Full-arch and All-on-X guided surgery

A full-arch case is not several single-implant cases carried out together. The implants have to relate correctly to one another and to a prosthesis that spans all of them, so an error in one position is not local — it propagates into how the whole restoration fits.

All-on-4 and All-on-6 describe protocols in which a full arch is supported on four or six implants respectively, often with the posterior implants tilted to make use of available bone and to spread support without grafting.

What makes them harder to guide

• There are frequently no teeth left to seat a guide on, so seating and fixation must be designed rather than assumed.
• Tilted implants have to be planned against both the anatomy and the restoration at once.
• Bone is often reduced before placement, which changes the surface the guide was designed against.
• Several stages may happen in one appointment, each needing the same reference position.

Where stackable guides come in

A stackable system separates the base from the stages. A base component seats and is fixed to the arch; each subsequent component stacks onto that base in a defined position. Because everything indexes to one fixed reference, the planned position survives across stages — including a stage that removes the bone the original scan was taken of.

That is why stackable designs are associated with full-arch work: it is the situation where a single reference across multiple stages is hardest to maintain and matters most.