Rapid Sintering of Dental Oxide Ceramics via Multi-Stage Cooling
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Solution Overview
Problem
Conventional sintering processes for dental ceramics are time-consuming, typically taking over 4 hours due to low heating rates, which is unsuitable for chairside treatments, and accelerated methods often result in ceramic materials that do not meet the high mechanical and optical requirements of dental restorations.
Innovation Solution
A method involving at least one heat treatment and controlled cooling steps with varying cooling rates to achieve rapid sintering of oxide ceramic materials, resulting in dental restorations with excellent mechanical properties and aesthetic qualities that mimic natural tooth material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional slow sintering processes are used, then high density and good mechanical properties are achieved, but production time exceeds 4 hours which is unsuitable for chairside treatments
Solution Approach 1:
The patent applies parameter changes by modifying the heating rate from conventional slow rates to rapid rates of 100-500 K/min, and by implementing a specific two-stage cooling process with different cooling rates (T1 ≥ 10 K/min and T2 ≥ 50 K/min) to achieve rapid sintering while maintaining high density and mechanical properties in reduced production time
Solution Approach 2:
The patent employs periodic action through a structured two-stage cooling process where the first cooling stage uses a moderate cooling rate (T1) to maintain density, followed by a second cooling stage with a higher cooling rate (T2) to complete the process rapidly, enabling chairside treatment feasibility
2Productivity
If rapid heating rates are used to accelerate sintering, then production time is reduced, but the ceramic materials do not meet high mechanical and optical requirements
Solution Approach 1:
The patent resolves this contradiction by optimizing multiple parameters simultaneously: heating rate (100-500 K/min), maximum sintering temperature (1300-1700°C), and a two-stage cooling process with specific cooling rates (T1 ≥ 10 K/min and T2 ≥ 50 K/min). This coordinated parameter optimization achieves rapid sintering while maintaining high density (≥95%), mechanical strength, and optical properties
Solution Approach 2:
The patent applies dynamics by implementing a dynamic cooling process that transitions from a first cooling stage with moderate rate T1 to a second cooling stage with higher rate T2. This dynamic adjustment of cooling rates allows the material to achieve rapid processing while maintaining the necessary mechanical and optical properties
3Reliability
If multiple work steps including milling, coloring, sintering, glazing and polishing are performed, then comprehensive dental restoration properties are achieved, but the production cycle becomes excessively long
Solution Approach 1:
The patent applies merging by integrating multiple work steps into a unified rapid sintering process. The dense sintering and coloring operations are combined into a single sintering cycle with rapid heating and two-stage cooling, eliminating the need for separate prolonged processing steps and significantly reducing the overall production cycle while maintaining restoration quality
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
The method enables the rapid production of dental restorations with high density and optimal optical properties, significantly reducing production time while meeting the high standards of dental restorations, with a sintering process that can be completed in a tenth of the time of traditional methods.
Implementation Method 1
the oxide ceramic material (a) is subjected to at least one heat treatment and (b) is cooled
Implementation Method 2
cooling (b1) a first cooling step with the cooling rate T1 and (b2) a second cooling step with the cooling rate T2
Data Source
AI summary
The invention relates to a method for manufacturing a dental restoration, in which an oxide ceramic material (a) is subjected to at least one heat treatment, wherein the oxide ceramic material is heated in step (a) to a temperature in the range of 1100 to 1700°C, (b) is cooled, wherein the cooling (b1) comprises a first cooling step with a cooling rate T1, (b2) a second cooling step with a cooling rate T2, wherein step (b2) takes place in a temperature range of 1000 to 1500°C, and the cooling rate T2 is less than 40 K/min, and (b3) a third cooling step with a cooling rate T3, wherein the cooling rate T2 is less than the cooling rates T1 and T3, and wherein the cooling rates T1 and T3 are at least 40 K/min.