The main disadvantage is that alginate has a very poor dimensional stability. That is mainly due to the ingredient list. There is a slight evaporation that leads to shrinkage of the material. Dentists and dental technicians should pour the mold as soon as possible. Since the material has a low strength it is susceptible to tear. Alginate impressions have to be done with at least 3mm of material in every area. It is not recommended for cases where the dentist needs a high accuracy. They have a low adhesion power, so if the tray is not perforated, the dentist has to use additional measures to provide adhesion.
Uses:
Dentists usually use alginate materials to take preliminary impressions for dentures. Another widespread use is for patients that produce a lot of saliva. Dental arches with undercuts are also a strong indication of an alginate impression. Partial dentures with clasps are also often based on an alginate impression. Other uses include a mold for inspection, diagnosis and planning, mold from opposing teeth, duplicate molds and more.