Vitamin D deficiency (VDD) is a prevalent global health concern that has been linked to altered pain perception through its effects on inflammatory pathways, nociceptor activity, and neurotrophic signaling. While its role in chronic pain has been widely studied, limited evidence exists regarding its impact on acute postoperative dental pain. This triple-blinded randomized controlled clinical trial aims to evaluate the effect of moderate-dose vitamin D supplementation on postoperative pain following single-visit root canal treatment (RCT) in patients with symptomatic irreversible pulpitis affecting mandibular first molars. A total of 54 vitamin D-deficient patients (serum 25(OH)D <30 nmol/L), aged 20-45 years, will be randomly allocated into three groups: a single preoperative dose group (150,000 IU vitamin D₃), a fractionated dose group (50,000 IU over three consecutive days), and a placebo group. All participants will undergo standardized single-visit RCT procedures. Postoperative pain will be assessed using a Modified Visual Analog Scale (VAS) at baseline and at 6, 12, 24, and 48 hours post-treatment, while analgesic intake will be recorded as a secondary outcome. It is hypothesized that vitamin D supplementation will significantly reduce postoperative pain levels and analgesic consumption compared to placebo. This study seeks to explore vitamin D as a safe, cost-effective adjunct in endodontic pain management, with potential implications for improving clinical outcomes in patients with VDD undergoing RCT.

This study is a triple-blinded randomized controlled clinical trial designed to evaluate the effect of vitamin D supplementation on postoperative pain following single-visit root canal treatment (RCT) in patients with symptomatic irreversible pulpitis affecting mandibular first molars.

Vitamin D deficiency (VDD) is highly prevalent worldwide and has been increasingly linked to pain modulation mechanisms, including effects on nociceptors, inflammatory pathways, neurotrophic factors, and immune responses. Despite evidence supporting its role in chronic pain, limited research has investigated its effect on acute dental pain, particularly postoperative endodontic pain.

Aim

To assess whether moderate-dose vitamin D supplementation reduces postoperative pain levels in vitamin D-deficient patients undergoing RCT.

Study Design & Participants Sample size: 54 patients (18 per group)

Population: Adults (20-45 years) with:

Vitamin D deficiency (<30 nmol/L) Symptomatic irreversible pulpitis in mandibular first molars All treatments are performed in a single visit under standardized clinical conditions.

Intervention Groups Group A: Single high dose (150,000 IU vitamin D₃) preoperatively Group B: Fractionated dose (50,000 IU for 3 days: pre-op + 2 days post-op) Group C: Placebo

Vitamin D is administered with dietary fat to enhance absorption.

Outcome Measures

Primary outcome:

Postoperative pain assessed using Modified Visual Analog Scale (VAS) at:

Preoperative baseline 6, 12, 24, and 48 hours post-treatment

Secondary outcome:

Analgesic intake (number of patients and tablets consumed) Methodology Highlights

Standardized RCT protocol including:

Rubber dam isolation Rotary instrumentation (crown-down technique) Sodium hypochlorite irrigation (5.25%) Continuous wave obturation Only ibuprofen (600 mg) allowed as rescue analgesic Strict triple blinding (patient, operator, assessor) to eliminate bias Hypothesis Null hypothesis: No difference in postoperative pain between vitamin D and placebo groups.

Significance

This study addresses a gap in endodontic pain management, exploring vitamin D as a potential adjunctive, low-cost, and biologically plausible analgesic strategy. If effective, it may influence clinical protocols for managing acute pulpitis-related pain and postoperative discomfort.

Inclusion Criteria:

• Patients with serum 25-hydroxyvitamin D level below 30 nmol/L with no vitamin D supplementation for the preceding 3 months.
• Patients diagnosed with symptomatic irreversible pulpitis.
• Mandibular first molar:

Classification of root canal configuration according to Weine's classification:

• Distal root: with one portal of exit

• Mesial root: Type III, two separate and distinct canals extend from the pulp chamber to the apex.

  • Patients with moderate to severe pre-operative pain with pain score from 6-10.
  • Medically free patients with no systemic disease: (American Society of Anesthesiologists / (ASA Class I or II).
  • The age range is between 20 to 45 years.
  • Patients have restorable mandibular permanent molars that were diagnosed with symptomatic irreversible pulpitis.
  • Positive patient's acceptance for participating in the study and signing informed consent

Exclusion Criteria:

• Patients that have been taking vitamin D supplements in the last 3 months.

• Patients with serum 25-hydroxyvitamin D level above 30 nmol/L.

• Patients diagnosed with necrosis, partial necrosis, acute or chronic abscess.

• Presence of periapical radiolucency.

• Patients with systemic conditions that may affect pain perception (e.g., fibromyalgia, diabetes, chronic pain disorders).

• Pregnant or lactating females.

• Psychologically disturbed patients.

• Patients with a history of allergy to any medication used in the study are excluded.

• Patients with mild to moderate pain with pain scores less than 6.

• Teeth that have:

  • Periodontally affected molars with grade 2 or 3 mobility.
  • Non-restorable teeth.
  • Abnormal anatomy and calcified canals.
  • Previous root canal treatment.

• Patients above 45 years old or below 20 years old.

• Non-compliant patients to follow ups.

• Patients with very poor oral hygiene.