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': 'Finish line in acrylic jacket crown is: \nSelect and explain. \nA. Shoulder, B. Shoulder with bevel, C. Radial shoulder, D. Exaggerated chamfer', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Shoulder\n\nIt is a right-angled finish line.\nProduces a wide ledge which resists compressive occlusal forces.\nRequires more preparation, hence it is not conservative.\nIndicated for ceramic restorations – all ceramic and metal ceramic (where ceramic forms the margin).\nIt is prepared using a flat-end tapering diamond. This is produced by sinking in the entire diamond into the tooth. The tip produces the shoulder while the sides give the necessary taper to the axial surface. End-cutting diamond is used to finish the shoulder. It has a cutting tip and noncutting sides.\nSharp internal line angle can produce stresses in all-ceramic crowns\n\nKey Concept:\nFinish line in acrylic jacket crown is butt shoulder ﬁnish line with 0.5 mm width around the entire\xa0 tooth.\nRef: Textbook of prosthodontics V Rangarajan Ed. 2nd', 'role': 'assistant'}]