In orthodontics, the term malocclusion, or “bad bite”, describes the misalignment of teeth or the abnormal contact of opposing teeth in the upper and lower jaws. One of the most common types of malocclusion is dental crowding, which is characterized by overlapping and/or crooked teeth. Here, dental experts share some important yet little-known facts about teeth crowding.
There are different types of dental crowding.
Dental crowding can be mild, moderate, or severe—depending on the size of your jaw and the number of teeth you have—and it may affect the teeth in the front (anterior) or back (posterior) of your upper and lower jaws.
While definitions of mild, moderate, and severe crowding may differ slightly among experts, a 2016 article published by the European Journal of Orthodontics offers the following guidelines:
- Mild dental crowding: 0-3 mm crowding/spacing discrepancy
- Moderate dental crowding: 4-8 mm crowding/spacing discrepancy
- Severe dental crowding: >8 mm crowding/spacing discrepancy
Multiple factors may play a role in dental crowding.
“Crowding can occur for many reasons," Beth Rosenberg, DDS, MS, tells WebMD Connect to Care.
"As a child, crowding can occur when there is a discrepancy in the size of your teeth and the size of your jaw (genetics), if you lose a primary tooth too early and other teeth move into that empty space, permanent teeth that do not erupt properly, frequent pacifier use, and even childhood allergies that cause the jaw to develop improperly,” Rosenberg explains.
Additional factors that can cause dental crowding include:
- Hereditary predispositions such as a naturally smaller jaw, a misaligned jaw, or a cleft lip or palate
- Tongue thrusting or reverse swallowing
- Breathing through your mouth
- Facial/dental injury or trauma
- Poor dental care
Dental crowding can occur later in life, even after braces.
As you get older, your jaw bone loses density and shrinks, according to the American Association of Orthodontists. Over time, this can result in overlapping or crowding teeth—particularly in the bottom front teeth.
“As an adult, crowding occurs to your teeth over time, especially in the anterior teeth,” Rosenberg says.
There is also a phenomenon known as mesial drift, which refers to the teeth's natural inclination to move toward the center of the dental arch (the front of your lips). Mesial drift can occur even after corrective orthodontic treatment like braces.
“Even if you’ve had braces, once they are removed, your teeth can still shift, and you can experience crowding again. As I always say to my patients and lectures: ‘Shift happens!’” Payam C. Ataii, DMD, founder and author of the Elevate Program, tells WebMD Connect to Care.
“So, it is important to wear your retainer to prevent crowding from happening again,” Ataii adds.
Teeth crowding can lead to a range of surprising health issues.
Because crowded teeth are so close to one another, they can often be uncomfortable. Misaligned teeth can also cause a bite issue that contributes to temporomandibular joint pain and migraine headaches.
In addition, crowded teeth can create hygiene problems. “Having crowded teeth means you need to work even harder with your floss, waterpik, and toothbrush to get all the plaque out," Michelle Farnoush, DMD, a Nevada-based cosmetic and implant dentist, tells WebMD Connect to Care.
"Not only is it almost impossible to get the floss between those very crowded teeth, it becomes a lot harder to keep your teeth clean, and puts you at a higher risk for cavities. Crowded teeth house hidden bacteria, and can not only cause halitosis [bad breath] but make you more prone to bone loss and gum disease,” Farnoush explains.
According to Farnoush, crowded teeth may also trigger other health problems such as sleep apnea. “When teeth are crowded, there's not enough space in your mouth for your tongue, which gets pushed back towards your throat and reduces your airway while you're sleeping, causing you to snore or even stop breathing throughout the night,” Farnoush says.
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