Casting Abutment Step-Like Collar Geometry

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Solution Overview

Problem

The conventional lost wax method for manufacturing dental casting abutments often results in metal overflow at the collar area due to insufficient surface cleaning, leading to casting defects, imprecise fits, and gaps between the abutment and dental implant, which are costly to rectify.

Innovation Solution

A casting abutment with improved geometry featuring step-like areas and platforms that slow down the flow of molten precious metal, reducing the need for graphite barriers and ensuring homogeneous wall thickness to prevent thermal shock and deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a straight running collar area is used on the casting abutment, then the manufacturing process is simple, but the molten precious metal overflows at the collar area causing casting defects

Engineering Contradiction:

Improvecollar area geometryVSAvoidcasting quality

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The collar area is segmented into multiple step-like areas with different diameters instead of a single straight running collar. This segmentation creates distinct zones that control the flow of molten metal, allowing it to slow down and solidify progressively, thereby preventing overflow and casting defects while maintaining manufacturing simplicity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The step-like geometry is pre-designed into the collar area before casting. The decreasing diameters of successive steps are predetermined to control the flow characteristics of molten metal, creating a built-in flow control system that prevents overflow before it occurs during the casting process

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If graphite is applied to stop the flow of molten precious metal, then the overflow problem is solved, but graphite particles contaminate the precious metal in contact areas

Engineering Contradiction:

Improveflow controlVSAvoidgraphite contamination

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The graphite barrier is completely removed from the casting process. Instead of using graphite to stop metal flow, the invention extracts this harmful element and replaces it with a geometric solution - the step-like collar areas that naturally control flow through their shape alone, eliminating contamination risks

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the geometric parameters of the collar area from a uniform straight running design to a stepped configuration with varying diameters. This parameter change fundamentally alters the flow characteristics of molten metal, creating natural flow control without requiring any additional materials like graphite

Inventive Principle:

Principle #35Parameter changes

3Productivity

If the molten precious metal flows quickly through the collar area, then the casting process is fast, but the wall thickness becomes non-homogeneous causing thermal shock and deformation

Engineering Contradiction:

Improvecasting speedVSAvoidwall thickness uniformity

Core Design Contradiction:

ProductivityVSStability of the object's composition

Solution Approach 1:

The collar area is divided into multiple stepped sections with progressively decreasing diameters. This segmentation creates a series of flow control zones that slow down and distribute the molten metal flow, ensuring homogeneous wall thickness throughout the casting while maintaining overall process efficiency

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The step-like geometry creates curved transition zones between different diameter sections. These curved surfaces guide the molten metal flow smoothly, preventing turbulence and ensuring uniform distribution of metal that results in homogeneous wall thickness without causing thermal shock

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 design enhances the precision and durability of the metal model by optimizing flow characteristics and minimizing graphite contamination, ensuring a reliable connection between the casting abutment and dental implant under compressive forces.

Implementation Method 1

the step-like areas and platforms, which collectively form a collar surface... slow down the flow of the gated precious metal

Methodology Applied

Scientific EffectFlow characteristics optimization:

Implementation Method 2

ensuring homogeneous wall thickness to prevent thermal shock and deformation

Methodology Applied

Scientific EffectThermal shock prevention: Thermal Shock

Implementation Method 3

minimizing graphite contamination

Methodology Applied

Scientific EffectContamination minimization:

Data Source

PatentUS8267687B2Casting abutment with improved geometry

Publication Date: 2012.09.18 STRAUMANN HOLDING AG

AI summary

Casting abutment for a dental implant that includes an apical socket portion, a transition portion bordering coronally on the socket portion, and an occlusal portion bordering coronally on the transition portion, having an apical circumferential collar area. The collar area is provided with an axially closer lying first circumferential platform and with at least two adjacent circumferential step-like areas, wherein the largest diameter of a first step-like area is smaller than the smallest diameter of a second step-like area the second step-like area lying apically with respect to the first step-like area.