In permanent premolars, what is different about their eruption pattern?

• A. They erupt after primary molars are shed
• B. They rotate during eruption
• C. They develop between roots of primary molars
• D. They have no eruption pattern difference

Answer: (C)

Permanent premolars form in a unique location: their tooth germs develop in the jaw between the roots of the deciduous molars. This interproximal position means they erupt into the arch by moving into the spaces that open up as the roots of the primary molars are resorbed and those teeth are shed. In other words, premolars are replacement teeth for the primary molars, so their eruption pattern is defined by that development between primary roots, not simply by eruption after the primary molars have fully shed, nor by a notable rotational eruption. This interradicular development explains why their eruption sequence and positioning differ from other permanent teeth.