Many young patients have upper and lower jaws which do not
fit together. Probably the most common
issue related to a poor fitting bite is a narrow upper jaw relative that
patient’s lower jaw. This narrowness can
be caused from overactive muscles of the face restricting the upper jaw
development (i.e. thumb-sucking, lip sucking), genetics (i.e. mom’s upper jaw
and dad’s lower jaw), and/or mouth-breathing (when a patient’s nasal air
passages are blocked frequently enough to prevent breathing through the
nose). Mouth breathing is particularly
common in regions with higher than average allergens such as Austin. When a patient breathes through their mouth,
the tongue rests on the floor of the mouth while the cheeks push inward from
the sides, thus constricting the upper arch of teeth. Compare this to breathing through the nose
which requires the tongue to be raised against the roof of the mouth, behind
and against all of the front teeth. With
the support of the tongue against the inside of the upper teeth, the force from
the cheek muscles is balanced and there is no tooth movement or resistance to
growth.
Once the upper jaw is too narrow to fit well with the lower
jaw (termed a crossbite), the lower jaw can shift to one side or the
other so at least some of the back teeth fit well. It will also constrict the development of the
lower arch causing severe crowding. If a
shift remains throughout growth, or the constriction remains, the lower jaw can
begin to grow more sideways, become asymmetric, and/or remain smaller creating
a long-term discrepancy between the size of the teeth and the size of the
arch. This is the reason crossbites
are corrected as soon as possible after the permanent first molars erupt,
around age 6 to 7. Expansion is
performed by pushing two bones of the upper jaw away from each other and
allowing bone to form in the middle. The
upper jaw bones are easily moved as a child but fuse in the late teens making
expansion increasingly less successful as the child becomes an adult.
Expansion can be successfully performed in all patients up
to age 15 (although side effect from years of ill-fitting jaws may not be
easily reversible). Past age 15, the
bones of the upper face begin to fuse and it becomes more difficult to expand
the upper jaw. After 18, most patient
will require surgery for expansion (the surgery simply re-opens the space that
used to exist between the bones).
Bonded Expander as it looks in the mouth. |
Typical bonded Expander (RPE) |
Dr. James R. Waters is a practicing Board Certified
Orthodontist in Austin, TX. He is a 1996
graduate from UTHSC Dental School in San Antonio, 1997 graduate of Advanced Dentistry
from the UNMC in Nebraska and the 2001 Valedictorian graduate from the
prestigious Saint Louis University Orthodontic Program receiving the J.P.
Marshall award for clinical excellence in 2001.
He holds a Bachelor’s Degree in Science, Doctorate in Dental Surgery, a
post-doctorate certificate in Advanced Dentistry, post-doctorate Degree in
Orthodontics & Dentofacial Orthopedics and a Master of Science Degree in
Orthodontics. Dr. Waters and his wife of
18 years live in Austin, TX with their 4 children where he has a thriving,
multi-faceted Specialist practice. You
can learn more about Dr. Waters at BracesAustin.com.
No comments:
Post a Comment