Periodontitis (Stage 3)NCT07279896
Determination of RNA/DNA Damage Associated With Oxidative Stress in Periodontitis Patients
An observational study of Periodontitis (Stage 3) and Smoking, run by Zehra Hasgül at 1 site in Turkey (Türkiye).
Trial summary
This study looked at whether a type of gum disease called Stage III periodontitis and cigarette smoking are linked to higher levels of "oxidative stress." Oxidative stress can damage DNA and RNA, which are important parts of our cells. Read more about this study
- Who is it for?
- Ages 18 to 65 yearsHealthy volunteers can take part
- Conditions the study is for
- Periodontitis (Stage 3), Smoking
- How many people
- 88 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 5 May 2025to 15 Aug 2025
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 65 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Study population: The study population consisted of systemically healthy adults aged 18-65 years, including individuals with Stage III periodontitis and periodontally healthy controls. Participants were categorized into four groups based on periodontal status and smoking habits: smokers and non-smokers with Stage III periodontitis, and smokers and non-smokers who were periodontally healthy.
Who may be able to join
- Individuals aged 18 years or older
- Having at least 16 permanent teeth, excluding third molars
- Not using orthodontic appliances
- Not pregnant or breastfeeding
- Systemically healthy individuals with no systemic diseases that could affect periodontal status
- No use of anti-inflammatory or antimicrobial medications within the last 6 months
- No periodontal treatment within the last 12 months
Who cannot join
- Pregnant or breastfeeding individuals.
- Use of anti-inflammatory or antimicrobial drugs in the past 6 months.
- Use of antioxidant supplements in the past 3 months.
- Periodontal treatment within the past 12 months.
- Diagnosis of psychiatric disorders.
- Any oral infection.
Show all 10Show fewer
- Fewer than 16 permanent teeth (excluding third molars).
- Alcohol dependence.
- Active infectious diseases (Acute hepatitis, AIDS, tuberculosis), malignancy, or any systemic condition that may affect periodontal tissues.
- Current use of medications known to affect periodontal tissues (phenytoin, cyclosporine A, calcium channel blockers).
Trial locations and contacts
1 site in 1 country.
Turkey (Türkiye)1 site
Ankara University Faculty of Dentistry, Department of Periodontology
Ankara, Yenimahalle, 06560
About this study
Official title: Evaluation of Smoking and Oxidative Stress-Induced RNA and DNA Damage in Patients With Stage III Periodontitis
This study looked at whether a type of gum disease called Stage III periodontitis and cigarette smoking are linked to higher levels of "oxidative stress." Oxidative stress can damage DNA and RNA, which are important parts of our cells. Two markers in saliva-8-OHdG (a sign of DNA damage) and 8-OHG (a sign of RNA damage)-were measured to understand this.
Researchers included four groups of adults: smokers with periodontitis, non-smokers with periodontitis, healthy smokers, and healthy non-smokers. All participants had a dental exam, which checked things like gum inflammation, bleeding, and pocket depth. After the exam, an unstimulated saliva sample was collected from each person. The samples were tested in a laboratory using a sensitive method that measures oxidative damage.
Read more
The study found that people with periodontitis had higher levels of DNA and RNA damage in their saliva than healthy people. The highest levels were seen in smokers with periodontitis. Even healthy smokers showed higher levels of oxidative stress than healthy non-smokers. In general, worse gum disease was linked to higher levels of oxidative damage.
These results suggest that saliva tests for 8-OHdG and 8-OHG may help identify gum disease in a simple, non-invasive way. The findings also show that smoking adds to the body's oxidative stress, especially when gum disease is present. The study provides new information about how smoking and gum disease together may affect cell health.
Read the detailed description
Periodontitis is a chronic inflammatory disease that leads to the progressive destruction of the tooth-supporting tissues. Oxidative stress plays a central role in its pathogenesis, as excessive production of reactive oxygen species (ROS) can damage cellular structures, including lipids, proteins, and nucleic acids. Among oxidative stress-related biomarkers, 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-hydroxyguanosine (8-OHG) are widely recognized indicators of DNA and RNA damage, respectively. These biomarkers reflect the biochemical consequences of oxidative stress and are increasingly used to evaluate host responses in periodontal disease.
Cigarette smoking is one of the strongest environmental risk factors for periodontitis and is known to enhance oxidative stress through multiple mechanisms. However, the combined effect of smoking and advanced periodontitis on salivary oxidative DNA and RNA damage has not been fully clarified. Assessing both 8-OHdG and 8-OHG simultaneously may provide deeper insight into the molecular pathways linking smoking, inflammation, and periodontal tissue destruction.
