Dental Mill Blank Resin Buffer for Chipping Prevention
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Solution Overview
Problem
Conventional mill blanks for dental CAD/CAM systems face issues such as chipping, cracking, and abrasion due to tight screw fastening and vibration, and require labor-intensive recess shaping for accurate metal arm alignment, leading to reduced tool life and increased processing time.
Innovation Solution
A mill blank with a ceramic portion and a resin portion of cylindrical or belt shape, where the resin portion is attached to the ceramic portion, providing a joint that prevents chipping and abrasion, and includes recesses for secure engagement with the CAM, allowing for prolonged tool life and efficient processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metal arm is used to join the ceramic mill blank to the CAM device, then the mill blank can be securely fastened, but chipping, cracking, and abrasion occur due to tight screw fastening and vibration
Solution Approach 1:
A resin portion is introduced as an intermediary material between the ceramic mill blank and the metal arm of the CAM device. This resin portion absorbs the stress and vibration during cutting operations, preventing chipping and cracking of the ceramic mill blank while still providing secure fastening. The resin acts as a buffer that protects the brittle ceramic material from the harsh mechanical forces transmitted through the metal arm.
Solution Approach 2:
The joining system transitions from a homogeneous metal-to-ceramic connection to a composite structure involving ceramic mill blank, resin portion, and metal arm. This composite material approach combines the advantages of each material: the ceramic provides structural integrity for cutting, the resin provides shock absorption and stress distribution, and the metal arm provides strong mechanical attachment to the CAM device.
2Manufacturing precision
If a recess is provided on the side surface of the mill blank for accurate metal arm alignment, then the mill blank can be precisely positioned, but labor and time are required for processing the recess
Solution Approach 1:
The resin portion is designed to inherently provide positioning features through its geometry and material properties. The resin's ability to flow and conform during curing, combined with its shrinkage characteristics, creates self-aligning features that eliminate the need for pre-machined recesses. The resin portion itself serves the dual function of both joining and precise positioning.
Solution Approach 2:
The invention changes the physical state and properties of the joining material from rigid metal to viscoelastic resin. This parameter change allows the joining material to adapt to the mill blank's position during curing, providing precise alignment without requiring pre-formed recesses. The resin's ability to undergo dimensional changes during setting enables self-positioning functionality.
Data Source
Figure 1(A)~2(B)
Figure 3(A)~4(C)
Figure 5~6(B)
AI summary
To provide a mill blank for dental CAD/CAM containing a ceramic material for preparing a dental restoration by being installed in a CAD/CAM device, wherein, the mill blank for dental CAD/CAM comprises a ceramic portion in which a dental restoration is cut out and a resin portion which joins with a CAD/CAM device, the mill blank for dental CAD/CAM has a columnar shape, the resin portion is provided at a side surface of the ceramic portion and has a cylindrical shape or a belt shape, a ceramic portion side of the resin portion contacts with the side surface of the ceramic portion, the ceramic portion has a columnar shape, the ceramic portion has a protrusion part, an upper surface and a bottom surface of the columnar shape of the ceramic portion are parallel to each other, the mill blank for dental CAD/CAM has at least two recesses which includes a first recess and a second recess in a circumference portion, the first recess and the second recess respectively include a first surface which is parallel to the upper surface and the bottom surface and a second surface which is a circumferential surface concentric with the circumferential surface of the mill blank for dental CAD/CAM and is vertical to the first surface, and the at least two recesses are formed within the resin portion.