Abutment Screw Hexagonal Ball Head Torque Transmission
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Solution Overview
Problem
Conventional abutment screws for dental implants often have protruding Allen screw heads that interfere with the placement and processing of further abutment parts, leading to instability and potential bacterial nesting due to uneven force distribution.
Innovation Solution
An abutment screw with a tapered threaded shank and a hexagonal ball head screw head that allows for a form-fitting, large-area connection with a conical section inside the implant, reducing the screw head size and enabling effective torque transmission, while a turning tool with a central recess facilitates easy insertion and torque application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional Allen screw head is used for fastening the abutment attachment, then the screw can be easily inserted and torqued, but the screw head protrudes above the abutment attachment and hinders the placement of further abutment parts
Solution Approach 1:
The hexagonal ball head is nested within a spherical recess in the abutment attachment, allowing the screw head to be contained within the overall assembly rather than protruding. The ball head fits into the recess like a nested structure, with the spherical attachment element providing the interface for torque application while remaining flush with the abutment surface.
Solution Approach 2:
The screw head transitions from a flat Allen key interface to a three-dimensional spherical attachment element. This dimensional change allows torque to be applied through rotational movement of the spherical element while the ball head remains seated within the recess, eliminating protrusion in the axial direction.
2Ease of operation
If the abutment attachment is bevelled to facilitate insertion, then the insertion process is improved, but the edge of the Allen screw head interferes with the bevelled surface
Solution Approach 1:
The ball head is nested within the spherical recess, allowing the bevelled insertion channel to accommodate the spherical shape without interference. The nested configuration ensures that the screw head does not protrude to interfere with the bevelled surface during machining and insertion.
Solution Approach 2:
The screw head adopts a spherical geometry that complements the bevelled insertion channel. The curved surface of the ball head fits smoothly within the conical insertion path, eliminating interference edges that would occur with a flat Allen screw head against a bevelled surface.
3Stability of the object's composition
If a flat head with chamfer is used (as in EP 2 269 538 A1), then the screw provides a stable connection, but the head size is large and interferes with lateral machining of the abutment attachment
Solution Approach 1:
The ball head is nested within the spherical recess, creating a compact configuration that provides stable connection through the tapered threaded shank while minimizing the lateral footprint. The nested structure allows the connection interface to be stable without requiring a large head diameter.
Solution Approach 2:
The screw head transitions from a two-dimensional flat chamfered surface to a three-dimensional spherical form. This dimensional change concentrates the connection function in the axial direction through the tapered shank while reducing the lateral dimension, thereby increasing the available lateral machining area.
4Area of stationary object
If the screw head is reduced in size to enable lateral machining, then more extensive machining is possible, but torque transmission to the screw may be compromised
Solution Approach 1:
The spherical attachment element provides an optimal geometry for torque transmission. The curved spherical surface allows for uniform distribution of contact stresses during torque application, enabling effective power transmission despite the reduced size of the screw head compared to conventional flat designs.
Solution Approach 2:
The spherical recess serves multiple functions: it contains and positions the ball head, provides the interface for torque application through the spherical attachment element, and enables lateral machining. This multi-functional design achieves both compact size and effective torque transmission.
Data Source
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AI summary
The present invention relates to an abutment screw (B) for fastening an abutment (A) to an oral implant, comprising a threaded shank (B101) for screwing the abutment screw (B) into the oral implant; and a screw head (B103) for insertion into a recess (W101) of a turning tool (W) and for transferring a torque, which is exerted by the recess (W101), onto the threaded shank (B101).