All-on-6 vs All-on-4 Dental Implants: Which One and What's the Difference?

Four implants to hold a full jaw of teeth. That's the idea behind All-on-4, and it's one of the most elegant solutions in modern dentistry. But then someone mentions All-on-6, and suddenly there's a question that didn't exist before: if four implants work, why would you want six? And if six is better, why doesn't everyone get six?

The answer is satisfyingly specific. The difference between four and six implants isn't about "more is better." It's about bone density, jaw anatomy, and what gives the best long-term outcome for a particular mouth. Some people genuinely benefit from six. Others are perfectly served by four. And the price difference between them is significant enough that understanding why matters.

The Numbers Side by Side

All-on-4 costs £8,000-£16,000 per jaw. For both upper and lower jaws, that's roughly £20,000-£30,000.

All-on-6 costs £11,000-£22,000 per jaw. Both jaws together: £25,000-£40,000.

The difference, £3,000-£6,000 per jaw, comes from two additional implant fixtures, the slightly longer surgery time, and the modified bridge design that distributes force across six points instead of four.

That's a meaningful sum. And the question people really want answered is: do those two extra implants buy anything proportionally meaningful in return?

What Four Implants Do

The All-on-4 concept, developed by Portuguese implantologist Paulo Maló over two decades ago, works on a principle that sounds deceptively simple.

Four implants go into each jaw. The two at the front are placed vertically in the dense anterior bone. The two at the back are tilted at 30-45 degrees, angling away from the sinus cavities (upper jaw) or nerve canal (lower jaw) to grip into the densest available bone.

That tilt is the innovation that made everything possible. A straight implant in the posterior jaw often runs into problems: thin bone, sinus proximity, nerve proximity. Tilting the implant sidesteps all of those issues while actually grabbing more bone surface area, up to 50% more than a straight posterior implant.

A full arch bridge is then attached across all four implants, spreading chewing force evenly. The bridge holds 10-14 teeth per jaw. The implants share the load. The engineering is sound, and the clinical evidence backs it up: ten-year survival rates for All-on-4 sit at around 94-98% across multiple large-scale studies.

For the lower jaw in particular, four implants are usually more than sufficient. The lower jawbone (mandible) is naturally dense, compact, and structurally strong. Four well-placed implants provide excellent support with significant safety margin.

What Six Implants Add

The argument for All-on-6 is most compelling in the upper jaw. The maxilla (upper jawbone) is structured differently from the mandible. It's less dense, more porous, and contains the maxillary sinuses, those air-filled cavities that limit where implants can go. The bone quality in the upper jaw is simply softer, and softer bone means each implant has less grip per unit of surface area.

Six implants in the upper jaw distribute the chewing force across a wider area, reducing the load on each individual implant. In softer bone, this wider distribution provides extra security. The bridge design accommodates the additional support points, and the overall stability of the arch increases.

The clinical literature shows very similar long-term success rates for both approaches, both sitting in the 94-98% range at ten years. The difference is more nuanced than survival rates alone capture: it's about how much safety margin exists in the system. Six implants in soft upper jaw bone create more redundancy. If one implant has a slightly imperfect integration, the remaining five continue to support the bridge without issue. With four implants, the margin is thinner.

For the lower jaw, the case for six implants is weaker. The bone is already dense enough that four implants provide ample support. Adding two more doesn't meaningfully improve an outcome that's already excellent. Most implant specialists recommend four for the lower and consider six for the upper, especially in patients with softer bone or a history of bone loss.

The Decision Framework

There's a clear way to think about which option suits a particular situation, and it comes down to a few specific factors.

Bone density is the primary consideration. If a CT scan shows good, dense bone in both jaws, All-on-4 provides excellent results at a lower cost. If the upper jaw bone is softer or has experienced significant resorption, All-on-6 in the upper jaw offers additional security.

History of bone loss matters. Patients who've been missing teeth for many years, or who've had gum disease that's eroded bone, tend to have less bone volume and density to work with. More implants spread the load across compromised bone more effectively.

Bruxism (teeth grinding) is worth considering. People who grind their teeth exert significantly higher forces on their dental work, sometimes two to three times normal biting force. The extra two implants in an All-on-6 provide additional resilience against those forces over decades of use.

And then there's the bridge material. A heavier zirconia bridge (the premium option at £4,000-£5,000 for the lab work) weighs more and transmits forces differently than a lighter acrylic bridge (£1,500 for the lab work). Some clinicians prefer six implants when placing a heavier zirconia bridge, particularly in the upper jaw, to ensure the support matches the material.

