What Is Dens Invaginatus?
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Dens Invaginatus - Tooth Within a Tooth

Written by 
Dr. Achanta Krishna Swaroop
 and medically  reviewed by Dr. Sowmiya D

Education: BDS

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Dr. Sowmiya is a Dentist with a clinical experience of six years. She completed BDS from Mahatma Gandhi Postgraduate Institute of Dental Sciences, Puducherry, in 2017. Dr. Sowmiya has sound experti... 

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Published on Jun 27, 2022 and last reviewed on Nov 07, 2023   -  4 min read


Dens invaginatus is one of the many developmental anomalies that occur as a disturbance during tooth bud development. Read the article to learn more.


Tooth formation is a highly regulated, intricate biological process that depends on a number of variables for its eventual success. Clinical alterations or modifications will be visible if tooth growth is interrupted in any way. One of the main effects of developmental disruptions is a change in size, where teeth might seem bigger, smaller, or even entirely different from what is expected in terms of their clinical appearance. Throughout this article, one such developmental anomaly is further discussed.

What Is Dens Invaginatus?

Dens invaginatus (DI) or "dens in dente" is defined as a developmental disturbance of the tooth during odontogenesis (stage of tooth development) characterized by enamel invagination (turning inside to form a cavity-like appearance). If the invagination is observed, along with the presence of a foramen cecum, it gives the diagnostic probability that there is a communication between the cavity of the invagination and the pulp chamber or root canal chamber of the tooth. In such cases, a treatment procedure called root canal pulp capping may be required.

Dens invaginatus is less frequent or relatively less observed in the primary dentition than in the permanent dentition. According to traditional literature, the prevalence rate of dens invaginatus (DI) in permanent dentition varies from around 0.04 to10 percent. Reports of severe forms of dens invaginatus are extremely rare or less common. DI has a 3:1 male-to-female predilection.

What Are the Different Types of Dens Invaginatus?

The invagination in DI may be categorized as follows-

i. Coronal Type

In this type, the pitting is either slight or prominent and is confined only to the crown of the tooth and does not involve the tooth root. Hence the chances of communication to the root canal or pulp chamber of the tooth are less and restorative modalities can be adopted by the dentist to correct them, especially if the pitting is minimal.

ii. Radicular Type

This type of DI involves most of the crown and root wherein clear communication or breaches in the pulp chamber or root canal is possible. In severe cases of DI, tooth extraction may be required. In contrast, if the tooth shows bacterial ingression and decay along with symptoms of pain or inflammation, the dentist can do endodontic treatment or root canal treatment.

The difference between these two types is that while the coronal type of invagination is lined only with enamel, the radicular type of invagination is lined with the cementum layer of the tooth. On clinical examination, as mentioned earlier, suspicion of an extremely deep fissure or pit on the lingual surface of anterior teeth or in the occlusal pits or surfaces of the posterior teeth will be a visual diagnostic criterion. However, the only reliable diagnostic criterion remains radiographic examination using three-dimensional or two-dimensional imaging like CBCT (cone beam computed tomography) or OPG (orthopantomogram) to diagnose this anomaly definitively.

In the popular classification system used to classify Dens invaginatus given by Oehlers, the basis of categorizing is upon the extent of invaginations:

i. Type 1: The invagination extends to or ends as a blind sac within the crown, tooth enamel, and dentin region.

ii. Type 2: The invagination extends into the root, i.e., apically beyond the cementoenamel junction.

iii. Type 3: The invagination extends even beyond the cementoenamel junction wherein a second "apical foramen" (other than the original foramen of the tooth that contains nerve and blood vessels) is evident.

iv. Radicular Dens Invaginatus (RDI): In this type, the invagination originates in the root, caused by the infolding of Hertwig's root sheath epithelium into the root, post the completion of crown development.

What Is the Clinical Significance of Dens Invaginatus?

The clinical significance of dens invaginatus is the risk of pulpal inflammation. Although enamel may line the coronal defects that may appear quite simple or superficial, these areas lined by the enamel are thin, fragile, and affected or even missing in the crown portion of the teeth. The cavity is thus only separated from the pulp chamber or the root canals by a thin wall that creates a passage into the external oral environment through a narrow constriction. As a result, patients may not only complain of food lodgement and sensitivity but maintaining oral hygiene is difficult when it comes to brushing or keeping the affected tooth's pit areas clean, creating favorable conditions for the development of dental caries. Deep dental carious lesions may thus rapidly involve the pulp and cause various dental caries symptoms such as pain and sensitivity.

