All-on-4 vs All-on-6

All-on-4 vs All-on-6: Which Full-Arch Implant Treatment Is Better?

Understanding the Differences Between Four- and Six-Implant Full-Arch Rehabilitation

For patients who have lost most or all of their teeth, implant-supported full-arch rehabilitation can provide an alternative to conventional removable dentures. Two terms patients frequently encounter when researching this treatment are All-on-4 and All-on-6.

Both approaches use a limited number of strategically positioned dental implants to support a complete arch of replacement teeth. Both can provide fixed implant-supported restorations, and both have demonstrated high implant survival rates when used in appropriately selected patients.

This naturally raises an important question:

Is All-on-6 better than All-on-4 because it uses more implants?

Not necessarily.

A recent systematic review and meta-analysis including 55 studies found broadly similar clinical outcomes for All-on-4 and All-on-6 rehabilitation. Long-term pooled implant survival was approximately 98.1% for All-on-4 and 97.5% for All-on-6, while mechanical and biological complication rates were also broadly comparable. The authors emphasized that the evidence was heterogeneous and that conclusions should therefore be interpreted cautiously.

The appropriate treatment depends on considerably more than implant number. Bone anatomy, implant distribution, bite forces, restorative space, soft-tissue loss, oral hygiene ability, prosthetic design and long-term maintenance requirements all influence the decision.

At Yeditepe University Dental Hospital, full-arch rehabilitation can involve Oral Implantology, Prosthetic Dentistry, Periodontology, Oral and Maxillofacial Surgery and Dentomaxillofacial Radiology according to the clinical requirements of the individual patient.

What Is All-on-4?

All-on-4 is a full-arch implant treatment concept in which four dental implants support a complete prosthetic dental arch.

In many All-on-4 designs, the anterior implants are positioned more vertically while the posterior implants may be angled. Angling the posterior implants can help make use of available bone, increase the anterior-posterior spread of implant support and, in selected cases, avoid anatomical structures such as the maxillary sinus or areas where bone volume is limited.

The concept is particularly useful because it may allow some patients to receive fixed full-arch rehabilitation without the number of implants traditionally used in older protocols.

However, All-on-4 should not be interpreted as “four implants are enough for everyone.”

Yeditepe University Dental Hospital states that fixed prostheses in a completely edentulous jaw can be made with a minimum of four implants using an All-on-4 approach, while also emphasizing that the optimal treatment alternative should be determined jointly by the surgical and prosthetic teams.

That distinction is important. Four implants may be entirely appropriate for one patient while a different number or distribution may be preferable for another.

What Is All-on-6?

The term All-on-6 generally describes a full-arch fixed restoration supported by six implants rather than four.

Unlike All-on-4, “All-on-6” is often used more broadly as a descriptive term rather than referring to one single standardized surgical protocol.

Six implants can provide additional support points across the jaw when sufficient bone and restorative space are available. Depending on their positions, this may allow different force distribution and prosthetic design possibilities.

However, the presence of two additional implants does not automatically mean greater clinical success.

Current evidence does not demonstrate a universal survival advantage for All-on-6 over All-on-4. The 2026 meta-analysis comparing the two approaches found high survival rates for both, without evidence that one technique is consistently superior across patients.

All-on-4 vs All-on-6: The Main Differences

The important point is that implant distribution and prosthetic design can be as important as implant number.

Six poorly positioned implants are not necessarily preferable to four implants placed in favourable positions as part of a carefully planned restoration.

Is All-on-6 Stronger Than All-on-4?

This question requires some qualification.

From a purely mechanical perspective, increasing the number of appropriately distributed implants can create additional points of support. This may be useful in some clinical circumstances, particularly where bite forces, arch dimensions or prosthetic requirements justify additional implants.

But this does not mean that every All-on-6 restoration is clinically “stronger” or will last longer than every All-on-4 restoration.

Full-arch biomechanics also depend on implant position, implant angulation, bone quality, cantilever length, prosthesis rigidity, framework design, opposing dentition and patient-specific bite forces.

Evidence from systematic reviews supports the view that All-on-4 can achieve outcomes comparable with full-arch approaches using a greater number of implants. A 2025 overview of systematic reviews reported cumulative survival rates for All-on-4 ranging approximately from 94.8% to 99.3% and found no statistically significant evidence that the concept was inferior to rehabilitation using more implants. The authors did, however, note limitations in the quality of the available evidence.

Therefore, “more implants” should not automatically be translated into “better treatment.”

Bone Availability: One of the Most Important Factors

Bone anatomy strongly influences the choice between different full-arch implant strategies.

