made by ai : Fixed Prosthodontics II - Post and Core

Coronal Tooth Structure Loss & Survival

Teeth with

10-Year Survival: Crown vs. Direct Restoration

Endodontically treated teeth restored with crowns have 91% survival vs 76% for direct restorations.

Purpose of a Core

Replaces missing coronal structure to provide retention and resistance for the final crown.

Indication for a Post

Indicated when there is inadequate coronal structure to retain a core. (Does NOT reinforce the root).

Required Apical Gutta-Percha Seal

At least 4 to 5 mm of apical gutta-percha must be retained.

Ideal Post Length Ratio

Equal to the length of the clinical crown (1:1 ratio) to minimize failure and leverage forces.

Ferrule Dimensions

Minimum 1.5 mm vertical height and 1 mm dentin thickness circumferentially (360°).

Methods to Increase Ferrule Height

Crown lengthening, forced orthodontic eruption, or subgingival margin placement.

Advantages of Cast Post and Core

Custom-fit to root configuration and adaptable to large or irregularly shaped canals.

Indications for Prefabricated Posts

Multi-rooted teeth with relatively circular canal cross-sections.

Strength Order of Core Materials

Amalgam > Composite Resin > Silver-modified Glass Ionomer Cement.

Eugenol Effect on Resin Cements

Eugenol poisons the catalyst and inhibits free-radical polymerization of resin cements.

NaOCl Impact on Bonding

Leaves residual oxygen and oxidizing byproducts that inhibit resin polymerization.

Role of Clearfil DC Activator / Sodium Ascorbate

Neutralizes residual oxidants from NaOCl prior to resin bonding.

Function of 10-MDP Monomer

Provides ionic bonding with calcium in hydroxyapatite via its phosphoric-acid ester group.