Questions to Ask Before You Sign an All-on-4 Plan

In the Austin area? Dr. Verrett provides this care in North Austin. See Replacing Several Teeth or a Full Arch, or request a consult.

A full-arch quote usually arrives at the end of a long appointment, with a scan on the screen, a smile design, a number, and sometimes a date. Most people sign or leave with the paperwork and then spend the next week trying to work out what, exactly, they were quoted for. That week is the right time to ask questions, and the questions below are the ones that turn a single number into something that can be compared with another office’s plan. None of them assumes the first plan is wrong. Many full-arch plans are sound, and asking these questions is how a patient finds that out.

Full-arch implants: how to decide compares the four options themselves. This article is narrower: it is for someone already holding a plan.

What Does “All-on-4” Actually Mean?

All-on-4 is a trademarked name for one version of a fixed full arch: four implants, the two at the back tilted forward to avoid the sinus or the nerve and to use the bone that remains, carrying one screwed-in arch of teeth. “All-on-X,” “teeth in a day,” “hybrid” and “fixed full arch” are related terms, and offices use them loosely. The useful thing to establish is not the name but the plan: how many implants, where, what the teeth are made of, and whether a temporary arch is attached the same day.

Fixed full-arch treatment is well documented when it is planned well. A systematic review by Heydecke and colleagues found full-arch fixed reconstructions on four to six implants surviving at 97.5 percent over five years and 95.0 percent over ten in the upper jaw, and 97.9 and 95.9 percent in the lower. The same review found it unclear whether three implants achieve similar results. Long-term data are thinner than marketing suggests: a systematic review by Kwon and colleagues found high survival for full-arch hybrid prostheses over five to ten years, but too few true long-term studies to determine survival beyond that.

There are also alternatives to a fixed arch, including a snap-in overdenture and, for some people, keeping and treating their own teeth. A plan that presents fixed teeth as the only possibility has left something out, even if fixed teeth turn out to be the right answer.

Are All of These Teeth Really Hopeless?

This is the first question, because extraction is the one step in a full-arch plan that cannot be reversed. A plan that removes every tooth in the arch deserves a second look whenever some of those teeth are not obviously failing.

The same Kwon review closed with an unusually direct sentence for a systematic review: the strategic removal of teeth with a satisfactory prognosis for the sake of delivering a full-arch hybrid prosthesis should be avoided. A systematic review of studies with at least fifteen years of follow-up by Levin and Halperin-Sternfeld found that implant survival does not exceed that of compromised but adequately treated and maintained teeth, and noted that a tooth can be extracted at any time, while extraction is final. Teeth judged doubtful often do better than expected: Hirschfeld and Wasserman followed 600 treated periodontal patients for an average of 22 years, and of 2,139 teeth originally given a questionable prognosis, 666 were lost and the rest were still in the mouth.

None of that means every tooth should be kept. Some teeth genuinely are hopeless, and holding on to them while bone keeps disappearing makes the eventual implant treatment harder. The point is that the decision should rest on a periodontal examination: pocket depths around every tooth, mobility, bone levels on the X-rays and scan, and bone loss between the roots of the molars. Questions worth asking:

• Which teeth, specifically, are hopeless, and why?
• Was a periodontal chart made, and can I have a copy?
• Is there a plan that keeps some teeth, even temporarily?

Can a loose tooth be saved? explains how prognosis is judged.

How Many Implants, and Where?

Four is not automatically too few, and six is not automatically better. A systematic review and meta-analysis by Daudt Polido and colleagues, covering 93 studies with a median follow-up of eight years, found no significant difference in implant or prosthesis survival between fewer than five and five or more implants per arch. Most of those studies were not randomized, so the honest reading is that both approaches work in the patients they were chosen for, not that the number never matters.

Tilted implants are similar. A meta-analysis by Chrcanovic and colleagues found no overall difference in failure or bone loss between tilted and upright implants, but when studies of the upper jaw alone were pooled, tilted implants failed more often. The evidence supports tilting as a reasonable technique; it does not make it equally suited to every jaw.

What decides the number is the individual case: the quality of the bone (the upper jaw is usually softer), the opposing bite, a grinding habit, the length of the arch the implants must support, and the material of the final teeth. Questions worth asking:

• How many implants, and why that number for my jaw?
• If one implant were lost, could the remaining ones still carry the teeth?
• Are any implants tilted, and are any placed in the cheekbone or another unusual site?
• Will grafting or a sinus lift be needed, and is it in the quote?

How Much Bone Will Be Removed?

Many full-arch plans include reducing the height of the ridge, called an alveoloplasty or bone reduction. There are legitimate reasons for it: it flattens a narrow, uneven ridge so the implants sit in wide bone, it creates room for a bridge thick enough to be strong, and it hides the junction between the bridge and the gum above the lip line when the patient smiles.

