Olfactory Function and Oral Malodor in Periodontitis Before and After Periodontal Therapy

February 23, 2026 updated by: Mustafa Baran, Batman University

Bidirectional Relationship Between Oral Malodor And Olfactory Function In Generalized Periodontitis: A Prospective Cohort Study Evaluating Changes After Nonsurgical Periodontal Therapy

This prospective cohort study investigated the relationship between oral malodor and olfactory function in adults with generalized periodontitis. A total of 101 patients were evaluated before and after routine nonsurgical periodontal therapy. Volatile sulfur compound (VSC) levels and psychophysical olfactory performance using the Sniffin' Sticks test (TDI score) were measured at baseline and one week after completion of three sessions of scaling and root planing (SRP). The study aimed to determine whether reduction of oral inflammation and halitosis is associated with improvement in olfactory performance.

Study Overview

Status

Completed

Conditions

Detailed Description

Generalized periodontitis is a chronic inflammatory disease associated with increased production of volatile sulfur compounds (VSCs), contributing to halitosis. Elevated intraoral malodor may interfere with olfactory perception through masking effects and inflammatory mechanisms.

Participants diagnosed with generalized periodontitis and complaining of halitosis underwent routine nonsurgical periodontal therapy consisting of three sessions of scaling and root planing performed at one-week intervals. Olfactory function (threshold, discrimination, identification; total TDI score) and total VSC concentrations were assessed at baseline (prior to first session) and one week after completion of the third session.

The study evaluated changes in chemosensory function and halitosis parameters following periodontal therapy and analyzed correlations between baseline VSC levels and olfactory performance.

Study Type

Observational

Enrollment (Actual)

101

Contacts and Locations

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

Study Locations

  • Turkey (Türkiye)
    • Batman
      • Merkez, Batman, Turkey (Türkiye), 72040
        • Batman University

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

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

The study population consisted of adults aged 18-55 years diagnosed with generalized periodontitis and presenting with complaints of halitosis who sought care at the Batman University Faculty of Dentistry Clinical Application Center. A total of 150 patients were screened, and 101 individuals who met the inclusion criteria were enrolled in this prospective cohort study.

Description

Inclusion Criteria:

  • Inclusion Criteria:
  • Adults aged 18-55 years
  • Diagnosis of generalized periodontitis
  • Complaint of halitosis
  • At least 15 natural teeth

Exclusion Criteria:

  • Self-reported smell loss or change within 2 weeks prior to baseline
  • Antibiotic or anti-inflammatory drug use for more than 7 days within the previous 6 weeks
  • Presence of upper respiratory tract infection
  • Unrestored advanced dental caries
  • History of COVID-19 infection
  • Pregnancy

Smoking was not an exclusion criterion.

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

Cohorts and Interventions

Group / Cohort
Generalized Periodontitis Patients With Halitosis
Adults aged 18-55 years diagnosed with generalized periodontitis and presenting with halitosis. Participants received routine nonsurgical periodontal therapy and were evaluated for olfactory function and volatile sulfur compound levels at baseline and after completion of therapy.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Total TDI Score
Time Frame: Baseline to 1 week after completion of third SRP session (approximately 4 weeks total)

Change in psychophysical olfactory performance measured by the Sniffin' Sticks Test (Threshold-Discrimination-Identification composite score).

The Sniffin' Sticks Test total TDI score ranges from 1 to 48, calculated as the sum of:

  • Odor Threshold (1-16).
  • Odor Discrimination (0-16).
  • Odor Identification (0-16).

Higher scores indicate better olfactory function.
Baseline to 1 week after completion of third SRP session (approximately 4 weeks total)
Change in Total Volatile Sulfur Compound (tVSC) Levels
Time Frame: Baseline to 1 week after completion of third SRP session

Change in total volatile sulfur compound (tVSC) concentration measured using the OralChroma portable gas chromatograph device.

tVSC levels are reported in parts per billion (ppb). Higher values indicate greater halitosis severity (worse outcome).
Baseline to 1 week after completion of third SRP session

Collaborators and Investigators

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

Sponsor

Batman University

Investigators

  • Principal Investigator: Mustafa Baran, Asst. Prof., Batman University

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)

December 3, 2024

Primary Completion (Actual)

March 20, 2025

Study Completion (Actual)

March 20, 2025

Study Registration Dates

First Submitted

February 13, 2026

First Submitted That Met QC Criteria

February 13, 2026

First Posted (Actual)

February 20, 2026

Study Record Updates

Last Update Posted (Actual)

February 25, 2026

Last Update Submitted That Met QC Criteria

February 23, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2024/08-03

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be shared due to privacy considerations and institutional data protection policies.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

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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