manufacture
Solution Approach 2:
The patent employs a porous green body structure with controlled porosity (20-40%) as the starting material for shaping. This porous structure facilitates dry milling by allowing coolant evacuation and improving chip removal, thereby enabling high-speed dry grinding operations that increase productivity without sacrificing manufacturability
2Reliability
If support structure is used during sintering, then the article is stable, but device complexity increases
Solution Approach 1:
The patent implements self-service by designing the porous green body to be self-supporting during sintering. The specific pore structure and material composition provide sufficient mechanical strength and structural stability during the sintering process, eliminating the need for external support structures and simplifying the overall process
3Reliability
If conventional sintering process is used, then the ceramic is formed, but translucency and aesthetic properties are limited
Solution Approach 1:
The patent optimizes sintering parameters including temperature (900-1100°C), holding time (5-30 minutes), and atmospheric conditions to achieve complete densification while maintaining fine-grained microstructure. These parameter changes maximize translucency by controlling crystal growth and pore elimination, producing highly aesthetic dental restorations with superior optical properties
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 enables the production of highly aesthetic dental restorations with improved translucency and coloration, while allowing for easy individualization and increased productivity through the use of dry milling and self-supporting sintering.
Implementation Method 1
sintering the porous 3-dim article having the shape of a dental restoration to obtain a sintered lithium disilicate glass ceramic dental restoration
Implementation Method 2
the sintering preferably being done under reduced atmospheric pressure conditions
Data Source
AI summary
The present invention is directed to a process for producing a sintered lithium disilicate glass ceramic dental restoration out of a porous 3-dim article, the process comprising the step of sintering the porous 3-dim article having the shape of a dental restoration with an outer and inner surface to obtain a sintered lithium disilicate ceramic dental restoration, the sintered lithium disilicate glass ceramic dental restoration comprisingSi oxide calculated as SiO2 from 55 to 80 wt.-%,Li oxide calculated as Li2O from 7 to 16 wt.-%,Al oxide calculated as Al2O3 from 1 to 5 wt.-%, andP oxide calculated as P2O5 from 1 to 5 wt.-%,wt.-% with respect to the weight of the dental restoration, the sintering being done under reduced atmospheric pressure conditions, the reduced atmospheric pressure conditions being applied at a temperature above 600° C.The present invention is also directed to a kit of parts comprising a porous 3-dim article having the shape of a dental milling block and a respective instruction of use.