Slight shift in bite

I was told by our pediatric dentist that our 6-1/2 year old son has a slight shift in his bite and will need an expander to correct this. How soon do you recommend that he get fitted with this appliance? I had an expander when I was younger and it hurt like hell each time my mother cranked it with a key. I am not looking forward to doing this to my much younger son.

What does the device look like and does it hurt when it is fitted or afterward? My dentist mentioned a new appliance that works with the body's own heat and does not need to be 'cranked' with a key. Are there limitations to who can use this? Is there anything else new out there is this area?


Dear Linda,

Does a "slight shift in the bite" mean your son has a crossbite (lower teeth overlap upper teeth)? If so, the treatment plan will also be based on whether or not it is an anterior or posterior crossbite, if it is caused by a skeletal discrepancy, or if it is caused by a tooth discrepancy.

An anterior crossbite caused by tooth discrepancy should be treated as soon as possible so no damage is caused to the misplaced tooth. This may require either a removable appliance (retainer with springs attached to move tooth) or bands and wires.

Linda, posterior crossbites can be more complicated to diagnose and treat. If it is a unilateral (one-sided) crossbite, an careful examination should be done to determine if it is a true crossbite or one caused by a premature contact between opposing teeth. If the midlines are deviated and the arch is asymmetrical, this is more of an indication of a true crossbite. With the primary teeth, if the occlusal surfaces (biting surfaces) of the teeth are in contact, not much is gained by correcting the crossbite at this time because the permanent teeth will not always erupt in the same position. If the 6 year old molar is erupted in crossbite and no other occlusal problems are detected, however, the molar position should be corrected.

If it is a bilateral posterior crossbite, an exam needs to determine if the crossbite is accompanied by a shift in the jaw upon closing the teeth together. If there is no shift in the jaw, it is a nonfunctional crossbite. If there is a shift in the jaw, it is a functional crossbite. Treatment of the bilateral nonfunctional crossbite should be deferred until about 9 or 10 years old during the late mixed dentition stage (stage when both primary and permanent teeth are present). Because there is no assurance the permanent teeth will erupt in proper position, if treatment is deferred until 9 or 10, uninterrupted orthodontic treatment can occur. If it is a functional bilateral crossbite, early treatment is preferred. This may help alleviate any possible problems with skeletal or muscular asymmetry.

To create proper skeletal and tooth position during treatment of bilateral crossbites, rapid palatal expansion with a fixed appliance is recommended. Expansion is usually complete within 1-3 weeks. There is a small lever arm which is used to adjust the screw, and all it takes is about a quarter turn once or twice a day. Then the appliance is left in place for 3 months for retention. Afterward, a retainer can be made for retention for another year. Generally, with only quarter turn, children are not too uncomfortable. Also, it is only for a short time period which helps. The device itself is attached to the most posterior erupted molars and additional bands can be attached to the primary canines. The small screw is attached to the bands by wires and acrylic with an opening down the middle of the palate for the screw to be opened. When first placed, the appliance may feel a little uncomfortable until the child gets used to it being there. Once the expansion is completed, there should be no discomfort. This appliance is quite effective.

I am not aware of the "new" appliance which uses body heat, but it sounds interesting. I am sure there are some limitations as to who can or cannot use this type of appliance. While you may have bad memories regarding this, some improvements have been made, and you should remember, this will be the best (and probably least expensive) long-term treatment for your son.

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