subject: Endodontic Materials, Cements And Liners Dental Materials [print this page] In restorative dentistry and prosthodontics, dental materials like bases, cements and liners are critical ingredients. A variety of these is available. After a cavity is prepared for treatment, there are chances of micro leakage which is the prime cause of bacterial infections. This often leads to an inflammation of the pulp causing tissue death. The dentist usually aims to minimize or completely stop micro leakage using endodontic materials to reduce sensitivity.
Sometimes, when tooth restoration is not done properly, there are chances of secondary caries, tooth discolouration and hairline fractures. This tends to happen where the restoration meets the cavity. It is therefore important to ensure that the seal at this meeting point is improved, so that micro leakages and replacements can be avoided. This can be done by using suitable restorative materials like cements and liners.
Choosing the right endodontic materials
The appropriate material depends on the specific patients dental condition and the remaining tooth structure. Dentists generally try to save the tooth as far as possible instead of removing it and trying to replace it with endodontic material.
The various options available in dental restoration products are:
Varnishes
Calcium Hydroxide
Zinc Oxide Eugenol and non Eugenol
Zinc Phosphate
Zinc Polycarboxylate
Glass Ionomer
Resin
Here is a brief overview of these:
Liners are commonly used as coatings after the cavity is prepared to be filled. They act as a barrier to prevent the infiltration of substances into the cavity but they do not insulate or add thickness. Liners are not hard or sturdy enough as standalone fillings in deep cavities. Examples of liners are Varnishes, Calcium Hydroxide, Glass Ionomers, and Resins.
Varnish is a gum or resin mixed in organic solvent. This is applied to the dentin in the tooth cavity where the solvent evaporates leaving the solute behind as a lining, sealing the area and minimizing micro leakage to prevent caries.
Calcium Hydroxide is considered suitable for capping the pulp as it aids in the progress of dentin growth. Another advantage is its resistance to bacterial growth.
Glass Ionomer or GI has been around for over three decades and has the ability to bond with the tooth structure, besides releasing Fluoride, which prevents caries formation. GIs are also antimicrobial and seal well, making them the preferred choice as cavity liners. An issue with GIs is their affinity for moisture, which lowers their physical attributes besides making them expand when exposed to water.
Resins are versatile with low solubility and come in a variety of shades and thicknesses. They tend to cost more and have limited shelf life and because of this, dentists prefer to use varnishes as cavity liners.
Bases are used as endodontic materials when dentin has been removed by caries or while preparing the cavity. They resist chemical irritation and condensation, insulating the cavity. They can be shaped and contoured easily.
Cements are used to hold a restoration or appliance in place, in addition to finding their use as restorative filling. They reduce micro leakage by sealing the space between the tooth and the restoration and can be temporary or final use.
Depending on where they are used, all of the above can be used as bases, cements or liners. Often the dentist will use more than one in the restoration procedure and this means taking care to see that the materials used are compatible with each other.
