Which of the following is considered as an accurate duplicating material?
DUPLICATING MATERIALS
Both types of hydrocolloids are used in the dental laboratory to duplicate dental casts or models for the construction of prosthetic appliances and orthodontic models. Agar hydrocolloid is more popular in the lab because it can be used many times. In addition, with intermittent stirring, agar hydrocolloid can be kept in a liquid form for 1 or 2 weeks at a constant pouring temperature. These factors make the cost of reversible impression materials quite reasonable.
These property requirements are identified in ANSI/ADA Specification No. 20 (ISO 14356; Dentistry—Duplicating material).
NOTE: Both alginate and agar are considered as accurate impression materials. Owing to the extensive use of agar as a duplicating material, agar can be a better choice.
Reference: PHILLIPS’ SCIENCE OF DENTAL MATERIALS, 12th ed page no 176
Agar
Alginate
Impression compound
None of the above