Crown and bridge procedures demand a dry, visible operative field at the critical moment of impression-taking or cementation. Blood and crevicular fluid contaminate impression materials, obscure preparation margins, and compromise the bond strength of resin cements. Tissue retraction — the deliberate and controlled displacement of gingival tissue away from the preparation margin — is the prerequisite for capturing that margin cleanly.
This guide covers the clinical categories of hemostatic agents and retraction cord available to Canadian dental practices, the evidence behind them, and how to build an efficient inventory that covers routine and complex cases without overstocking.
Understanding Hemostatic Agents: What They Do and How They Differ
Hemostatic agents used in restorative and prosthodontic dentistry achieve hemorrhage control through one of two mechanisms: chemical vasoconstriction (narrowing blood vessels to reduce flow) or astringent protein precipitation (coagulating surface proteins to form a clot). Some products combine both mechanisms. The choice affects not only bleeding control but also tissue colour, rebound bleeding risk, and compatibility with impression materials and cements.
Ferric Sulfate (15.5%–20%)
Ferric sulfate is the most widely used hemostatic agent in general dentistry. It works by reacting with blood proteins to form a ferric sulfate–protein complex that plugs capillary openings. Hemostasis is rapid — typically within 10–15 seconds of application — and the mechanism does not depend on vasoconstriction, which means there is no rebound bleeding once the agent is rinsed away.
The trade-off is staining. Ferric sulfate leaves a dark residue on enamel, composite, and soft tissue that must be thoroughly rinsed before impression-taking. Residual ferric sulfate also inhibits the polymerization of addition-reaction (VPS) silicone impression materials. Always rinse and air-dry the sulcus completely before seating the impression tray.
Clinically, ferric sulfate is the workhorse for routine crown preparations where bleeding is moderate and the tissue is healthy. It is less effective in cases of significant inflammation, where the volume of crevicular fluid overwhelms the protein-precipitation mechanism.
EBIKO Dental carries Ultradent ViscoStat 20% Ferric Sulfate Gel ($99.99 CAD) in the Indispense syringe format, which provides precise sulcular delivery through a fine metal tip. The gel viscosity keeps the agent in the sulcus rather than flowing onto adjacent surfaces, and the syringe format eliminates the waste associated with bottled liquids. For practices that prefer an aluminum chloride–free option, ViscoStat is the go-to ferric sulfate product.
Aluminum Chloride (10%–25%)
Aluminum chloride is an astringent hemostatic that works primarily through vasoconstriction and mild protein precipitation. It is gentler on tissue than ferric sulfate, produces less staining, and is generally compatible with VPS impression materials (though rinsing before impression-taking remains good practice). The trade-off is that hemostasis is slower and less aggressive — aluminum chloride is best suited for cases with mild bleeding and healthy sulcular tissue.
Aluminum chloride is the most common active ingredient in hemostatic retraction solutions (liquids used to soak retraction cord before placement). It is also the basis of several paste-based hemostatic systems.
Premier Hemodent (available at EBIKO Dental from $32.99 CAD) is a 25% aluminum chloride solution in an aqueous base. It is available in bottle form for cord soaking and in unit-dose applicators for direct sulcular application. Its long shelf life and low per-unit cost make it a practical choice for high-volume practices.
Aluminum Potassium Sulfate (Alum)
Alum-based hemostatics are among the oldest retraction agents in dentistry. They function as mild astringents with a lower risk of tissue irritation compared to ferric sulfate or higher-concentration aluminum chloride. However, their hemostatic potency is correspondingly lower, making them most appropriate for cases with minimal bleeding.
Epinephrine-Impregnated Systems
Epinephrine (adrenaline) at concentrations of 1:1000 to 1:100,000 achieves rapid hemostasis through potent local vasoconstriction. The clinical advantage is speed and effectiveness, particularly in inflamed tissue where astringent-based agents struggle. The concern is systemic absorption: epinephrine absorbed through the sulcular epithelium can produce transient increases in heart rate and blood pressure, which may be clinically significant in patients with cardiovascular conditions, uncontrolled hypertension, or concurrent use of certain medications.
