Screw-retained or cemented: the choice is made on margin depth, not preference

The comparison between screw-retained and cemented implant restorations has run for thirty years and is still presented as a matter of preference. It is instead a decision depending on measurable factors, and in most cases one option holds a clear advantage.

The decisive advantage of screw retention is retrievability. A screw-retained restoration is removed in minutes to repair ceramic, change a component, or access the implant for therapy: a cemented one is often destroyed in the removal.

On an extensive rehabilitation this difference changes the economic prognosis of the entire case. Chipping on a cemented bridge may mean remaking everything; on the same bridge screw-retained, it means dismounting and repairing it.

The second advantage concerns residual cement, which is no theoretical risk. Studies on peri-implantitis series have identified cement remnants in over half the cases examined, and the temporal relationship suggests a causal role.

Cement forced into the peri-implant sulcus is invisible on radiographs if radiolucent, cannot be removed with an interdental brush, and sustains an inflammation progressing slowly over years.

The disadvantages of screw retention are equally concrete. The access channel crosses the occlusal surface, reducing the ceramic area available and creating a structural weak point.

When the channel emerges on the buccal aspect of an anterior unit — because the implant is inclined — the screw-retained option becomes aesthetically unacceptable. This is the case where implant position decides for us.

Angulated screw-channel abutments have widened the possibilities: they allow the access to be brought back palatally even with marked inclination. They add components and cost, but resolve most cases that previously forced cementation.

Screw loosening is the recurring mechanical problem of screw retention, and its causes are known. Torque to the manufacturer's specification, retorque after ten minutes to compensate for settling of the surfaces, and occlusal contacts that generate no eccentric forces.

The hybrid solution — screw-retained abutment with the crown cemented onto it extraorally — combines both approaches. Cementation occurs on the model, where excess is completely removed, and the assembly is screwed in while remaining retrievable.

It is probably the most balanced solution for the single anterior unit, where aesthetics rule out a buccal channel but retrievability remains desirable.

Where cementation is unavoidable, one rule reduces the risk: a supragingival or at most equigingival margin, never deep. A visible margin allows complete cement removal to be verified.

In summary: screw-retained where implant position permits, hybrid on aesthetically critical anterior units, cemented only where there is no alternative and always with a controllable margin. Personal preference is the last of the criteria.