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Impact of 2D:4D Ratio on Oral Hygiene and Gingival Health

NCT07147998 · Status: COMPLETED · Type: OBSERVATIONAL · Enrollment: 126

Last updated 2025-08-29

No results posted yet for this study

Summary

The second-to-fourth digit ratio (2D:4D)-the ratio of the length of the index finger to that of the ring finger-has gained increasing attention as a non-invasive, stable biomarker of prenatal sex hormone exposure. The 2D:4D ratio is believed to reflect the balance of prenatal androgens (especially testosterone) and estrogens. Lower ratios (more masculinized) indicate higher prenatal testosterone exposure, whereas higher ratios (more feminized) are associated with lower testosterone and higher estrogen levels. Research has linked variations in 2D:4D to a broad spectrum of behavioral traits, cognitive abilities, and health outcomes. 2D:4D has been shown to have strong associations with motor performance, especially skills that require fine motor coordination. However, while many studies have examined the role of 2D:4D in sports and cognition, its relationship to health-related behaviors involving motor skills remains underexplored. One such domain is oral hygiene, which requires sustained fine motor coordination-particularly in actions like tooth brushing and flossing. Despite the clear motor demands of such behaviors, the potential connection between 2D:4D and oral hygiene has not yet been systematically investigated. This study aims to fill this gap by exploring the association between the 2D:4D digit ratio and oral hygiene practices.

Conditions

  • Oral Hygiene
  • Gingivitis

Interventions

OTHER

Oral hygiene instruction

Oral hygiene and gingival health of all patients were assessed using the Turesky Modification of the Quigley-Hein Plaque Index and the Gingival Index. Tooth brushing frequency was recorded. The 2D:4D ratio was calculated by dividing the second digit length by the fourth, with three measurements taken per finger to ensure reliability. A cut-off value of 1 was used to evaluate prenatal androgen influence, and participants were grouped by 2D:4D ratio (≥1 or \<1). All participants received standardized oral hygiene instructions from the same instructor, including Modified Bass brushing and interdental cleaning. A second clinical exam was performed one week later by the same examiner, and both indices were re-scored.

Sponsors & Collaborators

  • Okan University

    lead OTHER

Principal Investigators

  • Ekin Beşiroğlu Turgut · Okan University

Eligibility

Min Age
18 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2023-09-01
Primary Completion
2024-05-01
Completion
2025-08-01

Countries

  • Turkey (Türkiye)

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT07147998 on ClinicalTrials.gov