Tongue Thrusting, Open Bites And Orthodontic Treatment
In the May 2010 issue of The American Journal of Orthodontics appears a study by Smithpeter and Covell which analyzes the relationship between orthodontic patients who tongue thrust and open bite of the front teeth. In this context , open bite means the front teeth are apart when the back teeth bite. Vertical overlap of the front teeth is termed overbite whereas open bite ( also termed reverse overbite ) can be related to a growth discrepancy of the jaws and/ or tongue thrusting. When swallowing or at rest, the tongue should NOT be positioned between the front teeth.
We have seen open bites in the front and / or on one or both sides. Relapse or recurrence after orthodontic treatment does happen even when jaw surgery has been undertaken in conjunction with braces. There seems to be a correlation among tongue thrusting, mouth breathing, nasal airway obstruction, narrow upper jaws with crossbite tendencies and open bites though this study speaks only to thrusting and open bites.
In this study, 76 orthodontic patients with open bites 27 of whom ( experimental group) received myofunctional therapy (tongue placement therapy) before, during or after their braces and 49 of whom did not (control group ) were compared with respect to how well their cases stabilized after treatment. The differences were highly statistically significant and as we would predict, those who underwent therapy were more stable.
What does this mean for patients?
Tongue placement issues can effect dental development and even the shape of the arches
Early intervention is warranted in an effort to prevent serious bite issues later on
Intervention with a myofunctional therapist or MFT (
in our experience a speech therapist with specialized training) and/ or
the orthodontist ( appliance based therapy or APT) may be indicated
MFT is subjective by nature. Younger patients seem to do better with
APT though it provides only for negative reinforcement while MFT holds
open the possibility of retraining tongue position . Unfortunately,
relapse of the thrusting can unpredictably occur with either approach
and should be continually monitored after treatment for years. In our
practice, we sometimes design special removable retainers fitted with
prongs to remind the tongue to stay away from the teeth. They are
generally effective if worn as prescribed. Additionally, while we avoid
removable retainer wear during the day in favor of bonded retainers (
check out our website for examples and details), in thrusting patients
we sometimes design a removable palatal stent to maintain the width of
the upper jaw.
When allergy or nasal airway obstruction (
enlarged tonsils, adenoids, turbinates or deviated septums for example)
may be contributing factors to thrusting or mouth breathing, referral to
an allergist or ENT physician may be indicated. Such interdisciplinary
management can be challenging to maintain as not all healthcare
providers are familiar with the interrelationships that exist with
dental development and may require additional explanation from the
orthodontist. Interestingly, some orthodontists also do not recognize
these factors and fail to account for them in treatment planning their
cases. This study should reorient their thinking.
At Ziman
Orthodontics we are always asking ourselves why a patients case looks
the way it does and tongue thrusting is always in the backs of our minds
when we see open bites. We have routinely referred to myofunctional
therapists when indicated for over 20 years along with specialty
referral as needed.
Self Ligating Braces
Self ligating braces as a new technology have previously been reviewed under our New Technologies category. In the May 2009 American Journal of Orthodontics, authors Fleming, DiBase, Sarri and Lee compared the efficiency of aligning crowded lower front teeth on 66 consecutive patients using either conventional or self ligating braces from the same manufacturer. Results indicated that the efficiency of tooth movement was independent of bracket type. In other words, neither bracket demonstrated a superior ability to speed up treatment in these cases. It should be noted that per bracket cost of self ligating braces are 5-9 times that of conventional braces.
My own experience with self ligating brackets was somewhat frustrating in that over time, the engagement mechanism becomes looser and / or sticky with plaque, calculus and food debris making the insertion of the largest archwires needed to finalize the case problematic. In some cases, selected brackets required replacement near the end of treatment which is exactly what one does NOT want to be doing when attempting to finish up a case and is definitely not a timesaver.
