Treatment in the tooth root is a procedure to repair an infected or inflamed nerve. During the procedure, the nerve or pulp is cleaned and the inside of the pulp is filled and sealed with a biocompatible material, allowing the tooth to be saved.
Endodontic therapy, also known as endodontic treatment or root canal therapy, is a treatment sequence for the infected pulp of a tooth which results in the elimination of infection and the protection of the decontaminated tooth from future microbial invasion. Root canals and their associated pulp chamber are the physical hollows within a tooth that are naturally inhabited by nerve tissue, blood vessels, and other cellular entities. Together, these items constitute the dental pulp.
Endodontic therapy involves the removal of these structures, the subsequent shaping, cleaning, and decontamination of the hollows with small files and irrigating solutions, and the obturation (filling) of the decontaminated canals. Filling of the cleaned and decontaminated canals is done with an inert filling such as gutta-percha and typically a eugenol-based cement. Epoxy resin is employed to bind gutta-percha in some root canal procedures. Endodontics includes both primary and secondary endodontic treatments as well as periradicular surgery which is generally used for teeth that still have the potential for salvage.
The procedure is often complicated, depending on circumstances, and may involve multiple visits over a period of weeks.
Diagnostic and Preparation
Before endodontic therapy is carried out, a correct diagnosis of the dental pulp and the surrounding periapical tissues is required. This allows the endodontist to choose the most appropriate treatment option, allowing the preservation and longevity of the tooth and surrounding tissues. Treatment options for an irreversibly inflamed pulp (irreversible pulpitis) include either extraction of the tooth or removal of the pulp.
Removing the infected/inflamed pulpal tissue enables the endodontist to help preserve the longevity and function of the tooth. The treatment option chosen involves taking into account the expected prognosis of the tooth, and the patient’s wishes. A full history is required (which includes the patient’s symptoms and medical history), along with a clinical examination (both inside and outside the mouth), and the use of diagnostic tests
In the situation that a tooth is considered so threatened (because of decay, cracking, etc.) that future infection is considered likely or inevitable, a pulpectomy (removal of the pulp tissue) is advisable to prevent such infection. Usually, some inflammation and/or infection is already present within or below the tooth. To cure the infection and save the tooth, the dentist drills into the pulp chamber and removes the infected pulp and then drills the nerve out of the root canal(s) with long needle-shaped hand instruments known as files
Opening in the crown
The endodontist makes an opening through the enamel and dentin tissues of the tooth, usually using a dental drill fitted with a dental burr.
Removal of pulp tissue
- Filling the root canal
The standard filling material is gutta-percha, a natural polymer prepared from latex from the percha (Palaquium gutta) tree. The standard endodontic technique involves inserting a gutta-percha cone (a “point”) into the cleaned-out root canal along with sealing cement. Another technique uses melted or heat-softened gutta-percha which is then injected or pressed into the root canal passage(s). However, since gutta-percha shrinks as it cools, thermal techniques can be unreliable and sometimes a combination of techniques is used. Gutta-percha is radiopaque, allowing verification afterward that the root canal passages have been completely filled and are without voids
- Temporary filling
A temporary filling material is applied between the visits. A leaky temporary filling will allow the root canals to become reinfected by bacteria in the saliva (coronal microleakage). Khayat et al. showed that all root canals obturated with gutta-percha and root canal sealer using either lateral or vertical condensation were recontaminated in less than 30 days when exposed to saliva. Therefore, maintaining a coronal seal throughout root canal therapy is very important for the success of the treatment.
- Final restoration
Molars and premolars that have had root canal therapy should be protected with a crown that covers the cusps of the tooth. This is because the access made into the root canal system removes a significant amount of tooth structure. Molars and premolars are the primary teeth used in chewing and will almost certainly fracture in the future without cuspal coverage. Anterior teeth typically do not require full coverage restorations after a root canal procedure, unless there is extensive tooth loss from decay or for esthetics or unusual occlusion. Placement of a crown or cusp-protecting cast gold covering is recommended also because these have the best ability to seal the treated tooth.