Why are some permanent teeth missing from birth?

You may notice a baby tooth staying put longer than expected, or a gap that never seems to fill in. It’s natural to wonder whether the permanent tooth is just taking its time. Sometimes it is. In other cases, the tooth never developed at all, often because of genetic factors that affect tooth formation.¹ 

Dentists call this tooth agenesis, or congenitally missing teeth. An exam with X-rays can help separate it from a delayed or impacted tooth and give you a clearer picture of the options.¹ 

What you'll learn in this article: 

• What it means when a permanent tooth never develops 

• Which teeth are commonly affected and why 

• How dentists distinguish missing, delayed and impacted teeth 

• How treatment can change as your needs and jaw development change 

If you're trying to make sense of a missing permanent tooth, schedule an appointment with an Aspen Dental provider to discuss an evaluation and next steps. 

What are congenitally missing teeth and hypodontia? 

A congenitally missing tooth never formed. Despite the name, permanent teeth keep developing after birth, so a missing tooth can’t be confirmed in a newborn. Diagnosis is generally possible around age six.¹ 

You may hear a few names based on how many permanent teeth haven't developed: 

• Hypodontia: one to five teeth missing 

• Oligodontia: six or more teeth missing 

• Anodontia: all permanent teeth missing, found almost exclusively alongside a broader syndrome¹ 

Wisdom teeth are excluded from the hypodontia and oligodontia counts. These terms describe a developmental difference, not teeth lost through an extraction, injury or decay.¹ 

Why do some permanent teeth never develop? 

Genes help guide tooth development, and changes in those instructions can affect whether a tooth forms. Missing teeth can run in families, but there isn’t one inheritance pattern that applies to everyone. Factors early in life, such as certain cancer treatments or infections, can also affect tooth development in some cases. A dentist may ask whether relatives have missing teeth or unusual tooth shapes.¹ 

Tooth agenesis can occur on its own or as part of a broader genetic condition that also affects structures such as hair, nails or sweat glands. A missing tooth alone doesn’t establish that diagnosis.¹ Your dentist will consider your health history and other findings before recommending further evaluation. 

Bring up any family history you know, but don't worry if you don't have all the details. 

Which permanent teeth are commonly missing? 

Apart from wisdom teeth, commonly affected teeth include: 

• Lower second premolars: Teeth just in front of the lower molars. 

• Upper lateral incisors: The teeth immediately beside the two upper front teeth. 

• Upper second premolars: Teeth just in front of the upper molars.²

A front-tooth gap may be easy to notice. A missing premolar may be less obvious, especially if a baby tooth is still in place. 

How do dentists tell whether a tooth is missing or delayed? 

A baby tooth that stays longer than expected can be a clue. So can a difference in when matching teeth come through on opposite sides.² Neither finding confirms that a permanent tooth is missing. 

Your dentist reviews the tooth's development and uses appropriate dental X-rays to check beneath the gums. A delayed tooth is developing but hasn't emerged yet. An impacted tooth is present but unable to erupt normally. With tooth agenesis, the tooth hasn't formed.¹

In adults, earlier dental records can help establish whether a tooth never developed or was lost later.¹ If you’re changing dentists, sharing those records can make the history clearer. 

How can missing permanent teeth affect your bite? 

The effects vary. Retained baby teeth and bite changes are common findings when permanent teeth are missing, and some people have gaps or concerns about chewing and appearance.¹ Your dentist checks how the upper and lower teeth meet, the available space and the condition of the remaining teeth.² 

If a gap makes you reluctant to smile, mention that too. Your concerns belong in the treatment conversation. 

What are the treatment options for hypodontia? 

Treatment depends on your age, bite, remaining teeth and goals. A healthy baby tooth doesn’t automatically need removal, and an implant isn’t the only possible solution.² 

Your plan may include: 

• Keeping a baby tooth: A suitable retained tooth may be monitored and maintained.¹^,² 

• Closing the space: Orthodontic treatment may move neighboring teeth into a position that closes the gap.² 

• Preserving or preparing space: An appliance or orthodontic treatment may help create or maintain room for a replacement.² 

• Replacing the tooth: Depending on your situation, a prosthesis such as a bridge or removable partial denture, or an implant, may be considered.² These tooth replacement options serve different needs. 

Why does jaw growth affect implant timing?

Dental implants are typically not placed until jaw growth is complete. An implant doesn’t follow growth and tooth eruption like a natural tooth, so early placement can leave it out of alignment with neighboring teeth. Age alone isn’t a reliable guide, so your care team assesses your development.¹^,³ 

Treatment may happen in stages. Ask what needs attention now, what can wait and whether a temporary replacement would help while you grow. 

If you have a lingering baby tooth or an unexplained gap, schedule an examination with your local dental provider to understand your options. 

Why are some permanent teeth missing from birth? FAQs 

Can hypodontia happen without a family history? 

Yes. Some genetic changes occur for the first time in a family, and some relatives may carry a change without obvious signs.¹ Not knowing anyone with missing teeth doesn't rule it out. 

Does everyone need genetic testing? 

That’s an individual decision. A dentist may refer you to a genetics professional based on your dental findings, medical history and family history, and testing may help clarify the cause or inheritance.¹ 

Can a retained baby tooth last for life? 

It can be kept for a time, but that isn’t a guarantee. Dentists may preserve a baby tooth that has no permanent successor to hold space until growth is complete and a replacement can be placed.¹ Its roots, condition and position in the bite need monitoring, since baby teeth can wear away at the root or become fixed in the bone.² If it becomes unsuitable to keep, your dentist can revisit the plan for that space. 

Sources 

¹ University of Washington, GeneReviews: “Nonsyndromic Tooth Agenesis Overview.” https://www.ncbi.nlm.nih.gov/books/NBK572295/ 

² American Academy of Pediatric Dentistry, The Reference Manual of Pediatric Dentistry: “Management of the Developing Dentition and Occlusion in Pediatric Dentistry.” https://www.aapd.org/globalassets/media/policies_guidelines/bp_developdentition.pdf 

³ American Academy of Pediatric Dentistry: “Periodontal Conditions in Pediatric Dental Patients.” https://www.aapd.org/globalassets/media/policies_guidelines/bp_periodontal.pdf