OnychophagiaNCT07740889
Effect of Nail Biting Habit on Mandibular Bone Structure: A Retrospective Radiological Study
An observational study of Onychophagia, run by Recep Tayyip Erdogan University Training and Research Hospital.
Trial summary
Nail biting (onychophagia) is a common parafunctional habit characterized by repetitive and non-functional biting behavior. Although the effects of nail biting on dental structures and occlusion have been reported, its potential effects on mandibular bone structure remain unclear. Read more about this study
- Who is it for?
- Ages 8 to 10 yearsHealthy volunteers can take part
- Conditions the study is for
- Onychophagia
- How many people
- 100 participants
- Where
- No sites listed yet
- Study dates
- 27 Jul 2026to 7 Aug 2026
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
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 8 to 10 years
- All sexes
- Healthy volunteers accepted
- Child
Study population: The study population will consist of systemically healthy children aged 8-10 years who previously underwent routine dental examination at the Department of Pediatric Dentistry, Faculty of Dentistry, Recep Tayyip Erdoğan University. Existing panoramic radiographs obtained during routine clinical care will be retrospectively analyzed. Participants will be categorized into two groups according to the presence or absence of nail biting habit. A minimum of 100 participants will be included, with equal distribution between the nail biting habit group and the control group and balanced sex distribution. Mandibular bone characteristics will be evaluated using fractal dimension analysis and panoramic radiographic morphometric indices, including mandibular cortical width, panoramic mandibular index, mandibular cortical index (Klemetti index), and other mandibular bone measurements. No intervention will be performed; only existing radiographic records will be assessed.
Who may be able to join
- Children aged 8-10 years who were examined at the Department of Pediatric Dentistry, Faculty of Dentistry, Recep Tayyip Erdoğan University.
- Systemically healthy participants.
- Participants with available diagnostic-quality panoramic radiographs obtained during routine dental examinations.
- Participants with and without a history of nail biting habit.
- Panoramic radiographs with sufficient image quality for fractal dimension analysis and mandibular morphometric measurements.
- Radiographs without periapical pathology in teeth adjacent to the regions of interest (ROI) used for fractal analysis.
- Participants with at least 20 existing teeth.
- Radiographic records with available parental radiographic information and consent documentation.
Who cannot join
- Participants with systemic diseases or conditions that may affect bone metabolism, including diabetes mellitus, osteoporosis, osteomalacia, renal diseases, hypothyroidism, or hyperparathyroidism.
- Participants using medications that may influence bone density or bone metabolism.
- Participants with temporomandibular joint disorders affecting the subcondylar region.
- Participants with mandibular pathological conditions, including cysts, tumors, or other lesions affecting mandibular bone structure.
- Participants with periapical pathology adjacent to the regions selected for fractal analysis.
- Participants with fewer than 20 teeth.
- Panoramic radiographs with insufficient diagnostic quality or image artifacts that prevent reliable measurements.
- Radiographs that do not allow accurate evaluation of mandibular cortical and trabecular bone parameters.
Trial locations and contacts
No sites are listed yet. Contact the study team or a site near you to ask about taking part.
About this study
Official title: Evaluation of the Effects of Nail Biting Habit on Mandibular Bone Structure Using Fractal Analysis and Panoramic Morphometric Indices: A Retrospective Radiological Study
Nail biting (onychophagia) is a common parafunctional habit characterized by repetitive and non-functional biting behavior. Although the effects of nail biting on dental structures and occlusion have been reported, its potential effects on mandibular bone structure remain unclear. This retrospective radiological study aims to evaluate the association between nail biting habit and mandibular bone characteristics using fractal analysis and panoramic morphometric indices. Existing panoramic radiographs of individuals with and without nail biting habits will be retrospectively analyzed. Trabecular bone complexity, mandibular cortical width, panoramic mandibular index, and Klemetti index values will be compared between groups to investigate whether nail biting habit is associated with alterations in mandibular bone morphology.
Read the detailed description
Nail biting (onychophagia) is classified as a body-focused repetitive behavior and represents a common parafunctional habit, particularly among children and adolescents. Continuous repetitive mechanical forces generated during nail biting may affect the stomatognathic system; however, the possible effects of this habit on mandibular bone structure have not been sufficiently investigated.
Fractal analysis is a radiological assessment method used to evaluate trabecular bone architecture by quantifying structural complexity. Higher fractal dimension values indicate increased complexity of bone patterns. In addition, panoramic morphometric indices such as mandibular cortical width, panoramic mandibular index, and Klemetti index provide information regarding cortical bone quality and quantity.
