Before you start

What this guide covers

This guide follows two complete implant cases from a folder of DICOM files through to an exported guide and a printed report, in the order the work actually happens.

Part One is a single unit: a posterior mandibular site, a CBCT with an intra-oral scan, a tooth-supported guide at the end of it. Thirteen steps.

Part Two is a full arch: a maxilla planned on a radiographic guide, four fixtures, three anchor pins, a tissue/tooth-borne guide. Five chapters, and they assume Part One rather than repeating it.

Part Three is two set-up tasks that are not case steps — expanding the implant library and customising the surgical kit — each done once and then true for everything you plan afterwards.

Where the software offers a choice neither case took, the step says so in a short "More on this page" section rather than walking it.

Not covered:

• Bone reduction, sinus and bone grafting. All are pages in the workflow panel; neither recorded case uses them.
• Clinical protocol. The guide says what each control does and what to look at. It does not tell you which implant suits which site, how much clearance to the canal is enough, or when to load. Those belong with your own protocol and your own training.

The shape of the work

Whatever route a case takes, implant planning in GuideMia has the same six stages behind it. Knowing them makes the step order obvious:

1. Preparation. The patient's CT scan comes in, and anatomical structures — bone, teeth, nerve channels — are modelled from it. Optical scans of stone models or of the patient's dentition are imported and aligned with those structures. Steps 1 to 6.
2. Viewing and diagnosis. Measurement and the archiving of diagnostic findings, alongside the planning tools rather than separate from them. Step 8 covers the views used for this.
3. Planning. Implant selection, placement, adjustment and analysis. Steps 7 and 8.
4. Simulation. There are always errors in the clinical outcome of an implant procedure, whatever the data source and whatever the planning technology. Simulation lets you evaluate a plan under extreme error conditions. Covered in accuracy.
5. Design. Surgical guides, designed against your choice of surgical kit. Steps 9 and 10.
6. Manufacturing. A lab makes the guide from the exported STL with no or trivial post-processing. Outside this guide.

What a surgical guide is

A surgical guide exists to improve the accuracy and safety of a treatment, so that implants are placed where they were planned, for the best achievable aesthetic and surgical outcome. Every guide has the same basic elements, and recognising them makes the design steps read as one thing rather than several:

• An adaption surface, which fits onto the patient's anatomy. This is what steps 4 to 6 exist to produce and step 12 exists to verify.
• Drilling holes with sleeves inserted, which embody the treatment plan and guide the actual drills. Step 7 determines these.
• Optional form features — irrigation windows, screw holes, anchor pin holes, inspection openings. Step 10.

The two families of guide

Everything in the software follows from which surface the guide sits on, and there are only two answers.

Tissue-borne — also called tissue-level — guides sit directly on the patient's soft tissue and tooth surfaces, for non-invasive surgery. To make one fit, the system needs a duplicate or approximation of those surfaces, and it will take that from any of four sources:

• A prefabricated denture-like guide, usually called a radiographic guide, whose digital model comes from a CT scan and surface reconstruction — the route Part Two follows
• A stone or plaster model, scanned optically
• The patient's intra-oral scan — the route Part One follows
• An impression, digitised by CT or optical scan

Bone-borne — bone-level — guides are placed on the jaw bone, for invasive surgery in which the surgeon reflects the soft tissue. Here the geometric model of the bone and tooth structure is created from the CT scan itself, a model 2-3 mm thick is derived that fits the bone like a denture, and the drilling holes are cut into that.

Guides are designed to be used with a surgical kit. Implant manufacturers make kits to their own implant specifications, often with a version designed for image-guided surgery, and their job is to ensure the right drill sizes, orientations, depths and sequence. The guide has to be designed to match. When no kit exists for the implant a case uses, the guide is designed for pilot drills only — which is a real and useful outcome, not a failure, but it has to be a decision rather than a surprise.

The scanning protocols

The software can only be used on patients scanned according to specific protocols. Which one you used decides what the case can produce, and it is chosen in step 2 before any work is done. Beyond radiographic guides and dentures, GuideMia does not require or endorse scanning appliances, trays or help bodies of any kind.

The pattern is worth stating plainly: metal artefact is what forces the dual scan with a radiographic guide. If a patient has crowns or existing implants near the site, the optical protocols will struggle, and the radiographic guide route exists for exactly that case.

What follows is the short version, enough to know whether the data you have will work. The full protocols — CBCT parameters, patient preparation and the radiographic-guide checklist — are on scanning protocols.

Preparing the patient for the CT scan

Common to every protocol:

1. Remove all metal prosthesis and metal jewellery that might interfere with the region to be scanned.
2. Secure the bite with cotton pads or another highly radio-translucent material such as polyethylene. Avoid any radio-opaque material, which will prevent the tooth surfaces from being segmented later.
3. Upper and lower teeth must not touch during the scan.
4. Leave 5-10 mm between the jaws (5-8 mm for the stone-model protocol).
5. The patient must stay still, and must not move or swallow during acquisition.

Position so that the occlusal plane is parallel to the image slices, with no tilt, and set the height to centre the occlusal plane in the field of view. Where both arches are to be treated, provide a separate scan for each.

Slice thickness: 0.2-0.5 mm. Thinner slices demand more of the computer. Cases with slices thicker than 1 mm are not recommended at all — see accuracy.

