Fewer sites, less component cost, simpler placement. For narrow arches with balanced bite, four is a clean plan.
vs All-on-4
All-on-5 vs All-on-4 — when the fifth implant earns the difference.
All-on-4 is a proven minimum. All-on-5 is not "All-on-4 plus one." It is a different prosthetic span and a different load story. The decision is made at the scan, not at the price list.
Clinically reviewed · Last reviewed 24 May 2026 · Editorial & review
The honest difference
Four works when the span is short. Five works when it isn't.
A four-post bridge spans from anterior implants to angled posterior implants. The unsupported zone between them — the cantilever — is the most common reason a four-post plan becomes a five-post plan.
When the posterior span is long, a four-post bridge flexes more under load. The fifth implant shortens that span.
One more support point, typically anterior or mid-arch. The added implant divides the load before it reaches the posterior cantilever.
The prosthesis above is the same kind of fixed full-arch screw-retained bridge. The five-post version is engineered to a different stress profile, not a different category.
The decision matrix
Five reads from the scan, five conclusions.
R1
Arch width. Wider arches generally favour five. A narrow lower arch with controlled bite often does well on four.
R2
Posterior cantilever length. If the unsupported posterior span is longer than the rule-of-thumb threshold, the fifth implant is added to shorten it.
R3
Bite forces and parafunction. Heavy clenchers or grinders distribute load more aggressively; the five-post layout reduces concentration points.
R4
Bone volume at the proposed fifth site. If the CBCT shows no usable bone there, forcing the fifth implant creates more risk than benefit. Four is the cleaner plan in that case.
R5
Maintenance access. Five supports require enough space between them for hygiene tools to pass. A crowded layout becomes a cleaning failure later, not a strength.
What changes at the bill
Five implants is one implant, one abutment more — not a new procedure.
What changes from 4 to 5 · per arch
line items
- Additional implant
- +1 titanium post
- Additional abutment
- +1 multi-unit
- Surgical time
- +30–45 min, typical
- Bridge design
- Re-engineered for 5 support points
- Diagnostics
- No change — same CBCT, scan, wax-up
- Bridge material
- No change — same Porcelain / Zirconia / PMMA options
- Recall schedule
- No change — same six-monthly hygiene
If the difference between two quotes is much larger than this set of line items would suggest, the difference is being made up elsewhere — usually in the bridge material or the warranty.