An interventional study of Control - aPDT Without Additional Activation and Passive Ultrasonic Irrigation (PUI) in Apical Periodontitis and Endodontic Retreatment, sponsored by Karadeniz Technical University. Recruiting at 1 site in Turkey (Türkiye). Open to participants aged 18 Years to 65 Years. Per ClinicalTrials.gov, last updated 2026-11-06.
Sponsored by Karadeniz Technical University · Not applicable, Interventional, and Treatment
This randomized clinical trial aims to investigate the effects of different intracanal methylene blue agitation techniques used during antimicrobial photodynamic therapy (aPDT) on root canal microbiota, host inflammatory responses, postoperative pain, and periapical healing in previously root canal-treated teeth with asymptomatic apical periodontitis.
A total of 60 participants will be randomly allocated to four groups (15 participants per group): aPDT without additional methylene blue agitation (control), aPDT with standard needle irrigation(SNI), aPDT with passive ultrasonic irrigation (PUI), and aPDT with Er,Cr:YSSG laser-assisted irrigation (LAI).
All participants will undergo nonsurgical root canal retreatment. Methylene blue will be used as the photosensitizing agent, and photodynamic light irradiation will be performed using the LED FotoSan device in all groups.
Root canal samples will be collected at three treatment stages to investigate changes in microbial communities and inflammatory markers. Shotgun metagenomic sequencing will be performed in a subset of participants, while selected inflammatory cytokines will be measured using enzyme-linked immunosorbent assay (ELISA).
Postoperative pain and radiographic periapical healing will also be evaluated during follow-up.
The study aims to determine whether different methylene blue agitation techniques influence the microbiological, inflammatory, and clinical outcomes of antimicrobial photodynamic therapy during root canal retreatment.
This randomized clinical trial will investigate the molecular, microbiological, inflammatory, and clinical effects of different intracanal methylene blue agitation techniques used during antimicrobial photodynamic therapy (aPDT) in previously root canal-treated permanent teeth with asymptomatic apical periodontitis.
A total of 60 participants will be randomly allocated to four groups (n=15 per group):
Control group: aPDT without additional intracanal methylene blue agitation.
Standard needle irrigation (SNI) group: aPDT with conventional syringe agitation of methylene blue.
Passive ultrasonic irrigation (PUI) group: aPDT with passive ultrasonic agitation of methylene blue.
Laser-activated irrigation (LAI) group: aPDT with Er,Cr:YSSG laser-assisted agitation of methylene blue.
All participants will undergo nonsurgical root canal retreatment, including removal of the previous root canal filling material and chemomechanical preparation. Methylene blue will be introduced into the root canal system as the photosensitizing agent. The assigned intracanal agitation protocol will then be performed, followed by photodynamic light irradiation using the FotoSan device in all groups.
Root canal samples will be collected at three stages: S1, after removal of the previous root canal filling material; S2, after chemomechanical preparation; and S3, following antimicrobial photodynamic therapy.
Shotgun metagenomic sequencing will be performed in a subset of 24 participants, including eight participants from each of the SNI, PUI, and LAI groups. The analysis will investigate microbial taxonomic composition, microbial diversity, functional pathways, antimicrobial resistance genes, and virulence-associated factors.
Host inflammatory responses will be evaluated in all four study groups by measuring interleukin-1 beta (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10), interferon-gamma (IFN-γ), and tumor necrosis factor-alpha (TNF-α) using enzyme-linked immunosorbent assay (ELISA).
Postoperative pain will be assessed using a visual analog scale (VAS) at predefined intervals following treatment. Periapical healing will be evaluated radiographically during the follow-up period.
Within-group changes across sampling points and between-group differences will be evaluated to determine the influence of intracanal methylene blue agitation techniques on microbial communities, host inflammatory responses, postoperative pain, and periapical healing
280 studies on the registry are indexed under Periapical Periodontitis; 79 are open to participants now.
This study's planned enrollment of 60 is close to the median of 60 across 245 interventional studies indexed under Periapical Periodontitis.
Browse Periapical Periodontitis studies →Karadeniz Technical University is the lead sponsor of 153 studies on the registry; 22 are open to participants now.
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Exclusion Criteria:
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You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants will receive antimicrobial photodynamic therapy using methylene blue without additional intracanal agitation, followed by FotoSan light irradiation
Procedure: Control - aPDT Without Additional Activation
Participants will receive antimicrobial photodynamic therapy (aPDT) with intracanal agitation of methylene blue using a standard irrigation needle with back-and-forth movements, followed by photodynamic light irradiation using the FotoSan device.