This study was designed to evaluate salivary levels of oxidative nucleic acid damage in individuals with Stage III periodontitis who smoke or do not smoke, as well as in periodontally healthy controls. The study also aimed to investigate the relationship between these biomarkers and clinical periodontal measurements. By examining DNA and RNA oxidation together, the study sought to provide a multidimensional understanding of the host oxidative response in periodontitis.
All participants underwent full-mouth periodontal examination performed by a calibrated clinician. Unstimulated saliva samples were collected under standardized morning conditions, processed by centrifugation to remove cellular debris, and stored at -80°C until biochemical analysis. Levels of 8-OHdG and 8-OHG were quantified using a high-sensitivity ELISA method capable of detecting multiple oxidized guanine derivatives.
Biochemical findings demonstrated that oxidative DNA and RNA damage levels were higher in individuals with periodontitis compared to healthy controls, with smokers exhibiting the highest levels overall. Oxidative biomarker levels showed positive correlations with key periodontal parameters, including probing depth, clinical attachment loss, plaque accumulation, gingival inflammation, and bleeding on probing. These results suggest that the inflammatory burden of periodontitis amplifies oxidative stress at the nucleic acid level and that smoking contributes an additional biological load.
In addition to biochemical assessment, buccal mucosa samples were evaluated cytologically using hematoxylin and eosin staining. All specimens showed adequate cellularity, and no significant differences in epithelial dysplasia were observed across study groups. This may be related to the predominance of superficial epithelial cells in the collected samples.
Overall, this study provides an integrated biochemical and cytomorphological assessment of oxidative stress in periodontitis. The findings support the potential use of salivary 8-OHdG and 8-OHG as non-invasive biomarkers for disease monitoring and contribute novel evidence regarding the interaction between smoking, oxidative stress, and periodontal inflammation.
- Conditions
- Periodontitis (Stage 3), Smoking
- Keywords
- Periodontitis; Smoking; Oxidative Stress; 8-OHdG; 8-OHG; Saliva; Biomarkers
- Medical subject headings
- Periodontitis, Smoking
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Periodontitis Smoker | Participants diagnosed with Stage III periodontitis who are current cigarette smokers. No intervention was applied; biological samples (unstimulated saliva) were collected for biomarker analysis. | |
| Periodontitis Non-Smoker | Participants diagnosed with Stage III periodontitis who do not smoke. No intervention was applied; unstimulated saliva samples were collected for laboratory analysis. | |
| Healthy Smoker | Periodontally healthy individuals who are current smokers. No treatment or intervention was performed; only saliva samples and periodontal measurements were obtained. | |
| Healthy Non-Smoker | Periodontally healthy non-smokers. No intervention was provided; participants underwent periodontal evaluation and saliva sample collection. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Salivary oxidative DNA and RNA damage (8-OHdG and 8-OHG levels)
Concentrations of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-hydroxyguanosine (8-OHG) measured in unstimulated whole saliva using a high-sensitivity competitive ELISA kit. Saliva samples are collected at a separate baseline visit within the study period, after full-mouth periodontal examination and before any periodontal therapy. Biomarker levels (ng/mL) were compared across the four study groups and analyzed in relation to clinical periodontal parameters. Higher values indicate greater oxidative nucleic acid damage.
Measured: Baseline (periodontal examination visit and saliva collection visit, before any periodontal treatment)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted12 Dec 2025
- Study start5 May 2025
- Primary completion4 Aug 2025
- Study completion15 Aug 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (3)Papers the sponsor has linked to this study.
- Other trials for Periodontitis (Stage 3)Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Case-control
- Time perspective
- Cross-sectional
- Enrolment
- 88 participants (actual)
Sponsor and investigators
- Lead sponsor
- Zehra Hasgül
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Zehra Hasgül, Ankara University
- Investigators
- Sivge Kurgan, Principal investigator, Ankara University, Faculty of Dentistry, Department of Periodontology
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07279896
- Sponsor's protocol ID
- ZH-2025-OxidativeStress
- Status last verified
- Dec 2025
- First submitted
- 1 Dec 2025
- Last updated
- 12 Dec 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: Individual participant data will not be shared due to patient privacy concerns, data protection regulations, and the terms of the local ethics committee approval
Publications
Hendek MK, Erdemir EO, Kisa U, Ozcan G. Effect of initial periodontal therapy on oxidative stress markers in gingival crevicular fluid, saliva, and serum in smokers and non-smokers with chronic periodontitis. J Periodontol. 2015 Feb;86(2):273-82. doi: 10.1902/jop.2014.140338. Epub 2014 Oct 17.
PubMed 25325515Tonetti MS, Greenwell H, Kornman KS. Staging and grading of periodontitis: Framework and proposal of a new classification and case definition. J Periodontol. 2018 Jun;89 Suppl 1:S159-S172. doi: 10.1002/JPER.18-0006.
