Great article from Dunegan Orthodontics on Common Orthodontic Problems.
duneganorthodontics:
Underbite
An underbite is characterized by the lower jaw extending out, causing the lower front teeth to sit in front of the upper front teeth.
Spacing
Spacing problems may be caused by missing teeth, or they may only be a cosmetic or aesthetic issue.

Upper Front Teeth Protrusion
The…