After teeth are lost, the jawbone gradually remodels. In the upper jaw, posterior bone availability can also be affected by the position and size of the maxillary sinuses. In the lower jaw, the location of the inferior alveolar nerve is an important consideration.

All-on-4 was developed partly to make efficient use of available bone. Strategic angulation of posterior implants may allow clinicians to avoid certain anatomical limitations and, in selected patients, reduce the need for additional grafting procedures.

This does not mean that All-on-4 always eliminates bone grafting. Some patients still require grafting, ridge augmentation or another surgical strategy.

Similarly, All-on-6 is not restricted to patients with “perfect bone.” The question is whether six implants can be placed in prosthetically useful and biologically appropriate positions.

Yeditepe University Dental Hospital notes that implant treatment duration can be extended when available bone volume is insufficient and grafting is required.

Is All-on-6 Better for Patients With Strong Bite Forces?

Possibly in selected cases, but the number of implants should not be considered in isolation.

Patients with powerful chewing muscles or bruxism can generate considerable forces on an implant-supported restoration. Additional implant support may form part of the treatment strategy, but clinicians must also consider the prosthetic material, cantilever design, vertical restorative space, implant distribution and the condition of the opposing teeth.

For a patient who grinds heavily, simply adding two implants without addressing the bite and prosthetic design would not solve the entire biomechanical problem.

The final treatment plan must therefore consider the complete restorative system, not simply whether four or six implants are present.

Do Six Implants Provide More Security If One Implant Develops a Problem?

Six implants may sometimes provide greater prosthetic flexibility because the restoration has more support points.

However, this should not be presented as a guarantee that the prosthesis will continue functioning normally if an implant is lost. Whether a prosthesis can remain in use after an implant complication depends on the positions of the remaining implants, the framework design, the prosthetic material and the nature of the complication.

Similarly, adding implants also means adding additional implant sites that need to remain biologically healthy over time.

Treatment planning therefore involves balancing potential mechanical advantages with anatomy, surgery, hygiene and long-term maintenance.

Can All-on-4 and All-on-6 Provide Same-Day Teeth?

Both approaches may allow an immediate temporary fixed restoration in appropriately selected patients.

This is often described commercially as “same-day teeth” or “teeth in a day.”

However, an immediate prosthesis should not be confused with completed implant healing.

The implants still need to undergo osseointegration after surgery. During this period, the temporary restoration is designed to control forces while allowing the patient to have teeth during healing.

Immediate loading depends particularly on achieving adequate primary implant stability and an appropriate distribution of implants. Evidence indicates that immediate loading can produce favourable results in selected full-arch cases, but it is not automatically appropriate for every patient.

If adequate stability cannot be achieved, allowing the implants to heal before loading may be the safer approach.

Are All-on-4 and All-on-6 Always Fixed?

These terms usually refer to fixed full-arch restorations, particularly in patient-facing dental terminology.

However, full-arch implant rehabilitation is broader than All-on-4 or All-on-6.

Some patients may achieve a more appropriate result with an implant-retained removable overdenture rather than a fixed bridge. This can be particularly relevant when extensive bone and gum tissue has been lost, additional lip support is required or easier daily hygiene is an important priority.

The clinical objective should therefore not be “fixed teeth at any cost.” It should be to identify the prosthesis that best balances function, appearance, facial support, hygiene and long-term maintenance.

What Type of Teeth Are Used With All-on-4 and All-on-6?

Neither All-on-4 nor All-on-6 determines the material of the final teeth.

A common misconception is that an All-on-6 treatment automatically requires a zirconia bridge with a titanium bar, while All-on-4 requires an acrylic prosthesis. This is not correct.

Depending on the patient’s anatomy and prosthetic requirements, the definitive restoration may involve zirconia, a titanium or metal-supported acrylic hybrid prosthesis, a Toronto-type bridge, metal-ceramic construction, porcelain tooth options or other clinically appropriate combinations.

The correct material depends on the individual case.

Is Zirconia Always the Best Choice?

No.

Zirconia can provide excellent strength, colour stability and aesthetics and may be an appropriate material for many fixed full-arch restorations.

However, zirconia is relatively rigid. It requires appropriate restorative space, careful bite design and suitable implant distribution. Major repairs can also be more complex than with some hybrid alternatives.

A patient with extensive missing gum volume, for example, may benefit from a prosthesis capable of replacing both teeth and soft tissue without becoming excessively heavy or bulky.

In another patient, the ability to repair or replace individual prosthetic teeth over time may make an acrylic hybrid solution more practical.