PubMed 29926952Kurgan S, Onder C, Altingoz SM, Bagis N, Uyanik M, Serdar MA, Kantarci A. High sensitivity detection of salivary 8-hydroxy deoxyguanosine levels in patients with chronic periodontitis. J Periodontal Res. 2015 Dec;50(6):766-74. doi: 10.1111/jre.12263. Epub 2015 Feb 7.
PubMed 25662588
Study at a glance
From the registry record, last updated by the sponsor on 12 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluation of Smoking and Oxidative Stress-Induced RNA and DNA Damage in Patients With Stage III Periodontitis
- ClinicalTrials.gov ID
- NCT07279896
- Acronym / sponsor ID
- ZH-2025-OxidativeStress
- Conditions
- Periodontitis (Stage 3), Smoking
- Keywords
- Periodontitis; Smoking; Oxidative Stress; 8-OHdG; 8-OHG; Saliva; Biomarkers
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 88 participants (actual)
- Lead sponsor
- Zehra HasgülUniversity, hospital or other
- Study start
- 5 May 2025 (actual)
- Primary completion
- 4 Aug 2025 (actual)
- Study completion
- 15 Aug 2025 (actual)
- First posted
- 12 Dec 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This study looked at whether a type of gum disease called Stage III periodontitis and cigarette smoking are linked to higher levels of "oxidative stress." Oxidative stress can damage DNA and RNA, which are important parts of our cells. Two markers in saliva-8-OHdG (a sign of DNA damage) and 8-OHG (a sign of RNA damage)-were measured to understand this.
Researchers included four groups of adults: smokers with periodontitis, non-smokers with periodontitis, healthy smokers, and healthy non-smokers. All participants had a dental exam, which checked things like gum inflammation, bleeding, and pocket depth. After the exam, an unstimulated saliva sample was collected from each person. The samples were tested in a laboratory using a sensitive method that measures oxidative damage.
The study found that people with periodontitis had higher levels of DNA and RNA damage in their saliva than healthy people. The highest levels were seen in smokers with periodontitis. Even healthy smokers showed higher levels of oxidative stress than healthy non-smokers. In general, worse gum disease was linked to higher levels of oxidative damage.
These results suggest that saliva tests for 8-OHdG and 8-OHG may help identify gum disease in a simple, non-invasive way. The findings also show that smoking adds to the body's oxidative stress, especially when gum disease is present. The study provides new information about how smoking and gum disease together may affect cell health.
Detailed description
Periodontitis is a chronic inflammatory disease that leads to the progressive destruction of the tooth-supporting tissues. Oxidative stress plays a central role in its pathogenesis, as excessive production of reactive oxygen species (ROS) can damage cellular structures, including lipids, proteins, and nucleic acids. Among oxidative stress-related biomarkers, 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-hydroxyguanosine (8-OHG) are widely recognized indicators of DNA and RNA damage, respectively. These biomarkers reflect the biochemical consequences of oxidative stress and are increasingly used to evaluate host responses in periodontal disease.
Cigarette smoking is one of the strongest environmental risk factors for periodontitis and is known to enhance oxidative stress through multiple mechanisms. However, the combined effect of smoking and advanced periodontitis on salivary oxidative DNA and RNA damage has not been fully clarified. Assessing both 8-OHdG and 8-OHG simultaneously may provide deeper insight into the molecular pathways linking smoking, inflammation, and periodontal tissue destruction.
This study was designed to evaluate salivary levels of oxidative nucleic acid damage in individuals with Stage III periodontitis who smoke or do not smoke, as well as in periodontally healthy controls. The study also aimed to investigate the relationship between these biomarkers and clinical periodontal measurements. By examining DNA and RNA oxidation together, the study sought to provide a multidimensional understanding of the host oxidative response in periodontitis.
All participants underwent full-mouth periodontal examination performed by a calibrated clinician. Unstimulated saliva samples were collected under standardized morning conditions, processed by centrifugation to remove cellular debris, and stored at -80°C until biochemical analysis. Levels of 8-OHdG and 8-OHG were quantified using a high-sensitivity ELISA method capable of detecting multiple oxidized guanine derivatives.
Biochemical findings demonstrated that oxidative DNA and RNA damage levels were higher in individuals with periodontitis compared to healthy controls, with smokers exhibiting the highest levels overall. Oxidative biomarker levels showed positive correlations with key periodontal parameters, including probing depth, clinical attachment loss, plaque accumulation, gingival inflammation, and bleeding on probing. These results suggest that the inflammatory burden of periodontitis amplifies oxidative stress at the nucleic acid level and that smoking contributes an additional biological load.
