What Are All-on-4 and All-on-6 Implants?
Both All-on-4 and All-on-6 are full-arch implant solutions designed to replace all the teeth in one jaw with a single fixed prosthesis. Instead of placing one implant per missing tooth, these systems use a limited number of strategically positioned implants to support a complete bridge.
The All-on-4 concept, developed by Dr. Paulo Malo, uses four implants per arch. Two implants are placed vertically in the front of the jaw, and two are tilted at angles of up to 45 degrees in the back. This angulation allows the posterior implants to anchor into denser bone closer to the front of the jaw, often eliminating the need for bone grafting.[1]
All-on-6 follows the same principle but adds two more implants, typically in the premolar or posterior region. The additional implants provide extra support points and distribute biting forces across a wider area of the jawbone.
Key Differences Between All-on-4 and All-on-6
The choice between four and six implants affects several aspects of treatment, from surgical complexity to long-term force distribution. Here are the primary differences.
Stress Distribution and Biomechanics
More implants mean more points of contact between the prosthesis and the jawbone. With six implants, the chewing forces are spread across a larger area, reducing the stress on each individual implant. This can be particularly beneficial for patients who generate high bite forces, such as those who clench or grind their teeth (bruxism).
With four implants, each implant bears a larger share of the load. The All-on-4 system compensates by using angled posterior implants that engage more bone surface area. For most patients, four implants provide more than adequate support. However, in cases with higher mechanical demands, the additional support of six implants may reduce long-term stress on the bone and prosthesis.
Who Is a Candidate for Each?
All-on-4 is designed to work for patients with moderate bone loss, particularly in the back of the jaw. The angled implants bypass areas of low bone density, which is why many All-on-4 patients can avoid bone grafting entirely.
All-on-6 requires enough bone in more locations across the arch to support the additional implants. Patients with good overall bone volume are candidates for All-on-6. In some cases, minor bone grafting may be performed at the time of implant placement to accommodate the extra implants. Your prosthodontist and oral surgeon will evaluate your bone with CBCT imaging to determine which approach your anatomy supports.
Prosthesis Design
The prosthesis (the visible set of teeth) can be made from similar materials for both systems, including acrylic with a titanium or cobalt-chrome framework, or full zirconia. With six implants, the prosthodontist has more flexibility in designing a longer prosthesis that extends further back in the arch, potentially restoring more teeth in the posterior region.
With four implants, the prosthesis typically extends to the first molar region. With six, it may extend to include second molars, providing more chewing surface. The additional posterior teeth can improve chewing efficiency, though many All-on-4 patients report excellent function with the standard prosthesis length.
Cost Comparison: All-on-4 vs All-on-6
All-on-6 costs more than All-on-4 due to the additional implants, surgical time, and potentially more complex prosthesis design. Here are typical cost ranges for each approach. Costs vary by location, provider, and case complexity.
All-on-4 generally ranges from $15,000 to $30,000 per arch. This includes the four implants, the surgical placement, the temporary prosthesis provided on the day of surgery, and the final prosthesis placed after healing. The wide range reflects differences in prosthesis material (acrylic vs. zirconia), geographic location, and provider fees.[2]
All-on-6 generally ranges from $20,000 to $40,000 per arch. The higher cost reflects the two additional implants and the associated surgical and prosthetic work. If bone grafting is needed to support the extra implants, that adds $500 to $3,000 per graft site.
Most dental insurance plans provide limited coverage for implant-supported prostheses. Some plans cover a portion of the prosthesis as a denture benefit. Ask your provider about financing options, as many prosthodontic practices offer payment plans for full-arch treatment.
Long-Term Success and Outcomes
Both All-on-4 and All-on-6 have strong track records. The All-on-4 system has the longest history and the most published research, with studies reporting cumulative implant survival rates above 94% at 10 years and above 93% at 15 years.[3]
All-on-6 outcomes are also favorable, though the published long-term data is not as extensive as All-on-4. The additional implants provide a built-in safety margin: if one implant fails, the prosthesis can still be supported by the remaining five. With All-on-4, the loss of a single implant may require revision of the prosthesis design.
The most important factors for long-term success with either system are consistent oral hygiene, regular dental checkups, and avoiding habits that place excessive stress on the prosthesis. Smoking significantly increases the risk of implant failure regardless of the number of implants placed.
Maintenance and Follow-Up
Both All-on-4 and All-on-6 prostheses require professional maintenance. Your prosthodontist will typically recommend checkups every 6 months. During these visits, the prosthesis may be removed for cleaning underneath, and the implants and surrounding tissue are examined.
Daily home care involves brushing the prosthesis and using specialized tools like water flossers or interproximal brushes to clean around the implant abutments. Your prosthodontist will demonstrate the specific cleaning technique for your prosthesis type.
When Is All-on-6 Recommended Over All-on-4?
Your prosthodontist may recommend six implants over four in specific clinical scenarios.
- Upper jaw restoration: The upper jaw (maxilla) has less dense bone than the lower jaw, and the additional implants provide extra anchorage in softer bone.
- Bruxism (teeth grinding or clenching): Patients with heavy bite forces benefit from distributing those forces across more implants to reduce stress on each one.
- Longer prosthesis span: When the treatment plan calls for restoring teeth further back in the arch, including second molars, additional implants are needed to support the longer bridge.
- Adequate bone volume throughout the arch: Patients with good bone density across the full arch have the anatomy to support six implants and may benefit from the additional redundancy.
- Patient preference for maximum security: Some patients simply prefer the peace of mind that comes with extra implant support, even when four would be clinically sufficient.
Why See a Prosthodontist for Full-Arch Implants
A prosthodontist is the dental specialist trained in the design and placement of complex dental prostheses, including full-arch implant restorations. While oral surgeons and some general dentists place implants, the prosthodontist is the specialist who plans the prosthesis design, determines the ideal implant positions for the best functional and aesthetic outcome, and fabricates the final restoration.
For full-arch cases, the prosthodontist typically serves as the treatment coordinator, working with an oral surgeon or periodontist who performs the implant surgery. This team approach ensures that the implants are placed in positions that support the best possible prosthesis. Learn more about [prosthodontic care](/specialties/prosthodontics) and how a prosthodontist manages full-arch implant treatment.
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