Normal Jaw Relationship
Both upper (grey) and lower (pink) jaws are in normal relationship to the skull.
Retruded Lower Jaw
The lower jaw usually lags behind when there are childhood allergies, thumb-sucking, and mouth breathing. This phenomenon develops very early in life and has to be identified before a child hits adolescence. Consequences are future TMJ problems, sleep apnea, tooth crowding and a poor facial profile.
Retruded Lower And Upper Jaws
When both upper and lower jaws are lagging behind, it causes a “flat face” profile. A lot of times this condition is created by the orthodontist as four healthy teeth are extracted to create space. Functionally and esthetically this condition is a disaster.
Collapsed Vertical Relationship
When the space between the upper and lower jaws is diminished, either through excessive tooth loss, excessive grinding, or just developmentally dictated, it will always be a downward trend unless it is reversed. The deep bite will get deeper with time, causing TMJ problems, more tooth wear and crowding, and sleep apnea. During the growth phase, it is easy to correct. In adults, the approach is slightly different.
More on orthodontics principles – Growth and Aesthetics…