ANSWERS

How does a screw-retained restoration work?

A screw-retained restoration secures a crown or bridge directly to the implant abutment using a prosthetic screw threaded through an access channel in the occlusal or lingual surface. No cement is used. The access channel is sealed with composite after torquing the screw to manufacturer spec, typically 15 to 35 Ncm.

THE SHORT ANSWER

THE FULL PICTURE

Why it works this way

The mechanical workflow

A screw-retained restoration connects directly to the implant or to a multi-unit abutment through a titanium prosthetic screw. The screw passes through an access channel designed into the restoration (occlusal on posterior teeth, cingulum or lingual on anteriors). Torque values are manufacturer-specific: Nobel Biocare multi-unit abutments call for 15 Ncm on the prosthetic screw, Straumann SRA components run 15 Ncm, and most single-unit abutment screws torque to 35 Ncm per the 2023 ITI Treatment Guide. After final torque, the access channel is sealed with PTFE tape over the screw head and composite resin over the tape.

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When should I choose cement-retained instead of screw-retained?

Cement-retained is the right call when implant angulation forces a screw access channel into an unacceptable position and an angulated screw channel solution is not available for the implant system in use. It is also used when interocclusal space is too limited for a screw access channel plus restorative material thickness, typically under 4mm. Single posterior crowns with ideal implant positioning are also reasonable candidates. For everything else, particularly full-arch and multi-unit cases, screw retention is the default.

What torque values does Dani Dental document with each case?

Every screw-retained case ships with system-specific torque documentation. Nobel Biocare multi-unit abutment screws torque to 15 Ncm, Straumann SRA prosthetic screws to 15 Ncm, Neodent GM multi-unit screws to 20 Ncm, and most single-unit abutment screws to 35 Ncm per current manufacturer protocols. We include the exact value for the components used in the case, the torque driver size, and a backup screw. The technician on the case is reachable directly if anything in the seating sequence raises a question.

How does the access channel get sealed after final torque?

Standard protocol is PTFE plumber's tape packed over the screw head to fill the channel down to the screw, then a composite resin seal over the tape. The PTFE layer protects the screw head so the restoration remains retrievable: any future access starts by drilling out only the composite, then removing the tape to expose the screw. Some clinicians prefer cotton pellet plus composite, but PTFE is the lower-contamination option and is what we recommend in the case documentation.

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This answer is one piece of a larger workflow. The pillar page covers materials, turnaround, and how we build the case to your specification.

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