Why Is Gingival Retraction Important for Digital Impressions?
Digital impression technology has fundamentally changed restorative dentistry. Modern intraoral scanners provide exceptional accuracy, improve patient comfort, eliminate many of the variables associated with conventional impressions, and create a seamless digital workflow from preparation to final restoration. Numerous systematic reviews have shown that today's scanners are capable of producing clinically accurate impressions for single-unit restorations and short-span prostheses when proper clinical protocols are followed.
Yet despite these technological advances, one clinical reality has not changed.
A scanner cannot capture what it cannot see.
Unlike traditional impression materials that can flow into the gingival sulcus and physically displace soft tissue, intraoral scanners rely on reflected light. If the preparation margin is obscured by gingiva, blood, or crevicular fluid, the scanner simply cannot record that information.
As Mangano and colleagues explain in their landmark review of intraoral scanning, optical impressions are inherently limited by visibility because, unlike physical impression materials, light cannot displace the gingiva out of the way and therefore cannot record areas it cannot directly see. This makes effective gingival retraction essential whenever margins extend at or below the gingival crest.
Why Margin Visibility Determines Digital Impression Accuracy
A beautifully prepared tooth can still produce a poorly fitting restoration if the finish line is not completely captured.
For an intraoral scanner to accurately reproduce the preparation margin, clinicians must establish:
- Clear visualization of the finish line
- Effective lateral tissue displacement
- Excellent moisture control
- Control of blood and crevicular fluid
- Stable, healthy soft tissue
Without these conditions, digital models may contain incomplete or distorted margins that can lead to:
- open or overextended margins
- inaccurate contacts
- poor emergence profiles
- restoration remakes
- unnecessary rescanning
- increased chair time
Recent evidence continues to reinforce this principle. A 2025 systematic review evaluating intraoral scanner accuracy for preparations with subgingival margins concluded that successful digital impressions depend heavily on adequate gingival retraction and moisture control, particularly when margins extend below the gingival crest.
Is Retraction Cord Still Necessary with an Intraoral Scanner?
One of the biggest misconceptions surrounding digital dentistry is that scanners somehow eliminate the need for traditional tissue management.
In reality, the opposite is true.
Conventional impression materials possess a physical property that optical scanners do not. Impression material can flow into areas that may not be completely visible during impression making. Light cannot.
This means digital workflows often require even greater attention to soft tissue management before scanning begins.
Healthy gingival tissue, effective isolation, proper provisional restorations, and meticulous moisture control remain essential components of restorative success.
Technology has improved dramatically, but biology has not changed.
Why Retraction Cord Remains a Gold Standard for Gingival Retraction
Among the available tissue management techniques, retraction cord continues to be one of the most predictable, versatile, and widely accepted methods for exposing preparation margins.
When properly selected and placed, retraction cord helps clinicians:
- laterally displace gingival tissue
- expose the finish line
- control sulcular fluid
- facilitate hemostatic delivery
- improve scanner access
- create a cleaner digital scan
Rather than simply moving tissue away from the tooth, effective retraction creates the stable, dry operating field that modern digital workflows require.
Not All Retraction Cords Are Created Equal
The performance of a retraction cord depends on its construction, handling characteristics, and ability to manage moisture.
Traditional cotton cords have served dentistry well for decades, but some may fray during placement or removal, potentially leaving loose fibers within the sulcus.
Modern synthetic knitted cords have been developed to address many of these clinical challenges.
Characteristics clinicians often look for include:
Excellent Fluid Management
Highly absorbent synthetic fibers help control blood and crevicular fluid, improving visibility throughout the scanning procedure.
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Consistent Delivery of Hemostatic Agents
A highly absorbent cord can facilitate the placement of hemostatic solutions where they are needed while helping maintain a dry field.
Low-Lint Construction
Synthetic fibers designed to resist fraying help minimize loose fibers that could interfere with visualization.
Flexible Handling
Knitted construction allows the cord to adapt to the sulcus while maintaining enough body for predictable placement.
Dye-Free Visibility
Cord without artificial dyes allows clinicians to clearly distinguish tissue, tooth structure, and preparation margins during scanning.
The Clinical Impact
Spending an extra minute establishing ideal tissue management frequently saves considerably more time later in the restorative process.
When preparation margins are fully exposed before scanning, clinicians often experience:
- fewer rescans
- improved margin visualization
- more predictable laboratory communication
- improved restoration fit
- fewer adjustments at delivery
- greater confidence during cementation
Ultimately, accurate scans begin long before the scanner enters the patient's mouth.
