Shaping the Indications for Periodontal Adjunctive Antibiotics in Dental Practice (PAAS)

April 9, 2026 updated by: Georgios A. Kotsakis, DDS, MS, Rutgers, The State University of New Jersey

Shaping the Indications for Periodontal Adjunctive Antibiotics in Dental Practice: A PBRN Clinical Trial

Periodontitis is a bacterial inflammatory disease and antibiotic use is being empirically used as part of its treatment. However, a clinical practice guideline on periodontal treatment adjuncts published in 2015 identified weak evidence on the use of systemic antibiotics and large heterogeneity across small scale studies, suggesting that larger pragmatic clinical trials would benefit clinical decision making. This will be a prospective, randomized, placebo-controlled trial, stratified by practice and practitioner. The study will investigate the effectiveness of adjunctive antibiotics as adjunct to scaling and root planing (SRP) compared to SRP with placebo for the treatment of generalized grades A-C periodontitis in patient participants from National Dental PBRN practices. Periodontal data will be collected at baseline, re-evaluation (6 weeks), and final (4-12 months) study visits. Changes in periodontal clinical and patient-reported outcomes will be assessed to determine the effectiveness of SRP plus adjunctive systemic Amoxicillin / Metronidazole antibiotics (AMXM) versus SRP with Placebo.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Précis: Periodontitis is a bacterial inflammatory disease and antibiotic use is being empirically used as part of its treatment. However, a clinical practice guideline on periodontal treatment adjuncts published in 2015 identified weak evidence on the use of systemic antibiotics and large heterogeneity across small scale studies, suggesting that larger pragmatic clinical trials would benefit clinical decision making. This will be a prospective, randomized, placebo-controlled trial, stratified by practice and practitioner. The study will investigate the effectiveness of adjunctive antibiotics as adjunct to scaling and root planing (SRP) compared to SRP with placebo for the treatment of generalized grades A-C periodontitis in patient participants from National Dental PBRN practices. Periodontal data will be collected at baseline, re-evaluation (6 weeks), and final (4-12 months) study visits. Changes in periodontal clinical and patient-reported outcomes will be assessed to determine the effectiveness of SRP plus adjunctive systemic Amoxicillin / Metronidazole antibiotics (AMXM) versus SRP with Placebo.

Objectives and Outcomes: Primary: The primary objective will assess the effectiveness of SRP plus adjunctive antibiotics compared to SRP with placebo in periodontitis individuals from baseline to 6 weeks following non-surgical periodontal therapy (NSPT) as determined by changes in site-level periodontal probing depth (PD).

Secondary: To assess changes in: i) gingival inflammation (measured by bleeding on probing (BoP)), ii) periodontal tissue attachment (measured by clinical attachment level (CAL)), iii) reduction in diseased sites (measured by remaining sites with maximum probing depth ≥5 mm), and iv) disease remission (measured by number of participants with ≤4 sites with PD≥ 5mm); comparing SRP plus AMXM to SRP with a placebo adjunctive in periodontitis individuals from baseline to re-evaluation (6 weeks) to final (4-12 month) study visit following intervention. Also, assess changes in periodontal probing depth from baseline measurements to final visit (4-12 months) following intervention. The patient-reported impact of periodontal treatment (measured by the Oral Health Impact Profile-5 (OHIP-5)) and treatment-related adverse events between groups will also be assessed.

Population: A sample size of 214 patient participants enrolled from up to 34 National Dental PBRN practices will be enrolled for adequate power. All patient participants are indicated to receive SRP and have been diagnosed with periodontitis stages II-III, grades A-C.

Description of Intervention: The intervention will involve either SRP, which is considered the standard of care treatment for debriding root surfaces, in conjunction with 500 mg Amoxicillin and 500mg Metronidazole orally every 8 hours (q8h) for ten days following SRP or SRP with placebo.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
236

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • United States
    • Alabama
      • Birmingham, Alabama, United States, 35233
        • University of Alabame

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • The study will recruit patient participants presenting for periodontal treatment within the National Dental PBRN practices participating in this study.

To be eligible to participate in this study, a potential patient participant must meet all the following criteria:

  • Adult who is at least 35 years old.
  • Presence of ≥ 15 permanent teeth excluding 3rd molars.
  • In good general health as evidenced by medical history (ASA Class I or II) per the practitioner.
  • Planned to receive periodontal care for Generalized Periodontitis and a minimum of two quadrants of SRP (CDT code 4341) in practices participating in the National Dental PBRN.
  • Willing to comply with all study visits and be available for the duration of the study (12-15 months)
  • Willing to provide contact information for self, including a cellular phone number for study text, and one to two emergency contacts to be reached for the follow-up visits and any other study-related matters for the duration of the study.

