Final answer:
Not all premolars have exactly two cusps; there can be variations. Typically, premolars are bicuspids designed for mashing food, with two on each side of the upper and lower jaws, but dental anatomy can vary among individuals.
Step-by-step explanation:
False, not all premolars have two cusps; while many do, variations can occur.
The term premolars, also known as bicuspids, generally indicates teeth with two cusps designed for crushing and mashing food. Typically, premolars are located posterior to the cuspids—or canines—and anterior to the molars. However, in human dentition, there can be exceptions based on genetic variations or evolutionary traits where a premolar might have more or fewer than two cusps. For instance, the upper first premolars often have two cusps, but the lower first premolars sometimes have just one prominent cusp or sometimes more.
The typical dental formula for humans includes eight premolars in total, with two on each side of the upper and lower jaws. Premolars play a significant role in the mastication process by transferring food to the molars for further grinding before swallowing. The number of cusps on a premolar can influence the effectiveness of this process. It is noteworthy that variations in dental anatomy can be common and therefore, stating that all premolars have exactly two cusps would be an oversimplification.