Variation in Gingival Inflammatory Responses

November 10, 2025 updated by: Jeffrey McLean, University of Washington

Mechanisms Underlying the Variation in Rate and Levels of Gingival Inflammatory Responses Among the Human Population

The aim of this NIH National Institute of Dental and Craniofacial Research (NIDCR) funded study is to identify molecular mechanisms underlying observed variations in human responses to natural accumulation and maturation of dental plaque.

Study Overview

Status

Status

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

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

This study will employ the split-mouth Experimental Gingivitis model where healthy study participants are asked to abstain from oral hygiene on a select set of teeth (test teeth) for a period of 21 days. The study consists of 3 phases; Hygiene Phase (Day -14-0), Experimental Induction Phase (Day 0-21), and Resolution Phase (Day 21-35). Abstaining from oral hygiene on the test teeth will result in the natural accumulation and maturation of dental plaque (a bacterial biofilm) on the tooth surface which will in induce a host inflammatory response. By investigating the onset of microbially induced inflammation directly in humans using this highly utilized and well-described experimental gingivitis model, the research community are able to better understand the host-microbial interactions during the initiation, induction of host response, and resolution of mucosal inflammation at the molecular level. The investigators central hypothesis is based on our previous experimental gingivitis studies conducted here at the University of Washington Bamashmous et al. Human Variation in Gingival Inflammation PNAS 2021 and NCT03750955. The investigators hypothesize that specific clinical inflammatory response phenotypes (High, Low and Slow responders) are dependent upon both microbial factors regulating the subgingival plaque growth and maturation rate as well as host factors regulating the human gingival inflammatory mediator levels and type.

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 (Estimated)

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.
80

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.
  • Not Applicable

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.
  • Name: Marilynn Rothen, RDH, MS
  • Phone Number: 206-685-8132
  • Email: rothen@uw.edu

Study Locations

  • United States
    • Washington
      • Seattle, Washington, United States, 98195
        • Recruiting
        • University of Washington
        • Contact:
          • Marilyn Rothen
          • Phone Number: (206) 685-8132
          • Email: rothen@uw.edu
        • Sub-Investigator:
          • Kristopher A Kerns, PhD
        • Contact:
          • Jeffrey S McLean, PhD
          • Phone Number: (206)-616-1808
          • Email: jsmclean@uw.edu

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

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • Provide signed and dated informed consent form
  • Willing to comply with all study procedures and be available for the duration of the study
  • Male or female, aged 18-35 years
  • Good general health, ASA I (healthy with no systemic conditions)
  • No clinical signs of gingival inflammation at > 90% of sites observed (whole mouth) (< 10% of sites with GI of < 2 and no sites with a score of 3; < 10% sites with BOP +).
  • Probing depth (PD) ≤ 3.0 mm (Whole Mouth)
  • Attachment loss (AL) = 0 mm (Whole Mouth)
  • Gingival health at Visit 2 (Day 0) for study sites (Test/Control teeth): Average Gingival Index (GI) ≤ 0.1 with no site having a score of 3 and bleeding on probing (BOP)(-)
  • Never smokers
  • The ability to understand and communicate with the examiner.
  • Willing and able to comply with study procedures.

Exclusion Criteria:

  • Medical condition which requires premedication prior to dental treatments/visits
  • Subjects unable or unwilling to sign the informed consent form
  • History of periodontal disease
  • History of systemic inflammatory or immune conditions, Diabetes
  • Use of antibiotic or anti-inflammatory drugs within 30 days of enrollment
  • Self-reported pregnancy, planned pregnancy during the planned study commitment, and/or breastfeeding at the time of screening.
  • Concurrent orthodontic treatment
  • Untreated carious lesions and/or inadequate restorations on maxillary posterior teeth
  • Participation in any other clinical study or test panel within 1 week prior to enrollment into this study
  • Use of tobacco products
  • Subjects who must receive dental treatment during the study dates
  • Orthodontic bands, appliances, or crowns and bridges, or removable partial dentures affecting the maxillary posterior teeth
  • Missing tooth/teeth within the study sites test and control
  • History of allergy to common dentifrice ingredients
  • Immune-compromised individuals (for example: HIV, AIDS, and immune-suppressive drug therapy)

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: Basic Science
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

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: Healthy Volunteers

Study participants abstain from oral hygiene on a select set of four teeth for a period of 21 days.

The use of a custom made acrylic intraoral stent (mouthguard) will be used to protect teeth on designated test sides for each study participant during normal oral hygiene (approximately 4 minutes each day: 2 times for 2 minutes) throughout the induction phase (Day 0-21).
Behavioral: Abstinence of oral hygiene on select teeth
Study participants abstain from oral hygiene on a select set of four teeth for a period of 21 days
Other Names:
  • Split Mouth Experimental Gingivitis

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
Identification of clinical responder types
Time Frame: Day 0 to Day 21
Identification of clinical responder types through comparative analysis of the levels of clinical parameter for Bleeding on Probing Index (% BOP) at Day 14 of the plaque overgrowth/induction phase measured by calibrated examiners.
Day 0 to Day 21

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
Change in relative abundance of bacteria
Time Frame: Day 0 to Day 21
The rate of change in relative abundance of gram positive Firmicutes bacteria compared to that of gram negative Bacteroidetes bacteria through the plaque overgrowth/induction phase (Day 0-21) assessed through 16S rRNA and Metagenomic Sequencing.
Day 0 to Day 21

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.
University of Washington

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)

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: Jeffrey S McLean, PhD, University of Washington

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.

General Publications

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.
June 30, 2023

Primary Completion (Estimated)

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.
October 1, 2026

Study Completion (Estimated)

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.
December 31, 2027

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).
July 14, 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.
July 27, 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.
August 1, 2023

Study Record Updates

Last Update Posted (Estimated)

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.
November 13, 2025

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.
November 10, 2025

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.
November 1, 2025

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.
  • STUDY00016247
  • R01DE031470 (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

No

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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