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': 'Cavity varnishes have: \nSelect and explain. \nA. average bonding to tooth, B. low bonding to tooth, C. excellent bonding to tooth, D. no bonding to tooth', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Cavity varnish is a solution of one or more resins which when applied onto the cavity walls, evaporates leaving a thin resin film, that serves as a barrier between the restoration and the dentinal tubules.\nVarnishes neither possess mechanical strength nor provide thermal insulation because of the thin film thickness. The film thickness ranges from 2 to 400 µm. The solubility of dental varnishes is low; they are virtually insoluble in water.\n\nRef- Manapallil 3rd Ed P:81', 'role': 'assistant'}]