Normal eruption of teeth is of primary importance to dentists. Eruption is the process which causes the tooth to move from its original position in the bone to its final position in the mouth. It must be corresponding with the growth of the jaws. Though deviations from normal time of eruption are often observed in clinical practice, delayed tooth eruption is the most commonly encountered deviation from normal eruption time.

Late eruption of a permanent tooth may be a significant concern for children in the mixed dentition stage and their parents. Late development and eruption can lead to disturbance to developing occlusion. Besides providing support for chewing, permanent molars eruption is very essential for organization of growth of face.

Normally, once milk tooth is shed off, permanent adult tooth should erupt within 6 months. But if the interval exceeds beyond 12 months, it may be of importance in a child. Therefore, most dentists consider eruption delayed if it goes beyond 12 months from its average time of eruption.

Delayed eruption can be identified if an affected tooth fails to move along the path that has been cleared for it and the normal time for eruption has crossed.

Also, if the tooth is not present in the oral cavity and shows no potential for eruption; the completely formed root of unerupted tooth recognizes condition as late eruption of tooth.

Causes of Delayed Eruption

Delayed or failure of eruption can also occur including a range of medical conditions and genetic alterations. Hindrances to tooth eruption can include bone, unfavorable tongue position, digit sucking habit or other teeth. The obstruction can also be important to the tooth in case if tooth joins to bone. This further result in ankylosis which then prevents further eruption of tooth.

The most common cause of delayed eruption of the upper permanent front teeth is the presence of supernumerary or extra tooth.

Local Conditions Which Can Cause Delayed Eruption

Localized causes can be dilacerations i.e, deformed root, malpositioning of the tooth, crowding, cysts, odontoma, or trauma to the corresponding milk tooth. The most common local cause of delayed eruption is physical obstruction. These can occur as a result of supernumerary teeth, mucosal barrier, and tumors.

Supernumerary (extra tooth) tooth can cause tooth irregularity, displacement, rotation, failure of eruption, or even delayed eruption of associated teeth. The most common supernumerary tooth is the mesiodens which is present between upper front teeth.

Tuberculate type of supernumerary is more common in patients with delayed eruption.

Tuberculate Supernumerary Tooth

Tumors have also been reported to be responsible for delayed eruption.

Disturbances during tooth development for example, Regional odontodysplasia, also called “ghost teeth,” can also lead to delayed eruption. Shapes of teeth are altered. Upper front teeth are most frequently involved. It can occur in either of the jaws and both milk and permanent teeth can be affected.

Severe gingival swelling can be a barrier to tooth eruption. Reasons for this could be hormonal or hereditary, vitamin C deficiency or drugs such as phenytoin.

Injuries to milk teeth have also been implicated as a cause of delayed eruption. Injured milk tooth might fuse with the bone and so this leads to it’s over retention and hence interferes with the eruption of permanent teeth.

X-ray radiation has also been shown to affect tooth eruption.

Normal eruption of the tooth usually resumes once the obstruction is removed

Systemic Conditions Which Can Cause Delayed Eruption

Delayed eruption is frequently reported in patients who are lacking in some essential nutrient. It might influence the eruptive process of tooth. Besides entire body, endocrine gland disturbances also affect human teeth. Hypothyroidism, hypopituitarism, hypoparathyroidism, and pseudohypoparathyroidism are the most common endocrine disorders associated with delayed tooth eruption. Endocrinal disturbances can cause medical delayed teeth eruption.  

In hypopituitarism or pituitary dwarfism, the eruption and shedding of the teeth are delayed along with growth of the body. The dental arch gets smaller than normal; it cannot accommodate all the teeth, thus irregularity of teeth develops. The roots of the teeth are also shorter than normal in dwarfism.

It is also common in preterm babies with respect to the milk teeth. In very low birth weight babies, maturation of permanent teeth delays.

HIV patients also reported to have delayed eruption of teeth. Unerupted milk and permanent teeth were more common in Children with cerebral palsy.

Some other systemic conditions such as anemia, renal failure, are also associated with delayed eruption and other abnormalities in dentofacial development.

Medical delayed teeth eruption occurs in these conditions.

