All-on-X: five, six, eight, or zygomatic implants
Four and six are the best-known numbers, but they aren't the only ones. "All-on-X" is the umbrella term.
Medically reviewed by Dt. Hüseyin Yavuz Özbek, implant surgeon · Updated October 2026All-on-X means a full arch of fixed teeth on however many implants a dentist plans, usually between four and eight. Five is sometimes used in lower jaws, and eight in upper jaws with plenty of bone. When there's very little upper-jaw bone, long zygomatic implants anchored in the cheekbone can be an alternative to grafting. The number should follow your scan, not a package name.
What "All-on-X" means
All-on-X is a general way of saying "a full arch of fixed teeth on X implants". The bridge and the idea are the same whatever the number. What changes is how many implants hold it and where they go.
The common numbers
| Implants | Where it's often used | Worth knowing |
|---|---|---|
| Four | Upper or lower jaw, especially with limited bone at the back | Back implants usually tilted. All-on-4® explained |
| Five | Mostly lower jaws | A middle ground; a fifth implant at the front |
| Six | Upper or lower jaw with enough bone along the arch | More supports, more bone needed. All-on-6 explained |
| Eight | Mostly upper jaws with plenty of bone | Sometimes made as two or more bridge sections |
More implants isn't always better
It's tempting to think eight beats six and six beats four. The research doesn't support that as a rule. A 2018 review of 93 studies found no significant difference in implant or bridge survival between fewer than five and five or more implants per jaw. An earlier review of studies with at least five years' follow-up found no link between the number of implants and survival, complications or bone loss, although only two of its studies directly compared numbers.
Every extra implant needs bone, adds surgery and adds something to keep clean. The aim is enough well-placed implants for your jaw and bite, not the highest number.
Zygomatic implants: when there's very little bone
Sometimes the upper jaw has so little bone that standard implants have nothing to hold. One option is a bone graft or sinus lift, then implants months later. Another is zygomatic implants: long implants that run up to anchor in the cheekbone.
- It's specialist surgery with its own risks, so ask about the surgeon's experience with it.
- It's usually more expensive than standard implants.
- Not everyone told they have "no bone" needs it. A second opinion on your scan is reasonable.
Ask why, not just how many. A good plan explains why your dentist chose that number, using your scan. If a clinic offers a fixed package name before seeing your X-ray, ask what would change once they do.
Common questions
Is All-on-8 better than All-on-6?
Not automatically. Eight implants need plenty of bone and mean more surgery. Reviews haven't shown that more implants always last longer. Eight is a choice some dentists make for upper jaws with good bone or very strong bites.
What are zygomatic implants?
Long implants that anchor in the cheekbone (zygoma) instead of the upper jawbone. They're used when the upper jaw has too little bone for standard implants. It's more complex surgery, done by specialists, and not everyone needs it.
Why would a clinic offer All-on-5?
Five implants are sometimes used in lower jaws, where the space between the nerves allows a fifth implant at the front. It's a middle ground between four and six.
Sources
- Polido et al. (2018), Clinical Oral Implants Research — Number of implants placed for complete-arch fixed prostheses: systematic review and meta-analysis
- Dental Elf — Number of implants and full-arch prosthesis survival (summary of de Luna Gomes et al., 2018)
- Nobel Biocare — All-on-4® treatment concept
Checked October 2026. Where we give our own view as a clinic, we say so.
Only a scan can settle it.
Send us an X-ray or scan if you have one. A dentist will tell you which option suits your bone, and say so honestly if neither is the right step.