Guided Implant Surgery, Explained
What changes when the position is decided on a screen
I have not placed a freehand implant since 2016. That is not a statement about skill — I placed several hundred freehand before that, and most of them are still working. It is a statement about where an implant should be positioned and how you can be sure it goes there.
The problem with placing to the bone
Freehand implant placement is guided by what the surgeon can see and feel: the shape of the ridge, the resistance of the bone, the position of the neighbouring teeth. All of that pushes the implant toward wherever the bone is most generous.
The trouble is that the crown needs to be somewhere specific — under the opposing tooth, in line with the arch, emerging through gum at the right angle. Where the bone is thickest and where the crown needs to be are frequently not the same place.
An implant placed where the bone was easiest gives you a crown that has to be built at a compromise. Nobody sees the implant. Everybody sees the crown.
Planning backwards
Guided surgery inverts the order. We start with a CBCT scan and an intraoral scan, superimpose them, and design the final crown first. Only then do we position the implant — under that crown, at the angle the crown requires, and at the depth that gives the gum the right emergence profile.
The software then checks that position against the anatomy: the inferior alveolar nerve, the sinus floor, the roots of adjacent teeth, and the amount of bone on the buccal side. If the ideal prosthetic position does not have enough bone around it, that is the moment to plan a graft — weeks before surgery, not during it.
Transferring the plan
A guide is then printed. It seats precisely over the teeth or the bone and carries metal sleeves that control the angle and the depth of every drill in the sequence.
In practice this means the surgery is shorter, often flapless, and the implant ends up within a few tenths of a millimetre of where it was planned. It also means the abutment and crown can be designed in advance, because the position is known before the patient sits down.
What it does not solve
Guided surgery is a transfer mechanism, not a substitute for judgement. A badly conceived plan executed accurately is still a badly conceived plan. The guide does not decide whether a tooth should be extracted, whether the bone will accept an immediate placement, or whether the soft tissue needs augmenting.
It also does not remove the need to be able to place freehand. Guides fracture, teeth move slightly between the scan and the surgery, and occasionally what you find when you open the site is not what the scan suggested. A surgeon who can only work with a guide is not ready to use one.
Why we use it for every case
The argument for guiding straightforward cases is the same as the argument for a checklist in aviation. The cases that go wrong are rarely the ones that looked difficult. They are the routine ones where a small angulation error was absorbed into the restoration and showed up as a problem five years later.
