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': 'Modifications of bur design does not include which of the following? \nSelect and explain. \nA. Increased use of crosscuts, B. Extended heads on fissure burs, C. Rounding of sharp tip angles, D. Small diameter sizes', 'role': 'user'}, {'content': "Answer: A \nExplanation: As the effectiveness of small burs has increased, they have replaced larger burs in many procedures.\nThree other major trends in bur design are discernible:\n\nReduced use of crosscuts\nExtended heads on fissure burs\nRounding of sharp tip angles.\xa0\n\nCrosscuts are needed on fissure burs to obtain adequate cutting effectiveness at low speeds, but they are not needed at high speeds. Because crosscut burs used at high speeds tend to produce unduly rough surfaces, many of the crosscut sizes originally developed for lowspeed use have been replaced by noncrosscut instruments of the same dimension for high-speed use.\nRef: Sturdevant's art and science of operative dentistry. 4th edition page 333", 'role': 'assistant'}]