Why You’re Missing Permanent Teeth: Hypodontia

Hypodontia, also known as dental agenesis, is when you are congenitally missing teeth from birth. It is one of the most common dental anomalies that occur and can negatively impact the function of your bite, depending on how many teeth are missing. Technically speaking, hypodontia is considered a birth defect of the permanent and/or primary teeth, causing them not to develop at all. Hypodontia can be barely noticeable and easily manageable to rather difficult to correct. 

The most common place for hypodontia to occur (although it can happen anywhere in your mouth) is the upper lateral incisors and second premolars. Although wisdom teeth frequently go missing, they are not included in the classification of hypodontia.

The number of people missing one or more teeth ranges from 1.6% to 6.9%, and this can vary by group. There are different types of tooth missing conditions:

• Congenitally Missing Teeth (CMT): This happens when a tooth's initial stages don't form right in an unborn baby's gums.
• Tooth Agenesis: This is when teeth just don't grow.
• Oligodontia: This is when someone is missing six or more teeth.
• Anodontia: This is when someone has no teeth at all.

Missing teeth usually affect permanent teeth more than baby teeth.

How Does Hypodontia Affect My Oral Health?

Hypodontia affects your smile by impacting the general function of your mouth. Without all of your permanent teeth developing properly, you can run into developmental or growth problems that need to be addressed. Some of the biggest challenges you may face are related to speaking, chewing, and your overall appearance. When you have missing permanent teeth, it can throw off the proper spacing or alignment of the other teeth and usually requires orthodontic intervention, especially if other teeth tilt and impact others. Problems with speaking or skeletal growth changes can also cause problems if not addressed quickly in young children. Chewing issues like only chewing on one side of the mouth or chewing heavily with front teeth can cause excessive wear or TMJ issues over time. 

What Are The Symptoms Of Hypodontia?

Hypodontia symptoms can include missing adult teeth, smaller than average-sized teeth (such as peg laterals,) and excessive gaps between teeth. In some cases, hypodontia is related to certain genetic disorders, including ectodermal dysplasia. Ectodermal dysplasia is a grouping of genetic disorders that can impact your teeth, skin, hair, nails, and sweat glands. The symptoms include dry and brittle skin, extremely thin and delicate hair, nails that have difficulty growing, and malfunctioning sweat glands. Hypodontia can also be associated with lip protrusion and a reduced anterior facial height (both types of malocclusions/bite discrepancies.) Luckily, these symptoms can be managed with the help of professionals like orthodontists. 

Thankfully, hypodontia does not pose any serious health risks. 

What Causes Hypodontia?

Hypodontia is a largely inherited trait. If your parents have missing permanent teeth, you are at a higher likelihood to also have congenitally missing teeth. In other words, you don’t get them because your parents didn’t have them either. This inherited trait often comes from a mutation of a gene responsible for a specific layer of tissue during the development of teeth, known as the dental lamina. The lamina layer of tissue is the basis for tooth and jaw development in utero. While hypodontia is the most common form of genetically missing teeth, there is some research that suggests environmental factors can also play a part. Other factors that can contribute to missing teeth may include:

• Infections
• Hormonal issues
• Gum Disease
• Genetics
• Trauma 
• Viruses
• Smoking
• Low Birth Weight
• Environmental exposures

What Genes Are Involved?

The specific genes responsible for developing hypodontia include WNT10B, EDA, EDAR, and EDARADD. 

These genes can be inherited in 4 ways: autosomal recessive, autosomal dominant, X-linked dominant, and X-linked recessive. 

In autosomal recessive, a copy of an abnormal gene comes from each parent and results in hypodontia. 

In autosomal dominant, only one copy comes from one parent and causes hypodontia. 

In X-linked recessive traits, a female that carries an abnormal gene on the X chromosome has a 25% chance that a son will have hypodontia, a 25% chance a son will not carry the gene or be affected, a 25% chance a daughter will carry the gene, and a 25% chance a daughter does not carry the gene at all. 

In X-linked dominant, there is an abnormal gene on the X chromosome where a male can pass the gene on to all future daughters. 

How Is Hypodontia Treated?

While hypodontia is not a serious threat to your health, it is still a condition that requires proper management. Even though you can’t treat the genetic issue or prevent it from happening, there are ways to treat the results of hypodontia at a later point in time. Some of the recommended treatments may include:

1. Braces

To adjust for spaces created by missing teeth, orthodontic treatment such as braces are often recommended. If there is too much spacing, we move permanent teeth together to align them better. Braces can also be used to make room for possible future restorations between teeth, such as implants, bridges, or partials. 

2. Dentures

For people with multiple teeth missing, partial dentures are a fast and affordable solution. Partial dentures replace all of the missing teeth with a removable prosthesis. 

3. Bridges

If you want a more permanent fix to replace multiple missing teeth, a bridge is one of the traditional treatment options. A bridge will fill in the gaps as long as you have healthy, stable teeth on either side to support the bridge. You are essentially crowning the supporting teeth and suspending a false tooth between them, filling in the open space. Bridges help to improve chewing and overall function while maintaining the spacing of the teeth around them. Bridges are significantly more affordable than implants and are fixed in place.

4. Dental Implants 

Dental implants are one of the top options available to replace single or multiple missing teeth. Dental implants are also the strongest tooth replacement option, serving both functional and aesthetic purposes. Best of all, they’re not invasive to adjacent teeth and can usually last for the rest of your life. Dental implants truly look and feel the most like natural teeth. They can also help prevent surrounding teeth from shifting, providing your smile with more stability. 

5. Bonding and Veneers

If hypodontia causes smaller than normal permanent teeth, such as peg laterals, bonding or veneers can be a great option for you. By shaping tooth-colored composite bonding over smaller-than-average lateral incisors, your dentist can make these teeth appear appropriately sized without any major restorative work! Veneers also serve as a great aesthetic solution to help teeth appear fuller and properly shaped. Keep in mind both restorations will need enough tooth structure to support them—similar to cosmetic dental crowns—so be sure to discuss your options with your dentist.  

Can I Prevent Hypodontia?

Unfortunately, hypodontia cannot be prevented. Due to its inherited genetic nature, there is no control over preventing it from occurring. It’s important to remember that if you do carry the hypodontia gene, it's not a guarantee that you will pass it on to your future children. They also may carry the gene as well but never experience missing teeth.

Congenitally Missing Teeth Recap

If you or someone you know has hypodontia, there are still various treatment options to improve their smile’s appearance and function. Luckily, hypodontia is not a serious health condition and, with the help of a great dental provider, can be managed with one or two treatments. Talk to your dentist to discuss what treatment options are best for you and your dental needs. Thanks to the various restorative options available today, you can replace your missing teeth with an option that looks and feels as great as the real thing.