It depends. As with any orthodontic treatment plan, the decision to extract teeth (premolars or otherwise) depends on a few factors:
1) The patient's presenting complaint: if there is concern about protruded upper front teeth, then extractions may be considered to gain space to correct the incisor angulation.
2) The severity of crowding: the worse the amount of overlaps between the teeth, the more severe the crowding.
3) The bite pattern: a shallow overjet or overbite may require extractions to correct crowding without worsening
4) The presence of compromised teeth: very severely decayed, extensively repaired or root canal-treated teeth may be removed preferentially if the treatment plan requires extractions.
5) To camouflage an underlying skeletal proportion issue non-surgically. For example, removing 2 upper premolars for a patient with an underlying skeletal class 2.
Other options for space creation without extractions include distalization and interdental reduction (IPR). These options may be suitable for a case that does not have high space requirements (on the mild/moderate end of the spectrum).
The aim of orthodontic treatment is NOT to eliminate overbite and overjet but to optimise it. Having an overbite and overjet is IDEAL at the end of any orthodontic case, so each case has to be judged individually.