Bone that is removed cannot be put back, and it is the same bone a future implant would need if one were ever lost. The amount varies a great deal between cases and between offices. There are no good comparative trials on how much reduction is right, so this is a matter of planning judgment rather than settled evidence, and it is reasonable to ask for the reasoning in plain terms:

• How many millimeters of bone are planned to be removed, and where?
• Is that measured from the 3D scan, against a design of the final teeth?
• Is there a design that needs less reduction, and what would it give up?

What Will the Temporary and Final Teeth Be Made Of?

Most full-arch plans have two sets of teeth. The temporary arch, attached the day of surgery when the implants are stable enough or later when they are not, is usually acrylic. It is meant to be worn during healing, which is commonly several months, and in this practice’s experience it is the one most likely to crack or need adjusting, which is expected rather than a failure.

The final arch is usually one of two kinds. An acrylic hybrid has denture teeth set in acrylic over a titanium or fiber-reinforced frame. It is lighter, gentler on the opposing teeth, and often repairable when a tooth chips, but the teeth and acrylic wear and are replaced periodically. Zirconia is milled from a solid ceramic block. It resists wear and staining better, but it is harder and heavier, and a fracture usually means remaking it rather than patching it. A systematic review of full-arch zirconia by Bidra and colleagues found a low short-term failure rate of 1.4 percent, but minor complications in 16.1 percent of prostheses, mostly chipping of the porcelain layered over the zirconia; its authors noted that monolithic zirconia, or zirconia layered only at the gum, looked promising but still needed long-term studies.

Whatever the material, fixed full-arch teeth need service. A systematic review by Papaspyridakos and colleagues of fixed full-arch prostheses followed for at least five years found chipping or fracture of the veneering material to be the most common technical complication, screw fracture the most common implant-related one, and only 29.3 percent of prostheses free of any complication at five years. Most of those events were repairs rather than failures, and many of those prostheses used older materials, but the point holds: the teeth are dental work and wear like dental work. Questions worth asking:

• What is the temporary made of, how long will I wear it, and are adjustments and repairs to it included?
• What is the final arch made of, and why that material for my bite?
• Is a night guard included if I clench or grind?
• If the final arch chips or breaks, who repairs it, and what does that involve?

Who Places the Implants, and Who Makes the Teeth?

A full arch has two halves: the surgery and the teeth. Some offices do both under one roof; in others, as at this practice, a surgeon places the implants and the patient’s own dentist or a prosthodontist makes the teeth. Either arrangement can work well. What matters is that the patient knows who is responsible for each part before treatment starts, rather than the day something breaks.

Periodontics, oral and maxillofacial surgery and prosthodontics are all recognized dental specialties, and many general dentists also place implants after additional training. The title matters less than the training and experience behind it. Questions worth asking:

• Who will do the surgery, and what is their training in implant and full-arch surgery?
• Is the doctor I met at the consult the one who will operate?
• Who designs and makes the final teeth, and who will I see if they need repair?
• Who will see me for maintenance in five and ten years?

Dr. Verrett is a board-certified periodontist and the only doctor at this practice; his training is on his page, and what a periodontist is explains the specialty.

Was the Plan Made on a 3D Scan?

A full-arch plan should be built on a cone-beam CT, a 3D X-ray that shows the height and width of the bone, the sinus above the upper teeth and the nerve in the lower jaw. Ideally the teeth are designed first and the implants positioned to support that design. A full arch is one of the situations in which a surgical guide made from the plan is usually indicated. The systematic review and meta-analysis by Tahmaseb and colleagues found guided placement accurate within a clinically acceptable range in most situations, with full-arch cases less accurate than partial ones and a safety margin of at least two millimeters still advised. Guided implant surgery explains when a guide helps and when it adds little. Questions worth asking:

• Was a 3D scan taken, and can I have a copy of the scan and the plan?
• Were the teeth designed before the implants were positioned?
• Will a surgical guide be used, and if not, why not?

What Happens If an Implant Fails?

Early failure, when an implant does not integrate with the bone, happens in a minority of cases and should be planned for rather than improvised. The implant is removed, the site heals or is grafted, and another is placed when the bone is ready. In a full arch, the temporary or final teeth may have to be adjusted or remade around the change. Questions worth asking:

• If an implant does not integrate, what is replaced, and at whose cost?
• Does that cover grafting, a new temporary, and changes to the final teeth?
• How long does that coverage last, and what is excluded?

At this practice, an implant placed by Dr. Verrett that fails early, meaning it does not integrate or is lost within the first year, is removed and replaced at no surgical cost once the site is ready, with associated grafting included. The patient’s own dentist handles the teeth. When a dental implant is failing covers later problems.

