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NCT Number: NCT07701551

Hypertonic Saline as a Final Flush and Post-Operative Pain After Single Visit Root Canal Treatment in Mandibular Premolar.

This randomized controlled trial evaluates whether a final flush with 3% hypertonic saline, compared with 0.9% normal saline, reduces post-operative pain and periapical Substance P (SP) levels after single-visit root canal treatment in mandibular premolars with symptomatic irreversible pulpitis. Forty adult patients will be randomized 1:1. Pain will be measured with the Visual Analogue Scale (VAS) at 6, 12, 24, and 48 hours post-operatively. Periapical fluid SP levels will be measured by ELISA at two intra-operative time points (after working length determination, and after the final flush). The number of ibuprofen 400 mg tablets consumed within 24-48 hours will also be recorded.

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Key information

Conditions

Symptomatic Irreversible Pulpitis (SIP)

Age range

18 year–60 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 4

About this study

Post-operative endodontic pain is linked to periapical release of Substance P (SP), a neuropeptide that sustains neurogenic inflammation via NK-1 receptor binding. 3% hypertonic saline has documented osmotic decongestant and NF-κB-mediated anti-inflammatory/cytokine-suppressive effects in non-dental models, providing biological rationale for its use as a final irrigant. This is a two-arm, parallel-group, participant- and assessor-blinded RCT conducted at the outpatient endodontic clinic, Faculty of Dentistry, Cairo University. After standardized access, working length determination, and a baseline periapical fluid sample (S1), canals will be shaped with continuous rotary NiTi instrumentation and irrigated with 2.5% NaOCl. After smear layer removal (2.5% NaOCl then 17% EDTA), participants receive a final flush of either 5 mL 0.9% normal saline (control) or 5 mL 3% hypertonic saline (intervention), delivered via a 30-gauge side-vented needle 2 mm short of working length. A second periapical fluid sample (S2) is then collected. Canals are obturated by lateral compaction in the same visit. Participants record VAS pain scores pre-operatively and at 6, 12, 24, and 48 hours, and log ibuprofen 400 mg tablet consumption at 24 and 48 hours. SP will be quantified from S1/S2 samples by ELISA, blinded to group allocation.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age 18-60 years, any sex
  • Systemically healthy
  • Mandibular premolar with clinically/radiographically diagnosed symptomatic irreversible pulpitis (prolonged, exaggerated response to cold testing; no periapical radiolucency)
  • Able to use the VAS scale and complete follow-up

Exclusion criteria

  • Medically compromised patients
  • Pregnant or lactating women
  • Allergy/hypersensitivity to local anesthetics or NSAIDs
  • Analgesics, anti-inflammatories, or antibiotics within 12 hours pre-treatment
  • Vertical root fracture, root resorption, or previous RCT
  • Radiographic periapical pathology
  • Non-restorable teeth
  • TMD, bruxism, or traumatic occlusion interfering with pain assessment

Treatment and study plan

Normal (0.9%) saline

Drug

Isotonic 0.9% NaCl solution used as final canal flush, no pharmacological activity

Hypertonic 3% saline

Drug

Osmotic/anti-inflammatory final irrigant hypothesized to reduce periapical edema and suppress pro-inflammatory cytokine-mediated SP release via NF-κB pathway inhibition.

Primary outcomes

  1. Post-operative pain intensity at 6 hours

    Time frame: 6 hours post-operatively

    Visual Analogue Scale (VAS), 0-10 (0 = no pain, 1-3 mild, 4-6 moderate, 7-10 severe)

Secondary outcomes

  1. Post-operative pain intensity at 12, 24, and 48 hours

    Time frame: 12, 24, and 48 hours post-operatively

    VAS, 0-10, same categorization as primary

  2. Change in periapical Substance P expression (ΔSP = S2 - S1)

    Time frame: S1 = after working length determination (intra-operative); S2 = immediately after final flush (intra-operative)

    Quantified by ELISA (human Substance P kit) from periapical fluid collected via paper point; pg/mL

  3. Number of rescue analgesic tablets consumed

    Time frame: 24 and 48 hours post-operatively

    Ibuprofen 400 mg tablets, patient-recorded tablet-count chart, max 3 tablets/24 h

Study contacts

Contact information is provided by the study sponsor or research team.

Kariman Ameen Ismaiel

CONTACT

[email protected]

+201013665586

Sponsors and collaborators

Lead sponsor

Cairo University

Other

Registry information

Official study title

Effect of Hypertonic Saline (3%) as a Final Flush Irrigant on Post-Operative Pain and Substance P Expression Following Single-Visit Root Canal Treatment in Patients With Symptomatic Irreversible Pulpitis Related to Mandibular Premolars: A Randomized Controlled Trial

Acronym: Hypertonic

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Jul 14, 2026
Registry last updated
Jul 14, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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