Endo-Perio Lesion

July 04, 2020

  

"Endo" literally refers to "inside" or "within." The branch of dentistry which is concerned with the internal structures of the tooth is called endodontics. The tooth is attached to the underlying bone with the help of a ligament. This ligament is called the periodontal ligament. It is one of the four main components which comprises the periodontium. The branch of dentistry concerned with the periodontium is called periodontics.

The human tooth can suffer from problems that can involve not only the tooth itself but also the surrounding tissues. When a carious lesion starts on the chewing surface of the tooth, it is often neglected. If not treated at an initial stage, this lesion can travel from the outer layer (enamel) to the inner layers (dentin, pulp). It can then travel through various connections and reach the periodontal apparatus, thereby infecting it. However, there are various ways through which these infections take place. Let us take a look at these scenarios.

The primary route that connects an endodontic lesion with a periodontic lesion is through a periodontal pocket. This pocket is present between the tooth and the gingiva attached to it. It forms when microorganisms of the plaque and calculus attached to the tooth cause the gingiva's inflammation, thereby forming a thin deep path.

When an endodontic infection travels from the pulpal region to the roots, noxious agents exit the roots and drain through these pockets and present themselves near the crown of the tooth. This way a purely endodontic lesion can mimic a periodontal disease.

Pockets can go deep enough to be in close proximity with the roots of the teeth. When a lesion of the endodontic component reaches the deepest portion of the pocket, it can cause a swelling large enough to destroy the periodontium and the socket of the tooth. This is often manifested as a black region attached to the roots of the tooth on a dental radiograph.

The pockets are a viscious component of the Endo-Perio lesions. The plaque and calculus microorganisms can travel all by their own within the periodontal pocket. Connections between the pulp and the periodontal pocket can cause these pathogens to infect the pulp in a way that leads to the development of pulp stones in these regions.

There are also cases where an existing lesion of the periodontal component can travel in a reverse direction, enter through the roots of the tooth and thus go on to infect and inflammate the pulp. This type of Endo-Perio lesion is called retrograde pulpitis.

Apart from the above mentioned scenarios, a Endo-Perio lesion can exhibit itself by simultaneous presence of both the endodontic and periodontic lesions that are independently developed.
Up until now we have attributed the cause of endo-perio lesions to microorganisms that can infect the pulp or those that are responsible for periodontitis. However, there are cases when a fracture along its Y-axis (vertical) can initiate the endo-perio lesion. The causes of endo-perio lesions can also be iatrogenic, meaning that there is no definitive cause behind the impairment.

An endo-perio lesion is treated by knowing which component, endodontic or periodontic, is primarily involved. A dentist first accesses the tooth by palpating the surrounding soft tissue, checking if the tooth is mobile and percussing it to determine the extent of pain.

Checking the presence, extent and depth of the periodontal pockets is done through an instrument called the periodontal probe. This gives the dentist an idea of how severe the Endo-Perio lesion can be. Based on the extent of the pocket, various treatment modalities can be considered. Some pockets resolve by simply irrigating the pocket and debriding the plaque and calculus. Some more severe ones may be treated by removing the associated gingiva or the corresponding pocket wall.

If the lesion is primarily because of an endodontic origin, then a root canal treatment which debrides the tooth's innards from all the pathogenic microbes can resolve the lesion.
If periodontic, then a periodontal therapy is carried out. This involves cleaning the tooth below the gingival levels in a way that all the plaque and calculus is removed. However, if the affected tooth is the source of an endo-perio lesion that is extensively spread out, then extracting the tooth is often considered by the dentist.

Finally, it is important to note that the prognosis of a tooth with a single root is worse than that of a multi-rooted tooth. It often becomes a challenge for the dentist to differentiate between a lesion of endodontic or periodontic origin. The knowledge of the type of pain the patient presents with and the connection of the different types of tissues of the tooth and its surrounding structures can guide the dentist in making a thorough diagnosis.

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