Causes and Risk Factors of Pulp Necrosis
- Dental caries
- Dental trauma (luxation, extrusion, fractures without pulp exposure)
- Dental treatment
- Pulpitis
- Infection or abscess in the tooth
- Severity and type of dental injury
- Delayed treatment or inadequate management of dental trauma
- Extent of dental decay
- Presence of inflammation or infection in the pulp
- Age of the patient, with primary teeth being more susceptible

Histopathology and Inflammation in Pulp Necrosis
- Dental pulp is surrounded by dentine, limiting fluid build-up
- Increased pressure in the pulp due to inflammation can lead to necrosis
- Suppuration and purulence are common clinical signs
- Chemical mediators released from necrotic tissues cause further inflammation
- Destruction of pulp leads to periapical pathosis and bone resorption
- Initial inflammatory infiltrate includes lymphocytes, plasma cells, and macrophages
- Non-specific inflammatory mediators are released in response to bacterial assault and tissue injury
- Neuropeptides and calcitonin gene-related peptide (CGRP) are involved in the inflammatory response
- Increase in tissue pressure, blood viscosity, and decrease in blood flow cause necrosis
- Necrosis occurs gradually, with bacterial invasion leading to infection

Odontoblasts in Pulp Necrosis
- Odontoblast cell bodies decrease in number and size
- Tubular fluid flow can cause odontoblast nuclei to be aspirated into dentinal tubules
- Odontoblasts may release tissue injury factors
- Vacuolization, decrease in endoplasmic reticulum, and degeneration of mitochondria can occur
- It is unknown how odontoblasts die (apoptosis or necrosis)

Signs and Symptoms of Pulp Necrosis
- Pain (described as spontaneous, exacerbated by hot temperatures, relieved by cold temperatures)
- Crown discoloration (yellow, grey, or brown)
- Abscess and/or fistula
- Internal root resorption
- Increased tooth mobility
- Radiographic signs may include untreated caries, deep restoration, or previous pulp capping

Diagnosis and Treatment Options of Pulp Necrosis
- Negative vitality, periapical radiolucency, and grey tooth discoloration help diagnose pulp necrosis
- Altered translucency in the tooth is due to disruption of the apical neurovascular blood supply
- Thermal tests, pulse oximeter test, radiographic examination, and MRI scans are used for diagnosis
- Root canal treatment, pulpotomy, apexification, apexogenesis, and regenerative endodontic procedures are treatment options
- Extraction of the affected tooth as a last resort when other treatments are not feasible or successful
- Complications of pulp necrosis include periapical abscess or infection, tooth discoloration, loss of tooth vitality and function, spread of infection, and potential impact on the growth and development of permanent teeth in children.