Procedure: Standard Needle Irrigation (SNI)
Participants will receive antimicrobial photodynamic therapy (aPDT) with intracanal activation of methylene blue using passive ultrasonic irrigation, followed by photodynamic light irradiation using the FotoSan device.
Procedure: Passive Ultrasonic Irrigation (PUI)
Participants will receive antimicrobial photodynamic therapy (aPDT) with intracanal activation of methylene blue using an Er, Cr:YSGG laser-assisted irrigation technique, followed by photodynamic light irradiation using the FotoSan device
Procedure: Laser-Activated Irrigation (LAI)
All participants will receive antimicrobial photodynamic therapy (aPDT) using methylene blue as the photosensitizer, followed by photodynamic light irradiation with the FotoSan device. The groups will differ according to the intracanal activation technique applied to methylene blue.
Methylene blue will be activated within the root canal using passive ultrasonic irrigation before photodynamic light irradiation with the FotoSan device.
Methylene blue will be agitated within the root canal using a standard irrigation needle with back-and-forth movements before photodynamic light irradiation with the FotoSan device.
ethylene blue will be activated within the root canal using an Er,Cr:YSGG laser-assisted irrigation technique before photodynamic light irradiation with the FotoSan device
Postoperative Pain Intensity Assessed Using a Visual Analog Scale (VAS)
Postoperative pain intensity will be assessed using a 100-mm Visual Analog Scale (VAS), ranging from 0 (no pain) to 100 (unbearable pain). Participants will record their pain intensity at 24 hours, 72 hours, and 1 week after treatment. Mean VAS scores at each time point will be compared among the four treatment groups.
Time frame: Up to 7 days after treatment (24 hours, 72 hours, and day 7)
Periapical Radiographic Healing Assessed Using the Periapical Index (PAI)
Periapical radiographic healing will be assessed using digital periapical radiographs obtained with the paralleling technique. Periapical status will be evaluated using the Periapical Index (PAI), scored from 1 (normal periapical structures) to 5 (severe periodontitis with exacerbating features). Teeth with PAI scores of 1 or 2 will be classified as healed, whereas teeth with PAI scores of 3, 4, or 5 will be classified as not healed. Changes in PAI scores will be evaluated over time and compared among treatment groups. Periapical healing will be assessed using the Periapical Index (PAI) before treatment, immediately after treatment, and at 6 and 12 months after treatment.
Time frame: From baseline through 12 months after treatment (baseline, immediately post-treatment, month 6, and month 12)
Changes in Root Canal Microbial Composition
hanges in root canal microbial composition will be assessed using shotgun metagenomic sequencing of samples collected at three treatment stages. Taxonomic profiles will be evaluated before and after antimicrobial photodynamic therapy (aPDT) and compared among the standard needle irrigation (SNI), passive ultrasonic irrigation (PUI), and laser-activated irrigation (LAI) grou
Time frame: Day 1 (before treatment, after irrigation activation, and after antimicrobial photodynamic therapy)
Changes in Microbial Functional Gene Profiles
Changes in microbial functional gene profiles will be evaluated using shotgun metagenomic sequencing of root canal samples collected at S1, S2, and S3. Functional gene profiles will be compared across sampling stages and among the SNI, PUI, and LAI groups
Time frame: Day 1 (before treatment, after irrigation activation, and after antimicrobial photodynamic therapy)
Changes in Antimicrobial Resistance Gene Profiles
Antimicrobial resistance genes (ARGs) in root canal microbial samples will be characterized using shotgun metagenomic sequencing. Changes in ARG profiles will be evaluated across S1, S2, and S3 and compared among the SNI, PUI, and LAI groups.
Time frame: Day 1 (before treatment, after irrigation activation, and after antimicrobial photodynamic therapy)
Changes in Intracanal Inflammatory Cytokine Levels
Intracanal levels of IL-1β, IL-6, IL-8, IL-10, TNF-α, and IFN-γ will be measured using enzyme-linked immunosorbent assay (ELISA) in samples collected at S1, S2, and S3. Changes in cytokine levels will be evaluated across sampling stages and compared among the four study groups.
Time frame: Day 1 (before treatment, after irrigation activation, and after antimicrobial photodynamic therapy)
Plan to share: No — Individual participant data (IPD) will not be shared with other researchers to protect participant privacy and confidentiality. Study findings will be reported in aggregate form in scientific publications
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