This randomized controlled clinical trial aims to evaluate the effect of the number of rotary files on working length negotiation and postoperative pain in the second mesiobuccal (MB2) canals of maxillary first molars. Patients are assigned to one of four groups according to the number of rotary files used: single-, two-, three-, or four-file systems. Postoperative pain is assessed on each of the seven consecutive postoperative days (Days 1-7) using a visual analog scale (VAS), and working length negotiation success is recorded during canal instrumentation.
Who can participate
Age range
20 Years – 65 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
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
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
What they're measuring
1
Postoperative Pain Intensity (VAS Score)
Timeframe: Daily assessment for 7 consecutive days following treatment (Days 1-7)