What Will It Take to Keep It Healthy for Twenty Years?

The largest long-term risk to a full arch is not the implants breaking; it is disease in the tissue around them. The 2017 World Workshop defined peri-implantitis as a plaque-associated condition with inflammation around an implant and progressive loss of the supporting bone, and recommended that baseline X-rays and probing measurements be taken once the final teeth are in, so later changes can be recognized. It is common: a systematic review of epidemiology by Derks and Tomasi estimated a weighted mean prevalence of 22 percent, with wide variation between studies and case definitions. Those figures come mostly from implants in general rather than full arches specifically.

The workshop’s review of risk factors by Schwarz and colleagues found strong evidence of higher risk in people with a history of periodontitis, poor plaque control and no regular maintenance after treatment, and limited evidence linking it to implant positions that make cleaning difficult. That matters for full-arch patients in particular, many of whom lost their teeth to periodontitis, and for bridge design: the underside of a fixed arch has to be shaped so it can be cleaned. Maintenance makes a measurable difference. In a five-year study by Costa and colleagues of patients who already had inflammation around an implant, peri-implantitis developed in 18 percent of those who kept preventive maintenance and 43.9 percent of those who did not, and a meta-analysis by Monje and colleagues concluded that maintenance therapy is part of implant treatment, suggesting a recall interval of no longer than five to six months. Questions worth asking:

• How often will I need maintenance visits, and who provides them?
• Will the bridge be unscrewed periodically so the implants can be cleaned and checked?
• Will baseline X-rays and measurements be recorded when the final teeth go in?
• How will I clean under the bridge at home, and will someone show me?
• If I lost teeth to gum disease, how does that change my maintenance?

What periodontal maintenance means describes those visits.

What Should the Written Estimate List?

Two full-arch numbers are only comparable once both are itemized. A single total can hide the fact that one quote includes grafting, sedation and the final teeth while the other does not. Ask each office for a written estimate that lists, line by line:

1. The examination, X-rays, 3D scan and digital planning.
2. Each extraction, by tooth.
3. Bone reduction, and any bone grafting or sinus lift, by site.
4. The surgical guide, if one is used.
5. Each implant, and how many.
6. The abutments and screws that connect the implants to the teeth.
7. Sedation or anesthesia, and which kind.
8. The temporary arch, and adjustments, relines or repairs to it during healing.
9. The final arch, and its material.
10. A night guard, if one is recommended.
11. Follow-up visits during healing, and for how long they are included.
12. Maintenance visits after the final teeth, and how often.
13. What happens, and what is charged, if an implant fails or the teeth break.

An estimate that uses dental procedure codes is easier to compare than one written in plain words, because the codes say exactly what is planned. Ask, too, which parts are billed by a different office, so that one total is not being compared with half of another. What treatment costs and what drives the number explains how estimates are built here; fees are set at the consult, from the examination and the scan, rather than quoted by message.

A Printable Checklist

Take this to the consult, or to the phone call afterward.

The diagnosis

• Which teeth are hopeless, and why? Is there a periodontal chart?
• Is there an option that keeps some teeth?
• What are the alternatives to a fixed arch, such as a snap-in overdenture?

The surgery

• How many implants, where, and why that number?
• Are any tilted or placed in unusual sites?
• How much bone will be removed, and why?
• Is grafting or a sinus lift needed?
• Was the plan made on a 3D scan, with the teeth designed first? Will a guide be used?
• Who performs the surgery, and what is their training?

The teeth

• What is the temporary made of, and how long will I wear it?
• What is the final arch made of, and why that material?
• Who makes the final teeth, and who repairs them?
• Is a night guard included?

When things go wrong

• What happens if an implant does not integrate, and who pays?
• What happens if the teeth chip, crack or come loose?
• How long do those commitments last?

The long run

• How often are maintenance visits, and who provides them?
• Will the bridge be removed periodically for cleaning and checks?
• Will baseline X-rays and measurements be taken when the final teeth go in?
• How do I clean under the bridge at home?

The paperwork

• An itemized written estimate, with procedure codes.
• Copies of my X-rays, 3D scan and treatment plan.
• Which parts are billed by another office?

Bring the Plan for a Second Opinion

A second opinion on a full-arch plan is a full periodontal examination, with a 3D scan when the case needs one, and the original plan and estimate read alongside it. Dr. Verrett gives a written, item-by-item comparison: where the plans agree, where they differ, and why. When the first plan is sound, the patient hears that plainly and is sent back to have it done where it was planned. Nothing is scheduled unless the patient asks.

Sending the X-rays, scan, treatment plan and estimate ahead of the visit lets them be reviewed before the patient arrives. Second opinions explains what to bring and how to request records, or request a second opinion directly. The office is in North Austin at (512) 346-6097.