In this retrospective case-control study, existing panoramic radiographs of individuals with and without nail biting habits will be evaluated. Radiological parameters including fractal dimension, mandibular cortical width, panoramic mandibular index, and Klemetti index will be compared between groups. This study aims to determine whether nail biting habit is associated with measurable changes in mandibular trabecular and cortical bone characteristics.
- Conditions
- Onychophagia
- Medical subject headings
- Nail Biting
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 |
|---|---|---|
| Nail Biting Habit Group | This cohort includes systemically healthy children aged 8-10 years with a documented nail biting habit. Existing panoramic radiographs obtained during routine dental examinations will be retrospectively analyzed. Mandibular trabecular bone structure will be evaluated using fractal dimension analysis, and cortical bone characteristics will be assessed using mandibular cortical width, panoramic mandibular index, and Klemetti index measurements. No intervention will be performed. | |
| Control Group Without Nail Biting Habit | This cohort includes systemically healthy children aged 8-10 years without a history of nail biting habit. Existing panoramic radiographs obtained during routine dental examinations will be retrospectively analyzed using the same radiological evaluation methods. Mandibular trabecular and cortical bone characteristics will be compared with those of the nail biting habit group. No intervention will be performed. |
What is being measured
The primary outcome is the main question the study is designed to answer.
Mandibular Trabecular Bone Structure Assessed by Fractal Dimension Analysis
Mandibular trabecular bone architecture will be evaluated using fractal dimension analysis on panoramic radiographs. Fractal dimension measurements will be performed using the box-counting method described by White and Rudolph. Four regions of interest (ROIs) in the mandible will be analyzed, including the condylar subcortical region, supracortical region above the mandibular angle, area above the mandibular canal distal to the mental foramen, and anterior region of the mental foramen. Measurements will be performed bilaterally, and the mean fractal dimension value will be calculated for each participant. Higher fractal dimension values indicate greater trabecular bone complexity. The fractal dimension values will be compared between individuals with and without nail biting habit.
Measured: Baseline
Secondary outcomes (1)
Panoramic Mandibular Index (PMI)
The panoramic mandibular index (PMI) will be calculated on panoramic radiographs as the ratio of mandibular cortical width to the distance between the inferior border of the mandible and the inferior margin of the mental foramen. Measurements will be performed bilaterally, and the mean value will be used for analysis.
Measured: Baseline
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Aug 2026
- Study start27 Jul 2026 (estimated)
- Primary completion5 Aug 2026 (estimated)
- Study completion7 Aug 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for OnychophagiaStudies 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 crossover
- Time perspective
- Retrospective
- Enrolment
- 100 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Recep Tayyip Erdogan University Training and Research Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, DİLARA NİL GÜNAÇAR, Recep Tayyip Erdogan University Training and Research Hospital
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07740889
- Sponsor's protocol ID
- 2026/315
- Status last verified
- Jul 2026
- First submitted
- 28 Jul 2026
- Last updated
- 3 Aug 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 3 Aug 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Evaluation of the Effects of Nail Biting Habit on Mandibular Bone Structure Using Fractal Analysis and Panoramic Morphometric Indices: A Retrospective Radiological Study
- ClinicalTrials.gov ID
- NCT07740889
- Acronym / sponsor ID
- 2026/315
- Conditions
- Onychophagia
- Study type
- Observational
- Recruitment status
- Not yet recruiting
- Enrolment
- 100 participants (estimated)
- Lead sponsor
- Recep Tayyip Erdogan University Training and Research HospitalUniversity, hospital or other
- Study start
- 27 Jul 2026 (estimated)
- Primary completion
- 5 Aug 2026 (estimated)
- Study completion
- 7 Aug 2026 (estimated)
- First posted
- 3 Aug 2026 (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.
Nail biting (onychophagia) is a common parafunctional habit characterized by repetitive and non-functional biting behavior. Although the effects of nail biting on dental structures and occlusion have been reported, its potential effects on mandibular bone structure remain unclear. This retrospective radiological study aims to evaluate the association between nail biting habit and mandibular bone characteristics using fractal analysis and panoramic morphometric indices. Existing panoramic radiographs of individuals with and without nail biting habits will be retrospectively analyzed. Trabecular bone complexity, mandibular cortical width, panoramic mandibular index, and Klemetti index values will be compared between groups to investigate whether nail biting habit is associated with alterations in mandibular bone morphology.
Detailed description
Nail biting (onychophagia) is classified as a body-focused repetitive behavior and represents a common parafunctional habit, particularly among children and adolescents. Continuous repetitive mechanical forces generated during nail biting may affect the stomatognathic system; however, the possible effects of this habit on mandibular bone structure have not been sufficiently investigated.
