Using different numbers of rotary files to reach the MB2 canal and affect pain after an upper first molar root canal

Effect of Number of Rotary Instruments on Negotiating Second Mesiobuccal Canals to Working Length and on Postoperative Pain: A Randomized Clinical Trial

NA · Mustafa Kemal University · NCT07091981

This trial tests whether using one, two, three, or four rotary files helps find and work the MB2 canal and changes short-term pain after root canal treatment in patients with necrotic maxillary first molars.

Quick facts

PhaseNA
Study typeInterventional
Enrollment152 (estimated)
Ages20 Years to 65 Years
SexAll
SponsorMustafa Kemal University (other)
Locations1 site (Antakya, Hatay)
Trial IDNCT07091981 on ClinicalTrials.gov

What this trial studies

This randomized clinical trial assigns patients needing primary endodontic treatment of maxillary first molars with an MB2 canal to one of four instrumentation protocols (single-, two-, three-, or four-file rotary systems). Operators will attempt working length negotiation of the MB2 canal during instrumentation and record success rates, while postoperative pain is measured daily for seven days using a visual analog scale (VAS). The trial excludes symptomatic or retreatment cases, recent use of certain medications, pregnancy, and limits periapical lesion size to under 5 mm. Procedures are performed at a single center using commercially available rotary file kits specified in the protocol.

Who should consider this trial

Good fit: Systemically healthy adults aged 20–65 who need primary root canal treatment of a maxillary first molar with pulp necrosis, asymptomatic apical periodontitis, an identifiable MB2 canal, and periapical lesions smaller than 5 mm are ideal candidates.

Not a fit: Patients with symptomatic apical periodontitis or acute abscess, retreatment cases, recent use of narcotics/antibiotics/sedatives/antidepressants, pregnancy or breastfeeding, or inability to follow instructions are unlikely to benefit from this protocol.

Why it matters

Potential benefit: If successful, the results could identify an instrumentation approach that improves MB2 canal access and reduces short-term postoperative pain for these molars.

How similar studies have performed: Previous studies have compared rotary systems and reported mixed results on MB2 canal negotiation and postoperative pain, so this approach builds on existing but not definitive evidence.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Systemically healthy individuals aged between 20 and 65 years
* Requiring primary endodontic treatment of maxillary first molars
* Diagnosis of asymptomatic apical periodontitis and pulp necrosis based on clinical and radiographic findings
* Presence of a second mesiobuccal (MB2) canal in the maxillary first molar
* Absence of or only minimal preoperative pain or symptoms
* Periapical lesions smaller than 5 mm in diameter
* Ability to comply with follow-up visits and effectively communicate during the treatment process

Exclusion Criteria:

* Presence of symptomatic apical periodontitis or acute apical abscess
* Retreatment cases (teeth previously treated endodontically)
* Use of medications such as narcotics, antibiotics, sedatives, or antidepressants within one week prior to treatment
* Presence of a sinus tract, periapical abscess, or facial cellulitis
* Pregnancy or breastfeeding
* Inability to understand or follow the study instructions

Where this trial is running

Antakya, Hatay

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Postoperative Pain, Pulp Necrosis, VAS Pain Scale, Endodontic Treatment, Rotary Files

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.