Straumann RC on BL and BLT: is the connection the same?

“Is Straumann RC the same thing on BL and BLT?” — a question we get from both technicians and clinicians. The answer is yes. Bone Level (BL) and Bone Level Tapered (BLT) use the very same interface — CrossFit: a conical-cylindrical connection with a four-groove index.

CrossFit comes in two platforms: NC (Narrow CrossFit) for 3.3 mm implants and RC (Regular CrossFit) for 4.1 and 4.8 mm. An RC abutment seats identically on a BL 4.1 and a BLT 4.8 — prosthetically the two lines do not differ.

So what is different between BL and BLT

Only the implant body. BLT is the tapered version: a more aggressive thread and a narrowing profile for primary stability in soft bone and fresh sockets. That matters to the surgeon; for prosthetics and CAD the implant ends at the connection level — everything above it is shared.

The practical takeaway for the lab: one CrossFit library (NC/RC) covers both lines. Do not hunt for separate “BLT” files — they do not exist, and that is by design.

What not to confuse it with

BLX is a different system. It uses the TorcFit connection, which is incompatible with CrossFit: abutments, scan bodies and libraries are not interchangeable. If a case just says “Straumann”, first find out: BL/BLT (CrossFit) or BLX (TorcFit)?

Tissue Level is the third case: classic Straumann implants with the polished neck use the synOcta connection with its own prosthetics. Shoulder diameters 4.8/6.5 (RN/WN) are not the same thing as RC.

So Straumann has three prosthetic worlds: CrossFit (BL/BLT), TorcFit (BLX), synOcta (Tissue Level). Full compatibility inside a world, zero between them.

Which exocad libraries to install

For crowns and bridges on BL/BLT look for libraries marked with the NC or RC connection — in our catalog cards the connection and platform are listed right in the specification. Below is a Straumann selection including titanium bases and a BLX option for comparison.

The pre-milling rule is the usual one: confirm the platform against documentation or the scan body; the CAD library guarantees the geometry inside your project.