Preparing the optical scan

1. Scan the preparation area, preferably the full arch.
2. Leave a 3-5 mm margin beyond the tooth surfaces.
3. Where the case justifies a tooth setup and there are multiple units, place the teeth virtually in your scanner or CAD software and save the diagnostic model as a separate STL.
4. For an immediate-extraction case, remove the tooth being extracted — not the root area — in the scanner or CAD software and save that as a separate STL. This and the previous step can be combined.
5. Scan the antagonist. Recommended for both restorative and implant planning, and used in step 6.

Trim the scan along its edges if your scanner software can, keeping the margin above. Inspect the STL for overlapping triangles, self-intersections and holes before you bring it in — a defect that is invisible at registration will surface later, when the guide will not cut. 5-20 MB is a normal STL size for this work.

Preparing a radiographic guide

If your case takes the dual-scan route, the guide is where its accuracy is decided, and it is made before anyone opens the software:

• Design it with prototype restorations, 2.5-4 mm thick, containing no metal or radio-opaque material, with buccal flanges extended enough for markers and anchor pins, fitting properly on the patient's anatomy.
• Add 6-8 radiographic markers — gutta percha, radio-opaque glass beads or similar — 1.5-2.5 mm, spherical, never cylindrical or specially shaped. Half lingual, half buccal, and deliberately not evenly distributed.
• Make a bite registration in radio-translucent material.
• Scan twice: the patient wearing the guide, and the guide alone.

A denture can serve as the radiographic guide if it has teeth of proper size, shape and length, a well-established occlusion, buccal flanges wide enough for markers and pins, a hard reline only, a secure close fit, and no metal.

What the software reads and writes

The three surfaces

Knowing which part of the interface owns what saves most of the hunting a first case involves:

The Wizard walks the steps. One page each, Previous and Next Step at the bottom, and only the controls that step needs.

The sidebars carry additional tools for the current page — the ones a straightforward case can ignore and a difficult one cannot.

The workflow pages, in the dock widget, hold the full interface, including advanced work the Wizard never surfaces. Each chapter of this guide ends with a More on this page section describing what lives there.

The Wizard is a path through the software, not a smaller version of it. Nothing it offers is unavailable elsewhere — but a good deal that lives elsewhere never appears in the Wizard.

Two things that will bite

Update after you change something. Several steps compute from inputs you set: change a parameter and the result does not follow until you tell it to. Add/Update Implant and Generate/Update surgical guide both work this way, and both will keep showing you the old geometry in the meantime.

Finish the registration. Alignment previews dynamically as you place markers, which looks finished long before it is. Pressing Align is what commits it.

Where the software will struggle

Some conditions the system either does not support or will not produce good results from. Recognising them before you start is cheaper than discovering them at guide design:

• CT slice thickness over 1 mm — leads to inaccurate models.
• Slices larger than 2048×2048 pixels — generally supported, but real-time performance depends on the hardware.
• Too many slices. 512 slices is comfortable on the recommended configuration. More than 1024 is generally supported but slow — use Export DICOM file series to cut a smaller dataset from the volume of interest and plan on that.
• Excessive scatter in the CT, from metal crowns, fillings or existing implants. This is the condition that pushes a case onto the radiographic guide protocol.
• Very loose jaw bone where a bone-level guide is wanted, such that a bone model cannot reliably be built from the CT.
• Poor-quality STL from the stone model or intra-oral scan — excessively tiny triangles, overlapping triangles and similar defects.

A note on versions

This guide was written against GuideMia Implant Master V8. The underlying workflow — and everything in this chapter — has been stable across releases, but the toolbar layout, the icons and the placement of individual controls differ between versions. Where you cannot find a button where a figure shows it, look for it by name on the workflow panel rather than assuming it is absent; the function is almost always still there.

The terms this guide uses

The software's vocabulary is specific, and several terms are used in ways that are not quite their everyday meaning.

Radiographic guide — a denture-like model carrying radiographic markers, fitting on the patient's teeth and/or soft tissue. Also called a scan template, and the software uses both names.

Segmentation — separating a particular structure out of a CT dataset.

Nerve tracking — following the nerve channels through the dataset and creating surface models of them, to simulate the nerves in the patient's anatomy.

Surgical guide — a model embodying the treatment plan, with implant holes and drilling sleeves, fitting the patient's anatomy, used to guide the drilling.

Master model — the patient's bone and tooth structure, optionally with soft tissue, with implant holes added. For case study, further planning, and guide fabrication.

Bone reduction guide — a guide with a base fitting the bone and an opening exposing the area to be removed.

Virtual tissue model — a model generated from the CT to simulate the actual soft tissue and tooth surfaces. Named by analogy with a stone model, which includes the same surfaces.

Virtual tooth — a tooth model from an STL library, placed in the 3D views as a planning reference.

Safety zone — the space around an implant that must not interfere with adjacent roots, implants, nerves or sinuses.

Drilling sequence — the series of drilling operations making one implant hole. The first is the pilot drill.

Drilling sleeve — the metal tube inserted into the guide that guides the drill.

Assembly view — the 3D view showing the patient scan, the radiographic guide scan, the implants and every other model. Segment view, or current object view, is the other 3D view, showing only the current working object.

Arch curve — the curve outlining the shape of the arch, used to create the panoramic view.

Placement widget — the handles, axes and planes used to position a model in 3D.

Snapshot — a captured image of a rendering window together with the display parameters that produced it, so the same view can be recovered.