October 12, 2021
Ectopic refers to something being out of position. Enamel is the outer, hard tissue covering of the crown of the tooth. Ectopic enamel is a condition when the enamel is formed away from its normal position. It was first described in 1841 as a "pin head" when deposits of enamel were found at the region of roots. Since then, it has been referred by many names. Some of them are enameloma, enamel pearls, enamel globules, enamel knots, enamel droplets, enamel globules, enamel nodules and adamantoma. The use of the word enameloma is now discouraged as it refers to a cancerous lesion.
Etiology and Types
Ectopic enamel occurs as a result of disturbance during the development of tooth. The root of the tooth is formed by a layer of cells known as Hertwig's Epithelial Root Sheath (HERS). Once the root is formed, the HERS disintegrates into a few other small groups of cells known as cell rests of Malassez. These cell rests are located at areas other than the crown. They have the ability to differentiate into ameloblasts. Ameloblasts are the cells that are responsible for the formation of enamel. Thus, enamel is formed in an ectopic location.
Depending on the area and composition of the enamel pearl, they are of four types:
a) True enamel pearls
They are made entirely of enamel.
b) Composite enamel pearls
They are made of enamel and dentin.
c) Enamel Dentin Pulp pearls
They are present in an area which consists of cells of enamel, dentin and pulp.
Size and Location
Ectopic enamel formations can range from 0.3 mm to 8 mm. They are commonly found at the furcation areas of the tooth. These are areas where teeth with more than one roots share a common point from where the roots bifurcate or trifurcate.
There can be more than one ectopic enamel formation on a tooth and there can be multiple teeth with enamel pearls in the same patient.
Diagnosis of ectopic enamel is done through radiographic and histological investigations. Ectopic enamel appear whitish on radiographs. Histological examination can confirm the different types of cells that make up the ectopic enamel. It has also be found that the enamel found in ectopic enamel is different from the normal enamel. The ectopic enamel is much more hypomineralized and is attached with a weaker bond to the tooth structure.
Ectopic enamel is seen commonly in Asian males. They are more commonly seen in the upper molars, followed by lower molars. However, they can also occur on incisors, canines and premolars.
Ectopic enamel formations can cause plaque accumulations that can further cause inflammation of gingiva and underlying tissues. When these formations are present in areas involving the pulp, that they might be discomforting for the patient.
Ectopic enamel can act as hubs for accumulation of plaque if oral hygiene is not maintained properly. In such cases, they might need to be trimmed through procedures known as odontoplasty. In this, the surface of ectopic enamel is flattened to prevent any further accumulation of calculus.
In some cases, when the ectopic enamel is clinically visible, it is often mistook as a calculus during scaling of teeth. In an attempt to remove this "calculus" the force applied on it might lead to its traumatic removal and subsequent exposure of the pulp might occur. The pulp is the soft tissue that contains the blood vessels and nerves of the tooth. Ultimately, the exposure of the pulp can be painful and requires either an extraction or root canal therapy.
Ectopic enamel of larger sizes can cause destruction of the underlying bone. Thus, whenever an enamel pearl is diagnosed, it is necessary to eliminate it at the soonest. Flap surgeries that involve raising the soft tissue to better visualise the ectopic enamel might be needed in severe cases.
In primary teeth, enamel pearls are rare. If present, their presence can delay their exfoliation which ultimately results in the permanent tooth erupting ectopically or delayed.
Ectopic enamel is relatively rare, but can cause many problems if not treated upon diagnosis. Better and advanced radiographic techniques like CBCT can help in quicker and efficient diagnosis and subsequent treatment plan formulation.