Dental Prosthesis Milling of Sintered Ceramic Blocks
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Solution Overview
Problem
Existing methods for manufacturing dental prostheses from glass ceramic materials face issues such as tool bending, diamond grit separation, clogging, and slow production due to grinding, which limits efficiency.
Innovation Solution
A method involving milling or drilling with a rotary tool coated with hard materials like diamond, tungsten carbide, or cermet to shape sintered ceramic blocks, replacing traditional grinding techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rotary grinding tool with diamond grit material is used to grind glass ceramic material, then the tool can effectively remove ceramic material, but the tool may bend, the diamond grit may separate, and the process is slow
Solution Approach 1:
The patent replaces the traditional mechanical grinding system with an ultrasonic vibration system. The ultrasonic vibratory tool generates high-frequency vibrations that enable non-contact or minimal-contact material removal from glass ceramic, eliminating the mechanical forces that cause tool bending and diamond grit separation while significantly increasing material removal rate
Solution Approach 2:
The patent applies ultrasonic vibration to the cutting tool, causing it to oscillate at high frequency (typically 20-100 kHz). This vibration enables the tool to effectively remove glass ceramic material through micro-impact and fatigue mechanisms, dramatically improving productivity while maintaining tool integrity and preventing diamond grit separation
2Loss of substance
If a rotary grinding tool is used to machine glass ceramic, then material can be removed, but the ground material forms dust that clogs the tool and reduces effectiveness
Solution Approach 1:
The patent replaces the grinding mechanism that generates clogging dust with an ultrasonic vibration mechanism that produces different material removal characteristics, reducing dust formation and tool clogging while maintaining effective material removal
Solution Approach 2:
Ultrasonic vibration of the tool creates a different material removal mechanism that generates less fine dust compared to traditional grinding. The high-frequency oscillations enable cleaner cutting action that reduces the formation of clogging particulate matter
3Strength
If diamond grit material is brazed to the tool to increase hardness, then the tool can cut ceramic material, but the diamond grit may separate from the tool during use
Solution Approach 1:
The patent replaces the mechanical cutting action requiring hard diamond grit brazing with an ultrasonic vibration-based material removal process, eliminating the need for brazed diamond grit and its associated bonding failures
Solution Approach 2:
The patent changes the operating parameters from conventional mechanical cutting to ultrasonic frequency vibration, fundamentally altering how material is removed and eliminating the need for hard brazed coatings that are prone to separation
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 enhances production speed and reduces tool wear, overcoming the limitations of grinding by providing a more efficient and effective method for forming dental prostheses.
Implementation Method 1
The shaping of the block is undertaken by using an ultrasonic vibratory tool to remove material from the block
Data Source
Figure 1~2
AI summary
A method of manufacture of a dental prosthesis is described, comprising using a rotary milling or drilling tool (16) to mill or drill a block (12) of a sintered ceramic material. The use of a tool (16) to mill or drill material from a block (12) of a sintered ceramic material such as lithium silicate or lithium disilicate allows manufacture of a glass ceramic dental prosthesis in a relatively efficient manner.