Fractal analysis is a radiological assessment method used to evaluate trabecular bone architecture by quantifying structural complexity. Higher fractal dimension values indicate increased complexity of bone patterns. In addition, panoramic morphometric indices such as mandibular cortical width, panoramic mandibular index, and Klemetti index provide information regarding cortical bone quality and quantity.
In this retrospective case-control study, existing panoramic radiographs of individuals with and without nail biting habits will be evaluated. Radiological parameters including fractal dimension, mandibular cortical width, panoramic mandibular index, and Klemetti index will be compared between groups. This study aims to determine whether nail biting habit is associated with measurable changes in mandibular trabecular and cortical bone characteristics.
Study design
- Observational model
- Case crossover
- Time perspective
- Retrospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Nail Biting Habit Group | – | –This cohort includes systemically healthy children aged 8-10 years with a documented nail biting habit. Existing panoramic radiographs obtained during routine dental examinations will be retrospectively analyzed. Mandibular trabecular bone structure will be evaluated using fractal dimension analysis, and cortical bone characteristics will be assessed using mandibular cortical width, panoramic mandibular index, and Klemetti index measurements. No intervention will be performed. |
| Control Group Without Nail Biting Habit | – | –This cohort includes systemically healthy children aged 8-10 years without a history of nail biting habit. Existing panoramic radiographs obtained during routine dental examinations will be retrospectively analyzed using the same radiological evaluation methods. Mandibular trabecular and cortical bone characteristics will be compared with those of the nail biting habit group. No intervention will be performed. |
Who may qualify
- Ages
- 8 to 10 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Child
- Study population
- The study population will consist of systemically healthy children aged 8-10 years who previously underwent routine dental examination at the Department of Pediatric Dentistry, Faculty of Dentistry, Recep Tayyip Erdoğan University. Existing panoramic radiographs obtained during routine clinical care will be retrospectively analyzed. Participants will be categorized into two groups according to the presence or absence of nail biting habit. A minimum of 100 participants will be included, with equal distribution between the nail biting habit group and the control group and balanced sex distribution. Mandibular bone characteristics will be evaluated using fractal dimension analysis and panoramic radiographic morphometric indices, including mandibular cortical width, panoramic mandibular index, mandibular cortical index (Klemetti index), and other mandibular bone measurements. No intervention will be performed; only existing radiographic records will be assessed.
Key inclusion criteria (8 listed)
- Children aged 8-10 years who were examined at the Department of Pediatric Dentistry, Faculty of Dentistry, Recep Tayyip Erdoğan University.
- Systemically healthy participants.
- Participants with available diagnostic-quality panoramic radiographs obtained during routine dental examinations.
- Participants with and without a history of nail biting habit.
- Panoramic radiographs with sufficient image quality for fractal dimension analysis and mandibular morphometric measurements.
Key exclusion criteria (8 listed)
- Participants with systemic diseases or conditions that may affect bone metabolism, including diabetes mellitus, osteoporosis, osteomalacia, renal diseases, hypothyroidism, or hyperparathyroidism.
- Participants using medications that may influence bone density or bone metabolism.
- Participants with temporomandibular joint disorders affecting the subcondylar region.
- Participants with mandibular pathological conditions, including cysts, tumors, or other lesions affecting mandibular bone structure.
- Participants with periapical pathology adjacent to the regions selected for fractal analysis.
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
Mandibular Trabecular Bone Structure Assessed by Fractal Dimension Analysis
Time frame: Baseline
Mandibular trabecular bone architecture will be evaluated using fractal dimension analysis on panoramic radiographs. Fractal dimension measurements will be performed using the box-counting method described by White and Rudolph. Four regions of interest (ROIs) in the mandible will be analyzed, including the condylar subcortical region, supracortical region above the mandibular angle, area above the mandibular canal distal to the mental foramen, and anterior region of the mental foramen. Measurements will be performed bilaterally, and the mean fractal dimension value will be calculated for each participant. Higher fractal dimension values indicate greater trabecular bone complexity. The fractal dimension values will be compared between individuals with and without nail biting habit.
1 secondary outcome
Panoramic Mandibular Index (PMI)
Time frame: Baseline
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 3 Aug 2026.
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Recruiting
Habit Awareness Device for Treatment of Onychophagia
Nail Biting
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.
Questions about this trial
What is this clinical trial studying?
An observational study of Onychophagia, run by Recep Tayyip Erdogan University Training and Research Hospital.
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 8 inclusion and 8 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: opening soon, as of the sponsor's last update on 3 Aug 2026. Status can change between updates, so confirm with the study contact before making plans.
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?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Dilara Nil GÜNAÇAR (+905412940104, dilaranil.tomrukcu@erdogan.edu.tr), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Mandibular Trabecular Bone Structure Assessed by Fractal Dimension Analysis (time frame: Baseline). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 3 Aug 2026.