Material selection should therefore be based on the patient’s anatomy and functional requirements rather than on the assumption that one material represents a universally “premium” solution.

Are Titanium Bars Always Better?

Titanium is an important material in implant prosthodontics because it combines strength, relatively low weight and biocompatibility.

A titanium framework or bar may be used to reinforce selected full-arch restorations and provide an accurate connection between implants.

However, not every All-on-4 or All-on-6 restoration requires a titanium bar.

Depending on the prosthetic design, implant positions and selected restorative material, another framework or restoration configuration may be more appropriate.

The most expensive or technically complex prosthesis is not necessarily the best prosthesis for an individual patient.

What Is a Toronto Bridge?

A Toronto bridge is a fixed implant-supported hybrid restoration designed to replace both missing teeth and lost gum tissue.

It can be useful when extensive bone and soft-tissue resorption would otherwise require excessively long replacement teeth.

A Toronto-type prosthesis can be manufactured using different framework, gingival and tooth materials. Its design therefore cannot be reduced to one specific combination such as “titanium plus zirconia.”

Toronto bridges, acrylic hybrids, metal-ceramic restorations and zirconia bridges represent different prosthetic solutions that can be considered according to clinical requirements.

Aesthetic Results: Does Six Implants Mean a Better Smile?

No.

The number of implants does not determine how natural the finished teeth will look.

Aesthetic outcome is influenced more directly by prosthetic planning, tooth position, smile line, lip dynamics, facial proportions, replacement of lost gum tissue and the choice of restorative materials.

A successful full-arch restoration must also provide adequate facial and lip support.

This is particularly important in patients who have experienced extensive jawbone resorption. A beautiful row of teeth alone does not necessarily provide a natural facial result if lost soft-tissue support has not been considered.

Which Is Easier to Clean?

Hygiene depends largely on the shape and accessibility of the final prosthesis rather than whether it is supported by four or six implants.

A fixed full-arch bridge must allow the patient to clean beneath the restoration and around each implant.

This may require specialized floss, interdental brushes, implant brushes or oral irrigation devices.

Adding more implants can potentially create additional areas that require cleaning. Therefore, the assumption that six implants are automatically better must also be considered from a maintenance perspective.

Long-term implant success depends on maintaining healthy peri-implant tissues. Yeditepe University Dental Hospital includes Periodontology among the disciplines responsible for prevention, diagnosis, treatment and maintenance of conditions affecting the tissues surrounding teeth and dental implants.

What Are the Possible Complications?

Both All-on-4 and All-on-6 treatments have high reported survival rates, but neither is complication-free.

Biological problems can include peri-implant inflammation, progressive bone loss or failure of an implant to remain integrated. Prosthetic complications may include screw loosening, wear, fracture of acrylic components, ceramic chipping or damage requiring repair or replacement.

The 2026 systematic review comparing All-on-4 and All-on-6 reported pooled mechanical complication rates of approximately 5.9% and 6.6%, respectively, and pooled biological complication rates of approximately 6.5% and 7.4%. These pooled values should not be interpreted as individual patient probabilities because the studies varied substantially in design and follow-up.

This evidence is another reason to avoid describing either technique as universally superior or risk-free.

How Long Do All-on-4 and All-on-6 Implants Last?

Both approaches can provide long-term function, but no implant treatment should be guaranteed for life.

In the recent meta-analysis, pooled implant survival beyond five years was approximately 98.1% for All-on-4 and 97.5% for All-on-6. These results support the long-term viability of both approaches but do not mean that every implant or prosthesis will last indefinitely.

Implant survival also differs from prosthetic maintenance.

Even when the implants remain healthy, the restoration itself may eventually require adjustment, screw replacement, repair, polishing or replacement of worn components.

Long-term outcomes are influenced by oral hygiene, smoking, bruxism, general health, prosthetic design, implant positioning and attendance at professional maintenance appointments.

So, Which Is Better: All-on-4 or All-on-6?

The most scientifically accurate answer is:

Neither treatment is universally better.

All-on-4 may be appropriate when four well-distributed implants can safely support the planned restoration, including cases where strategic posterior implant positioning helps manage anatomical limitations.

All-on-6 may be appropriate when the anatomy allows additional implants and the prosthetic or biomechanical plan benefits from additional support points.

But implant number is only one part of the decision.

The dentist must also determine where the implants can be placed, how the final teeth should be positioned, how much gum tissue must be replaced, what material should be used, whether the patient can clean the restoration and how chewing forces will be managed.

How Full-Arch Treatment Is Planned at Yeditepe University Dental Hospital

At Yeditepe University Dental Hospital, full-arch implant rehabilitation can involve several dental disciplines rather than being approached as a standardized implant package.

