Nanozymes in Endodontics

This study aims to fill critical knowledge gaps identified in prior clinical findings by optimizing the integration of nanozymes into endodontic workflows and thereby improving treatment outcomes for teeth with apical periodontitis. The study will evaluate the topical application of a low-dose ferumoxytol formulation (Feraheme/H2O2) within the prepared canal system of patients undergoing routine root canal therapy. Antimicrobial efficacy will be compared to the standard sodium hypochlorite irrigant via intracanal microbial sampling. Periapical tissue regeneration and long-term clinical outcomes will be assessed at 6-month and 1-year follow-up intervals using cone-beam computed tomography (CBCT).

• Nanozyme treatment (Drug), also known as Iron oxide nanoparticles, Feraheme, Ferumoxytol: Experimental arm: topical intra-canal irrigation with ferumoxytol (Feraheme®) diluted to 6 mg/mL in 0.1 M sodium acetate, activated with 3% H₂O₂. The solution is instilled into an isolated, dried canal, physically agitated for \~60 s to promote nanozyme activation and convective mixing, held for a brief contact time (<10 min), then aspirated per SOP; post-treatment intracanal sterile paper-point samples are collected. Topical nanozyme mechanism (catalytic ROS generation from low-dose H₂O₂), defined low topical dose and brief contact time (non-systemic).
• Control (Standard treatment) (Drug), also known as NaOCl, Sodium hypochlorite: Control arm: standard clinical irrigation with 3% sodium hypochlorite (NaOCl) using matched total volume and institutional activation method, with identical pre/post sampling and follow-up.

Primary outcomes

• The change in bacterial count between the experimental group (Ferumoxytol/H2O2) and the standard of care (NaOCl) group. [1 Year]: By measuring reduction in bacteria colony forming units (CFU) before and after treatment for the experimental group (Ferumoxytol/H2O2) and the standard of care (NaOCl) group, then comparing the two groups. Samples 1-2 will be taken during the first root canal treatment visit. Sample 1 before cleaning or shaping the root canal. Sample 2 after cleaning and shaping of the root canal using laser or NaOCl. Sample 3 will be taken in the second visit, upon completion of final routine irrigation protocol.

Secondary outcomes

• Periapical Bone Changes from Baseline in Periapical Radiographs at 6, 12, and 24 Months Follow Up [2 Years]: Periapical radiographs will be taken at baseline (preoperative) then at 6 months follow up post root canal filling. Radiographically, Following periapical index (PAI) by Órstavik 1986, description of radiographic findings: 1. Normal periapical structures. 2. Small changes in the bone structure. 3. Change in the bone structure with mineral loss. 4. Periodontitis with a well-defined radiolucent area. 5. Severe periodontitis with exacerbating features. Success is defined as either complete (radiographic resolution of a periapical lesion - the radiographic sign of inflammatory processes surrounding a root tip) or incomplete healing (scar tissue formation) and failure includes uncertain healing (radiographic reduction of a periapical lesion or same lesion size) or unsatisfactory healing (increase in lesion size) as determined on the radiograph.

Sex: All, ages: 18 Years to any

Inclusion Criteria:

1. Patients willing to participate in the study.
2. Patients are 18 years or above.
3. Non-contributory medical history (Patient can be seen for regular dental appointment in PDM; ASA classes I and II).
4. Tooth requiring root canal treatment with radiographic presence of periapical radiolucency and

   1. responding to thermal sensitivity testing negatively (Difluordichlormethane at 50 °C, Endo-Ice,
   2. Coltène/Whaledent Inc., Cuyahoga Falls, Ohio) or a negative response to EPT testing.
5. Tooth with adequate remaining tooth structure for proper isolation with rubber dam.
6. No history of previous endodontic treatment on the tooth.
7. Teeth with single roots or multirooted teeth.

Exclusion Criteria:

1. Self-reported pregnancy.
2. Patients requiring antibiotic premedication prior to dental treatment.
3. Patients with multiple drug allergies.
4. Patients with known hypersensitivity to Ferumoxytol nanoparticles or any iron products.
5. Patients who are scheduled for MRI for the head region within three months after Ferumoxytol nanoparticles application.
6. Periodontal changes (pockets 3 mm, mobility Grade I, or gingival edema).
7. Patients who cannot return for a subsequent appointment or follow-ups.
8. Radiographic presence of resorptive processes.
9. Cracked and fractured teeth.

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