One of the basic goals of conservative dentistry is to preserve the health of the pulp as it is subjected to many insults such as caries, trauma, operative procedures, restorative materials.

Pulpal irritants can be classified as microbial, mechanical, chemical, thermal.

NEED FOR PULP PROTECTION

• mechanical protection during restorative procedures.
• barrier to the chemical components of restorative materials.
• thermal protection against temperature changes in the pulp .
• electrical protection against galvanic currents.
• pulp medication to allow the recovery of the pulp in case of deep defects.
• adequate seal at the restorative -tooth interface against bacterial ingress.

PULP PROTECTIVE AGENTS

CLASSIFICATION

• cavity sealers- cavity varnish, resin bonding agents.
• cavity liners
• cavity bases

CAVITY SEALERS: These are materials that provide a protective coating to the walls of the prepared cavity .They are applied to all the walls of the cavity and seal the interface between the restoration and the tooth . Eg: cavity varnish and resin bonding agents.

CAVITY VARNISH: A varnish is a natural gum or a synthetic resin dissolved in an organic solvent . Once it is applied to tooth surface the organic solvent evaporates leaving behind a protective film. Varnish is used beneath amalgam restoration to seal the amalgam tooth interface until corrosion product form to reduce the marginal gap. Thickness of varnish is 2-5 micrometer . They does not provide thermal protection and are contraindicated for GIC .

RESIN BONDING AGENTS: Currently the best method for the bonding composite resin to the tooth structure. Apart form adhesion it also provides cavity sealing. They are also employed for bonding amalgam restorations to reduce micro leakage .

CAVITY LINERS :They are used to provide a barrier against the passage of irritants from the cements or other restorative materials and to reduce the sensitivity of freshly cut dentin . They are usually suspension of calcium hydroxide in a volatile solvent . TYPES : TYPE III GIC , TYPE IV ZOE . Thickness is 0.5 mm

CAVITY BASES: A base is a layer of cement placed beneath the permanent restoration to encourage recovery of the injured pulp and to protect it against numerous types of insults. TYPES : high strength bases and low strength bases .

HIGH STRENGTH BASES provide thermal protection for pulp and mechanical support for the restoration . Eg : zinc phosphate , zinc polycarboxylate, RMGI, GIC

LOW STRENGTH BASES have minimum strength and rigidity . act as a barrier to irritation , chemicals and to provide therapeutic effect to pulp.Eg calcium hydroxide . ZnOE .

REFERENCE : STURDEVANT’S 7TH EDITION

ASHTINDER 🖊