In addition to biochemical assessment, buccal mucosa samples were evaluated cytologically using hematoxylin and eosin staining. All specimens showed adequate cellularity, and no significant differences in epithelial dysplasia were observed across study groups. This may be related to the predominance of superficial epithelial cells in the collected samples.
Overall, this study provides an integrated biochemical and cytomorphological assessment of oxidative stress in periodontitis. The findings support the potential use of salivary 8-OHdG and 8-OHG as non-invasive biomarkers for disease monitoring and contribute novel evidence regarding the interaction between smoking, oxidative stress, and periodontal inflammation.
Study design
- Observational model
- Case-control
- Time perspective
- Cross-sectional
- Number of arms
- 4
| Arm | Type | Receives |
|---|---|---|
| Periodontitis Smoker | – | –Participants diagnosed with Stage III periodontitis who are current cigarette smokers. No intervention was applied; biological samples (unstimulated saliva) were collected for biomarker analysis. |
| Periodontitis Non-Smoker | – | –Participants diagnosed with Stage III periodontitis who do not smoke. No intervention was applied; unstimulated saliva samples were collected for laboratory analysis. |
| Healthy Smoker | – | –Periodontally healthy individuals who are current smokers. No treatment or intervention was performed; only saliva samples and periodontal measurements were obtained. |
| Healthy Non-Smoker | – | –Periodontally healthy non-smokers. No intervention was provided; participants underwent periodontal evaluation and saliva sample collection. |
Who may qualify
- Ages
- 18 to 65 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
- Study population
- The study population consisted of systemically healthy adults aged 18-65 years, including individuals with Stage III periodontitis and periodontally healthy controls. Participants were categorized into four groups based on periodontal status and smoking habits: smokers and non-smokers with Stage III periodontitis, and smokers and non-smokers who were periodontally healthy.
Key inclusion criteria (7 listed)
- Individuals aged 18 years or older
- Having at least 16 permanent teeth, excluding third molars
- Not using orthodontic appliances
- Not pregnant or breastfeeding
- Systemically healthy individuals with no systemic diseases that could affect periodontal status
Key exclusion criteria (10 listed)
- Pregnant or breastfeeding individuals.
- Use of anti-inflammatory or antimicrobial drugs in the past 6 months.
- Use of antioxidant supplements in the past 3 months.
- Periodontal treatment within the past 12 months.
- Diagnosis of psychiatric disorders.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Salivary oxidative DNA and RNA damage (8-OHdG and 8-OHG levels)
Time frame: Baseline (periodontal examination visit and saliva collection visit, before any periodontal treatment)
Concentrations of 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-hydroxyguanosine (8-OHG) measured in unstimulated whole saliva using a high-sensitivity competitive ELISA kit. Saliva samples are collected at a separate baseline visit within the study period, after full-mouth periodontal examination and before any periodontal therapy. Biomarker levels (ng/mL) were compared across the four study groups and analyzed in relation to clinical periodontal parameters. Higher values indicate greater oxidative nucleic acid damage.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 12 Dec 2025.
- Results publication: PubMed 25325515Hendek MK, Erdemir EO, Kisa U, Ozcan G. Effect of initial periodontal therapy on oxidative stress markers in gingival crevicular fluid, saliva, and serum in smokers and non-smokers with chronic periodontitis. J Periodontol. 2015 Feb;86(2):273-82. doi: 10.1902/jop.2014.140338. Epub 2014 Oct 17.
- Results publication: PubMed 29926952Tonetti MS, Greenwell H, Kornman KS. Staging and grading of periodontitis: Framework and proposal of a new classification and case definition. J Periodontol. 2018 Jun;89 Suppl 1:S159-S172. doi: 10.1002/JPER.18-0006.
- Results publication: PubMed 25662588Kurgan S, Onder C, Altingoz SM, Bagis N, Uyanik M, Serdar MA, Kantarci A. High sensitivity detection of salivary 8-hydroxy deoxyguanosine levels in patients with chronic periodontitis. J Periodontal Res. 2015 Dec;50(6):766-74. doi: 10.1111/jre.12263. Epub 2015 Feb 7.
- Individual participant dataSharing planned: No. Individual participant data will not be shared due to patient privacy concerns, data protection regulations, and the terms of the local ethics committee approval
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Sivge Kurgan principal investigator
Ankara University, Faculty of Dentistry, Department of Periodontology
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Periodontitis (Stage 3) and Smoking, run by Zehra Hasgül at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 12 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Salivary oxidative DNA and RNA damage (8-OHdG and 8-OHG levels) (time frame: Baseline (periodontal examination visit and saliva collection visit, before any periodontal treatment)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07279896, which also lists 3 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 12 Dec 2025.