Quartz 4

W1 Liners and Bases

5 min read

Liners1

Liners are materials that are placed as a thin coating (usually 0.5 mm) on the pulpal surface of a cavity preparation.

  • Although they provide a barrier to chemical irritants, they are not used for thermal insulation or to add bulk to a cavity preparation.
  • Furthermore, these materials do not have sufficient hardness or strength to be used alone in a deep cavity

Classification2

Thin liners:

  • Solution liners (varnish)
  • Suspension liner
  • Bonding agent

Thick liners (cement liners):

  • Hard setting calcium hydroxide cement
  • Light cured calcium hydroxide
  • Low viscosity type IV zinc oxide eugenol cement
  • Resin modified glass ionomer cement

Calcium Hydroxide3

Properties

  • Low thermal conductivity
  • Stimulates the production of irregular secondary (tertiary) dentine
  • pH of 11–12 (i.e. alkaline)
  • Bactericidal properties

Advantages

  • Easily manipulated
  • Stimulates the formation of irregular secondary (tertiary) dentine

Disadvantages

  • Moisture sensitive
  • Low strength

Indications

  • For use with direct or indirect pulp capping
  • Only used when within 1–2 mm of pulp or direct pulp capping
  • May be used underneath a base

GIC and RMGIC lining cements (resin modified GIC)4

Advantages of GIC and RMGIC

  • can bond to the dentine
  • releases fluoride
  • is radio-opaque

RMGIC Specifics

  • it has greater cohesive strength than conventional GIC
  • it is light cured ⇒ control setting time
  • Not suitable for direct pulp capping

Additional Notes

  • Vitrebond - Resin modified GIC
  • For tooth-coloured restorations, you need to use dentine conditioner prior to placing the GIC and RMGIC
  • The resin present in the liner can bond to the composite restoration above it as well as the dentine underneath it

Ledermix5

  • Used to calm down an inflamed pulp causing pain
  • Two versions - Do not get confused
  • LEDERMIX PASTE: used in endodontics and never sets!
  • LEDERMIX CEMENT: used as a liner in restorative and does set!

Odontocem6

  • calcium silicate-based cement
  • provides a biocompatible layer advantageous for successful direct pulp capping
  • Contains 0.2% triamcinolone acetonide, a potent steroid, to provide transient relief of pain
  • Low dose of the steroid Inflammatory response required for the formation of the dentinal bridge is only temporarily delayed.

Suspension liners7

  • Calcium hydroxide and zinc oxide in resinous solution, but greater film thickness than varnish
  • Film thickness still not sufficient for thermal or electric insulation

Image Description: A syringe containing PULPDENT Paste (Calcium Hydroxide Pulp Capping and Canal Treatment Paste 3ml) is shown on the right side of the slide.

Calcimol LC8

  • Light cured Calcium hydroxide: Urethane dimethacrylate (UDMA) + Calcium hydroxide + low viscosity monomer

Clinical application9

FIG. 13.43 A, Cavity preparation of tooth 30 before placing cavity liner. B, Preparation after placement of cavity liner.

Application Guidelines10

  • The liner material should be added only to one aspect of the ball end of the applicator
  • When the liner material is applied to the pulpal floor, keep it off the walls and out of any macro-mechanical retention

Vitrebond or Dycal or both?11

  • Dycal has low compressive strength and is soluble, so it benefits from being covered with a stronger, more durable material like Vitrebond.
  • Vitrebond provides a better seal, helping to bond the restoration to the tooth structure, and releases fluoride, which can further protect the tooth.
  • Liners approx. 0.5mm thickness
  • Calcium hydroxide liner illustration.

Detailed Application Steps12

  • Applying a Dental Liner Preparation: Ensure the cavity is clean and dry.
  • Selection: Choose an appropriate liner material, such as calcium hydroxide or glass ionomer.
  • Application: Use a Dycal Applicator.
  • Calcium Hydroxide: Apply a thin layer over the exposed dentine/pulp (if pulp capping) using a small applicator.
    • This material helps in dentinal sealing, pulpal protection, and stimulates the formation of secondary dentine.
  • Glass Ionomer: Apply a thin layer to provide additional benefits like fluoride release and chemical bonding to the dentine.
  • Curing: light cure if required

Bases13

Applying a Dental Base

  • Selection: Choose a base material, such as zinc oxide eugenol, glass ionomer, or resin-modified glass ionomer.
  • More commonly used under amalgam restorations.
  • 1-2mm thickness – to replace lost dentine; thermal protection for pulp

Application:

  • Zinc Oxide Eugenol: Mix the material and apply a relatively thick layer on the floor of the cavity preparation. This material provides thermal insulation and absorbs occlusal forces.
  • Glass Ionomer: Apply a thicker layer to protect the pulp and provide thermal insulation.
  • Curing: light cure if required.
  • Inspection: Ensure the liner and base are properly set and cover the intended areas.

Diagram of Base and Liner Application

ulation and absorbs occlusal forces.

  • Glass Ionomer: Apply a thicker layer to protect the pulp and provide thermal insulation.
  • Curing: light cure if required.
  • Inspection: Ensure the liner and base are properly set and cover the intended areas.

Diagram of Base and Liner Application

Footnotes

  1. Original PDF page 2: W1 Liners and Bases, p.2 ↩

  2. Original PDF page 3: W1 Liners and Bases, p.3 ↩

  3. Original PDF page 4: W1 Liners and Bases, p.4 ↩

  4. Original PDF page 5: W1 Liners and Bases, p.5 ↩

  5. Original PDF page 6: W1 Liners and Bases, p.6 ↩

  6. Original PDF page 7: W1 Liners and Bases, p.7 ↩

  7. Original PDF page 8: W1 Liners and Bases, p.8 ↩

  8. Original PDF page 9: W1 Liners and Bases, p.9 ↩

  9. Original PDF page 10: W1 Liners and Bases, p.10 ↩

  10. Original PDF page 11: W1 Liners and Bases, p.11 ↩

  11. Original PDF page 12: W1 Liners and Bases, p.12 ↩

  12. Original PDF page 13: W1 Liners and Bases, p.13 ↩

  13. Original PDF page 14: W1 Liners and Bases, p.14 ↩

Graph View