"All-on-4" started life as a trademarked protocol from Nobel Biocare: four implants per arch, the back two tilted to avoid the sinus and the nerve, carrying a full fixed bridge. It worked so well that the phrase escaped the trademark and became shorthand for any fixed full-arch bridge on implants. "All-on-6" adds two implants. "All-on-X" is the newer umbrella term clinics use when they want to decide the number after seeing your scan, which is honestly the right way round.
Why the number changes
The implants are the foundations of a bridge that has to survive decades of chewing. More foundations spread the load, give the prosthesis more support, and leave you with a fallback if one implant fails. Fewer foundations mean less surgery, less cost, and fewer places bone needs to be adequate. Surgeons pick the number based on three things:
- Bone volume and density. Soft or thin bone, especially in the upper jaw near the sinuses, pushes towards six. Dense lower-jaw bone often does fine on four.
- Bite force and habits. Heavy grinders, people with a strong opposing arch of natural teeth, and younger patients who will load the bridge for 40 years tend to get more implants.
- Prosthesis design. A longer, cantilevered bridge (more teeth hanging past the last implant) needs more support. Six implants shorten the cantilever.
All-on-4
The minimum for a fixed arch. Suited to the lower jaw and to patients with reasonable bone who want the lowest fixed-arch cost. The tilted design is specifically meant to avoid sinus lifts and nerve grafting, which is why it became the go-to for people who were told they were "not implant candidates." If one implant fails during healing, the arch usually has to be converted to a removable temporary until it is replaced.
All-on-6
Six implants, straighter placement, more redundancy. Common in the upper jaw where bone is softer, and for patients who want the extra security. The extra two implants add surgery time and roughly 15 to 25 percent to the cost, but the arch tolerates a single implant failure without losing its fixed status.
All-on-X
Not a different treatment, just an honest label. It tells you the clinic plans to place between four and six (occasionally eight) implants depending on what the CT scan shows. When a clinic quotes "All-on-X" they should tell you the price at four and at six so you know the ceiling.
The immediate-load question
Most full-arch protocols deliver a temporary acrylic bridge within 24 to 72 hours of surgery, so you leave with teeth. The final zirconia or acrylic-titanium bridge comes after the implants have integrated, usually four to six months later, and that can be done on a second trip or, at some clinics, by a partner lab at home. Ask which. Ask also what the final bridge is made of, because a monolithic zirconia bridge and an acrylic-on-titanium bridge differ in price, feel and repairability.
Which one should you ask for?
None of them. Ask for the scan, then ask the surgeon to justify the number. A clinic that quotes All-on-4 before seeing a CBCT is selling a package, not planning a case. A clinic that walks you through why your upper arch wants six and your lower arch is fine on four is doing the job. Related: the snap-in alternative, full-arch cost US vs abroad, and who qualifies for teeth in a day.
Full-arch cases are the reason most people fly. Colombian clinics routinely deliver All-on-4 and All-on-6 with immediate temporary teeth in a seven to ten day trip, using the same implant systems, at roughly a third of US pricing. See the vetted clinics at colombiadentist.co, full-mouth cases at fullmouthrestoration.co, or start at the network hub, colombiamedical.co.
Frequently asked
Is All-on-6 always better than All-on-4?
Not always. In dense lower-jaw bone, four well-placed implants perform very well and add less surgery. Six is more common in the upper jaw and for heavy biters. The decision should follow the CT scan, not a menu.
Can I get All-on-4 in one trip?
Usually yes. Extractions, implants and a temporary fixed bridge are typically done within a seven to ten day trip. The final bridge is fitted after four to six months of healing, on a second visit.
What if one implant fails?
With four implants the arch is often converted to a temporary removable until the implant is replaced. With six, the bridge can usually stay fixed on the remaining five. That redundancy is the main practical argument for six.
All prices are typical 2026 ranges drawn from published US self-pay data and Colombian clinic price lists, not quotes. USD/COP moved from roughly 3,805 to 3,070 during 2026, so dollar figures for Colombia have risen versus older articles. Only a clinic that has reviewed your scan can give you a real number. This is educational content, not medical advice.
