To obtain an accurate diagnosis of vital pulps in traumatised or cariously exposed teeth is a crucial step in order to achieve successful treatment. For such purpose, several indirect methods of pulp testing methods are used in clinical practice, which unfortunately only provide subjective results relied on patients' symptoms. The aim of our study was to evaluate non-invasive sensitivity and vitality tests for assessment of pulp tissue status, not yet used in clinical practice, in comparison to histological analysis of pulp tissue's components and inflammatory infiltration, regarding the progression of carious lesions. The methods used were magnetic resonance imaging (MRI), measurement of pulp tissue oxygenation using pulse oximetry (SpO2) and electrical sensibility test. Results were also compared between teeth having closed or open root apices. The study included 26 teeth of individuals aged between 11 and 19 (mean 14.3 ± 2.4). Before extractions, measurements of electrical sensitivity, SpO2 and MRI were performed. Levels of potential carious lesion progression were assessed on tooth surfaces using ICDAS (International Caries Detection and Assessment System). After extractions, histological analysis of vascularity, ground substance and collagen fibers presence as well as innervation of pulp tissue was preformed. These results were correlated with those of MRI (relaxation times of T2 mapping), SpO2 values and measurements of patients' electrical sensitivity threshold. SpO2 values statistically positively correlated with vascular volume density (p = 0.0182) and negatively with the volume density of residual pulp tissue (p = 0.00156). Measurements of patients' electrical sensitivity threshold negatively correlated with pulp innervation density (p = 0.0328). Teeth with closed apices were more densely innervated compared to group of teeth with open apices (p = 0.0268). SpO2 values negatively correlated with T2 relaxation times (p = 0.0446). Positive correlation between the level of carious lesion progression, assessed via ICDAS, and macrophage infiltration of pulp was found (p = 0.0284). Positive correlation was also found between T2 relaxation times and T lymphocyte pulp infiltration (p = 0.0183). The results of our study imply that the most appropriate method for assessment of vascularity of pulp tissue is pulse oximetry, and of innervation is an electrical sensibility test. Inflammatory response of pulp tissue infiltration with macrophages increases with progression of carious lesions. Inflammatory infiltration with T lymphocytes is best assessed with MRI using T2 mapping.
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