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Completed

NCT Number: NCT07734935

The Effect of Retraction Cord on the Surrounding Periodontal Tissues in Restorative Treatment

The goal of this clinical trial is to learn whether a retraction cord affects gum health when used during tooth restoration procedures. A retraction cord is a thin thread that dentists sometimes place between the tooth and the gum surrounding it, to gently push the gum aside so the restoration can be performed in a clean surface isolated from saliva.

The study includes adult teeth with tooth damage near the gumline that has not been caused by decay, yet needs a restoration. The main research question is: Does using a retraction cord make a difference for gum health as opposed to not using one? Participants will be assigned into four separate groups. Two groups will receive a restoration with one type of bonding material, either with or without a retraction cord. The other two groups will receive a restoration with a different kind of bonding material, either with or without a retraction cord.

Researchers will check gum health status before the restorations and again on days 1, 7, and 28. They will observe symptoms such as swelling in the gums, bleeding of the gums, and gum margin positions. A fluid sample from the area between the gum and tooth will be collected to test for molecules of inflammation.

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Key information

Conditions

Tooth Abrasion Gingival Crevicular Fluid Gingival Diseases Gingival Inflammation Gingival Recession Gingival Recessions Gingivitis Infections Mouth Diseases Non-Carious Cervical Lesions (NCCLs) Periodontal Atrophy Periodontal Diseases Periodontal Health Stomatognathic Diseases Tooth Diseases Tooth Wear

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Istanbul University Faculty of Dentistry

Istanbul, 34116, Turkey (Türkiye)

About this study

Study Rationale Retraction cord is commonly used during composite resin restoration of non-carious cervical lesions to control gingival crevicular fluid and improve visibility. Its effect on periodontal health in this specific application has not been well characterized. This study compares clinical periodontal parameters and gingival crevicular fluid (GCF) biomarker levels with and without cord placement.

Study Design This is a randomized, tooth-level (split-mouth), double-blind clinical trial following a 2×2 factorial design: adhesive system (G-Premio Bond vs. 3M Scotchbond Universal Plus) × retraction cord use (with vs. without). Eligible participants had multiple qualifying lesions, allowing individual teeth to be randomly allocated by coin-flip to different groups within the same participant. The participants and the examiner performing periodontal measurements were blinded to group allocation.

Procedures All restorations were placed by a single operator. In cord groups, an Ultrapak retraction cord was placed in the gingival sulcus before adhesive application and left in situ throughout the restorative procedure. Clinical periodontal parameters (Plaque Index, Gingival Index, Bleeding on Probing, Probing Pocket Depth, Keratinized Tissue Width, relative gingival margin position) and GCF samples were collected at baseline and on days 1, 7, and 28 after restoration. GCF biomarkers (TNF-α, IL-8, MMP-8, TIMP-1, PGE-2, LXA-4) were quantified using enzyme-linked immunosorbent assay (ELISA).

Enrollment Twelve participants (69 teeth) were initially enrolled; the study was completed with 10 participants (57 teeth) following two withdrawals.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age 18 years or older
  • Systemically healthy
  • Non-smoker
  • Periodontally healthy (whole-mouth bleeding on probing <10%, mean probing pocket depth ≤3 mm, mean Plaque Index and Gingival Index ≤1.1)
  • At least 20 teeth in occlusion (full/near-full dentition)
  • At least 4 non-carious cervical lesions, each ≥1 mm in depth, involving both enamel and dentin, with vital pulp status

Exclusion criteria

  • Presence of systemic disease
  • Use of medication known to affect inflammatory response during the study period
  • Inability or unwillingness to comply with follow-up visits
  • Pregnancy or lactation
  • Current smoking
  • Presence of periodontal disease

Treatment and study plan

Gingival Retraction Cord

Device

A knitted retraction cord placed in the gingival sulcus prior to composite restoration to displace gingival tissue and control gingival crevicular fluid during the bonding procedure.

Composite Resin Restorative

Device

anofilled resin composite used for restoration of non-carious cervical lesions in all study groups.

