Broadening the smile - A dubious treatment
INTRODUCTION TO JAW EXPANSION:
The term jaw expansion refers to "widening" of the back teeth. In general, the upper set of teeth should fit around (outside) the lower set of teeth. As such, the upper jaw should be "wider" than the lower jaw.
The upper jaw is usually the one undergoing expansion. Expansion of the lower jaw is occasionally utilized, but a very unusual and dubious treatment.
Expanders can be fixed (glued in) or removable.
WHEN TO EXPAND:
Expansion is generally utilized when the upper jaw is too narrow to fit around the lower jaw. As such, the upper jaw is widened until it fits around the lower jaw.
Expansion can also resolve crowding by enlarging the circumference in the are of the front teeth. As circumference increases, the dental arch perimeter increases. An enlarged arch perimeter allows crowded teeth to align along the greater perimeter.
Broadening the Smile - A dubious treatment:
Expansion for any reason other than Posterior Crossbites or Crowding is dubious. While some doctors try to "broaden" the smile via expansion, this "broadening" is not supported by the literature in orthodontics. In fact, the literature would advise against "broadening."
Why not broaden? If no crossbites exist, and you expand the upper jaw, the upper jaw becomes too wide for the lower jaw. Therefore, the lower jaw must be expanded to fit the widened upper jaw. Widening of the lower jaw has a tendency to develop TMJ problems. Additionally, both jaws will be unstable and have a tendency to collapse back to their original position after treatment is complete.
AGE AND JAW EXPANSION:
Children with crossbites should be treated as early as reasonable (generally not earlier than 5 years old if possible). Since children are growing, crossbites tend to force the jaw into non-centered positions, and the jaw can grow off center during childhood growth. Additionally, crossbites of children results in TMJ problems over time.
Expanding the upper jaw of a child is straight-forward, because the upper jaw is soft and formable before the age of 16 years.
Adults with crossbites should also be treated, but some level of TMJ damage will be apparent on the jaw joints (sometimes debilitating damage).
Treating adults with crossbites can be different than treating children with crossbites. Adults with crossbites are not growing. As such, many orthodontists only expand adults with crossbites using "surgically assisted" jaw expansion. This involves a surgery that cuts down the center of the upper jaw.
Interestingly, most adults that undergo surgically assisted jaw expansion do not need a surgery to solve their crossbite! They do not need "jaw expansion." They often only need "dental expansion."
Adults should carefully select their orthodontist to avoid unnecessary procedures. Visit the Adult Orthodontics section to learn more about adult treatment.