Which characteristic property of irreversible hydrocolloid (alginate) is its primary disadvantage as an impression material?

Correct answer: B. Low tear strength

• A. INCORRECT — Alginate is actually one of the LEAST expensive impression materials, which is one of its main advantages.
• B. CORRECT — LOW TEAR STRENGTH is the primary and most clinically significant disadvantage of alginate (irreversible hydrocolloid). It tears easily when removed from the mouth, especially from undercuts, compromising impression accuracy.
• C. INCORRECT — Alginate has a relatively SHORT and controllable setting time, which is considered an advantage.
• D. INCORRECT — While alginate is not the most dimensionally stable material (it undergoes syneresis and imbibition), its dimensional accuracy at the time of pouring is acceptable for study models; tear strength is the more fundamental limitation.