Overbite vs. Underbite: What’s the Difference?

What Is an Overbite?

An overbite (also known as a deep bite) occurs when the upper front teeth overlap significantly with the lower front teeth. A slight overbite is normal, but when the overlap becomes too large, it can lead to issues with your bite and overall oral health.

Causes of Overbite

Overbites can be caused by a variety of factors, including:

• Genetics: Family history plays a significant role in the development of overbites. Some people are born with jaws that are not properly aligned.
• Childhood Habits: Prolonged thumb-sucking, pacifier use, or tongue thrusting in childhood can lead to an overbite by pushing the upper teeth forward.
• Teeth Grinding (Bruxism): This can wear down teeth and worsen an overbite over time.
• Improper Tooth Alignment: Crowded or misaligned teeth can lead to an overbite due to irregular spacing and bite patterns.

Symptoms and Complications of Overbite

If left untreated, an overbite can lead to several issues, including:

• Jaw Pain: An overbite can put extra stress on the jaw joints, leading to discomfort or even temporomandibular joint (TMJ) disorder.
• Worn Teeth: Overbites often cause excessive wear on the teeth, particularly the lower teeth.
• Speech Problems: Severe overbites may lead to difficulties in speech, especially with sounds that require the teeth to come together.
• Gum Damage: In extreme cases, the lower teeth may press against the gums behind the upper teeth, causing gum recession or injury.

What Is an Underbite?

An underbite occurs when the lower teeth extend outward and sit in front of the upper teeth when the mouth is closed. This condition, also known as prognathism, can vary in severity, from a slight overlap to a more noticeable misalignment.

Causes of Underbite

Underbites are often inherited, but other contributing factors include:

• Genetics: The shape and size of the jaw are often passed down through generations. People with an underbite typically have larger lower jaws or smaller upper jaws.
• Childhood Habits: Prolonged thumb-sucking, using a bottle beyond infancy, and mouth breathing may all contribute to an underbite.
• Injury or Trauma: Severe injury to the jaw can sometimes lead to an underbite, particularly if the bones heal improperly.
• Tumors or Growths: Tumors in the jawbone or mouth can cause the jaw to protrude, leading to an underbite.

Symptoms and Complications of Underbite

Like overbites, underbites can cause complications if left untreated:

• Chewing and Biting Difficulties: The misalignment caused by an underbite can make it difficult to bite and chew food properly.
• Speech Issues: An underbite can cause speech problems, such as a lisp or difficulty pronouncing certain words.
• Jaw Pain: Similar to overbites, an underbite can place extra pressure on the jaw, potentially leading to TMJ disorders and chronic pain.
• Tooth Decay and Wear: Improper alignment can cause uneven wear and tear on the teeth, making them more susceptible to cavities and fractures.

Key Differences Between Overbite and Underbite

Treatment Options for Overbites and Underbites

There are several treatment options available for both overbites and underbites. The right approach depends on the severity of the condition, the patient’s age, and whether the issue is structural or dental in nature.

1. Braces

Braces are one of the most common treatment methods for correcting both overbites and underbites. Traditional braces use brackets and wires to slowly move teeth into their correct positions over time.

• How They Work: Braces apply constant pressure on the teeth, gradually shifting them into proper alignment.
• Duration: The treatment typically lasts between 18 months and 3 years, depending on the severity of the bite problem.
• Effectiveness: Braces are highly effective for both children and adults in treating dental misalignments.

2. Invisalign

For those looking for a more discreet option, Invisalign is a clear aligner system that can correct overbites and underbites.

• How It Works: Invisalign uses a series of clear plastic aligners to move teeth into their proper position. The aligners are custom-made and worn for about 22 hours a day.
• Duration: Treatment can take anywhere from 12 to 18 months, depending on the complexity of the case.
• Effectiveness: Invisalign is suitable for mild to moderate overbites or underbites. Severe cases may still require traditional braces or surgery.

3. Jaw Surgery (Orthognathic Surgery)

In cases where the overbite or underbite is caused by skeletal misalignment, jaw surgery may be required.

• How It Works: Surgery is used to reposition the upper or lower jaw, correcting the bite and ensuring proper alignment.
• Duration and Recovery: The procedure takes a few hours, but recovery can last several weeks to months. In some cases, braces are worn before and after surgery to complete the alignment.
• Effectiveness: Jaw surgery is typically reserved for severe cases and is highly effective in correcting structural issues that braces alone cannot fix.

4. Headgear and Expanders (For Children)

For children with developing jaws, interceptive treatments like headgear or expanders can guide jaw growth to prevent or reduce the severity of an overbite or underbite.

• How It Works: Headgear and expanders help widen the upper jaw or correct the growth pattern of the lower jaw to improve bite alignment.
• Duration: These appliances are typically worn for several months to a year, depending on the treatment goals.
• Effectiveness: These treatments are most effective when used during childhood, while the jaw is still growing.

5. Tooth Extraction

In cases where crowding contributes to an overbite or underbite, tooth extraction may be recommended to create more space in the mouth, allowing the remaining teeth to move into proper alignment.

• How It Works: One or more teeth are removed, and then braces or aligners are used to shift the remaining teeth into alignment.
• Duration: The extraction is done as a single procedure, but orthodontic treatment will continue for the usual duration of 1-3 years.
• Effectiveness: Tooth extraction can be highly effective in cases of overcrowded teeth, but it is often used in combination with braces or aligners.

Preventing Overbites and Underbites

While many overbite and underbite cases are due to genetics and cannot be fully prevented, certain habits can help minimise the risk of developing these bite issues, particularly in children.

• Avoid Prolonged Thumb-Sucking or Pacifier Use: These habits can push the teeth forward or cause jaw misalignment. Limiting their use after the age of 3 can reduce the risk of bite problems.
• Early Orthodontic Evaluations: Having a child evaluated by an orthodontist by age 7 can help detect and address potential bite issues early, possibly preventing the need for more extensive treatment later.
• Good Oral Hygiene: Ensuring proper oral care can prevent tooth decay and early tooth loss, which can lead to misalignment.

Overbites and underbites are common dental issues that can affect both appearance and function. While they have different causes and characteristics, both conditions can be effectively treated with modern orthodontic techniques such as braces, Invisalign, or jaw surgery. Early intervention, especially in children, can make treatment easier and more effective, while adults can still benefit from a variety of corrective options.

If you or your child have concerns about an overbite or underbite, consult with a dental specialist in Singapore to discuss the best treatment plan tailored to your needs. With proper care, you can achieve a healthy, aligned bite and improve your overall oral health and quality of life.