Efficacy of Different Disinfection Technologies in Molar Non-Surgical Retreatment

NCT07469150 | Not Yet Recruiting

• 2 other identifiers: IRB-300015590Pending
• Study Type: interventional
• Target: 60
• Locations: 1 country
• Sites: 1

Brief Summary

Post-treatment apical periodontitis is commonly associated with persistent intracanal infection following root canal treatment. Effective disinfection of the complex root canal system during nonsurgical retreatment remains challenging due to anatomical complexities that may harbor microbial biofilms. Conventional retreatment protocols typically involve nickel-titanium rotary instrumentation combined with irrigation using sodium hypochlorite and activation techniques such as Passive Ultrasonic Irrigation (PUI). The GentleWave System (GWS) is a minimally invasive irrigation technology designed to enhance tissue dissolution and microbial removal through multisonic energy, advanced fluid dynamics, and negative pressure. Although preliminary studies suggest promising results in root canal disinfection and patient outcomes, high-level clinical evidence comparing GWS with conventional retreatment techniques remains limited, particularly in molar teeth with post-treatment apical periodontitis. This randomized clinical study aims to compare the disinfection efficacy of GWS with a conventional nickel-titanium rotary instrumentation protocol combined with PUI in nonsurgical retreatment of molars with post-treatment apical periodontitis. Intracanal bacterial load will be quantified using quantitative polymerase chain reaction (qPCR), and microbial composition will be analyzed using next-generation sequencing (NGS). Residual organic debris will be evaluated using the chairside diagnostic device Endocator and facultative bacterial culturing. Postoperative pain levels will also be recorded to assess short-term clinical outcomes. The results of this study will provide clinical evidence regarding the comparative effectiveness, safety, and potential advantages of advanced irrigation technology for root canal disinfection in complex retreatment cases.

Conditions

Apical Periodontitis

Keywords

Post-treatment apical periodontitis; Endodontic retreatment; Root canal disinfection; GentleWave System; Passive ultrasonic irrigation; Nickel-titanium rotary instrumentation; Sodium hypochlorite irrigation; Intracanal bacterial load; Root canal microbiome; Quantitative PCR; Next-generation sequencing; Endocator; Postoperative pain

Outcome Measures

Primary Outcomes (2)

• change of the intracanal Bacterial Load

  Change in total bacterial load in the root canal system following disinfection, measured by quantitative real-time polymerase chain reaction (qPCR) targeting the universal 16S rRNA gene. Bacterial load will be quantified from microbiological samples collected before instrumentation (S1) and after completion of the disinfection protocol (S2) to determine the reduction in bacterial load between the two time points.

  During the treatment visit (baseline before instrumentation and immediately after completion of the disinfection protocol).

• Root Canal Microbiome Composition

  Differences in the prevalence and relative abundance of bacterial taxa in root canal samples before and after disinfection, assessed using next-generation sequencing (NGS) of bacterial 16S rRNA gene amplicons. Alpha diversity and beta diversity metrics will be analyzed to compare microbial community structure between treatment groups.

  During the treatment visit (baseline before instrumentation and immediately after completion of the disinfection protocol).

Secondary Outcomes (2)

• change of the Residual Intracanal Organic Debris Score

  During the treatment visit (before instrumentation and immediately after completion of disinfection).

• Post-operative Pain

  1 day, 2 days, 3 days, 5 days, and 7 days after the treatment visit

Study Arms (2)

GentleWave Disinfection Group

ACTIVE COMPARATOR

Participants with molars requiring nonsurgical endodontic retreatment will undergo root canal disinfection using the GentleWave System following minimal mechanical instrumentation. Microbiological samples will be collected prior to retreatment and before obturation to evaluate intracanal bacterial load and microbiome composition. Residual organic debris will be assessed using the chairside device Endocator, and postoperative pain will be recorded.

Procedure: GentleWave System

Conventional Rotary Instrumentation with Passive Ultrasonic Irrigation

ACTIVE COMPARATOR

Participants with molars requiring nonsurgical endodontic retreatment will undergo conventional chemomechanical preparation using nickel-titanium rotary instrumentation combined with irrigation using Sodium hypochlorite and activation with Passive Ultrasonic Irrigation. Microbiological samples will be collected prior to retreatment and before obturation to evaluate intracanal bacterial load and microbiome composition. Residual organic debris will be assessed using the chairside device Endocator, and postoperative pain will be recorded.

Procedure: Conventional rotary instrumentation with passive ultrasonic irrigation

Interventions

GentleWave System PROCEDURE

Minimally invasive root canal disinfection using the GentleWave multisonic irrigation system following minimal instrumentation. The system delivers multisonically activated sodium hypochlorite and EDTA solutions under negative pressure to enhance irrigation dynamics and debris removal within the root canal system during nonsurgical endodontic retreatment.

