Prosthetic Complications in Full-arch Screw-retained Implant Restorations Using Monolithic Zirconia Versus Titanium Frameworks: A Randomized Clinical Trial

Inclusion criteria

• Aged 18 years or older.
• Able to understand the study procedures and provide written informed consent.
• In good general health, classified as American Society of Anesthesiologists (ASA) Physical Status Class I or II.
• Completely edentulous in the arch to be treated (maxilla and/or mandible).
• A candidate for a full-arch, screw-retained implant-supported prosthesis, requiring 4 to 6 implants in the treatment arch.
• Sufficient bone volume at planned implant sites to place implants of at least 3.5mm in diameter and 8mm in length.
• Adequate crown height space (15-22 mm) for a fixed prosthesis.
• A zone of keratinized mucosa at the crest of the ridge measuring at least 2 mm in width.
• Opposing arch is fixed full-arch implant-supported prosthesis.
• Demonstrates acceptable oral hygiene and the motivation to maintain it.

Exclusion criteria

• Medical contraindications:

• Uncontrolled diabetes (HbA1c > 7.0%).
• History of radiotherapy in the head and neck region.
• History of intravenous bisphosphonate therapy.
• Immunosuppressed or immunocompromised status.
• Any other uncontrolled systemic disease that constitutes a contraindication for oral surgery.
• Behavioral Factors:

• Heavy smoking, defined as consumption of more than 10 cigarettes per day.
• Presence of parafunctional habits (e.g., bruxism, clenching) as diagnosed by clinical examination.
• Local Oral Factors:

• Active, untreated periodontal disease in any remaining dentition.
• Presence of acute oral infection or pathology at the intended surgical site.
• Crown height space less than 15 mm or more than 22 mm.
• Insufficient keratinized mucosa (< 2 mm width) that cannot be corrected with a simple surgical procedure prior to implant placement.
• General:

• Pregnancy or lactation.
• Participation in another interventional clinical trial.
• Perceived inability to comply with the study protocol and follow-up schedule.