Porosity measurements in four types of hand-mixed  cements  showed  that __________  cement had the highest porosity.: (A) Resin cement, (B) GIC, (C) Zinc phosphate cement, (D) Polycarboxylate cement
Answer is D. Porosity measurements in four types of hand-mixed cements showed that polycarboxylate cement had the highest porosity and resin cement had the least. Zinc phosphate and GICs had intermediate amounts of porosity.
Ref: Phillip’s Science of Dental Materials ed 12 pg 320