All-on-4 vs. All-on-6

I place All-on-6 on every full-mouth implant case, never All-on-4, sometimes six, sometimes eight, on the same single-day surgery. Six implants spread your bite across more anchor points and leave a margin of safety if one site ever has trouble. With four, a single implant complication can put the whole arch at risk. That redundancy is the entire difference.

The four-implant protocol was settled on in the 1990s for surgical speed and lower cost, not for longevity. Three decades later the case for “four as a floor” is far weaker than the brand name suggests, and I’ll show you why on your own scan.

A table on four legs falls when one leg slips. Six holds. I think of the mouth as six parts, front, middle, and back, on both sides, and I want an anchor in each one. The surgery is the same length, the same sedation, the same same-day fixed arch. The only thing that changes is whether one bad site can defeat your whole restoration twenty years from now.

This page assumes you have already decided on fixed implant teeth for a full arch. If you are still weighing that against a removable plate, start with dentures versus dental implants; if you are only missing a single tooth, the choice is usually an implant versus a bridge instead. Once full-arch implants are the plan, the four-versus-six question below is the one that decides how long that arch lasts.

Picture a table on four legs. It works fine, until one leg slips, and the whole thing comes down. That is what a single implant failure does to an All-on-4 arch: lose one of the four and the entire bridge is at risk, because the remaining three were never designed to carry the load alone. The cruel part is you feel nothing. The implants are splinted, so a loose one hides until the whole arch is moving. By the time I see it, the bone loss can be catastrophic.

Now picture six legs. Lose one and the table still stands on five, and I can repair the failed site without taking the whole structure apart. That is the margin of safety I want every patient to have, and it is a big part of how long a full arch actually lasts.

There is one more reason I refuse to stop at four: cantilevers. With four implants the back teeth of the bridge hang past the last screw with nothing under them. Any chewing force on that hanging end multiplies onto the nearest implant, like bending a stick by pulling its unsupported end, and the bone around that implant disappears fast. With six, I put an anchor at the very back of the arch instead. No cantilever, no lever forces, no implant doing a neighbor’s job. That is the biology-first call, and it is why I build for the long haul rather than the brochure.

Both designs survive well on paper, the gap is in what a failure costs you. A 2019 systematic review in the Journal of Dentistry (Howe et al., 2019) reports around 96% implant survival at ten years, with survival curves that flatten rather than fall sharply. The ADA puts general implant success at 90 to 95% over 10 years. Those are strong numbers for either approach.

The headline figure hides the geometry. With four implants, one lost site is rarely a single-implant problem, it can mean losing the whole arch, because there is no redundancy to absorb it. With six, biological variation across the sites is expected and survivable: when one of six has trouble, the prosthesis is almost always salvageable, and I lean on what actually drives implant failure to catch the rare problem early. When one of four fails, it usually is not salvageable.

The number I hold myself to is simpler: across the full-arch cases I’ve placed, I have never had a patient lose an arch. I track every implant in our practice software, which ones had problems and why, because a survival number you don’t verify is just marketing.

The original four-implant protocol was developed in the 1990s, when implants were expensive, CT planning was rare, and the goal was simply to get patients out of dentures as cheaply as possible. Four was the minimum count that met that goal, and for its time it was a real step forward. I don’t knock it as history.

Three decades later the math has changed. Implants are far cheaper, CT planning is standard, and surface treatments, the kind I rely on with UV-activated implants, have made integration much more reliable. The case for four-as-a-floor is weaker than it was. What keeps it the default is inertia and a recognizable brand name, not the biology.

High-volume operations still lean on four because it is faster to produce and easier to bill, some run several full arches a day, with no time for the bone-and-tissue work that six implants demand. I made a different choice, and I’m happy to defend it tooth by tooth.

Every full-arch case in our Downey operatory is planned as All-on-6 from the CT scan forward: six implants per arch, a surgical guide printed from your own anatomy, IV sedation run by an in-house anesthesia provider, a same-day temporary bridge, and the final zirconia bridge at about the four-month mark. Under that zirconia I design a titanium bar , a metal core that splints all six implants together so the bite is shared evenly, and that stops a crack from ever traveling across the bridge the way it would through zirconia alone. It dampens force like a roll bar in a race car. I would not do a full arch without one.

When the back of the jaw is short on bone, I don’t retreat to four, I add bone. A sinus lift, ridge augmentation, or tilted posterior implants let me reach six anchor points even with significant bone loss. That grafting, when it’s needed to reach the six-implant geometry, is included in the All-on-6 price, not itemized as a separate line the way many offices do it.

And for the rare upper jaw so atrophied that even grafting can’t rebuild the back, I place zygomatic implants anchored in the cheekbone. The geometry still reaches six. The principle does not bend.

All-on-6 starts at $20,000 per arch, all-inclusive, and a full set of both arches is $40,000. That price covers the consultation, the 3D CBCT scan, the surgical guide, all six implants, IV sedation with an in-house anesthesia provider, the same-day temporary, every post-op visit, and the final zirconia bridge. Bone grafting and sinus lifts, when they’re needed to reach the six-implant geometry, are included , not a surprise line on the plan.

The arch carries my 10-year biological warranty , the bone integration, the peri-implant seal, and the durability of the zirconia, surgery and lab included. I warranty the biology because that’s the part that actually fails; the restoration itself is built not to. (I don’t, and no honest practice should, promise a “lifetime implant warranty.”)

Here’s the part price-shoppers miss: the real cost of a full arch is whether it lasts. An arch done cheaply that has to be redone can cost you several times over, in dollars, in lost bone, and in months back in a temporary. Done right the first time, six implants are the more economical choice over a thirty-year horizon. If you want the full breakdown, I laid out what All-on-4 really costs per arch and why the lowest sticker price is rarely the cheapest in the end.

For qualified patients, 0% financing can bring a single arch to roughly $333 a month over five years. The exact figure, based on your scan and case complexity, is written down at your consult, with no deposit to see it.

If another office has quoted you All-on-4, you don’t have to take it. Bring the imaging and the treatment plan to your consult and I’ll walk you through the difference on your specific anatomy. The CBCT I take here will show you exactly where the six anchor points would sit and what the biological margin looks like next to four, on your own jaw, not a brochure.

I don’t lecture and I don’t push. I tell you what I would do for myself, why, and what the long-term data says, then you decide. The consultation is free, with no deposit, and it’s applied to your treatment if you move forward.

Forty-five minutes with me personally, not a treatment coordinator. You leave with a written plan, exact pricing, and a clear understanding of why six holds when four would not.