The hospital provides services in Oral Implantology, Prosthetic Dentistry, Periodontology, Oral and Maxillofacial Surgery and Dentomaxillofacial Radiology, allowing surgical, biological and prosthetic requirements to be considered as part of the treatment plan.

Assessment may include clinical examination, radiographic evaluation and three-dimensional imaging when indicated, evaluation of available bone, examination of remaining teeth and gums, assessment of bite relationships and prosthetic planning.

The objective is to answer more than “four implants or six?”

The treatment team must determine whether remaining teeth should be preserved, whether fixed or removable rehabilitation is preferable, how implants should be distributed, whether bone augmentation is required, whether immediate loading is appropriate and which final prosthetic design is most suitable.

Individual Treatment Planning Matters More Than Implant Number

Full-arch implant rehabilitation should ideally be prosthetically driven.

This means that planning begins by considering the desired position, appearance and function of the final teeth and then determining how implants can best support that restoration.

A technically possible implant position is not necessarily an ideal prosthetic position.

Factors such as restorative space, lip support, smile line, speech, bite, cleaning access and replacement of lost gum tissue should therefore be evaluated before the final surgical plan is confirmed.

This is particularly important when comparing All-on-4 and All-on-6. The most appropriate treatment is not simply the one with the highest number of implants but the one in which the implants and prosthesis work together effectively.

Conclusion

All-on-4 and All-on-6 are both established approaches to fixed full-arch implant rehabilitation.

All-on-4 uses four strategically distributed implants and may be particularly useful when anatomical conditions favour efficient use of available bone. All-on-6 uses six implants and may offer additional support and prosthetic options when adequate bone and space are available.

Current scientific evidence does not demonstrate that All-on-6 is universally better or longer-lasting than All-on-4. A recent large systematic review found similarly high implant survival and broadly comparable complication rates for both approaches.

Likewise, the choice should not end with the number of implants. The final prosthesis must also be selected individually. Zirconia, titanium-supported designs, Toronto bridges, acrylic hybrid restorations, metal-ceramic restorations and other options each have particular advantages and limitations.

At Yeditepe University Dental Hospital, the appropriate full-arch solution is determined according to the patient’s bone and soft-tissue anatomy, oral health, implant distribution, functional requirements, facial support, hygiene ability and long-term prosthetic needs.

The goal is therefore not simply All-on-4 versus All-on-6.

The goal is to create the most appropriate complete rehabilitation for the individual patient.

Frequently Asked Questions

Is All-on-6 better than All-on-4?

Not necessarily. Current evidence demonstrates high survival rates for both approaches and does not establish All-on-6 as universally superior. The choice depends on anatomy and prosthetic requirements.

Is All-on-6 stronger because it has more implants?

Six implants can provide additional support points and different force-distribution possibilities, but the overall strength of the rehabilitation also depends on implant position, bite forces, cantilever design and prosthetic material.

Can All-on-4 provide permanent fixed teeth?

Yes. All-on-4 is designed to support a fixed full-arch restoration in suitable patients. The definitive prosthesis is generally provided after the appropriate healing and prosthetic stages.

Can All-on-6 provide same-day teeth?

Selected patients may receive an immediately loaded temporary fixed prosthesis. The decision depends particularly on implant stability and the overall clinical situation.

Does All-on-4 always avoid bone grafting?

No. Strategic implant positioning can reduce the need for grafting in some patients, but bone augmentation may still be required depending on anatomy.

Does All-on-6 require more bone than All-on-4?

Six implants require clinically suitable implant positions across the jaw. Whether sufficient bone is available must be determined through clinical and radiographic evaluation.

Are six implants safer than four if one implant fails?

Additional implants may sometimes provide greater prosthetic flexibility, but this cannot be guaranteed. The effect of losing an implant depends on its location, the remaining implant distribution and the design of the prosthesis.

Is zirconia better for All-on-6 than All-on-4?

The number of implants does not determine the ideal restorative material. Zirconia may be appropriate for either approach, while another prosthetic material may be more suitable for certain patients.

Do All-on-4 and All-on-6 feel like natural teeth?

Fixed implant-supported restorations can provide excellent stability and chewing confidence, but implants do not reproduce exactly the sensory feedback of natural tooth roots.

How do I know whether I need All-on-4 or All-on-6?

The decision requires clinical examination and appropriate imaging together with prosthetic planning. Bone anatomy, implant positions, bite forces, facial support, restorative space, hygiene requirements and long-term maintenance should all be considered.