Implant contact surfaces and screw loosening

English technical abstract

The study focuses on one of the most common service complications in implant prosthodontics: screw loosening. Rather than explaining it through tightening torque alone, it analyses how internal implant contact surfaces may influence force distribution, micromovement and loss of preload*.

For technical support, the article is valuable because it presents joint stability as the result of the complete geometry. The screw, abutment, implant and their contact surfaces operate as one mechanical system.

screwpreloadFEM*micromovementcontact

What the article covers and how to read it

PreloadTightening torque generates screw preload, which keeps the joint clamped against functional loading.

Contact geometryThe implant’s internal surfaces can influence where load is transferred and where micromovement occurs.

MicromovementRepeated loading can gradually reduce joint stability, particularly if the contact surfaces do not support even force transfer.

FEM analysisThe computational model helps visualise stress concentrations and changes within the joint that are not visible to the naked eye.

Relevance for the laboratory, dental practice and technical support

With recurrent screw loosening, assess not only torque but also occlusion, seating, connection geometry and possible small discrepancies in the restoration.
The correct screw and corresponding component matter because the joint is designed as a specific mechanical pair.
The article complements the screw-tightening page and helps explain why a precise service protocol is essential.

Limitations and cautious interpretation

The FEM study shows mechanical trends within a model. In clinical practice, screw loosening is also influenced by factors such as occlusion, parafunction, restoration accuracy and repeated manipulation.

Original source article

Original title: Effects of the internal contact surfaces of dental implants on screw loosening

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.

preload: Preload is the tensile force generated in a screw after tightening that keeps the joint clamped together.
FEM: FEM means finite element method, a computational simulation of stress and deformation in a model.

Implant contact surfaces and risk of screw loosening