Full-arch restorations.
A full-arch implant case is a treatment plan rather than a restoration, and the decisions that determine its success are made before the first implant goes in.
Plan from the prosthesis backwards
Tooth position, lip support, incisal edge position and occlusal plane are established first, and implant placement follows from them.
This inverts the sequence surgical convenience suggests, which is to place implants where the bone is. Bone-driven placement produces cases where the implants are stable and the prosthesis is compromised — screw channels emerging facially, longer cantilevers than intended, and a prosthesis built to accommodate positions rather than function.
A diagnostic set-up, or a duplicate of a satisfactory existing prosthesis, is the starting record.
Restorative space determines the prosthesis type
Measured from the implant platform to the planned occlusal plane, available space decides what can be made — and different prosthesis types have substantially different requirements.
A screw-retained prosthesis with denture teeth on a metal framework needs considerable vertical height for framework, teeth and the acrylic joining them. A monolithic zirconia prosthesis needs less, with its own minimum below which connectors become fragile. An overdenture on a bar needs room for bar, attachment, denture base and teeth — often the most demanding.
Where space is insufficient, the options are alveoloplasty at placement, a different prosthesis type, or a change to the occlusal plane. All are easier before surgery than after.
Distribution and anteroposterior spread
What matters is not only the number of implants but their distribution. The anteroposterior spread governs how much distal cantilever the prosthesis can safely carry.
Implants clustered anteriorly with a long distal cantilever concentrate bending moments at the terminal implants. Tilting posterior implants to gain spread extends it without additional surgery and shortens the cantilever the prosthesis has to carry.
Cross-arch splinting distributes load, which is why full-arch prostheses are generally splinted — and splinting is exactly what makes passive fit non-negotiable.
Passive fit
A splinted prosthesis on multiple implants must seat without inducing strain. Implants do not move, so a framework that does not fit passively loads the components permanently, and the consequences appear as screw loosening, screw fracture, component failure or marginal bone loss.
No recording method is immune. Conventional impressions distort; digital scans accumulate error across long edentulous spans where there are few landmarks to align against.
Verification is a planned step rather than an optional refinement. See verification jigs.
The provisional phase does real work
A provisional prosthesis establishes and tests the vertical dimension, the occlusal scheme, lip support, tooth position and phonetics, and lets the patient live with the result before it is committed to.
It also shapes the tissue, and the contour it establishes is what the definitive prosthesis should reproduce. A provisional adjusted into a form that works is a design document — record it and send it.
Skipping or rushing this phase is where full-arch cases most often go wrong in ways that are expensive to correct.
Design for maintenance
The prosthesis will need cleaning daily by the patient and periodically by a hygienist for as long as it is in service. If it cannot be cleaned, it will fail eventually regardless of how well it was made.
That means access beneath the intaglio surface, a convex and polished tissue surface rather than a concave one, and enough space for an interdental brush to pass. It also means the prosthesis should be retrievable, which in practice means screw retained.
These pull against the instinct to close every space and support every papilla. On a full arch, cleansability wins.
Talk to the laboratory before surgery
Full-arch work is the least suitable category for a prescription written at dispatch. The plan, the prosthesis type, the vertical dimension, the occlusal scheme and the verification approach should all be agreed at the outset.
A conversation at the planning stage is worth considerably more than any amount of documentation afterwards.
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Digital scans and conventional impressions are both accepted. Cases move by UPS and Purolator, and Fairmont works with practices throughout British Columbia and across Canada.