Hypodontia (Congenitally Missing Teeth)

How Is Hypodontia Classified by Severity?

Clinicians use a severity-based classification to guide treatment planning.

• Hypodontia refers to the absence of up to six teeth, excluding wisdom teeth. This is the most common form.
• Oligodontia describes more than six missing teeth, excluding wisdom teeth. This is a severe presentation and almost always requires specialist-led, multidisciplinary care.
• Anodontia is the complete absence of all teeth. It is rare and typically associated with a genetic syndrome such as ectodermal dysplasia.

Hypodontia can also be classified as syndromic (occurring as part of a broader condition such as Down syndrome, cleft lip and palate, or ectodermal dysplasia) or non-syndromic (occurring in isolation without an associated systemic condition). Non-syndromic hypodontia is far more common.

Which Teeth Are Most Commonly Missing?

Not all teeth are equally likely to be absent. Excluding wisdom teeth, the most frequently missing permanent teeth are:

• Lower second premolars (the small teeth in front of the back molars on the bottom jaw)
• Upper lateral incisors (the teeth on either side of the two front teeth)
• Upper second premolars (the small teeth in front of the back molars on the top jaw)

Wisdom teeth (third molars) are the most commonly absent teeth overall, though their absence is rarely a clinical concern.

In primary (baby) teeth, hypodontia is considerably less common than in the permanent dentition.

What Causes Hypodontia?

Hypodontia results from a combination of genetic and environmental factors that disrupt tooth development during early fetal growth.

Genetic factors are the most significant driver. Mutations in several genes — including MSX1, PAX9, AXIN2, and EDA — are known to disrupt tooth formation. PAX9 mutations are frequently associated with molar agenesis. A family history of missing teeth is a recognized risk factor, and in many cases hypodontia runs across generations of the same family.

Environmental factors during pregnancy have also been implicated, including:

• Maternal infections during the first trimester
• Low birth weight or premature birth
• Multiple pregnancies (twins, triplets)
• Exposure to certain medications or substances during fetal development

When hypodontia is syndromic, it occurs as part of a broader genetic condition. Conditions associated with missing teeth include ectodermal dysplasia, Down syndrome, cleft lip and palate, and Van der Woude syndrome.

In many cases, no single clear cause is identified. Early dental assessment can help determine whether further investigation is appropriate.

What Are the Signs and Symptoms of Hypodontia?

In primary teeth, the most obvious sign is a visible gap where a tooth should have erupted. A full set of primary (baby) teeth is usually in place by around age 3.

In permanent teeth, the absence may first be noticed when an adult tooth fails to replace a baby tooth — particularly during the mixed dentition phase (roughly ages 6 to 12). A retained baby tooth in an older child or adult can itself be a sign that no permanent successor formed beneath it.

Other signs that may be identified during a dental examination or on a panoramic X-ray (OPG) include:

• Gaps or spacing that cannot be explained by a previous extraction
• Teeth that appear smaller than expected (a condition called microdontia, sometimes associated with hypodontia)
• Unusual spacing patterns within the dental arch

Hypodontia is not typically painful. It is most often discovered during a routine dental check-up or orthodontic assessment. A panoramic X-ray is the standard diagnostic tool, and clinicians generally recommend that radiographic screening takes place no earlier than age 9 for permanent teeth.

Why Should Hypodontia Not Be Left Untreated?

A missing tooth — whether in a child or adult — does more than create a visible gap. When left unaddressed, the consequences can affect function, structure, and long-term oral health.

• Insufficient bone development. When a tooth bud never forms, the jawbone in that area does not develop normally either — alveolar bone forms alongside tooth development, so its absence means reduced bone volume from the outset. This can limit treatment options later, particularly if implants are planned.
• Tooth drift and bite problems. Neighboring teeth tend to shift into empty spaces, which can alter how the teeth come together. This can contribute to a malocclusion — an improper bite — if not managed.
• Spacing and aesthetic concerns. Gaps in the smile, particularly in visible areas such as the upper front teeth, can affect a patient's confidence and quality of life.
• Speech difficulties. Missing front teeth can affect the clarity of certain sounds, particularly in younger children.
• Functional impact. Missing premolars or molars can affect the ability to chew comfortably, which over time may place undue stress on the remaining teeth.

Early identification and a clear treatment plan — even if treatment itself begins later — significantly improves outcomes.

How Is Hypodontia Treated?

Treatment for hypodontia is almost always multidisciplinary. Depending on the number of missing teeth, their location, the patient's age, and the condition of the surrounding bone and bite, management typically involves specialists across orthodontics, prosthodontics, and — where implants are planned — implant surgery.

There are two broad strategic approaches: closing the space orthodontically, or opening and maintaining the space for a prosthetic replacement. The right strategy depends on individual clinical factors and is best determined through specialist assessment.

• Orthodontic Treatment

  Orthodontic treatment is the most commonly recommended first step in hypodontia management. It serves to redistribute spaces, correct the bite, and prepare the arch for any restorative work to follow. In some milder cases — particularly where missing teeth are in less visible positions — orthodontic space closure alone may produce a satisfactory result without the need for prosthetic replacement.

• Dental Implants

  For patients whose jaw has finished growing, dental implants are widely considered the most durable long-term option for replacing missing teeth. An implant replaces both the root and the visible crown, which helps maintain the bone and surrounding structures. Implants are placed by our Specialist Oral Surgeons and Specialist Periodontists and Implantologists. Where patients qualify, same-day implants may be an option — visit our same-day dental implants page for more information.

  Implants are not placed in growing patients, as jaw development must be complete before treatment can proceed. This is typically confirmed from the late teens onwards, assessed case by case.

• Dental Bridges and Resin-Bonded Bridges

  A crown and bridge solution spans the gap left by a missing tooth by anchoring an artificial tooth to the adjacent natural teeth. A resin-bonded bridge (sometimes called a Maryland bridge) is a more conservative option that requires minimal preparation of the neighboring teeth. It is often used as an interim solution in younger patients while they wait until they are ready for implants. For a closer look at how bridges and implants compare, visit our bridge vs implant guide.

• Dentures and Removable Partial Dentures

  In cases of oligodontia — where many teeth are missing — removable partial dentures may be used, particularly in children and adolescents where other options are not yet appropriate. These are typically considered an interim measure rather than a long-term solution for younger patients.

• Composite Resin Build-Ups

  Where teeth adjacent to a gap are smaller than expected, composite resin bonding can be used to reshape them and improve both aesthetics and spacing as part of a broader treatment plan.