For this reason, many Canadian dental professionals — guided by CDA and RCDSO standards of care — reserve epinephrine-impregnated retraction systems for cases where non-epinephrine agents have failed to achieve adequate hemostasis. When epinephrine is used, the patient's medical history must be reviewed, and the total dose applied should be documented.
Hemostatic Paste Systems: The Cordless Alternative
Hemostatic paste systems combine an astringent agent (typically aluminum chloride) with a kaolin or calcium sulfate carrier that provides both hemostasis and mechanical tissue displacement. The paste is syringed directly into the sulcus, left in place for one to three minutes, then rinsed away. No retraction cord is placed.
The leading example is the Premier Traxodent Hemodent Paste Retraction System (available at EBIKO Dental from $149.99 CAD for the 7-syringe starter kit). Traxodent combines 15% aluminum chloride with kaolin clay in a pre-loaded syringe with a fine application tip. The paste achieves both hemostasis and mild tissue displacement, making it suitable for cases where cord placement is difficult — thin biotypes, deep subgingival margins, or patients who are anxious about cord packing.
For practices with high crown-and-bridge volume, EBIKO Dental also carries the Traxodent Value Pack (25 syringes, 50 tips) at $459.99 CAD, bringing the per-syringe cost down significantly for multi-operatory practices. The Unit Dose Pack (24 units) at $171.99 CAD is another option for practices that want individual sealed doses for maximum shelf-life efficiency.
Pro Tip: Hemostatic paste is most effective when the sulcus is relatively dry at the time of application. For heavily bleeding sites, use a hemostatic agent like ferric sulfate first to achieve initial hemostasis, then follow with the paste system for retraction. Layering agents is a legitimate clinical strategy that many prosthodontists use routinely.
Retraction Cord: Knitted vs. Braided vs. Twisted
Retraction cord remains the gold standard for mechanical tissue displacement before conventional and digital impressions. The cord physically pushes gingival tissue away from the preparation margin, creating space for the impression material to capture the margin detail. Cord is available in three construction types, each with distinct handling properties.
Knitted Cord
Knitted retraction cord is constructed with interlocking loops that create a highly absorbent, compressible structure. It absorbs hemostatic solution readily, packs easily into the sulcus, and — critically — retrieves cleanly without leaving fibres behind. Knitted cord is the most popular construction type in North American dental practices for its combination of absorbency and atraumatic removal.
EBIKO Dental carries Ultradent Ultrapak Knitted Retraction Cord (from $24.99 CAD per jar), available in sizes #000 through #3 to accommodate different sulcus widths. The #00 and #0 sizes cover the majority of routine anterior and premolar crown preparations; the #1 and #2 sizes are appropriate for molar preparations with deeper sulci.
Braided Cord
Braided cord is tightly woven, giving it a firmer body and higher packing pressure per diameter than knitted cord. It is favoured in cases where aggressive tissue displacement is needed — deep subgingular margins, thick biotypes, or situations requiring a double-cord technique. The trade-off is that braided cord is slightly less absorbent and can be more difficult to remove from a tight sulcus without tissue trauma.
Twisted Cord
Twisted cord is the simplest construction: fibres wound together in a spiral. It is the most economical option but the least predictable in terms of expansion, absorbency, and retrieval. Most contemporary restorative practices have migrated to knitted or braided cord for clinical work, reserving twisted cord for cost-sensitive applications where precision is less critical.
The Double-Cord Technique: When and Why
The double-cord technique involves placing a thin cord (#000 or #00) deep in the sulcus before the preparation is finalized, then placing a larger cord (#0, #1, or #2) on top of it after the preparation is complete. The bottom cord remains in place during impression-taking to maintain tissue displacement and hemorrhage control, while the top cord is removed immediately before the impression to expose the preparation margin.
This technique is the standard of care in prosthodontic residency programs across Canada and is recommended for any case where the margin is subgingival, the tissue is inflamed or bleeding, or the restoration requires maximum margin accuracy — which, in practice, means most multi-unit bridges and many single-crown cases on anterior teeth where esthetics demand subgingival margins.
Pro Tip: Soak both cords in hemostatic solution before placement. For the bottom cord, aluminum chloride (such as Premier Hemodent, from $32.99 CAD at EBIKO Dental) provides sustained low-grade hemostasis without staining the preparation. For the top cord, consider a stronger agent if bleeding is significant. Always rinse the sulcus thoroughly after removing the top cord — hemostatic residue left on the preparation can interfere with impression material setting and cement bond strength.
