Green Stick Impression Compound: Dental Laboratory Uses

Green Stick Compound (also called low-fusing impression compound or pressure-indicating paste) is a thermoplastic material used in prosthodontics and dental laboratory procedures to record and adjust occlusal contacts.

Composition & Properties

• Base: Natural resins (colophony/rosin), waxes (beeswax, paraffin), fats (stearic acid), and filler (talc, kieselguhr).
• Colorant: Green dye (traditionally copper phthalocyanine) for visibility on teeth/models.
• Softening Point: 45–65°C (113–149°F) — lower than Type I impression compound (70–80°C).
• Form: Sticks (kneadable), cakes, or ribbons.
• Behavior: Softens in flame or hot water; flows under pressure; hardens on cooling. Does not melt or burn if heated correctly.

Primary Uses

1. Occlusal Contact Recording (Articulator): Placed between maxillary and mandibular casts on an articulator. When the casts are closed, the compound flows at premature contact points, creating thin marks that reveal high spots needing adjustment.
2. Try-In Verification: Used intraorally (on a trial denture or framework) to check occlusal contacts before final processing.
3. Border Molding Aid: Occasionally used to modify impression tray peripheries for functional impression.
4. Bite Registration (limited): For short spans; less dimensionally stable than silicones or wax bites.

Advantages

• Inexpensive, reusable (re-kneadable), easy to manipulate.
• High contrast green marks on plaster/stone models or teeth.
• Flows at low pressure, revealing premature contacts accurately.

Limitations

• Brittle when cold; can fracture if thin.
• Dimensional changes with temperature/humidity.
• Not for final impressions (use alginate, silicone, polyether).
• Messy; requires flame/water bath.

In modern practice, articulating paper, foil, or digital occlusion systems (T-Scan) often replace it for intraoral checks, but it remains a staple in the dental lab for cast articulation verification.