How Is Dens Invaginatus Diagnosed?

Dens invaginatus is usually diagnosed incidentally or during a routine dental examination. Upon clinical examination, the dental surgeon can visualize dens invaginatus in the permanent maxillary lateral incisors, which is the most commonly affected tooth by this condition. Deep lingual pits usually prompt the dentist to investigate further to differentiate between a deep pit and a Dens invaginatus. However, anterior teeth with dens invaginatus always have a normal shape and size in terms of crown structure. In the posterior teeth like premolars and molars, these teeth may possess an anomalous appearance when the pit is deepened palatally. Dens invaginatus commonly affects the maxillary lateral incisors, and case reports of occurrence in the mandibular anterior or posterior teeth are relatively rare in the dental literature.

Two-dimensional imaging, be it through intraoral periapical or panoramic radiographs, remains a commonly used radiographic method for detecting endodontic involvement of the invagination. If the tooth in question exhibits pulpal or periapical disease symptoms, then endodontic therapy is needed. However, three-dimensional images formed by computed tomography (CT) or CBCT (Cone beam computed tomography) are more reliable than these two-dimensional radiographs in diagnosing this developmental condition. That is because detailed information or analysis can be made before treatment about the internal root canal anatomy that may vary from individual to individual. With the widespread usage of CBCT imaging in endodontics, the diagnosis, and management of DI are easier for the dental surgeon to plan preoperatively and have an added advantage in analyzing complex root canal systems using low radiation dose compared to traditional CT scanning.

How Is Dens Invaginatus Treated?

The dental surgeon may consider extraction of the tooth only when endodontic treatment fails to control symptoms or in hopeless prognosis cases wherein the tooth decay is severe and considered a failure for endodontic sitting. However, endodontic or root canal treatment remains the first choice when the patient complains of pain or food lodgement. Furthermore, according to the reports, in cases of dens invaginatus, using a composite resin, amalgam, or glass ionomer cement as filling material in the long term results in the possibility of chronic irritation to the pulp or microleakage leading to pulp vitality loss. This is why most dentists prefer endodontic therapy to simple restorative treatment, especially in moderate to severe cases of DI.


Dens invaginatus requires a proper radiographic diagnosis, preferably by three-dimensional imaging, and also a timely treatment-based approach by the dentist or the endodontist wherein the treatment or endodontic approach is dependent only upon the extent of caries and pulpal inflammation inflicted by the invagination created in the tooth crown or root.

Frequently Asked Questions


What Is Dens in Dente and its clinical significance?

Dens in dente is a developmental abnormality due to the folding of enamel and dentin. It occurs when the enamel of the tooth folds into the dentin during the development of the tooth. It is the invagination of the enamel organ into the dental papilla. It is a small pit between the cingulum and the lingual surface of the incisor tooth. It commonly affects permanent maxillary central incisors (upper front tooth) and is uncommon in permanent mandibular teeth. The teeth appear wider, malformed, and peg-shaped.


How Can One Diagnose or Confirm a Dental Cavity?

Dental cavities or tooth caries are permanently damaged the hard structure of the tooth. It is caused by the accumulation of sugars on the surface of the teeth on which bacteria feed. The sticky sugars attract more bacteria that destroy the tooth structure. The symptoms of tooth decay are tooth sensitivity, visible holes or pits on the tooth, pain, and brown or black staining on the tooth surface. Dental X-rays can detect any degree of decay, whether it is small or large. The X-ray examination can detect the depth of the cavity.


Is Root Resorption Visible on X-ray?

Root resorption is diagnosed on dental radiographs. Root resorption occurs in roots, and it may or may be visible on normal X-rays. The symptom of resorption is a pinkish tint to the teeth. Root resorption causes swelling, loosening of teeth, and pain. Resorption affects the pulp, cementum, dentin, and root. The two types of resorption are internal and external resorption. External resorption is more visible to diagnose in X-rays than internal resorption.


What Is the Appearance of Internal Resorption on X-Rays?