Building Your Hemostatic and Retraction Inventory
A well-stocked restorative practice does not need every product in every category. Here is a practical inventory framework based on case mix.
Minimum Kit (General Practice, 3–5 Crown Preps per Week)
- Hemostatic agent: Ultradent ViscoStat 20% Ferric Sulfate — one syringe covers dozens of cases
- Retraction cord: Ultradent Ultrapak in sizes #00 and #1 — two sizes cover the majority of preparations
- Cord soaking solution: Premier Hemodent 10 mL bottle
- Hemostatic paste (optional): Traxodent Starter Kit for cordless cases
Expanded Kit (High-Volume Restorative, 10+ Preps per Week)
- Add ViscoStat Clear ($99.99 CAD) for anterior cases where staining is a concern — it uses 25% aluminum chloride instead of ferric sulfate
- Stock Ultrapak in the full #000–#2 range for double-cord technique flexibility
- Upgrade to Traxodent Value Pack (25 syringes) for per-unit savings
- Add Ultradent Astringedent ($104.99 CAD) — 15.5% ferric sulfate in liquid form for cord soaking when ferric-level hemostasis is needed on the cord itself
Surgical Kit Add-On (Extractions, Implants, Perio Surgery)
- Ethicon Spongostan Absorbable Gelatin Sponge ($49.99 CAD for 24 sponges) — for socket hemostasis after extraction or implant placement
- Astringedent Indispense Syringe ($104.99 CAD) — for direct application into extraction sockets or surgical sites
Compatibility with Impression Materials: What to Watch
Not all hemostatic agents play well with all impression materials. The critical compatibility concern is between ferric sulfate and VPS (vinyl polysiloxane / addition silicone) impression materials. Residual ferric sulfate on the preparation surface can inhibit VPS polymerization, resulting in a tacky, inaccurate impression surface at the margin — exactly where accuracy matters most.
The fix is simple: rinse thoroughly with water and air-dry the sulcus after removing the hemostatic agent and retraction cord. A 10-second rinse followed by thorough air-drying eliminates the incompatibility issue. Aluminum chloride–based hemostatics are generally compatible with VPS materials, but rinsing before impression-taking remains best practice regardless of the agent used.
Polyether impression materials (such as Impregum) are less sensitive to hemostatic residue than VPS materials, but their hydrophilic nature means they absorb sulcular fluid readily — so hemorrhage control before impression-taking is even more critical with polyether than with VPS.
Frequently Asked Questions
Q: Can hemostatic paste fully replace retraction cord for crown impressions?
Hemostatic paste systems like Traxodent can replace cord in cases with mild to moderate bleeding and adequate sulcus width. They are particularly useful for thin biotype tissue and anxious patients. However, for deep subgingival margins, heavy bleeding, or multi-unit bridge cases requiring maximum displacement, retraction cord — especially the double-cord technique — remains the more predictable option. Many practitioners use paste as a complement to cord rather than a replacement.
Q: Is epinephrine-impregnated retraction cord safe for patients with hypertension?
Epinephrine-impregnated cord should be used with caution in patients with uncontrolled hypertension, cardiovascular disease, hyperthyroidism, or those taking non-selective beta-blockers, MAO inhibitors, or tricyclic antidepressants. The CDA recommends reviewing the patient's medical history before using any epinephrine-containing retraction product. For medically compromised patients, non-epinephrine alternatives — ferric sulfate, aluminum chloride, or hemostatic paste — are preferred first-line options.
Q: What retraction cord size should a general dentist stock for routine crown preparations?
Two sizes cover the majority of cases: #00 (for anterior teeth and thin-biotype premolars) and #1 (for premolars and molars with standard sulcus depth). Adding a #000 provides a thin bottom cord for double-cord technique, and a #2 handles wide molar sulci. Most general practices can manage with #00 and #1 alone.
Shop hemostatic agents, retraction cord, and tissue management supplies at EBIKO Dental — free shipping on orders over $99 CAD in the GTA, $199 CAD in Ontario, and $299 CAD across Canada.