All-on-4 or All-on-6 in Jeju: are more implants always better?
Six implants are not always better, and four are not automatically inadequate.
The key is how implants can be placed securely within the available bone, distribute force through the connected teeth and remain maintainable over time.
Key points
Choose the number from bone, distribution, stability, the bite and the final restoration. Long-term cleaning and how problems will be managed are part of the decision.
Are more implants always better?
Numbers alone do not establish superiority. Several implants crowded together or poorly supported by bone may not distribute forces effectively. Four well-spread and stable implants can support a connected full-arch restoration.
A systematic review included in the 2018 ITI consensus found no significant survival difference between fewer than five and five or more implants supporting complete fixed arches. This does not mean four are suitable for everyone.
A more recent five-year randomised upper-jaw trial reported comparable survival and marginal bone outcomes with four and six, but more technical complications in the four-implant group. Maintenance therefore matters alongside cost and surgical scope.
Research informs the decision; individual bone, positions and restoration conditions may differ from those studied.
How do All-on-4 and All-on-6 differ?
Both connect several implants in a nearly or completely toothless jaw to fixed full-arch teeth.
All-on-4 generally uses four implants. Rear implants may be tilted to avoid anatomical structures and extend the supporting spread. All-on-6 generally uses six distributed implants, potentially adding support and design options where bone allows.
| Factor | All-on-4 | All-on-6 |
|---|---|---|
| Basic design | Four implants supporting one full arch | Six implants supporting one full arch |
| Surgery | Positions may be planned around limited bone | More sites require assessment of bone and anatomy |
| Force distribution | Front-to-back spread is particularly important | Well-positioned additional support can broaden distribution |
| Restoration | Careful planning of extensions, materials and connections | Additional support and cleaning space both need planning |
| Decision | Fewer implants do not automatically mean poorer treatment | More implants do not guarantee a better outcome |
What determines the implant number?
Planning works back from the final teeth rather than identifying available implant sites alone. CT, oral scans and bite records connect bone and anatomy with tooth form and loading.
- Upper or lower jaw, bone quantity and density
- Available front-to-back implant spread
- Expected initial stability of each implant
- Opposing teeth, chewing forces, grinding and clenching
- Restoration material, connections and rear extension length
- Daily cleaning and regular maintenance
- A plan for problems involving implants or the restoration
A surgical guide transfers a plan to surgery. Planning from the final teeth comes first.
Why can the upper and lower jaws need different plans?
The jaws differ in bone density and shape, available space and nearby structures. Even in one person, the same number may not be suitable for both.
Upper bone can be softer and the sinuses may limit placement. Six support points may be considered where conditions allow, but anatomy can require another design.
The lower front jaw often provides useful support, while the nerve can limit posterior positions and lengths. Four or six is chosen with anatomy, spread and forces in mind.
When might six implants help?
With enough bone and a useful distribution, six implants can add support, particularly in the upper jaw, with strong biting forces or a long restoration.
Implants too close together or poorly aligned with the final teeth may provide little benefit. Additional sites increase surgery and cost and can complicate cleaning-space design. The reason to add implants is a practical improvement in support and design.
What matters when using four implants?
Each position, initial stability and front-to-back spread is especially important. Rear extensions, material and thickness must accommodate repeated forces.
Same-day fixed temporary teeth depend on stability achieved during surgery, the connected support, grafting and the bite, rather than the number alone.
Four does not mean low-quality care, and it does not mean every patient can be treated with four.
How does Hyungje Dental decide?
We assess which teeth can be retained and plan the final tooth positions using CT and oral scans before deciding the implant number.
We generally consider six in the upper jaw and four, or six where suitable, in the lower jaw. Actual numbers depend on bone distribution, stability, the bite and restoration design.
The result needs to allow cleaning, examination and investigation of problems with screws, the restoration or implants.
Frequently asked questions
Do four implants have a shorter lifespan than six?
Number alone cannot predict lifespan. Position, distribution, bone stability, the bite, design, hygiene and reviews all contribute.
If there is enough bone, is six always better?
No. Extra implants should occupy positions that improve support or the restoration design.
What happens if one of four implants develops a problem?
The response depends on the cause, position, other implants and restoration. The dentist may remove the restoration to assess revision surgery, modification or a new design.
Does advanced age mean only All-on-4 is possible?
Age alone does not determine the number. Medical health, medication, bone, cleaning and follow-up are assessed together.
Can I use teeth on the day of All-on-4 or All-on-6 surgery?
Some patients can receive fixed temporary teeth if suitable conditions and initial stability are confirmed during surgery.
Related articles
References
- Polido WD, Aghaloo T, Emmett TW, Taylor TD, Morton D. Number of implants placed for complete-arch fixed prostheses: A systematic review and meta-analysis. Clin Oral Implants Res. 2018;29(Suppl 16):154–183.
- Toia M, et al. Fixed Full-Arch Maxillary Prostheses Supported by Four Versus Six Implants: 5-Year Results of a Multicenter Randomized Clinical Trial. Clin Oral Implants Res. 2025;36(3):298–313.
- Tallarico M, Meloni SM, Canullo L, Caneva M, Polizzi G. Five-Year Results of a Randomized Controlled Trial Comparing Maxillary Fixed Prostheses Supported by Four or Six Implants. Clin Implant Dent Relat Res. 2016;18(5):965–972.
This article provides general dental information. Individual diagnosis and treatment require an examination.