Universal Adhesive - G-Premio Bond

Device

Single-component universal adhesive system used for bonding the composite restoration to tooth structure.

Universal Adhesive - Scotchbond Universal Plus

Device

Universal adhesive system used for bonding the composite restoration to tooth structure.

Primary outcomes

  1. Change in Split-Mouth Gingival Index Difference (ΔGI) Over Time

    Time frame: Baseline, and Days 1, 7, and 28 after restoration

    Difference in Gingival Index (Löe & Silness) between cord-treated and no-cord teeth within the same participant (split-mouth design), assessed at each time point. The Gingival Index (Löe & Silness) ranges from 0 to 3, where 0 indicates healthy gingiva and 3 indicates severe inflammation; higher scores indicate a worse outcome.

Secondary outcomes

  1. Change in Plaque Index (PI)

    Time frame: Baseline, and Days 1, 7, and 28 after restoration

    Clinical assessment of dental plaque accumulation using the Silness & Löe Plaque Index. The Plaque Index (Silness & Löe) ranges from 0 to 3, where 0 indicates no plaque and 3 indicates abundant plaque; higher scores indicate a worse outcome.

  2. Change in Bleeding on Probing (BOP)

    Time frame: Baseline, and Days 1, 7, and 28 after restoration

    Percentage of probed sites showing bleeding on gentle periodontal probing.

  3. Change in Probing Pocket Depth (PPD)

    Time frame: Baseline, and Days 1, 7, and 28 after restoration

    Distance from the gingival margin to the base of the periodontal pocket, measured in millimeters with a periodontal probe.

  4. Change in Keratinized Tissue Width (KTW)

    Time frame: Baseline, and Days 1, 7, and 28 after restoration

    Width of keratinized gingiva, measured in millimeters from the gingival margin to the mucogingival junction.

  5. Change in Relative Gingival Margin Position

    Time frame: Baseline, and Days 1, 7, and 28 after restoration

    Position of the gingival margin relative to a fixed reference point, used to assess gingival recession or coronal displacement.

  6. Change in Gingival Crevicular Fluid Tumor Necrosis Factor-alpha (TNF-α) Concentration

    Time frame: Baseline (before restoration), and Days 1, 7, and 28 after restoration

    TNF-α concentration in gingival crevicular fluid (GCF) samples, quantified using enzyme-linked immunosorbent assay (ELISA), compared across treatment groups over time.

  7. Change in Gingival Crevicular Fluid Interleukin-8 (IL-8) Concentration

    Time frame: Baseline, and Days 1, 7, and 28 after restoration

    IL-8 concentration in gingival crevicular fluid, quantified using ELISA.

  8. Change in Gingival Crevicular Fluid Matrix Metalloproteinase-8 (MMP-8) Concentration

    Time frame: Baseline, and Days 1, 7, and 28 after restoration

    MMP-8 concentration in gingival crevicular fluid, quantified using ELISA.

  9. Change in Gingival Crevicular Fluid Tissue Inhibitor of Metalloproteinase-1 (TIMP-1) Concentration

    Time frame: Baseline, and Days 1, 7, and 28 after restoration

    TIMP-1 concentration in gingival crevicular fluid, quantified using ELISA.

  10. Change in Gingival Crevicular Fluid Prostaglandin E2 (PGE-2) Concentration

    Time frame: Baseline, and Days 1, 7, and 28 after restoration

    PGE-2 concentration in gingival crevicular fluid, quantified using ELISA.

  11. Change in Gingival Crevicular Fluid Lipoxin A4 (LXA-4) Concentration

    Time frame: Baseline, and Days 1, 7, and 28 after restoration

    LXA-4 concentration in gingival crevicular fluid, quantified using ELISA.

Sponsors and collaborators

Lead sponsor

Istanbul University

Other

Registry information

Official study title

Evaluation of the Effects of Retraction Cord Placed in the Gingival Sulcus on Periodontal Tissues in Restorative Treatment

Important dates

Study start
2025
Primary completion
2025
Study completion
2025
First posted
Jul 29, 2026
Registry last updated
Jul 30, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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