“The key to success is adhering to surgical and prosthetic protocols.”

Prof. Agliardi, you are well-known for advanced maxillofacial surgeries, especially for edentulous patients. When do you choose to use the All-on-4® treatment concept?

As a maxillofacial surgeon, I did a lot of bone grafting at the beginning of my career and I still do in selected cases. I saw how complicated it was and how high the biological and financial costs are for the patient and the clinician. In addition, and after several years of academic and clinical experience, I have learned that in grafts, residual bone – even if atrophic – plays a key role. The All-on-4® treatment concept makes the most of residual bone.

It allows me to drastically reduce the use of grafts. I use this technique for more than 70% of my edentulous patients, as it is less demanding for both the patient and the clinician. For the others, I use V-II-V in 25% of cases, and zygomatic implants or grafting in 5%.

For decision-making, I first check the residual bone availability. This ranges from full bone volume adequate to place straight implants, to complete alveolar bone resorption, for which I use four zygomatic implants. In fact, some modifications to the original protocol, such as V-II-V trans-sinus or trans-crestal implants have made it possible to extend the use of the All-on-4® treatment concept in a large majority of edentulous patients.

You have recently published a clinical study about full-arch treatment with up to 17 years of follow-up¹. What were the main outcomes of this study?

I started using the All-on-4® protocol in my private practice in 2004, so I could follow an original pool of 173 patients treated from April 2004 until January 2009, with 692 implants (72 maxillary and 101 mandibular arches). The majority of patients were scheduled for regular recall appointments, so I was able to collect data on bone loss and any complications. Some drop out occurred, as expected.

At up to 17 years of function, implant survival rates were 97.5% in the maxilla and 96.9% in the mandible, with no difference between axial and tilted implants. We used statistical models to analyze the relationship between implant failure and potential risk indicators. Only diabetes type 2 was very close to significance, where age at the time of surgery, gender, arch, smoking or history of periodontal disease were not contributing factors.

We also used peri-apical radiography to calculate marginal bone loss. At 10 years, it was 1.70 mm in the maxilla and 1.80 mm in the mandible. Also, the difference in marginal bone loss between axial and tilted implants was not significant after 10 years in the maxilla, while it was in the mandible. Moreover, bone loss was more pronounced in the mandible at both 5- and 10-year follow-ups. Statistical analysis showed a correlation between arch and bone loss, while no correlation was found with age, gender, smoking, diabetes, and history of periodontal disease.

Does the choice of the implant system and its premium design contribute to the predictability of the outcome?

I have been using Nobel Biocare implants for all my dental rehabilitation procedures, and I strongly believe that this choice has greatly contributed to the success of my treatments. As many as 80% of my patients present with complex initial conditions, including advanced bone atrophy, failed prior implant treatments, or poor bone quality, and are often referred to me by other patients or colleagues. I frequently encounter a limited amount of residual bone with poor density, requiring an implant that can provide secure anchorage without compromising the bone. With a wide range of implant morphologies and dimensions, Nobel Biocare offers a diverse portfolio of products, backed by substantial investment in research and development and close collaboration with global experts and opinion leaders.

Have you used the Nobel Biocare N1™ implant system in an All-on-4® case?

Would you say that the Nobel Biocare N1 system is for all situations?

I believe Nobel Biocare N1 is a versatile system that can be used in different situations, making it possible to safely treat patients with poor-quality bone such as those treated with bisphosphonate therapy or cancer patients who have undergone chemotherapy or radiotherapy. Furthermore, the new Xeal abutment surface provides a safe and stable soft tissue integration. I have seen this in my cases with three years of follow-up. Marginal bone remodeling has been minimal and the level of peri-implant soft tissue around Multi-unit Abutment Xeal has remained stable over time.