Dental Silica sol: A Is applied to the walls of the investment to produce hygroscopic expansion B Increase the strength and the setting expansion of the phosphate-bonded investments C Acts as a retarder in the silica bonded investments D Acts as a refractory in the silica bonded investments 💡 Explanation Silica sol: ✓ Correct Answer: B. Increase the strength and the setting expansion of the phosphate-bonded investments