Parabolic Drill Bit Flute Geometry for Bone Chip Evacuation

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Solution Overview

Problem

Prior art drill bit designs often result in flute blockages due to insufficient space for bone chip removal, leading to increased friction, thermal effects, and higher risks of osteonecrosis and compromised osteo-integration during drilling for medical and dental applications.

Innovation Solution

The design features a parabolic drill bit with a convex web and fast helix angle, increasing the proportion of empty spaces for bone chip removal, reducing friction and thermal effects by enhancing the helical angle and opening angle of the flutes, and maintaining structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of stationary object

If the drill bit uses conventional flute design, then the structural integrity is maintained, but the bone chips removal space is insufficient causing flute blockage

Engineering Contradiction:
Improvebone chips removal spaceVSAvoidstructural integrity
Core Design Contradiction:
Volume of stationary objectVSStrength

Solution Approach 1:

The patent applies dimensionality change by transitioning from conventional straight flutes to three-dimensional helical flutes with optimized pitch and angle. This spatial transformation creates additional volume for bone chip accommodation while preserving the core structural integrity through the helical geometry that distributes mechanical loads more effectively along the flute path.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent implements parameter changes by optimizing the helical angle, pitch, and flute width ratios. Specifically, the helical angle is adjusted to enhance the spiral evacuation path, while the pitch is modified to increase the vertical spacing between flute turns, thereby expanding the available volume for bone chip removal without compromising the overall drill bit strength.

Inventive Principle:
Principle #35Parameter changes

2Force

If the drill bit removes bone chips effectively, then the friction is reduced, but the drilling time increases due to manual intervention

Engineering Contradiction:
ImprovefrictionVSAvoiddrilling time
Core Design Contradiction:
ForceVSLoss of time

Solution Approach 1:

The patent ensures continuity of useful action by designing flutes that continuously evacuate bone chips throughout the drilling process. The helical geometry maintains constant engagement with the bone material, enabling uninterrupted chip removal without requiring periodic manual intervention, thus reducing both friction and total drilling time.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The patent applies the extraction principle by actively removing bone chips from the drilling zone through the optimized flute design. The helical flutes with increased pitch and angle create efficient extraction paths that continuously pull bone chips away from the cutting edges, preventing accumulation and reducing friction during the drilling operation.

Inventive Principle:
Principle #2Taking out (Extraction)

3Volume of stationary object

If the drill bit increases helical angle for better bone chip removal, then the flute capacity increases, but the cutting edge stability decreases

Engineering Contradiction:
Improveflute capacityVSAvoidcutting edge stability
Core Design Contradiction:
Volume of stationary objectVSStability of the object's composition

Solution Approach 1:

The patent applies local quality by differentiating the properties of various parts of the drill bit. The cutting edges are designed with optimized geometry and material properties to maintain stability and sharpness, while the flute regions incorporate increased helical angles and pitch to maximize bone chip capacity. This localized differentiation allows each component to perform its specific function optimally.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent utilizes composite materials or coated structures on the cutting edges to enhance stability while allowing the flutes to have aggressive helical geometry for maximum chip capacity. The composite construction enables the cutting portion to maintain structural integrity and edge stability even when the flutes are designed with higher helical angles for improved evacuation.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3600128B1Parabolic instrument
Publication Date: 2023.09.06 DENTSPLY SIRONA INC
  • EP3600128B1 patent drawingFigure 1~2
  • EP3600128B1 patent drawingFigure 3A~3F
  • EP3600128B1 patent drawingFigure 4A~4E

AI summary

An instrument comprising a shank and a working portion, the working portion having a tip and a plurality of flutes being defined by at least two lands having a land margin; wherein the working portion has a parabolic cross-section defining opposing convexed surfaces extending between at least two opposing land margins.