Antibacterial Effect and Post-operative Pain Following Various Techniques of Intracanal Heating of NaOCL

Assessment of the Antibacterial Effect and Post-operative Pain Following Various Techniques of Intracanal Heating of Sodium Hypochlorite: A Randomized Clinical Trial

The goal of this clinical trial is to is to assess the antibacterial effect of sodium hypochlorite heated inside root canals of necrotic teeth using various activation techniques

The main question it aims to answer is:

Does the antibacterial effect vary following various standardized techniques of intracanal heating of sodium hypochlorite in endodontic treatment?

Study Overview

• Status: Not yet recruiting
• Conditions: Necrotic Teeth
• Intervention / Treatment: Device: Ultrasonic activation; Device: System-B

Detailed Description

Root canal treatment success depends on the removal of necrotic and vital pulp tissues and bacteria and bacterial byproducts from the root canal system.

Mechanical cleansing and removal of necrotic or vital pulp tissue lead to the formation of a layer of debris called " Smear layer," which is made of organic and inorganic substances that should be removed from the root canal system with the help of irrigants.

The presence of complex anatomy like isthmi and anastomoses makes chemical cleansing of the root canal system difficult because they are filled with the smear layer.

The ideal features of root canal irrigants include cleansing, lubrication of endodontic instruments and root canal system, dissolution of inorganic and organic tissues, antimicrobial properties, absence of cytotoxicity without alteration of dental microstructure. Sodium hypochlorite (NaOCl) has been the most widely used irrigant in endodontics due to its antimicrobial and tissue-dissolving action.

Due to the presence of complex anatomy inside the root canal system, activation of irrigation is essential to improve the cleaning of such a complex system. Ultrasonic activation is presently the most popular method for activation of irrigation. It delivers the irrigant farther into areas of the root canal system untouched by instruments, and it improves the mechanical cleaning by increasing the wall shear stress.

NaOCl is used in concentrations between 0.5% - 6%. In high concentrations, it may have a faster dissolution capacity, but it is associated with toxicity in cases of extrusion; thus, methods to improve the action of less concentrated solutions become relevant, such as agitation of the irrigant, constant refreshment and volume, and heating of the solution. Using NaOCl solution at high temperature is related to an increase in reactivity and, therefore, a reduction in bacterial counts and bacterial biofilm dissolution. Although the dentin acts as a thermal insulator, the excessive increase in temperature could dissipate to the periapical tissues, causing damage to the bone tissue .

Initially, it was suggested to heat NaOCl before inserting it into the canals, but this was of little effectiveness .

Woodmansey demonstrated that NaOCl solution can dissolve pulp tissue 210 times faster at boiling temperature (90-120°C) than at room temperature. However, this method remained limited due to the lack of studies confirming its safety until Simeone et al. confirmed that when NaOCl solution is heated inside the canals at a temperature of 150°C for 10 seconds, the temperature of the periodontal tissues does not rise above 42.5°C, which is within the acceptable limits for the periodontal tissue.

Intracanal heating to 180°C using System-B Heat Source shows better antibacterial efficacy than preheated sodium hypochlorite at 60°C. Also, it has been suggested to use low-concentration NaOCl at elevated temperature to report the evidence for better antimicrobial and tissue dissolution properties.

A combination of these two activation methods by ultrasonic agitation of sodium hypochlorite, followed by intracanal heating, may have promising results with regard to the removal of bacteria.

Patients frequently encounter postoperative pain after root canal treatment, and one of the causes is that NaOCl at a higher concentration is irritant to surrounding tissue, particularly in the case of extrusion. Irrigation using lower concentration NaOCl was effective in reducing postoperative pain.

Based on the previous studies, studying the effect of irrigation using low concentration NaOCl (2.6%), which can be activated to increase its reactivity, could give predectible antibacterial effect while reducing postoperative pain and toxicity associated with extrusion.

