The association between the histological extent of pulpal inflammation and periapical radiographic findings in teeth with symptomatic irreversible pulpitis

Pulpal and periapical diagnosis of teeth with carious pulp exposure partly relies on patients’ clinical signs and symptoms. Understanding the pulpal histopathological changes is essential to refining therapeutic strategies. Therefore, this study aimed to examine the pathological changes within the pulp and to evaluate the association between the histological extent of pulpal inflammation and the preoperative periapical radiographic findings. A total of thirty extracted permanent molars were included in the study, comprising three with clinically normal pulps and twenty-seven diagnosed with symptomatic irreversible pulpitis. Following extraction, teeth were processed for histological analysis. The specimens were sectioned longitudinally to a thickness of 5 μm and stained with hematoxylin and eosin. Patients’ information, including clinical signs, symptoms, and radiographic findings, was recorded. Two blinded evaluators independently assessed all specimens’ histological features. The association between the periapical radiographic findings and the histological extent of pulpal inflammation was statistically analyzed. Histologically, teeth with symptomatic irreversible pulpitis exhibited various degrees, patterns, and extents of pulp inflammation. Most cases demonstrated the coexistence of inflamed pulp, pulp necrosis, and normal pulp. Inflammation was confined to the coronal pulp in 48% of teeth and extended into the root canal in 52%. Logistic regression revealed a significant association between inflammation extending into the root canal and the presence of periapical radiographic changes (OR = 16.00, p = 0.018). The clinical diagnosis of symptomatic irreversible pulpitis was consistent with histological features indicative of irreversible pulpal inflammation of various types and extents. Periapical radiographic changes were associated with radicular extension of pulpal inflammation and may serve as an adjunctive indicator of inflammation extending into the root canal.