Casting Investments and Refractory Die Materials | American Dental Association

Casting Investments and Refractory Die Materials

ANSI/ADA Standard No. 126 Executive Summary

What is ANSI/ADA Standard No. 126 about?

This standard provides the requirements for dental casting investments and refractory die materials used in the dental laboratory. It classifies such products into types and classes, according to their intended use and the burn-out procedure recommended by the manufacturer. It also specifies requirements for the physical and mechanical properties of the products, instructions for use and labeling.

What are the requirements I should know about investments and die materials?

The standard classifies dental casting investments and refractory die materials into the following types:

  • Type 1
    For the construction of inlays, crowns and other fixed prostheses
  • Type 2
    For the construction of complete or partial dentures or other removable appliances
  • Type 3
    For the construction of casts used in brazing procedures
  • Type 4
    For the construction of refractory dies

The instructions for use shall include the product classification, intended use, type of binding system used, recommended investing techniques and instructions for burn-out or firing procedures. If the product contains silica as the refractory phase in a concentration above 1%, the instructions shall carry specific labeling and instructions for silica as a hazardous material. In addition, the material must meet the following requirements:

  • Fluidity
    Must not vary by more than 30% of that stated by the manufacturer
  • Setting time
    Must not vary by more than 30% of that stated by the manufacturer
  • Compressive strength
    Not less than 70% of that stated by the manufacturer
  • Linear thermal dimensional change
    Must not vary by more than 30% of that stated by the manufacturer

What’s the bottom line?    

ANSI/ADA Standard No. 126 provides the requirements for the physical and mechanical properties of dental casting investments and refractory die materials for use in a safe and effective manner in its intended application. Labeling and instructions for materials that contain silica must have additional warnings and instructions for hazardous materials and care must be taken in handling them.