When patients need to replace an entire arch of missing or failing teeth, they face an important decision: how many implants are needed to support the new fixed prosthesis? The two most common protocols are All-on-4 and All-on-6. Both provide a fixed, non-removable bridge, but they differ in implant number, placement strategy, biomechanics, and long-term considerations.
For patients in Chickasha, Altus, Wichita Falls, Mustang, Norman, and the Oklahoma City metro, understanding the difference between these protocols helps guide treatment decisions. This guide compares All-on-4 and All-on-6 on stability, cost, candidacy requirements, and expected outcomes.
For a complete overview of same-day full arch restoration, see the Teeth in a Day subpillar article. For comprehensive dental services, visit the Pillar article on one-stop family, implant, and sedation dentistry.
Table of Contents
Key Takeaways (TL;DR)
- All-on-4 uses four implants per arch: Two straight anterior implants and two angled posterior implants. Often avoids bone grafting.
- All-on-6 uses six implants per arch: Four anterior and two posterior implants. Provides more even force distribution.
- All-on-4 costs less: Fewer implants and lower laboratory fees make it more affordable upfront.
- All-on-6 offers better long-term stability: Six implants share occlusal forces, reducing stress on each individual implant.
- All-on-4 works for most patients: All-on-6 is preferred for patients with heavy bite forces, bruxism, or longer prosthetic spans.
- Both allow same-day provisional teeth: Both protocols support immediate loading with a fixed temporary bridge.
What Are All-on-4 and All-on-6 Full Arch Implant Protocols?
The All-on-4 treatment concept was developed by Nobel Biocare and introduced in the late 1990s. It uses four implants per arch: two straight implants in the anterior (front) region and two angled implants in the posterior (back) region. The posterior implants are tilted up to 45 degrees to engage denser bone, often avoiding the need for bone grafting in the maxillary sinuses or mandibular nerve areas.
All-on-6 is a modification that adds two additional implants. In this protocol, four anterior implants are placed straight, and two posterior implants are placed either straight or slightly angled. The total of six implants provides more support points for the final prosthesis.
Both protocols allow for immediate loading. Patients receive a fixed provisional bridge on the day of surgery, eat a modified soft diet during osseointegration, and receive a final zirconia or acrylic prosthesis after 4 to 6 months.
Angled posterior implants in All-on-4 protocols serve two critical purposes. First, they allow longer implants to be placed because the angle avoids anatomical structures like the maxillary sinus and inferior alveolar nerve. Second, the angle improves the anteroposterior spread, which is the distance between the most anterior and most posterior implants. A wider spread provides better mechanical advantage and reduces cantilever forces on the prosthesis.
Key Differences Between All-on-4 and All-on-6
While both protocols achieve the same goal of a fixed full arch prosthesis, they differ in several important ways that affect candidacy, cost, and long-term outcomes.
All-on-4 uses 4 implants total. The two posterior implants are angled. All-on-6 uses 6 implants total. Usually 4 straight anterior implants and 2 straight or slightly angled posterior implants.
Six implants distribute occlusal forces across more abutments, reducing peak stress on any single implant. All-on-4 places more reliance on the angled posterior implants and the prosthesis cantilever.
All-on-4 was specifically designed to avoid bone grafting in most cases by angling posterior implants. All-on-6 may require grafting more often because straight posterior implants need adequate vertical bone height.
All-on-4 requires a longer cantilever (the part of the prosthesis extending beyond the most posterior implant). All-on-6 allows a shorter cantilever, which reduces leverage forces and lowers the risk of prosthetic fracture.
Side-by-Side Comparison: All-on-4 vs All-on-6
Which Protocol Is Right for You?
The choice between All-on-4 and All-on-6 depends on multiple patient-specific factors. No single protocol is universally superior. The right choice balances bone volume, bite forces, budget, and long-term expectations.
