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.
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.