This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
[{'content': 'The cavity varnish applied reduces post operative sensitivity in amalgam restoration by: \nSelect and explain. \nA. Decreasing conduction of heat to pulp, B. Minimize marginal leakage around restoration, C. By altering the chemical composition of restoration materials, D. By preventing penetration of corrosion products into the dentinal tubules', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Varnish reduces the infiltration of irritating fluids through marginal crevices and lessens pulpal\xa0irritation. Varnish\xa0is\xa0also\xa0claimed\xa0to\xa0prevent\xa0the penetration of corrosion products of amalgams into the dentinal tubules, thereby reducing the unsightly tooth discoloration often associated with amalgam restorations.\nPhillips 12 ed page 314', 'role': 'assistant'}]