- Moderate bone loss is present and bone grafting would add significant time and cost
- Budget is a primary consideration
- Normal to moderate bite forces (not a heavy grinder or clencher)
- Lower arch (mandible) with good bone density in the anterior region
- Patient wants to avoid sinus lifts or nerve repositioning procedures
- Adequate bone volume exists for six implants without extensive grafting
- Heavy bite forces or diagnosed bruxism (teeth grinding)
- Long-term prosthetic stability is the highest priority
- Longer prosthetic span (larger arch) requires additional support
- Patient wants redundancy in case one implant fails
- Previous All-on-4 prosthesis has experienced fractures or complications
A CBCT scan is the critical diagnostic tool. The scan reveals bone height, width, and density in all potential implant sites. The surgeon can then determine whether six implants can be placed safely without damaging anatomical structures. If bone volume is insufficient for All-on-6, All-on-4 remains a viable option.
For patients coming from Chickasha, Altus, Wichita Falls, Mustang, Norman, and Oklahoma City, a consultation with CBCT imaging is the first step. Dr. Phillips at 29th Street Dental Care performs this evaluation and discusses which protocol aligns with the patient’s anatomy and goals.
Frequently Asked Questions
People Also Ask
- Can I get All-on-6 if I have sinus issues? Yes, but the surgeon must evaluate sinus anatomy on CBCT. All-on-6 posterior implants often require adequate bone below the sinus. If sinus pneumatization has reduced bone height, a sinus lift may be needed, or the patient may be better suited for All-on-4 with angled implants that avoid the sinus.
- Which is easier to clean, All-on-4 or All-on-6? All-on-6 is slightly more difficult to clean because there are six abutments instead of four, creating more areas where food can trap. However, both require special cleaning tools including superfloss, water flossers, and implant-specific brushes. Neither is considered easy to clean compared to natural teeth.
- Do both protocols work for the upper and lower arch? Yes, both All-on-4 and All-on-6 can be used in the maxilla (upper) and mandible (lower). The upper arch typically has lower bone density, especially in the posterior regions, which may favor All-on-4 with angled implants. The lower arch usually has denser bone, making All-on-6 more feasible.
- What happens if one implant fails in All-on-4 vs All-on-6? In All-on-4, losing one implant leaves three supporting the bridge. The prosthesis may need to be modified or replaced. In All-on-6, losing one implant leaves five remaining, which usually provides adequate support without prosthesis modification. All-on-6 offers redundancy that All-on-4 does not.
- Are there alternatives to both All-on-4 and All-on-6? Yes. Alternatives include traditional removable dentures, implant-supported overdentures (snap-on dentures with 2 to 4 implants), and individual implant crowns for each missing tooth. The choice depends on budget, bone volume, and desired level of fixed vs removable function.
About the Author / Meet the Dentist
Dr. John Phillips III, DDS
Dr. Phillips has extensive experience placing All-on-4 and All-on-6 full arch restorations at 29th Street Dental Care in Chickasha, Oklahoma. He evaluates each patient with CBCT imaging to determine the optimal number of implants based on individual bone anatomy and functional demands. Dr. Phillips believes that treatment planning should be driven by what is best for the patient’s long-term oral health, not by a one-size-fits-all protocol.
Dr. Phillips serves patients from Chickasha, Altus, Wichita Falls, Mustang, Norman, and the Oklahoma City metro. He offers complimentary implant consultations that include a CBCT scan and detailed discussion of All-on-4, All-on-6, and alternative treatment options. To learn more about comprehensive dental care, visit the Pillar article on one-stop family, implant, and sedation dentistry.
Conclusion
Both All-on-4 and All-on-6 provide excellent outcomes for patients needing full arch restoration. All-on-4 offers a proven, bone-graft-sparing solution at a lower cost point. All-on-6 provides additional implant support, lower prosthetic complication rates, and redundancy if an implant fails. Neither is universally superior. The best choice depends on bone anatomy, bite forces, budget, and long-term expectations.
Patients considering full arch implants should undergo CBCT imaging and a comprehensive consultation with an experienced implant surgeon. Dr. Phillips at 29th Street Dental Care provides this evaluation and helps patients understand which protocol aligns with their specific needs. For more information on same-day full arch restoration, read the Teeth in a Day subpillar article.
Last reviewed: May 2026