I am excited to start discussing clinical cases and examples of orthodontic treatment. I will discuss the diagnosis of the cases and their treatment plans. I will also show the results from cases. I will be discussing various orthodontic issues in each of the blogs and will assemble a comprehensive treatment library for the reader to refer back to and learn from. Let’s begin with early orthodontic treatment, specifically, anterior crossbites.
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Just like the cover of a box, upper teeth should cover all the teeth in the lower arch. When the arch of the upper teeth are narrow in dimension compared to the arch of the lower teeth, either the front, the back, or all the teeth will be in “cross bite”. The orthodontist can identify crossbites at early age by examining the patients’ bite as they function and shift the jaw to find a comfortable bite. A functional shift of the jaw due to a crossbite is a significant orthodontic problem and if left untreated in a growing patient can lead to an imbalance in jaw growth. Early treatment is highly recommended.
A crossbite involving the front teeth is an ANTERIOR crossbite. A crossbite of the back teeth is a POSTERIOR crossbite. Each of these discrepancies in bite can be due to a SKELETAL or a DENTAL imbalance. Proper diagnosis is key to devise the proper treatment plan. The image on the right is of a posterior crossbite.
In this image – one of the upper front teeth is misplaced behind the lower front teeth. This is an ANTERIOR crossbite. The front tooth is tipped towards the tongue. This is a DENTAL crossbite.
You can see an indentation (blue arrow) in the gum tissue above the patients upper right front tooth. This was from a baby tooth that was over-retained and did not fall out as the adult tooth was erupting. Therefore the upper right adult central incisor tooth was deflected towards the tongue and grew in behind the lower teeth. If the baby tooth was pulled out earlier, the upper tooth may have grown into the proper position.
It can also be seen that the root of the patients lower right central incisor is being pushed forwards (green arrow). This can lead to recession of the gum tissue around the lower central incisor. Other reasons to treat this condition at an early age is increased tooth mobility and risk of improper tooth wear. Correction of an anterior crossbite is important at an early age.
These are two more examples of anterior crossbites that involve more teeth.
As was mentioned before, some crossbites are due to imbalances in skeletal growth (top images). This can be diagnosed from x-rays of the upper and lower jaws (the cephalometric x-ray). Growth modification and orthopedic appliances are needed to address this problem.
The bottom example shows a dental crossbite since some of the front teeth are in the correct orientation while some teeth are not. Simple tipping of the front teeth in crossbite is all that is needed to correct the crossbite.
A removable appliance (that looks like an orthodontic retainer) can be custom made to move one or more teeth. The appliance can also be designed to widen the dental arch. Both anterior and posterior crossbites can be corrected. There are clasps in the back of the appliance to hold it in the mouth. It is important to not play with the appliance otherwise these clasps will become loose. The springs in the front of the appliance are designed to tip the teeth in to position. The screw in the middle is opened/widened at home with a special key and can correct the posterior crossbite. Generally, these appliances are worn 20-22 hrs/day and taken out to brush, floss, and eat. Always put your appliance in your retainer case so it doesn’t get lost when it is not in your mouth! Monthly activations with the orthodontist is required to efficiently move the teeth.
A tongue depressor is one of the simplest removable appliances. In order to move a tooth, a force needs to be applied in the correct direction and for sufficient duration. For a tongue depressor, the patient is to use the tongue depressor for approximately 20-40 minutes per day when watching TV, reading, on the internet. The crossbite can be correct in 2 weeks and sometimes takes 2 to 3 months.
In this example of a very mild crossbite, where the patient can still bite the front teeth together and the patient shifts in to a crossbite, the tongue depressor was able to move the front teeth forwards.
It is important for the orthodontist to realize that a shift in the lower jaw is important to correct and once eliminated, the teeth will sit in their correct position.
Here is a before and after picture of the anterior dental crossbite presented earlier. This correction was accomplished in about 3 months and the patient is about 7 years old. We will follow-up with patients until all of the adult teeth are erupted and re-evaluate for full treatment to close any spaces and align the teeth when the patients are about 12 years old. Sometimes this correction is all that is needed for the patient and the rest of the adult teeth grown in to an acceptable position. Generally, future treatment is only needed if there is an esthetic issue and the patient and parents can make a decision for future treatment. If a functional deficit is not corrected at an early age, future orthodontic treatment is necessary.
Here is what the removable appliance looks like when it is in the patient’s mouth. The pads in the back of the appliance are key to allowing us to quickly correct the crossbite by taking away overlap of the front teeth.
Retainers are recommended to be worn 20-22 hours per day.
After the bite is corrected, the retainer is generally worn at night. The retainer is taken out to eat and when brushing.
The retainer will fit until the baby teeth start to fall out. Then, generally, the retainer is no longer needed.<