Four Implants or Six? Understanding Full-Arch Options

For most healthy adults who are missing, or about to lose, a full arch of teeth, All-on-4 and All-on-6 both provide fixed replacement teeth on the day of surgery, and both have documented five-year implant survival above 95%. Which one suits you depends on the volume of bone in your jaw, the force of your bite and how much built-in redundancy you and your clinician would like. Neither is simply the better option. At Eclat Dental Studio in Mountain View, we work through these trade-offs with you using a 3D scan and an honest conversation about your long-term goals.

What separates All-on-4 from All-on-6

In both treatments, a full-arch bridge of replacement teeth is fixed onto titanium implants placed in the jaw. The number simply tells you how many implants support that arch. All-on-4, developed in the late 1990s, uses four implants per arch, and the two at the back are tilted, often by as much as 30 degrees, so they reach denser bone and steer clear of the sinus and nerves. Thanks to that angle, many patients avoid bone grafting. All-on-6 works on the same idea but adds two more implants, spreading the forces of chewing over a broader base.

In short, both approaches can give you fixed teeth on the same day, but the number and angle of the implants change how load passes through the jaw and how much reserve you have should one implant ever need attention.

When four implants are sufficient

Large clinical studies following thousands of patients have found that arches supported by four implants and by six perform similarly at two and five years, provided patients are chosen carefully. Four implants often suit:

• People with moderate bone loss who would like to avoid extended grafting
• Lower arches, where the bone is denser and long-term survival is especially strong
• People in good general health who keep up with cleanings and care at home
• Those who would prefer fewer surgical sites and a simpler procedure

Professional consensus supports four well-spaced implants as the minimum for a single-piece fixed full-arch prosthesis. With sound planning, usually a cone-beam CT scan and a digital design, All-on-4 has served as a dependable foundation of full-arch treatment for over twenty years.

When six implants are the better choice

In some situations the extra support is worth it. Six implants are often favoured when:

• The upper jaw is being treated, because its bone is softer and long-term data show a slightly higher risk of implant loss than in the lower jaw
• Bite forces are heavy, or there is clenching or bruxism
• A long arch would benefit from support spread more widely
• Redundancy matters to the patient: should one implant ever run into trouble, five are left to hold the bridge

Six implants can also leave room to divide a future restoration into sections rather than making it as one bridge. The costs are more surgical sites, frequently a need for more bone, and a larger overall investment. We weigh these factors at the consultation, setting your scan findings alongside your medical history and habits.

Recovery and ongoing care

The general sequence is the same for either option:

1. Planning: a medical review, 3D imaging and a digital design of your new teeth
2. Surgery day: any extractions, placement of the implants and a fixed provisional bridge, so most people go home with teeth that day
3. Healing: three to six months while the implants bond with the bone
4. Final teeth: a permanent zirconia or hybrid bridge secured to the implants with screws

Looking after the implants matters as much as placing them. Most clinicians suggest professional cleanings every three to four months in the first year and every six months after that. Smoking, poorly controlled diabetes and irregular home care are the factors most likely to shorten an implant's life. Daily care usually involves a water flosser and interdental brushes, with a yearly check beneath the bridge. Our article on full-arch implant recovery covers the early weeks in detail.

Questions about All-on-4 and All-on-6

Will I have teeth when I leave on the day of surgery?

Most patients go home with a fixed provisional bridge that same day, whether four or six implants are used. The permanent teeth follow once the implants have fully integrated, typically three to six months later.

Does All-on-6 outlast All-on-4?

Direct comparisons have not found a meaningful difference in implant survival at five years or beyond when patients are appropriately selected. Six implants bring extra redundancy, but four carefully planned implants also have a strong long-term record.

Is bone grafting likely?

Part of the appeal of All-on-4 is that its tilted rear implants often work in jaws that would otherwise need a graft. All-on-6 can call for somewhat more bone. A cone-beam scan settles the question for your case, and our grafting article explains the options.

What does full-arch treatment cost?

The investment depends on the number of implants, whether extractions or grafting are required, the material of the final bridge (zirconia or hybrid acrylic) and any sedation. We provide a written estimate after the consultation and will check your PPO benefits in advance.

Can I move from a denture to a fixed arch?

Yes. Many people make the change from a removable denture to a fixed, implant-supported arch. The assessment includes imaging, a look at gum health and a discussion of your bite and your goals.

If you are weighing full-arch options, the most helpful next step is a personal evaluation. We review your scan, medical history and priorities, then recommend the configuration that fits your jaw rather than a standard package. For more, see our full-arch implants page or call the studio at (650) 917-8348.