All-on-4 or All-on-6: What the Two Extra Implants Change
Two more implants means two more surgical lines on the bill and a different set of supports under the same bridge. What it does not mean is a published verdict — no source we could read says one layout beats the other for a given jaw.
The difference between the two is two implants, and everything that follows from two implants: two more surgical sites, two more healing sites, two more lines on the plan, and a bridge whose load sits on six supports instead of four. The difference is not that one of them is the better treatment, because no published source we could read says that about jaws in general — and none could say it about yours without looking at it.
What is actually being compared
Both describe a single fixed prosthesis replacing one whole arch. All-on-4 is a trademarked treatment concept using four implants; "all-on-6" is the generic way people describe the same idea with six. The teeth on top look the same in an advertisement, which is why the comparison is usually made on price.
The published literature is more cautious than the marketing on either side. A 2024 review of fixed full-arch techniques in Dentistry Journal describes the variety of approaches and says that across them "the common denominator remains the use of three or more dental implants, with extensive support for the all-on-four treatment concept". Three or more is the floor it names. It ranks nothing above anything.
The procedure codes do not count implants
This is the part that clears up most of the confusion about quotes. On every fee schedule we read, the prosthesis for an edentulous arch is one line, billed per arch, and it says nothing about how many implants are underneath it. The implant count appears in a different place: the surgical line, billed per implant.
So the price difference between the two layouts is, on the face of the schedule, arithmetic on one code:
The surgical lines only, at two published schedules, for one arch
| How many implants | New York | Michigan |
|---|---|---|
| Four | $4,040.00 | $5,895.20 |
| Six | $6,060.00 | $8,842.80 |
| The difference | $2,020.00 | $2,947.60 |
Those are four and six multiples of the implant-body line: $1,010.00 each in New York, $1,473.80 each in Michigan. They are allowed amounts under public programmes rather than retail prices, and the full ladder they sit in is set out in what a whole arch costs, code by code.
What the arithmetic tells you is the shape of the difference, not the size of the bill. Two more implants may also change the imaging, the surgical time, the sedation, the framework and the laboratory work, and none of those are in the sum above.
The retail guides make the comparison worse, not better
Here is a useful demonstration that consumer price guides are not measurements. CareCredit publishes a cost guide for All-on-4 reporting a national average of $15,176, within a range of $11,640 to $27,500. It publishes a separate guide for a system that places six implants per arch and carries three bridge sections, reporting an average of $12,474, within $9,708 to $24,091.
Read casually, that says six implants cost less than four. Read properly, it says two articles, published a few months apart and drawing on the same market-research study, describe two differently-defined products with different sets of practices behind them. Both figures are attributed by the publisher to the 2024 Synchrony Average Procedural Cost Study, conducted by ASQ360° Market Research; neither is a like-for-like comparison of implant counts, and neither is ours.
If you take one thing from this page, take that: a national average for a procedure defined this loosely cannot be used to choose between two versions of it.
What the extra implants are meant to do
The arguments made for six are about engineering: more supports under the same bridge, shorter spans between them, load spread more widely, and — this one is worth asking about directly — the possibility that the prosthesis can be salvaged if one implant is lost. The arguments made for four are fewer surgical sites, less bone required, and a shorter, cheaper operation.
We are not qualified to adjudicate that, and we have not found a public source that adjudicates it either. What the same review does say, about the fixed acrylic version of this work, is that it is reported with "a success rate exceeding 95% for implant survival and 97% for prosthetic survival during a 1–6-year follow-up", with "screw loosening and acrylic component fracture" as the common complications. That is a figure for the approach in published studies over a few years — not a promise, not a lifetime, and not attached to an implant count.
Where the extra money actually lands
The surgical lines are the visible part of the difference, and they are not all of it. Two more implants can mean a longer operation, more time under sedation, more components, a larger laboratory bill for a framework spanning six connections rather than four, and in some cases imaging or planning work that a simpler layout would not need.
None of those appear in the arithmetic above, because none of them can be read off a fee schedule for your case. They appear in an itemised plan, which is the reason this site keeps asking for one: a comparison between layouts is only a comparison if both are costed the same way, line for line.
The questions that actually decide it
An honest consultation will answer these without being pushed:
- How many implants are you proposing for my arch, and what in my imaging makes that the number?
- What happens to the prosthesis if one implant fails — is it salvageable on this layout, and what would that cost?
- Does the number change what the bridge is made of, or how long the spans between supports are?
- Is the extra surgery in a six-implant plan possible with my bone volume, or would it need grafting?
- How does the plan's total change, line by line, between the two layouts?
Question five is the one people skip, and it is the one the fee schedules suggest is answerable: if a practice cannot show you which lines change and by how much, the comparison being offered is not a comparison.
What we will not tell you
Which is better. Not because it is diplomatic, but because it would be a diagnosis, and this page is written by editors who read documents rather than jaws. Bone volume, bite forces, the opposing arch, your general health and your ability to clean under a fixed prosthesis all belong to the examination.
The neighbouring question — what the brand names in all this actually denote — is taken apart in what "All-on-X" means when the codes carry no brand.
Questions about implant counts
Is six implants safer than four?
We found no published source that says so as a general rule, and we will not say it. The review we cite names three or more implants as the common denominator for fixed full-arch work and gives extensive support to the four-implant concept, without ranking layouts against each other.
Why is the six-implant guide cheaper than the four-implant one?
Because they are separate consumer cost guides about differently defined treatments, published months apart, not a controlled comparison. The lesson is about the figures, not about implants.
Does insurance care how many implants there are?
A plan pays against codes, so the implant line is the one that multiplies. Whether any of it is covered at all is a separate matter, worked through in our page on what coverage actually pays.
Can I start with four and add two later?
That is a clinical question for the surgeon who would do it, and the answer depends on bone, the prosthesis design and what is already in place. It is a reasonable thing to ask in a consultation.
Next on the same case
Acrylic or Zirconia: What the Arch Is Made Of, and What Breaks
The material of a fixed arch changes what fails, how it is repaired and what it costs — and not one of the three published fee schedules we read prices a prosthesis by material. That absence is the most useful fact on this page.
“All-on-X” Explained: A Brand, a Number, and What the Bill Says
All-on-X is what the industry writes when it means “a fixed arch on however many implants”, because the four-implant version of the phrase belongs to a manufacturer. The codes underneath carry no brand at all, which is both a relief and a problem.