Subgingival Safe End Dental Bur with Spherical Tip
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Solution Overview
Problem
Current dental burs with safe end tips struggle to create a flush margin of composite resin below the gum tissue without leaving microscopic ledges, which can harbor bacteria, and face challenges in fitting and cutting efficiently in limited spaces between teeth.
Innovation Solution
A new safe end bur design featuring a flat surface with a specific angle at the junction between the safe end and cutting surface, a preferred tip diameter of 0.5 mm, and a divergence angle of 2.23 degrees, allowing for efficient cutting and tactile feedback while preventing ledge formation and fitting between teeth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If prior art safe end burs with cylindrical or bulbous tips are used, then the bur can prevent cutting into tooth material at the join between cutting surface and safe end, but it leaves a microscopic ledge of composite resin when cutting below gum tissue
Solution Approach 1:
The safe end tip is designed with a specific curvature radius (0.2-0.5mm) that matches the desired margin depth below gum tissue. This spherical curvature allows the bur to roll smoothly along the tooth surface and create a perfectly flush margin without leaving ledges, while the rounded tip prevents cutting into tooth material through tactile feedback to the dentist.
Solution Approach 2:
The invention changes the geometric parameters of the safe end tip from conventional cylindrical or bulbous shapes to a specifically engineered spherical tip with controlled curvature radius. This parameter change enables the bur to simultaneously prevent tooth cutting and create flush subgingival margins by matching the curvature to the margin depth requirement.
2Length of moving object
If the safe end bur is made thinner to fit between teeth, then it can access limited spaces, but it digs into composite material creating a corduroy surface instead of smooth shaving
Solution Approach 1:
The spherical tip geometry distributes cutting forces evenly across the composite surface, preventing the digging effect that creates corduroy surfaces. The rounded contact area allows smooth rolling motion rather than point contact, enabling thin burs to maintain surface quality while accessing limited spaces between teeth.
3Ease of operation
If the safe end bur is made thicker to provide tactile feedback and cut efficiently, then it provides better tactile sense and cutting performance, but it cannot fit between teeth without cutting adjacent teeth
Solution Approach 1:
The invention optimizes the curvature radius parameter of the spherical tip to provide adequate tactile feedback surface area while maintaining overall bur thinness. The controlled curvature creates sufficient contact area for dentist sensation without increasing bur thickness to a level that would prevent fitting between teeth or cause damage to adjacent teeth.
4Ease of manufacture
If conventional safe end shapes are used, then the design is simple to manufacture, but it cannot create perfectly flush margins below gum tissue without leaving ledges
Solution Approach 1:
The spherical tip geometry, while requiring precise curvature control, can be manufactured using standard ceramic grinding and polishing processes. The uniform spherical shape simplifies the manufacturing workflow compared to complex multi-faceted designs, as it requires only controlled rotation and abrasion to achieve the desired curvature radius, thereby maintaining ease of manufacture while achieving superior precision.
Data Source
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AI summary
The invention is of a new dental bur with specific dimensions that enable the bur to be used for cutting and trimming filling material under the gum tissues and between teeth.