The procedure for doing Root Canal Treatment is a complicated one and needs special skill on the part of the dentist to do that. The dentists specializing in Root Canal Treatment are called Endodontists. The procedure of Root Canal Treatment varies from case to case. It can be done in single sitting and sometimes more than one visit to dentist is required to complete Root Canal Treatment. The procedure for Root Canal Treatment (RCT ) involves three main steps:
Gaining access to the nerve of the tooth
Cleaning and shaping the interior of the tooth i.e. the entire pulp containing area (pulp chamber and pulp canals)
Filling the canals with a sterile filling material
The first and foremost step before starting a root canal treatment ( RCT ) is to ensure to make the procedure painless. Most of the patients fear of undergoing a root canal treatment just thinking about the pain associated with it. But to your surprise a root canal treatment might not be painful at all most of the times because root canal treatment is mostly done in cases where the pulp tissue of the tooth has already undergone necrosis i.e. is already dead and there is no active infection or inflammation present, no nerve is alive to perceive pain so no pain is felt no matter how long the procedure of root canal treatment is. In fact root canal treatment will help you get rid of the pain due to infected pulp. Once the infected nerve tissue is removed completely no pain persists. But in cases where the pulp tissue is alive a dentist needs to give local anesthesia to the patient in order to relieve anxiety and make the procedure totally painless. Lidocaine is a commonly used anesthetic in dental office. In reality when the patient is relaxed a dentist can also carry out the procedure with much ease and speed. There are many ways to anesthise a tooth. It can be done by
Nitrogen oxide gas/laughing gas
Usually all other methods are preferred over oral injections. It’s mostly due to the fear of the patient for the shots and syringes.
After the tooth is completely painless a dentist will begin the procedure of root canal treatment which consists of three main steps as stated earlier.
Gaining Access to the Nerve of the Tooth
After your tooth is numb and before the actual procedure of gaining access to the root canal begins the dentist will place a rubber sheet called as the rubber dam around the tooth that has to undergo endodontic treatment. The rubber dam is held around the tooth by small clamps grasping it and is stretched outside mouth on a plastic frame. The purpose of placing a rubber dam is not only to increase the accessibility and visibility and workability of the tooth involved but also to prevent the bacteria present in saliva to enter in the root canal being treated and actually being made free of infection inside it, to avoid a future reinfection and treatment failure.
The dentist will now start the root canal treatment procedure by using a drill to gain access to the nerve tissue of the tooth. This is accomplished by making an access opening in the form of a hole in the crown portion of the tooth that extends to the pulp chamber of the tooth. This opening is made on the chewing surface of the tooth in the back teeth and is made on the back surface of the teeth in the front teeth. Special to mention is that in some cases the pulp tissue might be already exposed due to traumatic injury, accidentally by the dentist or due to any other cause like enamel and dentinal developmental defects leading to the exposure of the nerve tissue by wearing away of the defected overlying enamel or dentine etc. When this happens usually the pulp chamber can be seen directly and so the access can be gained directly and much more easily to remove the infected nerve tissue of the tooth as compared to teeth needing entry of unexposed pulp.
Cleaning & Shaping the Interior of the Tooth
After the access is gained the dentist starts with the next step of cleaning and shaping of the interior of the tooth which includes the pulp chamber and all the root canals of the tooth. Cleaning is necessary to remove any the entire infection which involves the bacteria, toxins, the infected nerve tissue and other debris present inside the tooth. The cleaning process is done with the help of instruments called as files which look like straight pins but are actually having small rough projections on their surface and are not smooth. There are various methods of shaping the root canal. The dentist will use files of increasing size to move up and down the tooth along with using twist and turn motion (i.e. push and pull motion along with rotating movement.)This action scraps off the engaged dentinal fillings and infected tissue thus cleaning the root canal completely. The dentist uses various disinfectants and antiseptics like normal saline, sodium hypochlorite to continuously flush out the debris being disengaged while using files. The dentist prepares and shapes the root canal till the desired length. The preparation should not extend beyond the root tip but ideally should end a little short (about 1- 2mm) of the root tip. A dentist can place the file and take a diagnostic x-ray to determine the right length needed to be prepared and before deciding to proceed ahead. These days instead of conventional method of manually preparing the root canal drills called endodontic hand-pieces are being used to which the files are attached and on operating they cause the twist or vibrating movements of the files causing them to clean and shape the canal. These instruments have made the procedure much more sophisticated and faster making single visit root canal treatments a reality.
Filling the Canal with a Sterile Material
Also in cases where pain is felt slightly at the root tips a dentist may give dressing with medicatements which will cause the death of the remaining pulp tissue causing the pain to proceed with the root canal filling in the next sitting. Even if there is periapical abscess present it needs time for infection to get removed. By doing access opening followed by cleaning and shaping of the root canal a dentist provides an outlet for the infection to move out of the tooth and giving instant relieve to the patient. In these cases a dentist waits for infection to subside. Review is done by using x-rays at following visits. But recently some dentists believe there is no need to wait till infection subsides as the infection will itself dissolve once we cut the communication of the bacteria to the oral cavity from where it gets its food supply.Once we are sure of a sterile and well prepared canal we precede with the filling. This step is the most important in deciding the success of the root canal treatment as incomplete filling is the most common cause of treatment failure. Out of many filling materials available these days a plastic material called gutta percha is most commonly used material these days. It is available in preformed cones in the same sizes as those of the files which were used to clean and shape the root canals. An appropriately sized gutta percha cone is selected to start with the filling as was the size of the last file used to prepare the root canal which is also called as the master cone. An x-ray should be done after placing the first gutta percha master cone to check for accuracy before proceeding ahead. If any discrepancy exists in the x-ray it should be corrected before proceeding ahead. After that the gutta percha cones are used in decreasing size so that the root canals of the tooth are completely filled. A root canal sealer, a paste is used for adhesion of gutta percha cones with the tooth and cohesion with each other. The sealer can be applied to the root canals of the tooth and also to the gutta percha cones. The gutta percha cones are filled till there is no more space left to fill more cones in the root canal. In cases of drills operated files used to prepare root canals one main gutta percha cone might be enough to fill the canal. These are also called protaper gutta percha cones. Sometimes the gutta percha cones are heated to make them soft so that they can be more precisely adapted to the shape of the root canals of the tooth. Also available is plasticized gutta percha which can be placed in the root canals with the help of a gun which is similar to a hot glue gun. It warms a tube of gutta percha to make it extremely soft to enable it to easily flow into the root canals on being squeezed. Many other materials are also available. After the entire filling is completed the dentist will fill the entire tooth hole with a temporary filling material which is replaced by a permanent one on the next visit. Single sitting root canal treatment
After the root canal cleaning and shaping is completed, the next step of filling it with a sterile root canal filling material. This step is started only after the canal is completely disinfected or free of infection and prepared to desired size and length. In some cases like single visit root canal treatment it is filled the same day but otherwise it may be done after one week following cleaning and shaping. Till that time a dentist may place and completely seal off the root canal of the tooth with a temporary filling material to avoid contamination and re infection.