Most people's upper and front teeth slightly overlap their lower front teeth. In most cases, it's so slight that it's not noticeable. Even when the upper teeth overlap more than normal (overbite) or stick out too far forward (overjet), it's usually a minor issue that doesn't need treatment.
It's a different case for a child who has an excessive overbite or overjet. Here's why these conditions cause concerns.
An overbite refers to vertically misaligned teeth. The top front teeth overlap the lower teeth when the mouth is closed. Some people refer to this as a "deep bite."
An overjet is a horizontal misalignment of teeth. The upper front teeth are pushed far forward, extending ahead of the bottom teeth. When excessive, some people call these "buck teeth."
Heredity is the most common cause of an overbite or overjet. That's because you inherit the shape and size of your jaws and teeth. For instance, a small lower jaw, influenced in part by genetics, can result in an overbite.
Childhood behaviors can also cause overbites and overjets, including:
Thumb sucking or pacifier use past age 3
Tongue thrusting where the tongue moves too far forward when swallowing and speaking
Excessive nail biting
An excessive overbite or overjet can cause serious oral health issues, such as:
Difficulty biting, chewing or swallowing
Tooth decay in hard-to-clean areas
Jaw issues or temporomandibular disorders (TMD/TMJ)
Difficulty fully opening or closing the mouth
Damage to the teeth, gums and palate
Crowded or crooked teeth
Social concern with appearance
Make sure to take your child to the dentist when teeth first appear or no later than the child's first birthday. During regular visits, the dentist will monitor your child's smile for alignment issues.
Around age 7, if an issue is detected, the dentist will likely refer your child to an orthodontist - a dentist who specializes in tooth and jaw alignment. The severity of the condition and how the child's permanent teeth, jaws and face are developing will determine what treatment is recommended and how soon the treatment will begin.
Overbites and overjets are often best corrected during puberty, while facial bones are still growing. This is most often accomplished with:
Traditional braces, consisting of metal brackets placed on teeth and connected by wire
Invisible aligners, a series of replaceable clear plastic retainers that move teeth like traditional braces
Dental appliances, such as a palatal expander to widen the roof of the mouth to make room for all teeth
In more serious cases, jaw surgery may be required to treat the issue, although this solution is more commonly used for adults.
Overbites and overjets are very treatable. Make sure to discuss any concerns you may have about the development of your child's teeth with their dentist.