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': 'In which of the following situations can air abrasion not be used? \nSelect and explain. \nA. Caries excavation, B. Debriding pits and fissures, C. Cavity preparation, D. Stain removal', 'role': 'user'}, {'content': "Answer: C \nExplanation: Although promoted for caries excavation, air abrasion is not able to produce well-defined preparation wall and margin details that are possible with conventional rotary cutting techniques.\nRef: Sturdevant's art and science of operative dentistry. 4th edition page 328", 'role': 'assistant'}]