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': 'Foam based fluoride solution has the following advantage EXCEPT- \nSelect and explain. \nA. Minimize the risk of fluoride over dosage, B. It is much lighter than a conventional gel, C. The surfactant in the foaming agent has a cleansing action by increasing the surface tension, D. Used in patients where saliva evacuation may not be feasible.', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Foam based agents were developed in an attempt to minimize the risk of fluoride over dosage as well as to maintain the efficacy of topical fluoride treatment. The advantages of foam - based APF agents are :\n1. It is much lighter than a conventional gel and therefore only a small amount of the agent is needed for topical application.\xa0\xa0\n2. The surfactant in the foaming agent has a cleansing action by lowering the surface tension. This also\xa0 may\xa0 facilitate the\xa0penetration\xa0 of\xa0 the\xa0 material\xa0 into interproximal surfaces where its action is most needed.\xa0\n3. Since\xa0 APF\xa0 foam\xa0 does\xa0 not\xa0 require suctioning, it offers advantages for home use as well as for the treatment of young\xa0children and\xa0 disabled\xa0 persons where saliva evacuation may not be feasible.', 'role': 'assistant'}]