What Is The Difference Between Overbite And Underbite?

Do you or your child suffer from a less-than-normal bite that leads to a not-so-perfect smile? Teeth misalignment is a common issue in over seventy-five percent of the human population, and orthodontics can treat almost all the issues or malocclusions. 

The way your upper and lower teeth align not just impacts your appearance but your overall health too. With misaligned teeth, you may face difficulties with some of the vital functions of our mouths, such as chewing, eating, and even speaking. Misaligned teeth are also prone to more wear and tear and tend to become crooked over time.

Two of the most common malocclusions are overbites and underbites, and many of us have this issue to some degree. In this article, we will learn in detail what overbites and underbites are, the difference between the two, the problems associated with these two dental misalignments, and some of the ways they can be rectified.

Overbite Explained

Normally your upper teeth overlap the lower one, but if there is excessive overlap, it results in an overbite. Overbite is also termed buck teeth.

• It is considered an overbite if your upper teeth extend over your lower teeth by four to ten millimeters.
• You can figure out if you have this issue by just looking in the mirror. If you do have an overbite, you will find your upper teeth wholly or partially covering your bottom teeth.
• Your dentist could also take dental X-rays to identify if you have buck teeth and the degree of overbite.
• When the overlap is too large, it is considered a deep bite.
• If this malocclusion is severe, you might even find the roof of your mouth irritated by your bottom teeth.
• Buck teeth are different from overjet, even though people use them interchangeably. You could have both these problems simultaneously, but overjet is when the horizontal distance between the upper and lower teeth is more than normal. In contrast, overbite occurs when the vertical space between the upper and lower teeth is huge.

Underbite Explained

When you have an underbite, your lower jaw is a little forward with respect to your upper jaw.

• The lower front teeth are placed outside the upper teeth in an underbite.
• Underbites are mostly skeletal, i.e., related to abnormal jaw growth (too long lower jaw or too small upper jaw.)
• People with severe underbite issues often have protruding chins.
• Underbite is different from crossbite even though the lower teeth are biting in the front of the top teeth in both conditions. With an underbite, the whole lower jaw is forward, while in crossbite, one or lower dentitions are in front of the upper pearly whites either at the back of the mouth (known as posterior crossbite) or the front of the mouth (called anterior crossbite)

Difference Between Overbite and Underbite

The salient thing that differentiates an overbite from an underbite is whether it involves the upper or lower jaw and teeth.

• If you have both types of malocclusions, you would have one arch of teeth too far in front of the other arch of the teeth. It occurs mostly due to discrepancies in jaw growth.
• Underbites are known to have more severe consequences than buck teeth, but neither condition should be ignored.

Reasons for Overbite

A very small lower jaw is usually the reason for buck teeth or overbites.

• A small lower jaw is usually genetic.
• If you have chronic habits like teeth grinding or teeth clenching, that can also cause overuse of chewing muscles and overbite.
• Excessive nail biting can also cause this condition.
• NNSB (non-nutritive sucking behavior) or thumb sucking past three can result in an overbite.
• Using a pacifier after three years of age can also cause buck teeth.
• If you habitually thrust your tongue, i.e., the tongue presses too forward into the mouth; you might develop buck teeth.
• If you have missing lower back teeth, your bite might collapse, giving you a buck teeth appearance.

Reasons for Underbite

Underbites are mostly genetic and depend on the skeletal and dental traits you inherit from your parents.

• Prognathism occurs when the upper jaw does not grow enough, or the lower jaw grows too much. It could also be a combination of discrepancies in the growth of both jaws.
• A few oral habits can also give you underbite, such as prolonged pacifier use, tongue thrusting, thumb sucking, etc., that interfere with jaw growth.
• Trauma or injury to jaw or face.
• Certain congenital disabilities, for instance, cleft palate and lip.
• Tumors in the jawbone.
• Mouth Breathing could also result in an underbite,

Complications Due To An Overbite

If the overbite is not treated, it can lead to:

• Trauma to the front teeth.
• Speech difficulties
• Uneven or excessive wear and tear of enamel (the hard protective covering on our tooth.)
• Headaches
• Issues with chewing and biting.
• Damage of soft tissue and gum around teeth.
• More prone to gum disease and tooth decay.
• TMJ (temporomandibular joint) and jaw dysfunction and pain. 
• Cosmetic issues such as receding or weak chin.
• If the lower teeth keep hitting the sensitive soft tissues behind the upper front teeth, then it could cause painful ulcers or sores.
• Airway obstruction and sleep disorders.

Complications Due To An Underbite

An untreated underbite can cause the following issues:

• TMJ (temporomandibular joint) and jaw dysfunction and pain. 
• Cosmetic problem since a protruding lower jaw gives a bulldog appearance.
• Speech issues.
• If the button teeth are sticking out, then there is an increased risk of trauma to those teeth.
• It is harder to clean misaligned teeth hence underbite makes you more prone to gum disease and tooth decay.
• Sleep disorders such as sleep apnea.
• Headaches and earaches.
• Wear and tear of enamel.
• Mouth breathing.

How to Fix Buck Teeth or Prognathism 

Both underbite and overbite are treated through similar orthodontic procedures as described below:

• Metal Braces- These metallic brackets sit on your teeth and are tightened with elastics and wires. They take about eighteen to twenty-four months to get your properly aligned teeth.
• Invisalign- They are clear or transparent trays custom-made to fit your teeth’s size and shape and are removable.
• Orthognathic surgery- If your problem is severe, it might require corrective jaw surgery. 

Overbite and underbite are the two most common dental issues which pose many health issues if not corrected. Many options are available to treat these problems, and your dentist can help you decide which treatment you should go for.