Dental Impression

 Alginate is an irreversible hydrocolloid impression material derived from seaweed, used primarily for taking fast, accurate, and economical preliminary impressions in dentistry. Valued for its ease of mixing, patient comfort, and good surface detail reproduction, it is the standard for creating study models, diagnostic casts, and custom trays. Its critical limitation is poor dimensional stability due to its water-based nature, requiring the impression to be poured in stone immediately to avoid shrinkage. As a hydrophilic material, it is technique-sensitive but remains an indispensable workhorse for initial records in general practice, orthodontics, and prosthodontics.