All-on-4 vs All-on-6: Which Full Arch Option Fits You?

Both replace every tooth in an upper or lower arch with a fixed bridge anchored to dental implants. The difference is how many implants hold it up: four or six. Neither number is better in the abstract. The right one depends on factors such as how much bone you have, how hard you bite, and which jaw is being treated, and it comes from an exam and imaging, not from the name of a package.

Two names for the same basic design.

In both, your new teeth are a single bridge running from one side of the arch to the other. It is usually secured to the implants with small screws and does not come out at home, which is the main difference from a denture. We compare those two paths in full mouth dental implants vs dentures.

All-on-4 is the name of a treatment concept associated with the implant company Nobel Biocare. It was first published in 2003, for the lower jaw, with four implants carrying a fixed acrylic bridge within two hours of surgery. All-on-6 describes the same idea with six implants. Many practices use these names loosely. What matters is the plan underneath.

How four implants can carry a full arch.

The classic four-implant design places two implants upright near the front of the jaw and two farther back, tilted at an angle, which lets each back implant reach toward the molars while staying in existing bone.

That is the appeal. A 2024 systematic review in Heliyon describes tilted implants as one of the techniques used to make the most of existing bone and avoid a bone graft. For some people, that can mean fewer procedures before the new teeth go in.

The trade off sits at the back of the bridge, which often extends a short distance past the last implant. Dentists call this overhang a cantilever. The same review cites biomechanical work showing that longer cantilevers raise stress, possibly with more bone loss, though it also notes recent studies that found no clear link.

What the research says about six.

Six implants share the load across more points. The Heliyon review cites biomechanical studies in which six-implant designs showed lower stress than four. In its pooled results, bone loss around the implants was lower with six, at about 0.46 mm against 1.02 mm. Differences in implant survival and in complications were not statistically significant.

Bone is a common deciding factor. The review lists poor bone quality, too little bone volume and the sinus expanding down into the upper jaw among the challenges of treating that jaw.

Bite force can matter too. Clinicians may weigh grinding (bruxism) when they decide how many implants a case needs, along with other risk factors such as smoking and health conditions.

The research does not crown a winner. In a five year randomized trial of upper jaw bridges published in Clinical Oral Implants Research, four implants were not inferior to six on bone levels, and implant survival and biological complications were comparable. The four-implant group did see more technical complications, meaning problems with the bridge and its parts. Preferences were split: four-implant bridges were preferred for appearance, six-implant bridges for function, particularly speech at the earlier checkups. With 47 patients, it is one careful data point, not the final word.

Same day teeth first, the final bridge later.

Many full arch treatments attach a provisional bridge on the day the implants go in, often called immediate loading or teeth in a day. Whether same day teeth are possible for you depends on your case. On our dental implants page we explain All-on-4, and whether it is right for you is something we assess at your consultation.

Think of the provisional as a working draft. The final bridge follows once the implants have healed, generally about three to six months, and it can take longer if bone grafting was done.

That final bridge can be made several ways. The American College of Prosthodontists lists a metal framework covered in denture acrylic, a milled titanium framework covered in composite resin, milled zirconia with or without a porcelain layer, and porcelain fused to an alloy substructure. Each has advantages and disadvantages. The useful question is which one suits your bite and your habits.

Cleaning a bridge that doesn’t come out.

A fixed arch is cleaned in place, around the implants and under the bridge where it meets the gums. The ACP advises brushing at least twice a day, along with floss, interdental cleaners and a water irrigator. It also recommends in-office maintenance every two to six months, depending on your risk, and it discourages taking the bridge off routinely at those visits unless something requires it.

Those maintenance visits are part of the treatment, not an extra. The FDA lists risks of implants that include damage to nearby teeth or tissue, nerve damage, infection and screw loosening, and it says to discuss them with your provider. Your health history matters here as well, and we cover it in who cannot get dental implants.

The plan comes first, not the package name.

A cone beam CT scan, or CBCT, builds a 3D image of the teeth and jaws. The FDA lists dental implant planning among its uses, and notes that it typically delivers more radiation than conventional dental X-rays, so it should be used only when it adds information other imaging cannot.

Sometimes the answer is four. Sometimes six. Sometimes bone needs rebuilding first, or a different option suits you better.

At our practice, our board certified periodontist places implants, and a plan may be part of full mouth rehabilitation. We offer oral sedation and IV sedation, the latter overseen by an on site anesthesiologist.

If you are comparing full arch options, bring your questions and any recent scans, and we can talk through what may suit your case. Results vary from person to person. Schedule A Consultation.

This article is general information, not medical or dental advice, and it is not a substitute for an exam by a licensed dentist. Reading it does not make you a patient of Perfect White Smile. If you have pain, or a symptom that concerns you, contact your dentist or schedule a consultation with Perfect White Smile. If you think you have an emergency, call 911.

Published by Perfect White Smile, the Beverly Hills practice led by Dr. David Frey, DDS. Meet the team.