Tooth 108 is the fourth premolar in the maxillary arch.
According to the provided reference, in the maxillary arch:
- First premolars (105, 205) have 1 root.
- Second and third premolars (106, 107, 206, 207) have 2 roots.
- Fourth premolars (108, 208) and first and second molars (109, 110, 209, 210) have 3 roots.
This clearly identifies tooth 108 as the fourth premolar.
