Pulp necrosis is the death of cells of the neurovascular bundle in the crown or root part of the tooth, resulting from complicated caries or traumatic damage to the tooth. The disease may be asymptomatic, but more often the main manifestation of pulp necrosis is a prolonged aching pain in the tooth from hot food. The diagnosis of this dental pathology is carried out on the basis of patient complaints, targeted dental x-ray, temperature tests and electrodontometry. For the treatment of pulp necrosis, endodontic treatment of root canals is carried out with their further filling.
Meaning
Pulp necrosis is an irreversible form of pulpitis. Some authors attribute pulp necrosis to chronic gangrenous pulpitis, others distinguish it as a separate pathology. With pulp necrosis, a part of the neurovascular bundle dies off in the crown or root pulp of the tooth. Due to the formation of necrotic nerve sites and impaired blood supply, the immune factors of the tooth are suppressed, conditions for the reproduction of bacteria arise. Pulp necrosis can develop in both milk and permanent teeth. Men and women of all ages are susceptible to this pathology. It is very important to diagnose pulp necrosis in time, because often inflammatory phenomena pass to the periodontal ligament and lead to damage to periodontal tissues.
Causes
There are several groups of factors that lead to the occurrence of pulp necrosis: chemical, bacterial, thermal and mechanical. Chemical necrosis of the pulp most often occurs as a result of the use of aggressive substances at the stage of caries treatment, for example, alcohol or phenol, etc. The substance penetrates into the pulp of the tooth through the dentine tubules, resulting in a chemical burn of the tissues of the neurovascular bundle of the tooth, which ends with its necrosis. Chemical necrosis of the pulp leads to the development of inflammatory phenomena in the periodontal ligament surrounding the tooth. This type of necrosis is detected by chance, when changes in the periapical tissues of the tooth are detected on the X-ray. Also, the doctor’s attention is attracted by the gray color of hard tissues. Such a tooth is most often previously treated for medium or deep caries.
With bacterial damage to the tooth pulp, mixed microflora is found in the tissues of the neurovascular bundle, while healthy tooth pulp is sterile. The main importance is assigned to streptococcus and Staphylococcus. Also, during microbiological examination, aerobic microorganisms are detected – Clostridium perfringens, Fusobacteria. Thermal necrosis of the pulp develops due to its burn during tooth processing, often during preparation for prosthetics. This occurs if the tips are used without water cooling, which causes overheating of the tissues.
Traumatic pulp necrosis can be the result of acute or chronic trauma. Acute tooth injury occurs with a single application of force, for example, as a result of a blow, fall. There is a rupture of periapical tissues, the blood supply to the tissues of the pulp chamber is disrupted, their necrosis occurs. Chronic trauma appears as a result of prolonged regular exposure to the periodontium. At first, this process is compensated, but later, due to a violation of the blood supply, pulp necrosis occurs. This phenomenon can occur with pathological tooth erasability, professional bad habits (for example, seamstresses – snacking on thread with their teeth, anglers – fishing lines).
Classification
In dentistry, there are colliquation and coagulation necrosis of the pulp. With colliquational necrosis, the affected tissue has a flabby consistency, may contain a large amount of fluid. This type of necrosis occurs when the tooth is affected by microorganisms and their waste products. Also, the development of colliquational necrosis is possible in the treatment of pulpitis by a biological method, namely, with direct coating of the tooth pulp with calcium hydroxide.
Coagulation necrosis is usually not associated with chronic infectious exposure. With this type of necrosis, hypoxia occurs and, as a result, necrotization of the tooth pulp site. Coagulation necrosis of the pulp occurs in acute periodontal trauma, when the nutrition of the neurovascular bundle of the tooth is disrupted. Most often, both types of necrosis are painless, pain occurs if such a type of bacteria as bacteroids is attached. This classification is important in the study of the pathophysiology of the process. In clinical practice, the main importance is given to the anamnesis of the disease, symptoms and data from additional research methods.
Symptoms
Pulp necrosis often develops asymptomatically. It may be detected accidentally during X-ray examination (orthopantomogram, computed tomography). In this case, necrosis is often combined with changes in the periapical tissues of the tooth. In some cases, the patient goes to the dentist with complaints of discoloration of the tooth. When examining the oral cavity, the dentist discovers a gray tooth. When opening the pulp chamber, a putrid odor is determined. The percussion of such teeth can be positive. The surface layers of the pulp are dirty gray, do not bleed. Root pulp probing can also be positive.
Some patients complain of pain from hot food. This is due to the vital activity of special bacteria, most often bacteroids. Exposure to hot temperature leads to the formation of gases in the tooth cavity. At the same time, a slow increase in pain is characteristic when the tooth is heated and a gradual fading when the irritant is eliminated. Patients with pulp necrosis almost always note that the tooth hurt earlier.
Diagnostics
Diagnosis of pulp necrosis is carried out on the basis of patient complaints, anamnesis of the disease, clinical picture. Thermal tests are used as additional research methods. So, a tooth with pulp necrosis will either not respond to thermal stimuli, or will give a positive reaction to hot.
On an X-ray (orthopantomogram, sighting images, computed tomography), changes in periodontal tissues are detected. There is an expansion of the periodontal gap, there may be bone resorption in the area of the tip of the tooth. With electrodontometry, results from 60 to 100 µA can be obtained, they are associated with the electrical conductivity of the pulp: the more nerve tissues are necrotized, the higher the conductivity of the electric current will be.
Differential diagnosis of pulp necrosis should be carried out with irreversible pulpitis and chronic apical periodontitis. With chronic apical periodontitis, painless probing will be observed throughout the root canal, there may be a fistula or a scar from the fistula, hyperemia of the transitional fold, such a tooth never reacts to temperature stimuli, EDI readings are more than 100mkA. With irreversible pulpitis, the reaction to temperature stimuli persists, probing is painful, night pains with irradiation to the adjacent area are characteristic.
Treatment
In case of pulp necrosis, endodontic treatment is performed. It implies careful treatment of root canals. Canal treatment is carried out in several stages. At the first visit, the walls of the root canals are mechanically cleaned with hand or machine tools, washed with antiseptic solutions based on sodium hypochlorite to remove necrotic organic pulp residues. To destroy microorganisms, calcium hydroxide is left in the channel for two weeks, which creates a highly alkaline environment that is harmful to bacteria. At the second visit, the channels are repeatedly washed with antiseptics (most often with a solution of chlorhexidine) and the root canals are sealed.
To prevent pulp necrosis, it is necessary to undergo regular examinations by a dentist, sanitize foci of chronic infection in the oral cavity, replace fillings with a violation of the marginal fit.
Literature
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