Internal resorptions are found on the apical or mid area of the root. Clinically, the tooth appears pink. In X-rays, the internal resorption appears to be continuous with pulp. The outline of the root canal is distorted. An oval or round-shaped radiolucent enlargement is seen in the pulp space. The internal resorption is due to the loss of dentin, which allows more blood vessels to enter the area and gives a pinkish color.


What Is the Clinical Importance of Root Resorption?

Internal root resorption is a rare condition, and if left untreated, it can lead to the destruction of surrounding structures. It can lead to infections, weakening of the tooth, misalignment, recession of the roots, and cavities. Root resorption leads to tooth loss and damage to the teeth, gums, and jaws. The loosening of teeth can cause irregular spaces between them. It causes symptoms such as pain and swelling. As a last option, the tooth has to be removed if it is highly infected.


Why Does a Dentist Plan Root Canal Therapy?

A dentist will suggest root canal therapy if the pulp is damaged by bacterial infection. The bacteria multiplies and spreads, leading to pain. The pain occurs during eating, drinking hot or cold. The symptoms disappear once the pulp is fully destroyed by the bacteria. So, to save the pulp of the teeth, root canal treatment is advised by the dentist. The main aim of a root canal is to remove the bacteria from the canal and to prevent the removal of the tooth.


Are Roots Visible in Dental X-Rays?

A periapical radiograph shows entre stricture of the tooth. It shows from the crown to the tip of the root. This X-ray helps in easy diagnosis and is effective in planning treatment. Gum diseases, bone loss, and decay of the roots can be easily detected in a periapical radiograph. A panoramic X-ray shows all the structures of the mouth in a single image where the roots of all the teeth inside the oral cavity are visible.


What Causes Internal Resorption?

The most common causes are physical trauma or injury to the pulp. It is a relatively rare occurrence. Internal resorption is a challenge faced by many dentists. It can occur due to chronic pulp inflammation due to trauma in that area or an accidental blow. The resorption is the loss of cementum, dentin, and bone of the teeth. The internal resorption is due to the progressive destruction of radicular dentin and dentinal tubules. The most common causes are trauma, orthodontic treatment (braces), and infection. Tooth grinding and bleaching can also cause resorption.


What Are the Signs and Symptoms of Internal Resorption?

The tooth appears to be pink in the initial stages of resorption. The following are the symptoms of tooth resorption-

- Crooked teeth.

- Tooth weakness.

- Cavity-like holes.

- Loosening of the teeth.

- The recession of the roots.

- Pain.

- Tooth sensitivity.

- Discoloration and weakness.

- Pink color spots on the enamel.


How Can a Dentist Measure the Depth of a Cavity?

The dentist can identify the depth of the cavity by measuring with an instrument and assessing through a radiograph. Dental explorers are used to measure the depth of the cavity. When the tactile examination is not sufficient to assess the interproximal surfaces, radiography is taken to detect caries as it gives additional information on the progression of the cavity.


Does the Dentist Need an X-Ray to Diagnose Cavities?

It depends upon the size of the cavity. If it is a big cavity, then an X-ray will be needed to diagnose the depth of the cavity. Dental X-rays help in detecting the extent of the cavity. A cavity is visible on the X-rays only when 20 to 30 percent of the tooth structure is dissolved. Periapical X-rays are taken to detect cavities in one or two teeth. If multiple cavities are present, then panoramic X-rays can be used to view the entire oral cavity.


How the Cavities Are Diagnosed by a Dentist?

The dentist checks for cavities by using a dental probe and mouth mirror (dental instrument). The decay between the teeth is usually diagnosed with X-rays. Depending upon the size of the cavity, the type of X-ray is selected. The probe is inserted in the proximal areas to detect the depth of the cavity. The patient is enquired about any history of food lodgement or sensitivity. The interproximal cavities (decay in between the teeth) are detected using a bite-wing X-ray. The cavity can be treated using a fluoride gel or filled with dental cement.


Does Root Canal Help in Treating Internal Resorption?

Yes, internal resorption can be treated with root canal treatment. The resorptive defect in an inflamed pulp can be treated through the blood supply to the tissues with root canal therapy. The root canal treatment is the only treatment of choice for internal resorption because root canal treatment removes the dead granulation tissue and replaces it with artificial material that mimics the pulp of the tooth.

Article Resources

Last reviewed at:
07 Nov 2023  -  4 min read

Dr. Sowmiya D

Dr. Sowmiya D



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