Early and late dental eruption

Examples of dentition with chronological eruption anomalies

Late eruption

• Find the anomaly! This 22-year-old young man has his wisdom teeth in the mouth… but not the upper canines that do not have enough space and are blocked by the temporary canines that should have been extracted more than 10 years ago. The permanent canines are formed normally, but their eruption is extremely late. Due to the significant lack of space, simply extracting the temporary canines will not be sufficient to allow them to come down and lodge themselves in the dental arch and an orthodontic intervention is necessary to create the space necessary to accommodate the canines.

(A) Panoramic radiograph showing all the teeth in the mouth, including the 4 wisdom teeth (there is one lower left premolar missing) and the upper canines that are impacted and do not have enough space. On the pictures and the radiograph, the yellow asterisks indicate the permanent (definitive) canines and the blue ones indicate the temporary or primary canines. (B) The temporary canines are in the mouth and the upper left canine is trying to come out, but will not have enough space to come down and lodge itself in the arch.

(A) Panoramic X-ray taken at 10.7 years of age. A late eruption is already visible. (B) Dentition and occlusion at 13.1 years of age, the late eruption continues. (C) At 16 years of age, the dental formation is normal despite the significant late eruption. It will still take several months for the teeth to shed naturally. See the above text for more details.

• This 16-year-old teenager presents a very significant late eruption that appeared as soon as her temporary dentition appeared.
  • (A) At 10 years of age, the formation of the permanent teeth was normal on the panoramic radiograph even if she already presented a late eruption of more than one year compared to the average for girls. The first premolars normally come out around 11 years of age, whereas in her case, based on the root formation, it will still take at least 2 years before they erupt.
  • (B) Almost 3 years later, she no longer has her temporary canines that were extracted to speed up the eruption and redirect the eruption path of the upcoming teeth. No new permanent teeth came out.
  • (C) At 16 years of age, the eruption still progresses but very slowly. She presents a late eruption of more than 4 years! The second molars, which come out around 12 years of age, are still deep and will take more than one year to erupt.
• Despite this significant late eruption, this girl’s dentition is normal; all her teeth are present (except the wisdom teeth) and they form normally despite the fact that they are late to erupt. She still can hope to have an esthetic and functional dentition once all her teeth will have erupted in her mouth and after orthodontic corrections.

Localized late eruption

When a tooth does not come out but its counterpart on the opposite side has been in the mouth for a while (more than 6 months), it is required to investigate the situation and a radiological examination is indicated to evaluate the cause of the late eruption.

• (A and B) The permanent upper left central incisor (yellow *) of this boy who is almost 9 years old is not out yet, whereas the right one and the lateral incisors have been in the mouth for more than one year. The temporary incisor is still in place and is very solid (blue *).
• The radiological examination confirms the presence of the permanent tooth (yellow *), but it is high, seems to have an abnormal root and is physically obstructed by the lateral incisor.
• This late eruption is localized because the other teeth develop and erupt normally.

• (B) At 8 years of age, this boy only has 2 permanent teeth in the mouth: the lower central incisors (a lower molar is also erupting).
• (A) However, a radiograph confirms that all the teeth are present and form normally despite a late eruption of 2+ years.

• In this example, a 12.9-year-old girl has a normal dental eruption and development for her age, except for the lower right second premolar (arrow on radiograph A) which shows a late formation of more than one year. The permanent second molars even completed their eruption. (B) All the teeth in the upper arch are in the mouth. (C) A late premolar is located under a temporary lower molar (* in A and C) that is still in the mouth.

• In similar situations where only one or two temporary molars are still in the mouth, it is important to verify with a radiograph the presence of the underlying premolar, because these teeth are among those that are the most often congenitally missing (anodontia).

Late eruption or bad supervision?

• Any tooth that erupts late is not necessarily affected by a “late” dental development. Bad supervision during the eruption phase of definitive teeth can cause eruption problems that will make the teeth come out late or prevent them from coming out at all. The upper canines being among the last teeth to erupt, they are often affected by such problems.

• In the above example, a 29-year-old woman who has an excellent occlusion also has an upper right primary canine that is still in the mouth (indicated by the asterisk in A, C and D), which made the permanent canine erupt in the palate (D – arrow). However, it can be noticed that the canine has sufficient space to lodge itself in the arch, but is used by the temporary tooth.
• If the primary canine had been extracted (which could have been done around 10-12 years of age!), this situation would have possibly not occurred and the relationship of teeth would have possibly been as good as on the opposite side where the canine is well positioned (C).
• Although correcting such a problem does not require a comprehensive orthodontic treatment, this could have probably been avoided with adequate supervision of eruption during childhood and at the beginning of adolescence.
• ➡ To learn more on impacted canines affected by eruption problems.

• Extreme late eruption in a 28-year-old woman with several temporary teeth remaining and impacted teeth.
• (A) The panoramic X-ray shows that 6 upper teeth have yet to erupt (2 premolars and the canine on both sides). However, it is normal to still see temporary molars in place in the lower arch, because there are no permanent premolars to replace them (anodontia, indicated by the yellow * asterisks).
• (B) The numerous temporary teeth are indicated by blue * asterisks. Even though no adequate supervision was probably provided for several years, it is surprising to see that the upper temporary teeth remain in the mouth for so long, despite the fact that their roots have severely resorbed (except the canines).

Early eruption

• These 2 radiographs show the fast progression of dental root formation in a girl between the age of 6 years and 11 months (A) and 9 years (B). The root formation, which normally takes nearly 3-4 years, barely lasted 2 years.
• In a dental point of view, orthodontic corrections could therefore be envisioned, even though the patient has just turned 9 years old! However, in such cases, the treatment can also be postponed for a while to allow the child to “gain” a little bit more maturity since an orthodontic treatment comes with an important responsibility.

• These two young girls of 9 years of age (A) and 9.9 years of age (B) have an early dental development and eruption; the second premolars, which usually come out around 12 years of age, are already in the mouth. It is thus possible to envision the beginning of orthodontic corrections at this time.
• Their treatment will be finished around the age when the other teenagers will start theirs!

• This 10-year-old boy shows a very “fast” dental development for his age; the canines and the premolars (except the lower left second premolar that does not have enough space to erupt) are in the mouth. Orthodontic corrections could begin at this time. His orthodontic treatment will end when the majority of boys will not have begun theirs!

Localized early eruption

• (A and B) The lower left second premolar (yellow *) of this 9-year-old boy has already completed its eruption, whereas this tooth should be among the last ones to erupt around 11 years of age.
• This early eruption is localized to one area only and is caused by the premature loss of the temporary molar that covered this tooth. The temporary tooth, affected by severe cavities, was lost prematurely, which sped up the eruption of the premolar and made it erupt ± 2 years in advance.
• In comparison, on the opposite side, the temporary tooth is still in the mouth (red *) (even if it is severely restored due to tooth decay) and the premolar, that has not completed its formation, will not come out until ± 2 years, which is normal.