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': 'Ackerman Proffit classification - outer envelope represent: \nSelect and explain. \nA. Alignment, B. Profile, C. Transverse relation, D. Vertical relation', 'role': 'user'}, {'content': 'Answer: A \nExplanation: ACKERMAN-PROFITT SYSTEM\xa0OF CLASSIFICATION\nCHARACTERISTIC 1 - ALIGNMENT\nIntra-arch alignment and symmetry are assessed as when seen in the occlusal view. A dental arch is classified as ideal/crowded/spaced.\nCHARACTERISTIC 2 - PROFILE\nThe profile can be convex/straight/concave. This also includes the assessment of facial divergence, i.e., anterior or posterior divergence.\nCHARACTERISTIC 3 - TRANSVERSE RELATIONSHIPS\nThis include the transverse skeletal and dental relationships. Buccal and palatal crossbites are noted. These are further subclassified as unilateral or bilateral. Distinction is made between skeletal and dental crossbites.\nCHARACTERISTIC 4 - CLASS\nHere the sagittal relationship of the teeth is assessed using the Angle classification as Class I/Class II/Class III. A distinction is made between skeletal and dental malocclusions.\nCHARACTERISTIC 5-OVERBITE\nMalocclusions are assessed in the vertical plane. They are described as anterior open bite/posterior open bite/anterior deep bite/posterior collapsed bite. Here, again a distinction is made as to whether the malocclusion is skeletal or dental.', 'role': 'assistant'}]