Exclusion Criteria:

  • Known drug allergy to any antibiotics or anesthetics.
  • Use of systemic antibiotics taken within the previous 3 months prior to enrollment.
  • Medical condition which requires antibiotic prophylaxis prior to dental treatments/visits.
  • Current use of medications that, in the opinion of the practitioner, may cause adverse effects with AMXM (such as disulfiram, warfarin, and oral contraceptives).
  • History of any periodontal therapy (including SRP D4341, D4342) within the last 6 months prior to enrollment.
  • Is currently pregnant or lactating per patient participant self-report.
  • Is considered immunocompromised, in the opinion of the practitioner (including diseases and conditions such as HIV/AIDS, immunosuppressive drug therapy and/or radiation), or has chronic mucosal lesions (e.g. pemphigus vulgaris) affecting the gingiva.
  • Has Diabetes mellitus with an HbA1c score of >/= 10% within the past 3 months as per patient participant self-report.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Test Arm
Patient participants in this arm will receive a combination of Amoxicillin 500mg & Metronidazole 500mg orally (AMXM) as adjuncts along with their scheduled non-surgical periodontal treatment as the study intervention. A loading dose of 1g of Amoxicillin and 1g of Metronidazole will be given 30-60 minutes prior to periodontal treatment. After the loading dose, each patient participant will be instructed to take Amoxicillin 500mg & Metronidazole 500mg every 8 hours for 10 days.
Drug: Amoxicillin
Amoxicillin belongs to the penicillin category, and it is a commonly prescribed broad-spectrum antibiotic as a periodontal treatment adjunct.
Drug: Metronidazole
Metronidazole is effective against anaerobic bacteria, and it is often combined with Amoxicillin for an enhanced antimicrobial effect as a periodontal treatment adjunct.
Placebo Comparator: Control Arm
Patient participants in this arm will receive a placebo capsules identical to the study drug capsules along with their scheduled non-surgical periodontal treatment as the placebo comparator in an identical frequency and duration fashion as the active drug group.
Other: Placebo
Placebo in identical drug-safe vials with capsules identical in appearance to the active drugs

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Probing Depth (PD) in millimeters
Time Frame: Baseline to Re-evaluation (6 weeks)
The primary outcome of treatment effectiveness will be assessed by full-mouth probing depth (PD) from baseline to 6 weeks following intervention. Full-mouth PD measurements (excluding 3rd molars) will be obtained utilizing a UNC 15mm periodontal probe.
Baseline to Re-evaluation (6 weeks)

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Probing Depth (PD) in millimeters at final visit
Time Frame: Baseline, Final study visit (4-12 months) after intervention.
This secondary outcome of treatment effectiveness will be assessed by the change in full-mouth probing depth (PD) from baseline to 4-12 months post-intervention. Full-mouth PD measurements (excluding 3rd molars) will be obtained utilizing a UNC 15mm periodontal probe.
Baseline, Final study visit (4-12 months) after intervention.
Clinical attachment level (CAL) in millimeters
Time Frame: Baseline, Re-evaluation (6 weeks), and Final study visit (4-12 months) after intervention.
This secondary objective will be assessed by clinical attachment level (CAL) changes from baseline to 6 weeks, and from baseline to 4-12 months post-intervention, adjusting for baseline CAL. CAL is a disease-related characteristic. Half-mouth CAL in millimeters (excluding 3rd molars) will be obtained utilizing a UNC 15mm periodontal probe to measure base of pocket to cementoenamel junction (CEJ).
Baseline, Re-evaluation (6 weeks), and Final study visit (4-12 months) after intervention.
Changes in the probability of bleeding on probing (BoP)
Time Frame: Baseline, Re-evaluation (6 weeks), and Final study visit (4-12 months) after intervention.
This secondary objective will assess changes in the probability of observing BoP, a common surrogate for gingival inflammation, at 6 weeks and at 4-12 months post intervention, adjusting for baseline BoP. BoP is assessed in conjunction with probing depths using a UNC 15mm periodontal probe and is recorded as a binary outcome per site, i.e., is the site bleeding? Yes/No.
Baseline, Re-evaluation (6 weeks), and Final study visit (4-12 months) after intervention.
Reduction in diseased sites
Time Frame: Baseline, Re-evaluation (6 weeks), and Final study visit (4-12 months) after intervention.
Reduction in diseased sites is a calculated variable from PD. We will assess the probability a site is observed with residual PD≥ 5 mm at 6 weeks and at 4-12 months post-intervention, adjusting for its baseline PD. PD≥ 5mm; The maximum probing depth per tooth will be recorded as ≥5 mm (yes/no).
Baseline, Re-evaluation (6 weeks), and Final study visit (4-12 months) after intervention.
Disease remission
Time Frame: Baseline, Re-evaluation (6 weeks), and Final study visit (4-12 months) after intervention.
Disease remission is defined as the number of study patient participants who have ≤4 sites with PD≥5mm. Patient participants will be considered 'in remission' if they display ≤4 sites with PD≥ 5mm; This is a dichotomization from the summation of PD≥ 5mm within person.
Baseline, Re-evaluation (6 weeks), and Final study visit (4-12 months) after intervention.
Changes in oral health-related quality of life
Time Frame: Baseline, Re-evaluation (6 weeks), and Final study visit (4-12 months) after intervention.
To evaluate oral health-related quality of life, the Oral Health Impact Profile (OHIP-5) will be utilized. OHIP-5 sum score based upon self-reported responses will be assessed. The OHIP-5 has 5 questions ranging from 0 = never to 4 = very often with higher scores translating to a worse outcome.
Baseline, Re-evaluation (6 weeks), and Final study visit (4-12 months) after intervention.

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Treatment-related adverse events
Time Frame: Through study completion, up to the 4-12 months final visit
The number and severity of adverse events related to SRP plus AMXM versus SRP plus placebo will be recorded to assess the safety of the intervention.
Through study completion, up to the 4-12 months final visit

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Rutgers, The State University of New Jersey

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
National Institute of Dental and Craniofacial Research (NIDCR)
National Dental PBRN

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Georgios Kotsakis, DDS, Rutgers University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
April 25, 2024

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
April 7, 2026

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
April 7, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
October 31, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
November 13, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
November 14, 2023

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
April 14, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
April 9, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • Pro2023001347
  • 4UH3DE031129-02 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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