All-on-4 restores a whole jaw on just four implants: two straight ones at the front and two rear ones tilted up to 45°. The tilt makes use of the existing bone in the front and bypasses the sinus (upper jaw) or the jaw nerve (lower jaw) — so in most cases no bone grafting is needed. A bridge of 10–12 teeth is screwed onto the four implants: provisional on the same day, permanent after healing.
Medically reviewed by the network's medical management · updated:
Why four, and why tilted
Jawbone resorbs over the years where there are no teeth, especially at the back. Instead of building new bone (a months-long process) the method uses the good bone that remains at the front: the rear implants “lie” at an angle and reach further back, so the bridge is supported along most of the jaw. Four implants joined by a rigid bridge brace each other, and because of that they can be loaded on the same day.
Pros and cons
| Pros | What to know |
|---|---|
| Fixed teeth the same day | The provisional bridge is acrylic; the permanent one comes after 3–6 months |
| Usually no bone graft | When the front bone is also very thin we consider All-on-6, longer implants or preparation |
| One surgery, fast recovery | A week of swelling and a soft diet for a few months |
| Easier to maintain than single teeth | Needs daily cleaning under the bridge and a yearly check-up |
| Lower cost than 8–10 single implants | If one of four implants does not fuse, the bridge loses a quarter of its support and it must be dealt with quickly — which is why the check-ups are not optional |
How it is done across the network
The plan is made at the network planning centre on your CT: four implants, the angles, and the bridge that will sit on them — before anyone touches your mouth. The surgical guide and the provisional bridge are printed from that plan and delivered to the clinic you chose. On the day: extractions if needed, implants through the guide, measurement, and if stability is sufficient the bridge is screwed in the same day. The permanent one comes after healing.
With us, All-on-4 is the default for the lower jaw, not the upper. Upper bone is softer, and we prefer six implants there even when four “would have done” on paper. It costs a little more, and we say why.
All-on-4 or All-on-6?
The decision follows from the quantity and quality of bone, the jaw (upper or lower), chewing force and habits (grinding). In the upper jaw, where bone is softer, we often prefer six implants. In the lower jaw four is enough in most cases. It is a decision made at planning, on the CT, and you see it on screen before anything is decided.
Frequently asked questions
Are four implants really enough for a whole jaw?
Yes, when they’re positioned correctly and joined by a rigid bridge. The idea isn’t “four instead of eight” but spread: two straight at the front, two at the back tilted at up to 45° so they reach far back and use the bone that’s left at the front. With all four joined in one bridge, force on one implant is shared among them all, and none moves on its own. The method has existed and been documented since the 1990s, with high success rates over the years. Where we’d prefer six: the upper jaw, where the bone is softer; people who grind their teeth; anyone who wants a longer bridge further back. In a lower jaw with good bone, four hold like six. The CT decides, and you’ll see why on screen.
How many teeth are in an All-on-4 bridge?
Usually 10–12 teeth per jaw — from the front teeth to the first molar on each side, sometimes the second. A full natural mouth has 14 per jaw (without wisdom teeth), so two to four are missing at the back. You don’t notice it when chewing: the rearmost molars contribute little and load a lot, and they’re the ones that would create a long lever on the back implants. You don’t see them when you smile either. What does decide how many teeth go in is where the back implants sit — the further back they reach, the longer the bridge can be. That’s one of the considerations when we suggest six implants rather than four for someone who wants a bridge up to the second molar.
Is a bone graft needed before All-on-4?
In most cases no, and that’s really the main advantage of the method. Bone resorbs over the years mainly at the back — in the upper jaw the sinus drops, in the lower the nerve is close — and instead of building new bone there (months of healing and another operation), the back implants are tilted to use the good bone that’s left at the front. So someone who was told “you’ve no bone” on the strength of a panoramic X-ray doesn’t necessarily need a bone graft. When you do: when the bone at the front is very thin as well. Then we talk about preparation — a bone graft, extra-long implants — or an alternative such as an implant overdenture. That’s measured on a 3D CT, not on a hunch.
Is All-on-4 a brand name?
Not exactly. It’s the name of a method a Portuguese dentist developed in the 1990s together with one implant manufacturer, which registered the name as a trademark. Since then the method has become a generic term for any bridge on four implants with two of them tilted — like “Jeep” for a 4×4. The medical idea belongs to no one: implants tilted at an angle, a rigid bridge joining them, and loading on the same day. The implants we use come from established manufacturers with a long clinical record — not necessarily that one — and the method is the same. What is worth asking, at any clinic: which manufacturer, where you get spare parts in ten years’ time, and whether you get an implant passport. You’ll have our answers in writing.
Does the bridge cover the palate?
No. That’s the big difference from an upper denture: the bridge sits on the implants only, as a slim arch along the ridge, and the palate is free. People who’ve switched from a denture talk about that more than about chewing — the taste and warmth of food come back, there’s no foreign-body feeling, no gagging, and you speak as before. Even the provisional bridge you leave with on the day of surgery has no palate. When part of the palate is covered: with a removable implant overdenture in the upper jaw — there the surface is needed for stability, though far less than with an ordinary denture. That’s one of the considerations when choosing between the two. And if you have a strong gag reflex — say so at the consultation; it affects the choice and how we scan.
How long does the permanent bridge last?
Zirconia — 15 years and more, and usually what gets replaced before that isn’t the bridge but what’s under it: a screw that loosens is tightened at the yearly check-up, a worn component is replaced. The zirconia itself doesn’t stain and doesn’t change colour. A hybrid bridge — a titanium frame with acrylic teeth — behaves differently: the teeth wear and are renewed after 7–10 years, the frame stays, and the renewal is done in the lab without touching the implants. What shortens a bridge’s life: grinding without a night guard (a crack in zirconia usually starts there), poor cleaning that causes inflammation around the implants, and skipping the yearly check-up where a loose screw is found before it breaks. All three are in your hands.
The results described are not guaranteed: they vary from patient to patient and depend on the starting condition, general health and adherence to instructions; the type of treatment is decided only after an examination.
Want to know if immediate loading is right for you?
A first consultation at any network clinic includes an exam, a reading of your scan and an explanation of the options — no obligation.