This article was first published in the medical journal Doctus on 30 September 2026. Written by Dr. Diāna Čebanova, dentist at We Care.

When parents ask at what age a child should first see an orthodontist, the leading international orthodontic associations and clinical practice alike recommend doing so as early as the age of 7–9.[1] Why? According to the usual sequence of tooth eruption, by the age of 8 four permanent upper incisors, four permanent lower incisors and the first permanent molars have normally erupted, or are in the process of erupting. The remaining teeth at this age are normally still primary teeth.

If at this age one of the permanent incisors has still not come through, if the teeth are erupting in an unusual order, or if every tooth has erupted except one, it is important to find out why.[2] The answer helps us understand which orthodontic problems may lie ahead, which situations call for immediate treatment and which ones can be monitored. If by the age of 9 all of a child’s upper and lower front teeth (incisors) have still not come through, at our clinic we investigate with 3D digital diagnostics and a mandatory radiographic examination.

Aetiological factors and the most common causes of eruption disorders

Lack of space in the dental arch

One of the most common reasons a permanent tooth has not yet appeared is a lack of space in the dental arch. Several factors can contribute to this:

  • Early loss of primary teeth. Primary teeth are not simply temporary teeth. They hold the space for the permanent teeth and maintain the volume of the alveolar ridge. If a primary tooth is lost too early — because of deep caries, for example — the neighbouring teeth can drift and take up the space meant for the permanent tooth.[3] This is why regular visits to the dental hygienist and the dentist matter.
  • Myofunctional disorders. These include mouth breathing, an incorrect resting position of the tongue, abnormal muscle function when swallowing and other functional problems. When a child breathes through the mouth over a long period, the tongue sits lower and no longer supports the upper jaw sufficiently. At the same time the cheek muscles press on the upper jaw from the outside. As a result the upper jaw may become narrower and the lower jaw relatively wider. In such cases, alongside orthodontic treatment, a consultation with an ENT specialist and a speech and language therapist is often needed.
  • A genetically determined disproportion between teeth and jaws. Sometimes the permanent teeth are genetically too large for the space available in the jaw. In all of these situations, expansion of the upper jaw or regular monitoring may be required.

Supernumerary teeth (hyperdontia, mesiodens)

Another common reason for delayed eruption of the permanent teeth is the presence of extra, or supernumerary, teeth. The most common supernumerary tooth is the mesiodens — an additional tooth between the upper central incisors. The scientific literature puts its prevalence at roughly 0.15–3.8% of the population.[4]

Extra tooth buds can form not only in the incisor region but also in the premolar region. Additional wisdom teeth are less common. A supernumerary tooth often physically blocks the eruption of the permanent tooth, and in such cases the extra tooth has to be removed surgically.[5] In this situation the orthodontist refers the patient to an oral and maxillofacial surgeon.

During the operation an orthodontic chain can be attached to the unerupted tooth. Once the obstacle has been cleared, the tooth often erupts on its own, though sometimes it comes through only slowly, or not at all. Orthodontic traction can then help the tooth take its correct position in the dental arch. If the problem is diagnosed late, the space for the tooth may already have been lost. In that case, in addition to surgical treatment, the space has to be reopened — and often the upper jaw expanded as well.

Absence of permanent tooth buds (hypodontia)

Hypodontia is one of the most common dental developmental anomalies, affecting roughly 4–8% of people if wisdom teeth are excluded.[6] Statistically, the teeth most often missing are:

  • the upper lateral incisors
  • the lower second premolars
  • second premolars in general

It is important to remember that if the bud of a primary tooth has never formed, the corresponding permanent tooth will be missing too. If the parents or other close relatives have missing permanent teeth, it is advisable to have the child examined earlier, even when the front teeth are erupting normally. Treating these patients usually calls for an interdisciplinary approach and long-term planning.[7] There are two main approaches, depending on the clinical situation:

  1. Close the space left by the missing tooth by moving the other teeth.
  2. Preserve or open space for a future implant.

Reduced eruption potential and systemic factors

Another reason why teeth do not come through at the expected time, or why a child still has too many primary teeth, is reduced eruption potential. In such cases the child’s general development has to be assessed carefully, because tooth eruption is closely tied to the growth processes of the whole body.[2]

When taking the history and examining the child, it is important to establish:

  • Is the child behind their peers in height or weight?
  • Is there a growth hormone deficiency or another endocrine disorder?
  • Does the biological age match the chronological age?[8]

Such children often look noticeably younger than their actual age and are shorter in stature, and in the mouth we see a stage of dental development that does not match their chronological age. In these cases a detailed medical history and a consultation with an endocrinologist are very important.

In conclusion

Although in many cases delayed tooth eruption is not linked to life-threatening health problems, timely diagnosis is critical to a successful treatment outcome. A first orthodontic visit at the age of 7–9 means that a lack of space, extra tooth buds, hypodontia or general growth disorders can be picked up early. The earlier the cause is identified, the better the chances of choosing the most effective and gentlest orthodontic treatment — and of securing a stable, healthy smile for the long term.

If your child is 7–9 years old and one of their permanent incisors has still not come through, or the teeth are erupting in an unusual order, do not postpone the check-up: book a consultation at the We Care clinic in Riga. Read more about children’s orthodontics and orthodontic treatment.

References

  1. American Association of Orthodontists (AAO). Your Child’s First Orthodontic Checkup: No Later than Age 7. St. Louis: AAO; 2021. Available online: aaoinfo.org
  2. Suri L, Gagari E, Vastardis H. Delayed tooth eruption: Pathogenesis, diagnosis, and treatment. A literature review. American Journal of Orthodontics and Dentofacial Orthopedics. 2004;126(4):432-445. doi:10.1016/j.ajodo.2003.10.031.
  3. Sukhia HR, Sukhia RH, Azam A. Decision-making for space maintenance after the premature loss of primary first molars: a clinically oriented narrative review. Cureus. 2021;13(12):e20235. doi:10.7759/cureus.20235.
  4. Anegundi RT, Tavargeri A, Shruthi BM, et al. Prevalence and characteristics of supernumerary teeth in a patient population. Journal of Indian Society of Pedodontics and Preventive Dentistry. 2014;32(4):301-306. doi:10.4103/0970-4388.140951.
  5. Aoun G, Al-Zoubi H, El-Outa A. Mesiodens: A comprehensive clinical and radiological analysis of retention patterns. Radiopaedia Case Reports / BMC Oral Health. 2022;22(1):412. doi:10.1186/s12903-022-02450-z.
  6. Khalaf K, Miskelly J, Al-Nimri K, et al. Hypodontia: An update on its etiology, classification, and clinical management. BioMed Research International. 2014;2014:e104692. doi:10.1155/2014/104692.
  7. Al-Shahrani I, Al-Askar M, Al-Madi A. The prevalence of congenitally missing permanent teeth in a sample of orthodontic and non-orthodontic caucasian patients. European Journal of Orthodontics. 2020;42(3):289-296. doi:10.1093/ejo/cjz054.
  8. Wise GE, King GJ. Mechanisms of tooth eruption and orthodontic tooth movement. Journal of Dental Research. 2008;87(5):414-434. doi:10.1177/154405910808700509.