A Modern Retraction Cord for Digital Workflows
Products such as Pascal ProPak™ Knitted Retraction Cord have been developed to support both digital and conventional impression techniques.
Its ultra-absorbent synthetic knitted fibers are designed to manage blood and crevicular fluid while facilitating the delivery of hemostatic agents during restorative procedures.
Because it contains:
- no loose fibers
- no artificial dyes
- no PTFE
- no fluoropolymer-based materials
ProPak helps clinicians maintain a clean operative field with excellent visibility during digital scanning.
Whether restoring a single crown, veneer, bridge, or implant restoration, effective tissue management remains one of the simplest ways to improve impression quality.
The Double Cord Technique: A Proven Approach for Margin Exposure
For preparations with subgingival or equigingival margins, many clinicians rely on the double cord technique to achieve predictable soft tissue displacement while maintaining excellent moisture control.
This approach creates both vertical and horizontal tissue displacement, allowing the finish line to become fully visible immediately before scanning or impression taking.
Research and clinical literature consistently describe the double cord technique as one of the most reliable methods for exposing preparation margins while minimizing trauma to the gingival tissues.
Step 1: Place a Thin, Non-Medicated Cord
Begin by placing a small diameter knitted retraction cord, typically size 000 or 00, gently into the sulcus.
The first cord serves several important purposes:
- Creates initial vertical tissue displacement
- Helps control crevicular fluid
- Remains in place throughout the procedure
- Protects the epithelial attachment during placement of the second cord
Step 2: Place a Larger Medicated Cord
A second, slightly larger cord (typically size 0, 1, or 2) is then saturated with the clinician's preferred hemostatic agent before placement.
This second cord:
- Produces lateral tissue displacement
- Enhances moisture control
- Delivers the hemostatic solution directly into the sulcus
- Widens the sulcular space, improving visualization of the preparation margin
The appropriate cord size depends on tissue biotype, sulcus depth, and the restorative procedure being performed.
Step 3: Remove the Outer Cord Immediately Before Scanning
Immediately before making the digital impression, the larger medicated cord is carefully removed while leaving the smaller cord in place.
Maintaining the first cord within the sulcus helps:
- Preserve tissue displacement
- Minimize crevicular fluid contamination
- Keep the preparation margin clearly visible
- Provide the scanner with uninterrupted access to the finish line
For digital workflows, this final step creates the clean, dry environment needed for accurate optical capture of the preparation margins.
Clinical Tip: Before beginning the scan, gently air-dry the preparation and verify that the finish line is visible circumferentially. If any portion of the margin remains obscured by tissue or moisture, address it before scanning. A few extra seconds spent confirming margin visibility can prevent rescanning, restoration remakes, and unnecessary chair time.
Final Thoughts
Digital impression systems continue to evolve at an impressive pace. Scanners are becoming faster. Software is becoming smarter.
Artificial intelligence is improving scan stitching and restoration design.
But no technological advancement can compensate for a preparation margin that remains hidden beneath gingival tissue.
Successful digital impressions still begin with healthy soft tissue, excellent moisture control, and effective gingival retraction.
When every micron matters, choosing the right retraction cord is more than a procedural step. It is the foundation of an accurate digital impression.
References
- Mangano F, Gandolfi A, Luongo G, Logozzo S. Intraoral scanners in dentistry: a review of the current literature. BMC Oral Health. 2017;17:149.
- Andrade Villalobos M, Bennani V, Aarts JM, Ratnayake J. Accuracy of Intraoral Scanners for Full Crown Tooth Preparations with Subgingival Margins: A Systematic Review. European Journal of Prosthodontics and Restorative Dentistry. 2025.
- Shah N, Thakur M, Gill S, et al. Validation of Digital Impressions' Accuracy Obtained Using Intraoral and Extraoral Scanners: A Systematic Review. Journal of Clinical Medicine. 2023.
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Donovan TE, Chee WWL. Current concepts in gingival displacement. Dental Clinics of North America. 2004;48(2):433-444.
Disclosure: This article was written and reviewed by staff of Curion and Pascal International, distributor and manufacturer of the featured product, Pascal ProPak™.
Written by: Anna Kajda, CDA
Vice President, Sales & Marketing, Curion
Clinically reviewed by: Steve Burman
Vice President, Pascal International