Alginate-based impressions are attractive as orthodontic study models for a variety of reasons. These are fast setting at room temperature, easy to prepare, and very cost effective. The mechanism of action is based upon the reaction between a soluble calcium salt and soluble alginate (usually a sodium or potassium grade material).
Alginates high in guluronic acid typically provide high gel strength impressions. Alginates high in mannuronic acid content, on the other hand, will result in a softer or “pudding like” texture.