Dental Ceramic Blank Preforms Reduce Milling Time
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Solution Overview
Problem
Current methods for producing dental moldings from ceramic blocks are inefficient, requiring long processing times and significant tool wear, which limits the use of unsintered or partially sintered ceramic materials due to sintering loss and material limitations.
Innovation Solution
A disc-shaped blank with preforms connected by webs, made from various materials including ceramics, metals, and plastics, is used, allowing for mechanical processing such as milling and drilling to produce dental parts like crowns, bridges, and veneers, with the preforms being adapted to the final shape and dimensions, reducing processing time and tool wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If unsintered or partially sintered ceramic material is used for blocks, then processing times are reduced and tool wear is acceptable, but sintering loss must be accounted for in dimensioning and material limitations persist
Solution Approach 1:
The patent applies preliminary action by creating preforms that are pre-shaped to anticipate the final dental molding geometry. These preforms are formed within the ceramic block before machining, taking into account the expected sintering loss. The preforms are dimensioned and positioned in advance so that after sintering, the final parts achieve the correct dimensions without requiring extensive post-processing or conservative over-dimensioning.
Solution Approach 2:
The patent utilizes parameter changes by transforming the ceramic material through sintering, which changes its physical and mechanical properties. The process leverages the transition from unsintered/partially sintered state (easier to machine) to fully sintered state (final product properties). The preforms are created in the unsintered state and then sintered to achieve the final dense ceramic structure with appropriate dimensional tolerances.
2Adaptability or versatility
If traditional solid ceramic blocks are machined, then material versatility is limited, but processing times are long and efficiency is reduced
Solution Approach 1:
The patent applies segmentation by dividing the solid ceramic block into multiple separate preforms, each corresponding to a specific dental molding to be produced. Instead of machining one part at a time from a solid block, the block is segmented into multiple pre-shaped segments (preforms) that can be individually processed. This segmentation increases material versatility by allowing different types of dental moldings to be produced from a single block while improving productivity through parallel processing potential.
Solution Approach 2:
The patent creates preforms in advance within the ceramic block, performing preliminary shaping actions before the final machining and sintering processes. These preforms are pre-positioned and pre-shaped to reduce the amount of material removal and processing time required in subsequent steps, thereby improving overall processing efficiency while enabling the production of various dental molding types.
3Productivity
If preforms connected by webs are used in the blank, then processing time is shortened and material usage is optimized, but the blank structure becomes more complex
Solution Approach 1:
The patent segments the blank into multiple preforms that are connected by webs. Each preform represents a future dental molding and is separated from the bulk material by cutting away surrounding material, leaving only thin web connections. This segmentation allows for optimized processing of each preform while maintaining structural integrity during handling. The webs are designed to be minimal in size, connecting preforms efficiently without excessive complexity.
Solution Approach 2:
The patent applies local quality by making the web connections between preforms as thin and minimal as possible, concentrating material only where needed for structural support. The majority of the blank volume is removed to create the preform shapes, with material strategically retained only in the web regions. This local retention of material optimizes the balance between structural integrity and processing efficiency, reducing overall blank complexity while maintaining necessary connections.
Data Source
Figure 1a~1b
AI summary
A blank which is provided for producing moulded dental parts, such as crowns, bridges, veneers, abutments etc., has at least one preform of a moulded dental part, which is provided for producing said moulded part. The preforms can be produced from the blank in particular by means of mechanical processing of the blank, preferably by means of cutting, sawing, grinding, drilling and/or milling. In particular, the preforms are preforms for individual crowns.