Final answer:
The terminal plane of the primary dentition is determined by the distal surfaces. This refers to the sides of the teeth that face toward the back of the mouth and is used to ascertain the vertical dimension of occlusion for the proper bite alignment.
Step-by-step explanation:
The surfaces used to determine the terminus or terminal plane of the primary dentition is the distal surfaces.
In dental terminology, the distal surface refers to the side of the tooth that is away from the midline of the dental arch. It is the surface that faces toward the back of the mouth. In the context of deciduous, or primary, teeth, which are the first set of teeth that erupt in human development, the distal surfaces of the most posterior teeth (usually the second primary molars) are often used as a reference point to determine the vertical dimension of occlusion. This is important for establishing proper bite alignment and for planning orthodontic treatment.
Throughout the human lifespan, teeth emerge in stages. Deciduous teeth typically appear during infancy, followed by the emergence of permanent teeth during childhood. The last to emerge are usually the wisdom teeth, which can appear in early adulthood, although sometimes they remain impacted and require surgical removal.