Introduction

Dental pulp originates from the neural crest cells by a proliferation of ectomesenchyme into dental papilla from which mature pulp is derived. It resides inside the pulp chamber enclosed by enamel, dentine, and cementum which provide protection from oral fluids and micro-organisms. Once this barrier is broken down, the pulp is exposed to various adverse stimuli in the oral cavity that lead to pulpal death or necrosis. It can occur as a result of caries, cracks, restoration margins and fractures. Microorganisms gain entry through these pathways and enter the pulp chamber, thereby destroying the pulp.¹

Definition of pulp necrosis

Pulp necrosis is defined as the death of pulp tissue with or without bacterial invasion. It can result from bacterial, mechanical or chemical irritation of the pulp. It is an unfavourable outcome of traumatic dental injuries and can also be seen in traumatised primary teeth. Any trauma to pulp is exhibited in the form of inflammation and if left untreated, progresses to necrosis.

Importance of addressing pulp necrosis

Any abnormality associated with the pulp should be immediately addressed because if left unattended, it can progress to serious and life-threatening conditions like oral sepsis. Infection from both maxillary and mandibular teeth can result in space infections and untreated teeth need to be extracted which also affects the dentition and overall health of an individual.²

Causes of pulp necrosis

Pulp necrosis is caused by the following reasons:

Dental trauma

Trauma due to dental apparatus in various forms like accidents, bruxism, root or crown fracture and severe intrusion can damage the pulpal blood supply and can cause pulp necrosis. 

Untreated dental caries

Dental caries serve as a pathway for the entry of microorganisms into the pulp and cause necrosis.

Dental procedures or surgeries

Various dental procedures like cavity preparation, pin insertion, acid etching, large restorations, and orthodontic movement can cause pulpal damage. 

Other contributing factors

Other factors that contribute to pulp necrosis include ageing, systemic disorders, and the seeping of chemicals from the oral cavity.³

Symptoms of pulp necrosis

Symptoms of pulpal necrosis are dependent on a variety of factors like number of infected teeth, age, type of organism, immune response and past medical history. Tooth discoloration is the first stage of necrosis marked initially by the crown turning pale to becoming darker in the later stages. If left untreated, pulp necrosis manifests itself as a painful and discomforting condition. Swelling, tenderness and abscess formation are also common symptoms of pulp necrosis.⁴

Diagnosis of pulp necrosis

The diagnosis of Pulp necrosis is based on a combination of clinical examination, vitality test and radiographic examination.

Clinical examination

A past history of trauma, restorations and caries is vital in diagnosing pulp necrosis. Pain may or may not be present. Sometimes patients complain of dull, continuous pain which is aggravated by heat and relieved by cold. 

Radiographic imaging

Radiographic changes are not significant in pulp necrosis and any periapical involvement occurs only when the necrotic pulp becomes infected.

Pulp vitality tests

A necrotic pulp doesn’t respond to vitality tests but this can give false positive results as there are other conditions like pulp calcifications, pulpotomy and previous restorations which also do not respond to vitality tests.⁵

Treatment options

Treatment of pulp necrosis depends on whether the tooth is mature or immature. 

If pulp necrosis occurs in an immature tooth, the root formation is not complete and conventional endodontic treatment is not possible because of the lack of apical stop. In such cases, regeneration of the apical stop followed by a conventional root canal procedure is the treatment of choice. This also ensures the deposition of secondary dentin and makes the tooth robust for future dental procedures if required. 

Immature teeth

Apexification

Apexification is defined as “a method of inducing a calcified barrier in a root with an open apex or the continued apical development of an incompletely formed root in teeth with necrotic pulp. Formation of the apical barrier using mineral trioxide aggregate (MTA) or calcium hydroxide is recommended to complete the root formation in immature teeth with necrotic pulp to induce apical closure.

Apical barrier

Non-surgical insertion of a Biocompatible material into a root canal to establish an apical stop is recommended for immature teeth. It is also known as one-visit apexification. The material to be inserted should be non-toxic as it has to come in close contact with the periapical tissues. It also should have good sealing ability, be dimensionally stable, be able to resist masticatory forces and should not be soluble in oral fluids. 

Regenerative endodontics

It is defined as a biological procedure that is designed to replace damaged dental apparatus including the pulp-dentin complex. Dental pulp has the potential for neural and vascular regeneration. This procedure allows the removal of necrotic pulp and its replacement with healthy pulp tissue.⁶

Mature teeth

Root canal treatment is the standard treatment procedure for teeth with necrotic dental pulp in which root formation is complete.

• The pulp chamber of the tooth is opened and any remaining debris or necrotic pulp is removed
• The root canals are then filled with any obturating material of choice. This procedure allows the healing and regeneration of the periradicular tissues
• It is essential to assess any remaining tooth structure before proceeding to perform any type of endodontic or restorative treatment
• Extraction of the tooth is carried out in cases where the prognosis is very poor⁷

Preventive strategies⁸

Regular dental check-ups

Annual or bi-annual oral examination ensures the maintenance of healthy teeth. Routine dental visits should be normalised and not considered a last resort but a preventive method. 

Prompt treatment of dental caries

Untreated caries progresses from enamel to dentine and reaches the pulp causing pulpal inflammation. If still left untreated, this condition can lead to pulp necrosis. Timely treatment can help prevent the pulp from getting necrosed. 

Protective measures during dental procedures

Care should be taken to ensure the vitality of the pulp is maintained during dental procedures. High temperatures, drying and desiccation of teeth and pulp during the use of drilling equipment should be avoided. 

Trauma prevention

Mouth guards and occlusal splints are required to prevent trauma from sports injuries or bruxism.

Proactive dental care

Diet

Decreased consumption of sticky and sugary foods and drinks. Tooth erosion from carbonated drinks should be avoided, gastric regurgitation should be treated with antacids, and proper brushing should be followed to avoid food accumulation and plaque deposits. 

Fluoridation

Water fluoridation is an effective strategy to reduce caries incidence which ultimately helps in preventing pulp necrosis. For children prone to caries, fluoride supplements should be given. 

Summary

Any tooth with a history of deep restorations, sensitivity to hot and cold, and incomplete caries removal is likely to have a damaged pulp and Root Canal Therapy is indicated in such cases. If a pulp is necrotic, the patient is unlikely to have any pain leading to the impression that there is nothing wrong with the tooth. In such cases, it is important that appropriate treatment is carried out to prevent the spread of infection in the later stages as a necrotic pulp is likely to get infected. Root canal therapy is the gold standard treatment followed by restorative procedures. Following a proactive approach to dental care, early intervention and regular checkups can help prevent the likelihood of necrotic pulp and promote oral health.