True skeletal expansion can only occur on the upper jaw. The upper jaw is made up of two bones that form the “cornerstone” of the face. Proper maxillary (upper jaw) expansion can effortlessly, with very little discomfort, push these bones apart, on a microscopic level, providing space for the future eruption of permanent teeth. The lower jaw is a single bone, consequently only the lower dentition can be expanded; i.e. the dentition is rounded out.
So, why do patients need expansion?
Expansion is often necessary to create enough room for erupting permanent teeth. Over 66% of young patients experiencing significant dental crowding have a narrow upper jaw. The choice is either extraction of baby and permanent teeth, or correct the real problem which is a narrow upper jaw. Note that future growth of the face does not correct the problem of a narrow upper jaw. A narrow upper jaw will always be narrow after the age of 7 unless corrected by an orthodontist trained in appropriate early treatment. A wide lower jaw is another reason to expand. A wide lower jaw cannot be made narrower orthodontically.
The younger the patient the better the skeletal expansion. Patients that are in the mixed dentition, 6 to 9 years of age, get better skeletal expansion than a patient that has all their permanent teeth in their teens. Teenagers, especially females, have achieved a significant amount of their facial growth, with very little growth remaining by the time they have a permanent dentition. Expansion is more difficult in patients that have expressed their full or near full facial growth since the sutures in the face have fused.
Proper upper jaw expansion takes experience, skill, and finesse. Just because someone says that they are expanding your child’s upper jaw doesn’t mean they possess the above three important requirements. The design of the appliance is as ultimately important as well as the skill of the practitioner and is the fourth requirement. An appliance that is removable cannot accomplish skeletal changes; all that is achieved is an outward tipping of the teeth. As soon as the appliance is removed, the teeth tend to tip back into place, resulting in little or no permanent dental change. Expansion appliances that are bonded in place, to multiple teeth, have the best results in positively changing the upper jaw and dentition. An appliance that is bonded in place means that they cannot be removed by the patient; resulting in the best chance for Orthodontics 101 significant orthodontic change.
Orthodontic expansion is less invasive compared to the extraction of teeth which is more traumatic, more expensive, and less effective.
Bradford N. Edgren DDS, MS, FACD, Diplomate, American Board of Orthodontics 3400 W. 16th St. Bldg 4-V, Geeley, CO 80634