Microbial Adhesion and Peri-Implant Tissue Health in All-on-Four Hybrid Prostheses Supported by Zantex or Zirconia Frameworks

Microbial Adhesion and Peri-Implant Tissue Health in All-on-Four Hybrid Prosthesis Supported by Zantex or Zirconia Framework. A Randomized Clinical Trial

This study compares two materials (Zantex and Zirconia) used to make fixed full-arch dental prostheses supported by four dental implants (the "All-on-Four" technique) in patients who have no natural teeth in the lower jaw. The study will evaluate how much bacteria builds up on each material and how healthy the gum tissue around the implants stays over time. Each patient will receive one type of prosthesis (either Zantex or Zirconia framework), and will be followed for three months after treatment. The goal is to help determine which material may provide better oral health outcomes for patients receiving this type of dental treatment.

Complete edentulism remains a major clinical challenge, particularly among aging populations. All-on-Four fixed implant-supported prostheses have become a widely used solution, but the long-term success of these restorations depends heavily on the framework material used, including its resistance to microbial adhesion and its effect on peri-implant tissue health.

This randomized clinical trial compares two framework materials: Zirconia, a high-strength ceramic material, and Zantex, a fiber-reinforced polymer material, both used to fabricate mandibular hybrid prostheses supported by four implants placed following the All-on-Four protocol.

Microbial adhesion will be assessed by evaluating biofilm accumulation on the prosthesis frameworks retrieved under sterile conditions at set time intervals. Peri-implant tissue health will be evaluated clinically at 1 week, 2 weeks, 1 month, and 3 months following prosthesis delivery, using standard clinical parameters including modified plaque index, modified bleeding on probing, and probing depth.

A total of 14 patients (7 per group) will be enrolled based on sample size calculations targeting 90% statistical power.

Inclusion Criteria:

1. Completely edentulous patients in the mandibular arch.

2. Patients with a completely edentulous maxillary arch rehabilitated with a conventional complete denture.

3. Patients with sufficient mandibular bone volume and quality to allow placement of four implants according to the All-on-Four treatment concept.

4. Patients suitable for placement of two axial anterior implants in the canine regions and two distally tilted posterior implants anterior to the mental foramina.

5. Patients with adequate restorative space to accommodate a full-arch hybrid prosthesis.

6. Patients who are willing and able to maintain adequate oral hygiene and attend all scheduled follow-up appointments.

7. Patients who are willing to participate in the study and sign the informed consent form.

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Exclusion Criteria:

• 1. Patients with systemic conditions that contraindicate implant surgery or may adversely affect osseointegration or wound healing.

  2. Patients receiving medications or undergoing treatments that significantly affect bone metabolism or healing.

  3. Patients with a history of radiotherapy involving the head and neck region that may compromise implant therapy.

  4. Patients with active or uncontrolled periodontal or oral infections. 5. Patients with inadequate mandibular bone volume or unfavorable anatomical conditions that prevent placement of four implants according to the planned All-on-Four protocol without additional augmentation procedures.

  6. Patients with severe parafunctional habits, such as uncontrolled bruxism, that may compromise the prosthetic rehabilitation.

  7. Patients unable or unwilling to maintain appropriate oral hygiene. 8. Patients unable to attend the scheduled follow-up visits. 9. Patients who decline to participate or fail to provide informed consent