• Study Type: Interventional
• Enrollment (Estimated): 36
• Phase: Phase 2; Phase 1

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

For patients:

• adult male or female patients
• medically free.

For selected teeth:

• asymptomatic necrotic single rooted teeth
• teeth with mature root
• restorable teeth.

Exclusion Criteria:

For patients:

• Patients with dental related symptoms
• patients with chronic or systemic diseases
• pregnant females.

For selected teeth:

• multirooted teeth
• vital teeth
• teeth with incompletely formed roots
• teeth with internal or external resorption
• previously root canal treated teeth

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Intracanal heating for activation using ultrasonics	Device: Ultrasonic activation; Activation of irrigation using ultrasonic
Experimental: Intracanal heating for activation using System-B heat carrier	Device: System-B; The irrigation activation by heating is achieved using System-B heat carrier
Experimental: Intracanal heating for activation using a combination of ultrasonics and System-B	Device: Ultrasonic activation; Activation of irrigation using ultrasonic; Device: System-B; The irrigation activation by heating is achieved using System-B heat carrier

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Bacterial reduction	Antibacterial effect is evaluated by counting number of bacterial colonies, samples are collected and placed in brain-heart infusion (BHI) broth and subjected to microbiological analysis to determine the colony-forming unit (CFU)/ml	after treatment, samples are sent to microbiology lab and bacterial count is measured day 1 after treatment.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Post-operative pain	Postoperative pain is assessed for each patient using Visual Analog Scale (VAS) with a score ranging from 0 (no pain) to 10 (unbearable pain)	Post operative pain is measured until day 3 after treatment

Collaborators and Investigators

• Sponsor: Misr University for Science and Technology

Publications and helpful links

General Publications

• Govindaraju, L., Shruthi, S.T., Gopal, R., Jenarthanan, S., Rajendran, M.R., 2024. Does increase in temperature of sodium hypochlorite have enhanced antimicrobial efficacy and tissue dissolution property?-A systematic review and meta-regression. J. Conserv. Dent. Endod. 27, 675-684. https://doi.org/10.4103/JCDE.JCDE_110_24
• Iandolo, A., Amato, M., Dagna, A., Poggio, C., Abdellatif, D., Franco, V., Pantaleo, G., 2018. Intracanal heating of sodium hypochlorite: Scanning electron microscope evaluation of root canal walls. J. Conserv. Dent. 21, 569. https://doi.org/10.4103/JCD.JCD_245_18
• Rathore, V., Samel, D., Moogi, P., Bandekar, S., Kshirsagar, S., Vyas, C., 2020. Antimicrobial efficacy of intracanal and extracanal heated sodium hypochlorite against Enterococcus faecalis: An in vitro study. Endodontology 32, 112-117. https://doi.org/10.4103/endo.endo_21_20
• Yared, G., Al Asmar Ramli, G., 2020. Antibacterial Ability of Sodium Hypochlorite Heated in the Canals of Infected Teeth: An Ex Vivo Study. Cureus. https://doi.org/10.7759/cureus.6975
• Simeone, M., Valletta, A., Giudice, A., Di Lorenzo, P., Iandolo, A., 2015. The activation of irrigation solutions in Endodontics: A perfected technique. G. Ital. Endod. 29, 65-69. https://doi.org/10.1016/j.gien.2015.08.005

Study record dates

Study Major Dates

• Study Start (Estimated): February 10, 2026
• Primary Completion (Estimated): June 1, 2026
• Study Completion (Estimated): June 1, 2026

Study Registration Dates

• First Submitted: February 3, 2026
• First Submitted That Met QC Criteria: February 11, 2026
• First Posted (Actual): February 19, 2026

Study Record Updates

• Last Update Posted (Actual): February 19, 2026
• Last Update Submitted That Met QC Criteria: February 11, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Sodium hypochlorite; Irrigation activation; Necrotic teeth,; Endodontic irriggation; Intracanal heating
• Other Study ID Numbers: 2024/0042

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No