The core difference
All-on-4 is a named full-arch treatment concept using four implants. All-on-X is a broader clinical and marketing term for full-arch implant treatment in which the number of implants can vary. That might mean four, five, six or another configuration based on the jaw, bone, restorative design and clinician's treatment philosophy.
Four implants vs six implants
| Question | All-on-4 | All-on-X / six-implant example |
|---|---|---|
| Implant count | Four | Selected by the clinician |
| Full fixed arch | Yes, when indicated | Yes, when indicated |
| Immediate provisional | May be possible | May be possible |
| Bone graft always avoided? | No | No |
| Best for everyone? | No | No |
With six implants, there may be more implant positions available to distribute support in some cases. But the extra implants also need adequate bone, safe spacing and a restorative reason to be there.
How the implant number is chosen
Factors can include bone volume and density, the shape of the jaw, location of nerves or sinuses, opposing teeth, parafunctional habits such as grinding, restorative material, prosthetic span, cantilever design and the clinician's preferred protocol. A well-planned four-implant case may be better than a poorly planned six-implant case.
Why 3D imaging matters
CBCT imaging can help a clinician evaluate the three-dimensional relationship between available bone and important anatomy. It is one component of planning, alongside the clinical exam and restorative design.
Can both approaches provide “teeth in a day”?
Potentially. Immediate provisionalization depends more on implant stability, case design and clinician protocol than on whether the label says All-on-4 or All-on-X. The final prosthesis is typically completed after the healing phase.
Which is better?
Neither label is universally better. A patient should care more about why a particular implant count is being recommended, the experience of the surgical and restorative team, whether the planned bridge is cleansable, the quality of the final prosthesis, the maintenance program and how complications are handled.
SmileCrafters' public implant information uses the All-on-X framework and explains that the “X” allows the number of implants to be chosen according to the case rather than assuming every jaw should receive exactly four or six.
Questions to ask at your consultation
- How many implants are you recommending for each arch and why?
- What happens if one implant cannot be placed in the planned position?
- How much cantilever will the final bridge have?
- What provisional and final materials do you use?
- How will I clean underneath the bridge?
- What follow-up schedule do you recommend?
General information only. Your implant number and treatment design require a clinical examination and imaging by a licensed dentist.