Driver angle, off-axis systems and hexalobular screws

English technical abstract

The article addresses an increasingly common situation in aesthetic and functional implant prosthodontics: the screw channel does not emerge directly along the implant axis, and the screw is tightened with an angled driver. Off-axis solutions provide prosthetic freedom, but they also place greater demands on the precision of the driver, screw and seating.

For the IPD website, the topic is particularly relevant to ASC*/TPA* channels. Angulation is not simply a hole shifted in the CAD design. It is a mechanical transfer of torque through a specific screw-head geometry and a specific driver.

off-axisTPAscrewdriverhexalobularangulation

What the article covers and how to read it

Off-axis accessAllows the screw-channel exit to be moved to a more favourable aesthetic or functional position.

Driver and screwAngulation changes the contact between the driver and screw head, making use of the corresponding system essential.

Torque and wearAn incorrect driver or excessive angulation can impair torque transfer and increase the risk of damaging the screw head.

LibraryCAD design must respect the actual capabilities of the component, the recommended angulation range and access for tightening.

Relevance for the laboratory, dental practice and technical support

Always verify an ASC/TPA solution as a complete system: Ti-base, library, screw, driver and recommended tightening torque.
With repeated manipulation through an angled channel, monitor the condition of both the screw head and the driver.
The article helps explain why screws and drivers must not be freely interchanged between TPA/ASC systems.

Limitations and cautious interpretation

The findings relate to the specific off-axis system and geometry tested. In clinical use, the manufacturer’s recommendation for the specific component remains decisive.

Original source article

Original title: The effect of screwdriver angle variation on the off-axis implant abutment system and hexalobular screw

Download the original PDF

The source document remains available so readers can verify the original wording, methodology and results.

PDF

Related IPD pages and workflows

Glossary of abbreviations and specialist terms

An asterisk next to a term in the text refers to its explanation below.

ASC: ASC means angulated screw channel, allowing screw access to be redirected away from the implant's straight axis.
TPA: TPA is IPD's solution for an angulated transocclusal fixation channel and screw tightening at an angle.

Effect of screwdriver angle on an off-axis system and hexalobular screw