FEATURE CPD: ONE HOUR An introduction to endodontics Images Plus ©wildpixel/iStock/Getty Peter V. Carrotte1 introduces the basic principles of endodontics and explains the difference between endodontics and root canal treatment. Introduction What is the difference between root canal treatment For many patients the thought of having to have a ‘root canal’ and endodontic treatment? causes fear and dread. All members of the dental team need to be Although the two terms are ofen used as if they mean the same, fully informed of exactly what this involves in order to put their root canal treatment is in fact just one part of endodontic treatment. minds at ease. Obviously the dentist will already be quite familiar Whenever any restorative dental treatment is carried out the dentist with these procedures, and the dental nurse will have a fairly has to protect the pulp from damage. Te total care of the pulp is good understanding. However, other members of the dental called endodontics. For example, if decay has spread very deeply team may not be quite so sure. into the tooth but the infection has not yet entered the pulp, the Here is an explanation of the processes involved so that dentist will seal the dentine tubules and may place a small amount of all members of the team can familiarise themselves with the calcium hydroxide on an exposed part of the pulp to promote normal procedures and the terminology associated with them. healing and keep the pulp alive. Tis would be endodontic treatment, but not root canal treatment. What is root canal treatment? Root canal treatment is carried out when the tooth’s pulp, Why would a patient need root canal treatment? the soft tissue core of the tooth containing the blood Root canal treatment is usually prescribed to relieve pain and there supply, nerves and connective tissue necessary for the are three classic painful conditions that may be diagnosed. tooth’s growth and health, becomes damaged in some A toothache that lasts briefy and is only brought on by a stimulus way. This is usually caused by bacteria entering the such as hot or sweet shows that the pulp is slightly infamed. Tis pulp through a deep cavity or failed filling. Root canal would be diagnosed as reversible pulpitis. Pulpitis means that the treatment involves removing the damaged and infected nerve is infamed, but reversible means that if the cause is found pulp, shaping the root canal spaces so that the entire root and treated (an early cavity or exposed dentine for example) the canal system can be cleaned and disinfected, and then damage will fully recover. However, if the pain lasts a long time filling the space so that no more infection can enter. and occurs some times without any stimulus (for example waking Figure 1 shows a diagram of the clinical situation, Figure the patient up at night) the pulpitis is diagnosed as irreversible. 2 shows a radiograph of a tooth that needs root canal Te pulp has been so badly afected that it is dying. Root canal treatment, and Figure 3 shows a successfully root- treatment will remove the pulp and the pain. treated tooth. If the irreversible pulpitis is severe the pulp may die and become infected. Te infection (or products of the infammation) leaks 1Retired Senior Clinical Teacher and Endodontic Specialist, the Division of Restorative Dentistry, Glasgow Dental Hospital and School. www.nature.com/BDJTeam BDJ Team 31 © 2021 The Author(s), under exclusive licence to British Dental Association FEATURE Fig. 3 A radiograph showing a completed root canal treatment Fig. 2 A radiograph showing the clinical Fig. 1 A diagram of the some of the terms picture of the diagram in Figure 1 used in this paper, and problems that may lead to a tooth requiring root canal treatment. A – Enamel; B – Old flling; C – root canal are quite specifc and easily Dentine; D – Decay; E – Dental pulp space; long-term prognosis of an implant might removed. Once other more toxic bacteria are F – Apical abscess; G – Vital pulp tissue; H – Apical foramen be better than that for a difficult molar root introduced, treatment becomes more difcult treatment. and less successful. An American endodontist Te dental team should also be aware once said that if you have a patient you don’t out of the root canal through the apical that the pain might be stopped by applying like, and you want the root treatment to fail, foramen (where the nerves and blood a steroid/antibiotic paste to the pulp. It must all you have to do is spit in the root canal! Of vessels entered the tooth) and causes be understood that this only stops the pain course, the efect will be the same whether infammation of the surrounding bone. and the tooth will