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': 'What should be the depth of grooves placed in occlusal surface of the tooth during tooth preparation? \nSelect and explain. \nA. At least 1.0 mm, B. At least 2.0 mm, C. At least 1.5 mm, D. At least 1.2 mm', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Guiding grooves for occlusal reduction\nA tapered carbide or a narrow, tapered diamond is recommended\xa0for\xa0placing\xa0the\xa0guiding\xa0grooves\xa0for occlusal reduction:\n\nPlace depth holes approximately 1 mm deep in the central, mesial, and distal fossae, and connect them\xa0so\xa0that\xa0a\xa0channel\xa0runs\xa0the\xa0length\xa0of\xa0the central\xa0groove\xa0and\xa0extends\xa0into\xa0the\xa0mesial\xa0and distal marginal ridge.\nPlace guiding grooves in the buccal and lingual developmental\xa0grooves\xa0and\xa0in\xa0each\xa0triangular ridge extending from the cusp tip to the center of its base.\n\nKey Concept:\nPlace depth holes approximately 1 mm deep in the central, mesial, and distal fossae, and connect them\xa0so\xa0that\xa0a\xa0channel\xa0runs\xa0the\xa0length\xa0of\xa0the central\xa0groove\xa0and\xa0extends\xa0into\xa0the\xa0mesial\xa0and distal marginal ridge.', 'role': 'assistant'}]