Final answer:
The type of tooth is not in the primary dentition but found only in the permanent dentition is: 3) Premolar.
Step-by-step explanation:
The human dentition consists of two sets of teeth over a lifetime. The first set, known as the primary dentition, typically includes 20 baby or deciduous teeth that emerge beginning around 6 months of age. These are replaced by a larger set of permanent teeth, which includes 32 teeth and features types of teeth that are not found in the primary set. The types of teeth included in the human mouth are incisors, canines (also known as cuspids), premolars (also referred to as bicuspids), and molars.
When comparing the primary and permanent dentitions, the notable difference is the presence of premolars in the permanent set. Children's primary teeth include incisors, canines, and molars, but do not have premolars. Upon reaching middle childhood, the permanent teeth replace the primary teeth and add the premolars to the mix. Therefore, the correct answer to the question is that premolars (option 3) are not found in the primary dentition but only appear in the permanent dentition.