Management of Delayed Teeth Eruption

Delayed teeth eruption might be a key indicator of local or systemic pathology. This delay in eruption can influence the precise diagnosis, treatment planning, and timing of treatment for the patient. Thus, it can have a considerable impact on patient’s proper health care.

Management depends on several factors, the most important being the age. Various options include observation, surgical exposure and luxation or removal of any obstacle and lastly  extraction  of tooth.

Any sort of surgical or orthodontic interventions should be avoided if the tooth is immature for eruption i.e, root formation is not complete. The most preferable method is tooth exposure and luxation. Patient has the most favorable prognosis with this.

Also if molars are luxated before completion of roots, they erupt spontaneously and continue to have their normal tooth development.

Criteria for Treatment of Delayed Eruption of Adult Teeth

There are certain criteria for treatment of delayed eruption of the permanent teeth.

If child’s chief complaint is delayed tooth eruption then the treatment is usually appropriate. Sooner or later, although the permanent tooth may erupt, but it can take up to a full year, and the parents and/or the child may not want to wait this long. Also, children are often the targets for teasing by their peers, so parents request for child’s treatment considering the esthetic grounds and the psychological benefit should not be neglected.

Teeth adjacent to the involved tooth may shift into the empty space and this can also further affect the eruption of tooth.  

The developmental stage of the unerupted tooth root will help in determining its treatment. If the tooth is fully formed and its erupting potential is lost, it will require orthodontic guidance.

Treatment Planning

Exact identification and scheduling of treatment is essential. Once the root tip is fully formed, it loses its tendency to erupt naturally. Therefore, when the cause of delayed eruption is the presence of supernumerary teeth, the unerupted tooth should be exposed.  

Surgical procedures and possible complications can be avoided by early diagnosis which helps to opt most appropriate treatment. After nonsurgical or surgical removal of the supernumerary tooth, the patient undergoes an initial stage of orthodontic treatment. Once the initial stage of orthodontic treatment is complete and sufficient arch space is available, then active treatment to extrude the unerupted permanent maxillary incisor can be started.


In patients with a delayed eruption, careful diagnosis and treatment planning allow the dentist to perform treatment at an early stage, rather than delaying treatment until the permanent teeth is in place.

Leave Comment


  • beene

    beene 12 - February - 2014, at 22:24 PM

  • daughter is6 yrs andher teeths r falling one by one so rapidly but not cuming since september2013 its al most 6 months passed plz advice I m so worried

  • Dr.Ritz

    Dr.Ritz 15 - August - 2012, at 22:37 PM

  • Dear ULKA, The time for eruption and shedding varies from children to children. The permanent teeth starts erupting at an age of 6 to 7 years (lower central incisors first) and continue till the age of 17-23 years (wisdom teeth). And the milk teeth starts shedding at an age of 6 years (lower Central incisor) and continues till the age of 11 years...So, if your child is having a problem of early shedding and delayed eruption then i would suggest you to visit a pedodontist. For more and detailed info on eruption and shedding visit the link...

  • ulka

    ulka 13 - August - 2012, at 00:04 AM

  • My daughter is 6 and a half and has lost 2 of her milk teeth about 2 months ago. There still is no sign of her permanent teeth appearing. In the meanwhile, 2 more of her milk teeth seem to be ready to fall. Is this something to be worried about? What is the average timeframe for permanent teeth to appear once the milk teeth fall out?

  • Dr.Ritz

    Dr.Ritz 10 - August - 2012, at 23:01 PM

  • Dear MUNIR HALIMZAI, Usually all the milk teeth fall by age to 12 and maximum by 15 years but there are many cases when the milk teeth are retained like: absence of permanent teeth, impacted permanent teeth. So, i would advise you to visit a dentist and get an Xray done to see what is the exact cause and plan the treatment accordingly.

    The options available with you are:

    1. Retaining the baby tooth as long as possible
    2. Get them reshaped to change their physical appearance and make them look like permanent tooth
    3. Remove the teeth and get dental implants, partial denture or bridge.

  • munir halimzai

    munir halimzai 10 - August - 2012, at 14:35 PM

  • sir ia m 22 year old and i have one milky tooth yet, and in its healthy condition, but its length is very small as compared to the other permanent tooth...please suggest any description.

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