The goal of this study is to evaluate the outcome of a Poly-ether-ether-ketone - acrylic resin prosthesis for full-arch rehabilitation of the atrophic maxillae through the All-on-4 Hybrid concept (standard and zygomatic implants) after one year of follow-up. The main question it aims to answer is:

- What is the survival outcome of the full-arch implant-supported Poly-ether-ether-ketone - acrylic resin prosthesis? The participants already rehabilitated with dental implants will receive a Poly-ether-ehter-ketone prosthesis as a definitive prosthesis.

Following the previous study on the full-arch rehabilitation of edentulous jaws using hybrid prostheses with polyetheretherketone (PEEK) infrastructure and acrylic resin teeth supported by implants in immediate function inserted through the All-on-4 concept it is necessary to further extend the evaluation to the full-arch rehabilitation of severily atrophic maxillae through the use of the same hybrid prostheses supported by immediate function zygomatic implants inserted alone or in combination with conventional implants. To test this, the study design to be used will be a single-centre, prospective, observational cohort study to evaluate the short term outcome of fixed prosthetic implant-supported rehabilitations. The sample of this study consists in 10 patients consecutively treated. The cohort will be evaluated after 4 to 8 weeks, 6 months, 12 months after connection of the prostheses and annually thereafter as long as the patient is willing, regarding: prosthetic survival, implant survival, marginal bone resorption, incidence of mechanical complications (loosening or fracture of prosthetic components), biological complications (peri-implant infection, suppuration, fistulae, sinus infection, gingival dehiscence), patient tissue reaction, aesthetic examination including staining, color stability and anatomic form; patient assessment of in mouth comfort, overall chewing ability, aesthetics and patient quality of life using the Oral Health Impact Profile OHIP-14 questionnaire; assessment of prosthetic preparation (technician satisfaction) concerning laboratory preparation time, clinical operative time and costs.

Inclusion Criteria:

• Subjects who, in the opinion of the Investigator, are able to understand this clinical study, co-operate with the procedures and are willing to return to the clinic for all the required post-operative follow-ups.
• Subjects who are able to give voluntary, written informed consent to participate in this clinical study and from whom consent has been obtained.

Exclusion Criteria:

• Female Subjects who are pregnant.
• Subjects who are known drug or alcohol abusers or with psychological disorders that could affect follow-ups or treatment outcomes.
• Subjects with any condition that would compromise their participation and follow-up in this clinical study.
• Subjects who are currently enrolled in a clinical study.

Anonymized database containing the study variables

Upon study completion and for 8 years.

Upon solicitation to the Investigators