All-on-4 vs All-on-6: Which Full-Arch Solution Is Right for You?

Neither All-on-4 nor All-on-6 is universally better — they suit different jaws. All-on-4 places four implants, the rear two angled to engage more bone and often avoid grafting, which makes it ideal where bone is limited; All-on-6 adds two posterior implants, shortening the bridge's unsupported cantilever and spreading bite force where bone is adequate. The right choice is decided by a 3D CBCT scan, not the bigger number. At Taki Dent in Antalya — Turkish Ministry of Health accredited and International Health Tourism authorised (Certificate ST-6335), led by Specialist Prosthodontist Dr. Sadık Taki — the protocol is chosen to fit your anatomy, with a 5-year written guarantee. This guide explains how to think it through.

What is the real difference between All-on-4 and All-on-6?

The number in each name tells you how many implants anchor a single full arch of fixed teeth. All-on-4 places four implants — the two at the front upright, the two at the back angled forward to engage more available bone and clear anatomical obstacles such as the maxillary sinus or the inferior alveolar nerve. All-on-6 follows the same fixed-arch principle but adds two more implants, usually toward the back, so the load is shared across six fixtures rather than four.

Both are legitimate, well-documented protocols with strong long-term track records, and it is a mistake to frame the decision as a winner and a loser. They are tools for different anatomies. The job of a good prosthodontist is to match the tool to the jaw — sometimes four, sometimes six — and to be able to explain exactly why.

Why does the cantilever decide so much?

The single most useful concept for understanding this choice is the cantilever. Every fixed full-arch bridge extends backwards a little beyond the rearmost implant, so that you have molars to chew with. That overhanging section is the cantilever, and it acts like a lever: the longer it is, the more leverage every chewing stroke places on the implants that support it.

This is where the extra two implants in All-on-6 earn their place. By adding posterior support, All-on-6 typically shortens the cantilever and distributes bite force across more points, which can be more forgiving for the supporting bone — particularly at the back of the mouth where chewing forces are highest. It also tends to give more confident rear-tooth chewing. The closely related idea is the crown-to-implant ratio: where a tall bridge sits on relatively short implants, leverage rises again, and the additional posterior support of All-on-6 can be protective. None of this makes All-on-4 inferior; it explains when the extra implants are worth having.

When is All-on-4 the better choice?

All-on-4 exists for sound clinical reasons, and for many patients it is the preferable option, not a compromise. Its defining feature — angling the posterior implants — lets the surgeon place fixtures in the densest available bone and frequently avoid a sinus lift or bone graft. That matters because long-standing tooth loss causes the jawbone to resorb, and many patients arriving for full-arch treatment simply do not have enough posterior bone to take two more upright implants safely.

In those cases, forcing six implants where the bone cannot support them is the wrong instinct. All-on-4 delivers a fully fixed arch with less surgical complexity, often no grafting, a shorter healing path and a lower cost — all without sacrificing the fixed, non-removable result patients want. If your CBCT scan shows limited posterior bone, expect a conscientious prosthodontist to recommend All-on-4 and to explain the anatomy behind it. You can read more on our dedicated All-on-4 page and our side-by-side All-on-6 vs All-on-4 comparison.

When is All-on-6 worth the extra two implants?

Where bone volume at the back of the jaw is adequate, All-on-6 becomes an attractive option. The two additional posterior implants shorten the cantilever, share the chewing load and add a margin of redundancy — if one implant were ever to face a problem, the arch is supported by more fixtures. For patients who chew vigorously, who grind, or who simply want the most robust load distribution their anatomy allows, that margin is meaningful.

The honest caveat is that this advantage is conditional on the bone being there. All-on-6 is not "All-on-4 plus a safety upgrade you can always buy"; it is a different plan that requires sufficient bone in specific sites. That is precisely why the decision cannot be made from a price list — it has to come from a scan.

How does a prosthodontist actually decide?

The decision is led by a 3D cone-beam CT (CBCT) scan, which maps your bone height, width and density site by site, and reveals the position of the sinus and nerves. Against that, the prosthodontist weighs your bite, any grinding or clenching habits, and your goals, then plans implant number, position and angulation digitally before any surgery takes place.

This evidence-led approach is reflected in Dr. Taki's own research. His work on the factors influencing marginal bone loss around dental implants, published in Quintessence International (2020), examined how implant-related variables affect the bone preserved around each fixture (DOI: 10.3290/j.qi.a43864) — directly relevant to how implant number and position are planned. A separate study on crestal bone loss comparing implant-supported prostheses with sinus augmentation against distal cantilevered prostheses without augmentation, published in the Journal of Oral Implantology (2021), speaks precisely to the trade-off at the heart of the All-on-4 versus All-on-6 question — how far back you can extend support, and at what biological cost (DOI: 10.1563/aaid-joi-d-19-00324). The clinical message from both is consistent: the right number of implants is the number the anatomy supports.

What about cost — does All-on-6 cost more?

All-on-6 usually costs a little more than All-on-4 because there are two additional implants and components to place. At an accredited Turkish clinic such as Taki Dent, All-on-4 sits at the lower end of the full-arch range and All-on-6 slightly above it, but both fall far below UK private prices of roughly £18,000–£28,000 per arch. The sensible way to compare is on an itemised quote that states the implant system, the number of implants and the final bridge material, so you are comparing like with like rather than two headline numbers. Our All-on-6 cost comparison for 2026 walks through exactly what an honest quote should contain.

The bottom line: let the scan choose

All-on-4 and All-on-6 are two well-evidenced routes to the same goal — a fixed, full arch of teeth that does not come out. All-on-4's angled design wins where bone is limited and grafting is best avoided; All-on-6's extra posterior implants win where bone is adequate and you want the most robust load distribution. The wrong way to choose is to assume more implants is always better. The right way is a CBCT-led plan from a named specialist who will recommend four or six on the merits of your jaw. At an accredited clinic such as Taki Dent in Antalya, led by Dr. Sadık Taki, that is exactly how the decision is made — and it is the decision, not the number, that protects your result.