Effect of Nail Biting Habit on Mandibular Bone Structure: A Retrospective Radiological Study

NCT07740889 | Not Yet Recruiting

• 1 other identifier: 2026/315
• Study Type: observational
• Target: 100
• Locations: 0 countries
• Sites: N/A

Brief 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. 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.

Conditions

Onychophagia

Outcome Measures

Primary Outcomes (1)

• 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.

  Baseline

Secondary Outcomes (1)

• Panoramic Mandibular Index (PMI)

  Baseline

Study Arms (2)

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.

Eligibility Criteria

• Age: 8 Years - 10 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Child (0-17)
• Sampling Method: Non-Probability Sample

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.

You may qualify if:

• 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.

You may not qualify if:

• 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.

Sponsors & Collaborators

• Recep Tayyip Erdogan University Training and Research Hospital: lead

MeSH Terms

Conditions

Nail Biting

Condition Hierarchy (Ancestors)

Habits; Behavior

Central Study Contacts

Dilara Nil GÜNAÇAR

CONTACT

+905412940104; dilaranil.tomrukcu@erdogan.edu.tr

Study Design

• Study Type: observational
• Observational Model: CASE CROSSOVER
• Time Perspective: RETROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Assoc.Prof.

Study Record Dates

• First Submitted: July 28, 2026
• First Posted: August 3, 2026
• Study Start: July 27, 2026
• Primary Completion: August 5, 2026
• Study Completion: August 7, 2026
• Last Updated: August 3, 2026

Record last verified: 2026-07