die painlessly. Root canal you spit in it or the patient does! Rubber dam Tis is diagnosed as periapical periodontitis treatment will still be required at some time prevents saliva entering the tooth during (infammation around the apex of the in the future. Of course, a patient who did not treatment. tooth) and results in loss of bone. Te classical sign on a radiograph can be seen in Figure 2. ‘There are three classic stages to root If the infammation in the bone becomes so severe that pus is formed the diagnosis canal treatment: isolation and is periapical abscess. Patients call all of these lesions abscesses, but it is only really an abscess when pus is present as seen in access; shaping and cleaning; Figure 4. Te pus will sometimes drain through the bone by making a narrow tube called a sinus, as seen in Figure 5. Once flling (usually called obturation). this happens the pain ofen disappears, but the patient may notice a bad taste. Root canal treatment is sometimes want to have root canal treatment may ask to Secondly, rubber dam also protects prescribed when there is no pain. Tis have such a dressing to preserve the tooth as the airway from the fne fles and strong might be if the root canal is needed for a long as possible before extraction becomes chemicals used. Figure 7 shows a fle that post to support a crown if the tooth is very inevitable. was dropped and had to be removed from broken down, or if the tooth is to be cut the patient’s intestines. Needless to say, an down to support an overdenture. What does root canal treatment expensive legal claim resulted which should involve? easily have been avoided. Once the tooth has What are the alternative treatments? Tere are three classic stages to root canal been isolated an access cavity is cut into the If the pain is severe the only real alternative treatment: isolation and access; shaping and pulp chamber to allow the fne instruments to may be extraction. However, the patient will cleaning; flling (usually called obturation). enter the nerve canals. Tis involves just the then have a gap that they may wish to be same drilling as for a routine flling. Figure 8 flled. If they don’t want to wear a denture this A. Isolation and access shows an access cavity for a lower molar. might involve a bridge requiring extensive It is essential that a rubber dam be applied to preparation of the adjacent teeth. the tooth being treated, as shown in Figure B. Shaping and cleaning Alternatively, and becoming increasingly 6, for two reasons: frstly, to prevent entry Shaping and cleaning involves opening the prescribed, would be an implant. The of non-dental bacteria to the root canal. root canals with fne fles to allow strong patient should be advised that the Te bacteria normally found in an infected disinfectant solutions to fush through 32 BDJ Team www.nature.com/BDJTeam © 2021 The Author(s), under exclusive licence to British Dental Association FEATURE improved shaping. The use of an EDTA Tere may be some discomfort around the lubricant, such as Glyde or FleEze, makes tooth following treatment; indeed, it is sensible filing easier and permits more efficient to warn the patient of this and advise the use dentine removal. of anti-infammatory painkillers for a few days Well shaped canals allow good access for following treatment. Patients are usually very the irrigant, ideally sodium hypochlorite. happy to do this if they have been warned in Tis is usually just called bleach, and may be advance, rather than being told when they bought from any supermarket. Tis will be telephone with discomfort on the day afer the a 5% solution, which may be diluted before appointment! use. All members of the team must know that Very, very occasionally a tooth that has this solution is being used, to protect their had a long-standing chronic periapical Fig. 4 Pus draining from a heavily infected own and the patient’s clothes from damage. infection may fare up seriously following tooth Needless to say, the patient should always treatment. Tis is called a ‘phoenix abscess’. wear protective glasses. If the irrigation Again, the patient should have been warned regime includes the use of an EDTA solution, that this might happen as part of obtaining the smear layer will be removed from the informed or valid consent, and antibiotics walls of the root canals and cleaning will be may be required. much better. Cleaning, or disinfection, may require an Is root canal treatment expensive? intervisit dressing of calcium hydroxide in To be carried out properly, root canal the root canals. A temporary flling will be treatment can be very time consuming and used to protect the root canal system between difcult.