A 49-year-old man presented to a prosthodontic department with several missing teeth and multiple remaining teeth that were severely mobile. The clinical examination revealed advanced, generalised periodontitis, gum recession and Grade III tooth mobility.
This was no longer a case of replacing one or two teeth. The remaining dentition could not provide a stable foundation for predictable long-term function. The treatment team therefore planned a complete rehabilitation of both jaws.
The treatment plan
Four implants were placed in the upper jaw and another four in the lower jaw. Instead of placing an implant for every missing tooth, the implants were distributed strategically so that each group of four could support a complete fixed arch.
The definitive prosthetic phase began three months after implant placement, once secondary implant stability had been established.
Accuracy was especially important. The team used splinted open-tray impressions to record the exact implant positions. A verification jig was then checked clinically and radiographically before the final restoration was produced.
The patient’s bite, jaw relationship and available restorative space were carefully recorded. The casts were scanned digitally, and the supporting frameworks were created using direct metal laser sintering. Each stage was verified before the fixed prostheses were completed.
The published report described the rehabilitation of both jaws as successful.
Why four implants can support an entire arch
The number of implants alone does not determine whether a full-arch treatment will succeed. Their position, angle, stability and distribution are equally important.
In the All-on-4 concept, the posterior implants may be angled to increase the distance between the front and back supports while reducing the unsupported end of the restoration. This can provide a stable foundation without placing an implant beneath every replacement tooth.
But “fewer implants” should never mean less planning. The final result still depends on several connected factors:
- The quantity and quality of available bone
- Primary and secondary implant stability
- Accurate transfer of the implant positions
- Passive adaptation of the framework
- Balanced biting forces
- A restoration that the patient can clean
- Regular professional maintenance
An error in any one of these areas can affect the entire arch.
What this case does—and does not—prove
This case demonstrates that four strategically positioned implants per jaw can support fixed full-arch restorations in a carefully selected patient. It also shows how much of the work happens between implant placement and delivery of the final teeth.
However, it is still a single clinical case. It cannot prove that All-on-4 is the correct solution for every patient, nor does it provide a universal timeline or long-term guarantee.
Although All-on-4 is frequently associated with immediate provisional teeth, the definitive prostheses in this published case were fabricated after a three-month healing period. The treatment name alone should therefore never be interpreted as a promise of “permanent teeth in one day.”
The most useful question is not simply, “How many implants do I need?” It is whether the available bone, implant stability, prosthetic design and maintenance plan can work together safely.
Published case reviewed: Minase et al., “Less Is More: A Case Report on All-on-4 Prosthesis,” Cureus, 2024. Individual results vary, and treatment requires a personal clinical and radiographic assessment.