GentleWave Disinfection Group

Conventional rotary instrumentation with passive ultrasonic irrigation PROCEDURE

Conventional nonsurgical endodontic retreatment using nickel-titanium rotary instrumentation followed by passive ultrasonic irrigation (PUI). Irrigation is performed using sodium hypochlorite delivered via a side-vented needle and ultrasonically activated irrigation to enhance canal disinfection after mechanical preparation.

Conventional Rotary Instrumentation with Passive Ultrasonic Irrigation

Eligibility Criteria

• Age: 16 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)

You may qualify if:

• Molars showing radiographic evidence of post-treatment apical periodontitis: a lesion that exceeds 3 mm in diameter on one or more roots.
• Evidence from periapical and CBCT examination suggests that retreatment is a viable option, i.e., there are low risks of vertical root fracture, no major root canal obstruction, evidence of coronal leakage, and potential improvement on the previous treatment.
• The initial root canal therapy was performed at least 2 years previously, or more than 1 year if the patient has signs and symptoms or symptomatic disease (pain, swelling, or sinus tracts).
• Patients show no chronic systemic disease that may influence the outcome of care, such as uncontrolled diabetes, autoimmune disease, malignancy treated with chemotherapy or patients who are on immunosuppressive medications or require antibiotic prophylaxis before dental treatment.
• Patients who are able to read and consent in English.

You may not qualify if:

• Patients with a tooth requiring RCT retreatment that also presents with periodontal pocket(s) deeper than 5mm
• Patients with a tooth requiring RCT retreatment that also presents with severe crown destruction that would prevent proper rubber dam isolation or an adequate restoration
• Patients with a tooth requiring RCT retreatment that also presents with evidence of vertical root fracture, or cracks with probing defects \> 5 mm
• Patients with a tooth requiring RCT retreatment that is deemed unrestorable
• Patients who received antibiotic therapy within the previous 3 months.
• Patients under the age of 16 or those incapable of providing informed consent
• Patients with a tooth requiring RCT retreatment that also presents with immature or open apices
• Patients with a tooth requiring RCT retreatment that also presents with apices in the maxillary sinus or those teeth where the apical lesion has eroded the bone of the maxillary sinus floor
• Patients with a tooth requiring RCT retreatment that also presents with apices that are less than 1 mm from the mandibular canal
• Patients with a tooth requiring RCT retreatment that also presents with internal or external root resorption

Sponsors & Collaborators

• University of Alabama at Birmingham: lead

Study Sites (1)

University of Alabama at Birmingham

Birmingham, Alabama, 35233, United States

Location

MeSH Terms

Conditions

Periapical Periodontitis; Pain, Postoperative

Condition Hierarchy (Ancestors)

Periapical Diseases; Jaw Diseases; Stomatognathic Diseases; Periodontal Diseases; Mouth Diseases; Periodontitis; Postoperative Complications; Pathologic Processes; Pathological Conditions, Signs and Symptoms; Pain; Neurologic Manifestations; Signs and Symptoms

Study Officials

• Can Wang, PhD

  University of Alabama at Birmingham

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Can Wang, PhD

CONTACT

205-934-1141; cw24@uab.edu

Ashraf F Fouad, DDS, MS

CONTACT

205-934-5373; afouad@uab.edu

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: Due to the nature of the interventions, the treating clinician cannot be blinded to the treatment allocation. However, laboratory personnel performing microbiological analyses, including quantitative polymerase chain reaction (qPCR) and next-generation sequencing (NGS), will be blinded to group assignment. In addition, investigators assessing Endocator results and analyzing study outcomes will be blinded to the intervention group to minimize potential bias.
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assistant Professor

Model Details: Participants with molar teeth diagnosed with post-treatment apical periodontitis requiring nonsurgical endodontic retreatment will be randomly assigned to one of two parallel treatment groups. The experimental group will receive root canal disinfection using the GentleWave System, while the control group will receive conventional chemomechanical preparation using nickel-titanium rotary instrumentation combined with Passive Ultrasonic Irrigation. Microbiological samples will be collected before treatment and prior to obturation to quantify intracanal bacterial load and evaluate microbial composition. Residual organic debris will be assessed using the chairside device Endocator and compared with PCR-based method as well as facultative bacterial culturing, and postoperative pain will be recorded as a secondary clinical outcome.

Study Record Dates

• First Submitted: March 9, 2026
• First Posted: March 13, 2026
• Study Start (Estimated): July 1, 2027
• Primary Completion (Estimated): June 1, 2030
• Study Completion (Estimated): December 1, 2030
• Last Updated: April 8, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)