The Mechanics of an Upper and Lower Jaw Expander

Between the ages of six and 13, according to the American Dental Association (ADA) Mouth Healthy site, your child's baby teeth will be replaced by permanent teeth. Unfortunately, not every child's jaw is big enough to accommodate his adult set, resulting in crowding and misalignment. Removing a tooth as a part of orthodontic treatment is one solution, but an upper or lower jaw expander can make room for your child's permanent teeth without extraction.

Upper Jaw Expander

An upper jaw expander stretches the bone and cartilage of the palate in order to expand a growing child's arch and prevent crowding and cross bites. According to orthodontist Dr. Greg Jorgensen, successful palatal expansion treatment is done before the child's growth plate or midpalatal suture fuses – usually between ages 14 and 16.

Upper expanders are traditionally attached to the molars with metal rings, but they can be removable in certain cases. Expansion screws are built into the appliance, and when activated, slowly separate and stretch the soft cartilage of the palate over the course of several weeks or months. As expansion takes place, you may notice a gap form between your child's two front teeth; this indicates that the palate is actually expanding rather than the teeth just tipping outward.

An expander may feel bulky and uncomfortable at first, and when screwed outward, kids may feel pressure on their teeth, roof of their mouth and sometimes behind the nose and eyes. But the pressure will dissipate. After the expander is placed, your child may also have an excess of saliva, and speech may be affected as he adjusts to the feeling. Until the expander feels natural, serve foods that don't require a lot of chewing, such as yogurt, ice cream, pudding, soup or mashed potatoes. Also encourage your child to stay away from sticky foods and candy that may get stuck against the expander.

Lower Jaw Expander

Lower arches can also be expanded when teeth are crowded, but the function of a lower expander is different than that of the upper. Dr. Jorgensen explains that because the lower arch doesn't have a suture to close, the bone cannot be expanded; instead, the lower expander simply moves the teeth. Lower expanders will "upright" teeth that are tipped inward, and if they don't need uprighting, the device will "flare" the teeth over the edge of the supporting bone. For either process to be safe and effective, there needs to be enough bone and gum tissue around the roots of the teeth. Otherwise the removal of teeth may be necessary for the best results.

Some appliances for lower jaw expansion look similar to those used in the upper arch, but some orthodontists prefer using removable retainers (sagittal appliances) with built-in expansion screws. Dr. Jorgensen opts for traditional fixed braces to tip and align the teeth at the same time, whereas others use lip bumpers or place a spring-activated wire behind the teeth.

Keeping Up with Oral Hygiene

Whether your child has traditional braces or expanders, a regular routine of oral care is important. Brushing twice a day with fluoride toothpaste like Colgate® Cavity Protection and flossing daily is a must to protect against tooth decay. And although wearing expanders can create homecare challenges, there are unique cleaning aides available to help your child keep his expander and teeth clean.

Food and debris can get caught under an expander. Therefore, orthodontist Dr. Cheryl Held recommends her patients use either a water jet or a special syringe, designed to squirt water under the expander in order to flush out debris. She also encourages the use of a flexible palate cleaner that slides under the expander to push out food debris and excess material. And for patients that have trouble flossing because of their appliances, consider a floss threader or a new flossing tool called a FlossFish.

Creating space so that big teeth fit into a little mouth means aligning the upper and lower jaws to meet properly, and this is the goal of an expander. An orthodontist will need to evaluate your child's overall orthodontic needs before deciding if this item will yield the best result and the most fantastic smile.

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