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

Overview

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.

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.