Humans acquire two types of dentitions in their lifetime. One is a deciduous dentition which are constituted by 20 milk teeth. These are replaced by 32 teeth which make up our permanent dentition. The eruption and shedding processes of the teeth in the oral cavity is one of the key signs of development of an individual.

A teeth's journey from a small tooth bud till it reaches a final position in the oral cavity is an extremely complex process. This journey involves the development and maturation of the main layers of a tooth's crown and the roots. Problems may arise when any one of these mechanisms are affected. It can hamper the overall shape of the tooth and might affect the function of the teeth. One such anomaly is called regional odontodysplasia (RO).

What is regional odontodysplasia?

RO (regional odontodysplasia) is an anomaly that can affect the teeth of either the upper or lower jaw. It can affect an entire segment of teeth. It is often seen that if the milk teeth are affected, the successing permanent teeth would also be affected. Moreover, the eruption of the permanent teeth might be delayed compared to their normal time of eruption. RO is a very rare dental disorder that is diagnosed through a radiograph.

A tooth's crown has three main layers: enamel, dentin and pulp. The former two are hard tissues that are hardened by calcification during the tooth's development. The pulp on the other hand is a soft tissue that contains the blood vessels and nerves that supply the tooth. In RO, the enamel and dentin are not calcified enough (hypcoalcification) and do not reach the needed maturative stage (hypomaturation). This leads to the two layers being extremely thin and brittle. It also affects the color of the teeth which can be yellowish or brownish. The pulp can be abnormally enlarged with the roots being under-developed. Calcified structures are consistently seen in pulp chambers of RO affected teeth and these are called pulp stones.

What are ghost teeth actually?

The plethora of disturbances in teeth affected with RO can be evidently seen on a radiograph. The enamel and dentin appear very thin, the roots are shorter than normal and the size of the pulp is bigger. This results in the teeth appearing translucent on the radiograph giving them a "ghost-like" appearance. They are thus called ghost teeth.

Ghost teeth are extremely tender on percussion, meaning, that a simple tap on the tooth will spike a sensation of pain. These teeth have a distorted shape and a surface that can be easily chipped off due to their improper maturation. The surrounding gingiva of the affected teeth are also abnormally discolored.

Ghost teeth and RO as a whole are still a mystery as the reason behind their occurence is not yet known. Researchers have proposed many theories. One of these is abnormality in the vascularity. This means that a defect in the blood supply to the teeth might cause the characteristic features of RO. It has also been proposed that RO is a finding associated with bigger anomalies like viral infections, metabolic defects, trauma or consumption of certain medications during pregnancy.

How do you treat ghost teeth?

Treatment of ghost teeth depends on how severely the teeth is affected. If a ghost tooth has a fluid-filled (infectious) cavity attached to its roots, then the tooth needs to be removed. If a ghost tooth has a cavity, then restoring it with a suitable material might pose as a challenge due to the poor condition of the enamel and dentin which might not be able to retain the restoration. If a ghost tooth does not cause any trouble and is not infected, clinicians often recommend leaving it untouched as the tooth can help maintain tbe height of the bone attached to it and can often aid minimally in the functions of oral cavity.

An extracted ghost tooth needs to be replaced with a suitable prosthesis. This prosthesis is usually an acrylic denture. In case of adults, an implant may also be given. A prosthesis helps in maintaining the aesthetics and aids in chewing. It maintains the positioning of the adjacent teeth and also the opposing teeth. Moreover, replacement of a lost tooth by a prosthesis can also be psychologically assuring for an individual.

Ghost teeth may or may not present with an unpleasant feeling in the oral cavity. Regular visits to the dentist from the time when an individual has milk teeth can help in keeping a track of one's oral health. This helps in early diagnosis of conditions like ghost teeth which can be accordingly corrected.