All-on-4 or All-on-6? How We Decide How Many Implants Hold Your New Teeth

Smile Maker of Texas Implant Treatment Center · 6201 Dallas Pkwy, Suite 220, Plano, TX 75024 · Serving Plano, Dallas, Frisco, McKinney, Allen, Richardson and Addison.

The question I hear most in consultations is, “Which one is better, four or six?” The honest answer is that neither is better. One of them is right for your jaw, and we can usually tell which one before you leave the first appointment.

Patients often arrive having read about All-on-4 online and assume it’s the standard version, with six as an upgrade. That isn’t how I think about it. The number of implants is decided by how much bone you have, how dense it is, where your nerves and sinuses sit, and how hard you bite.

Here is how that decision gets made.

What the “X” stands for

All-on-X is the name for the whole family of treatments. You may also hear it called X-on-X. In every version, a full arch of teeth is made as one bridge and screwed onto implants, so it stays in your mouth like natural teeth. There is no plate over the roof of your mouth the way there is with a denture. If you’d rather keep a removable option, implant-supported dentures are another route we offer.

Why four can be enough

The two back implants in All-on-4 are placed at an angle. Tilting them lets us use the denser bone toward the front of the jaw and reach farther back without running into the nerve in the lower jaw or the sinus in the upper. For many people who have lost bone after years without teeth, that’s what makes a fixed bridge possible without grafting first.

The lower jaw tends to be dense, so four well-placed implants often carry a lower bridge with room to spare.

Why the upper jaw often gets six

Upper jawbone is usually softer than lower jawbone, and the sinuses sit just above the back teeth. Softer bone grips an implant less firmly, so spreading the bite across six implants instead of four shares the load and adds a margin of safety. That’s why All-on-6 is frequently recommended for the upper arch.

Bite force matters too. If you clench or grind, or if the opposing arch has strong natural teeth, more support can be the better long-term choice.

How the scan decides

Every All-on-X consultation in our office includes a 3D CBCT scan on our R2 Studio Q. It maps bone volume, nerves and sinuses so the number and angle of every implant are planned before you’re ever numb. Here’s what I’m looking at:

• Bone volume. How tall and wide the bone is where each implant would go.
• Bone density. Softer bone usually calls for more implants.
• Nerves and sinuses. Where the implants have to stay clear of, and whether angled implants can avoid them.
• Your bite. How much force the bridge will carry every day.

Before I was a surgeon I spent eighteen years as a dental ceramist (more on that here), building bridges like these by hand. So I plan the implants around where the final teeth need to be, not only where the bone is easiest.

What the treatment looks like

All-on-X happens in four stages:

• Consultation and 3D scan. Complimentary. We take the CBCT scan and photographs, evaluate your bone and begin designing the smile.
• Surgery day. Sedation is available. Any remaining teeth are removed, the implants are placed with 3D guidance, and for most patients a provisional fixed bridge is attached the same day.
• Healing. Over 3–6 months the implants fuse with your jawbone. You wear the provisional teeth the whole time.
• Final bridge. A precision-milled, long-term bridge replaces the provisional.

Who it’s for

All-on-X is usually a good fit if most or all of the teeth in an arch are failing, if you wear a loose or uncomfortable denture, if you’ve lost bone from years without teeth, or if you have advanced gum disease or decay. You’ll need to be in stable overall health, and you’ll need to be a non-smoker or willing to stop during healing.

It was designed for exactly the patients who have been told they don’t have enough bone for individual implants. If you’ve heard that before, it’s worth getting a 3D scan before you rule it out.

Taking care of it

The implants can last decades, often a lifetime, with good hygiene and maintenance. The bridge on top may be refreshed after many years of wear. Day to day, brush twice a day, use a water flosser and floss threaders or interdental brushes under the bridge, and keep your hygiene visits. At those visits we can remove the bridge and clean it professionally.

Dr. Young Kyu Kim, DMD

Restorative, cosmetic and implant dentist at Smile Maker of Texas in Plano. DMD, University of Kentucky; Hiossen Master Course in implant surgery; trained in dental ceramics at the Osaka Dental Ceramic School in Japan, with 18+ years at the bench in laboratories in New York City and Weston, Massachusetts. His work spans full-mouth reconstruction, implant surgery and restoration, and prosthodontics.

This article is for general information and is not a substitute for an in-person examination or individual dental advice. The number of implants and the treatment plan are decided case by case. Treatment outcomes vary between individuals and can only be assessed at a clinical consultation.