Surgery Day: What's Different

The surgical experience is similar for both approaches. The difference is modest.

An All-on-4 surgery takes 2-3 hours per jaw. The four implant sites are prepared, the implants are placed (two vertical, two tilted), and a temporary bridge is fitted immediately. You walk out with teeth that day.

An All-on-6 surgery takes 2.5-4 hours per jaw. Two additional implant sites are prepared and placed, which adds to the surgical time. Everything else, the immediate temporary bridge, the same-day teeth, the aftercare, is identical.

The additional surgery time for two more implants is genuine, but it's not dramatic. An extra 30-60 minutes under local anaesthetic (or IV sedation if you prefer) for a result that lasts decades.

Recovery is essentially the same for both. Swelling peaks at 48-72 hours. Soft foods for the first few weeks. Most people are back to normal activities within a week. The two extra implant sites don't significantly change the recovery experience, because the surgical area is the same: the jawbone under the gum.

The Hybrid Approach

Something that's becoming increasingly common: All-on-4 in the lower jaw and All-on-6 in the upper. This tailors the approach to each jaw's anatomy rather than applying the same formula to both.

The lower jaw gets four implants in dense bone. The upper jaw gets six in softer bone. The total implant count is ten rather than eight (All-on-4 both jaws) or twelve (All-on-6 both jaws), and the cost sits somewhere in between.

This mixed approach recognises that upper and lower jaws are fundamentally different structures with different bone properties, and it treats them accordingly. Many experienced implant surgeons consider this the optimal balance of cost, engineering, and clinical outcomes for full mouth restoration.

The cost for this hybrid approach typically runs £22,000-£35,000 for both jaws, depending on the bridge material and the region.

Long-Term Maintenance

Both All-on-4 and All-on-6 require the same maintenance protocol, and it's worth knowing what that looks like over the years.

The bridge needs professional cleaning twice a year. This involves the dentist or hygienist using specialised instruments to clean under and around the bridge, reaching areas that a normal toothbrush can't access. Some practices include this in a maintenance plan; others charge per visit.

The implants themselves don't decay (they're titanium), but the gum tissue around them can become inflamed if plaque builds up. Good daily cleaning with a water flosser or interdental brushes keeps this in check.

An acrylic bridge has a functional lifespan of about 10-15 years before it needs replacing. The replacement bridge costs £1,500-£3,000 for the lab work, and the implants underneath stay exactly as they are. A zirconia bridge lasts 20-25 years or potentially longer, which is one of the arguments for the higher upfront cost.

None of these maintenance considerations differ between All-on-4 and All-on-6. The bridge design, the cleaning protocol, the check-up frequency: it's all the same. The only difference is what's underneath, and that difference is invisible once the bridge is in place.

The Consultation Conversation

The decision between All-on-4 and All-on-6 isn't one you need to make before walking into a consultation. It's one that emerges from the consultation, based on what the CT scan reveals about your bone and what the implant specialist recommends for your specific anatomy.

Going in with a fixed idea of which one you want can actually work against you. The clinician who's looking at your three-dimensional bone scan has information you don't. If they recommend six implants, it's because your bone tells a story that benefits from the extra support. If they recommend four, it's because the bone is strong enough that additional implants would add cost without adding meaningful benefit.

At UrgentCare Dental, the implant consultation includes CT imaging and a thorough assessment of bone volume and density. The recommendation, whether that's All-on-4, All-on-6, or the hybrid approach, comes from the clinical picture rather than a one-size-fits-all philosophy.

The consultation conversation is also where the financial picture becomes clear. Payment plans can spread the cost across manageable monthly instalments, and knowing the exact figure before committing means the financial decision is as informed as the clinical one.

The Bottom Line

All-on-4 is the more established, more affordable, and brilliantly engineered solution that works excellently for the majority of patients. All-on-6 offers additional support that's most valuable in the upper jaw, in softer bone, and in patients with specific risk factors.

The £3,000-£6,000 per jaw difference buys two additional implant fixtures and the peace of mind that comes with extra redundancy in the system. Whether that's worth it depends entirely on what the bone looks like and what the specialist recommends.

Four implants hold a full jaw of teeth. Six implants hold a full jaw of teeth with extra security. Both approaches have decades of clinical evidence, excellent success rates, and outcomes that transform lives.

The right answer is the one that matches your anatomy. And the consultation is where that answer becomes clear.