Screening for objective indicators in pulp blood to distinguish the degree of pulpitis

This study aimed to (1) evaluate the accuracy of pulp blood color parameters-L* (brightness) and a* (red chroma)-in assessing the clinical severity of pulp inflammation; (2) identify key biomarkers in pulp blood associated with pulp inflammation degree.

Teeth in clinical cases were categorized into four groups based on pre-operative diagnosis and intra-operative microscopic evaluation of the dentine, exposed pulp tissue, and bleeding. Group 1 included intact teeth with normal pulp as the control group. Groups 2, 3 and 4 were teeth with carious pulp exposure: Group 2 exhibited no signs of infection in the pulp tissue or surrounding dentine; Group 3 exhibited infected pulp tissue or dentin surrounding the exposure that was confined to the coronal portion; and Group 4 had infected pulp tissue extending into the radicular pulp. Pulp blood samples were obtained from pulp exposure sites of above teeth. After centrifugation, twenty inflammatory biomarkers in the supernatant of pulp blood were quantified using a multiplex immunoassay. Color parameters (L* and a*) of the residual pulp blood samples were measured using a spectrophotometer. One-way ANOVA was used to compare the L* and a* values across groups. The Kruskal-Wallis test was used to compare biomarker levels. The level of significance was set at 2-tailed P < 0.05.

A total of 97 cases were included in the final analysis: Group 1 (n = 25), Group 2 (n = 17), Group 3 (n = 25) and Group 4 (n = 30). With increasing clinical inflammation severity from Groups 1 to 4, the L* value of pulp blood significantly decreased, while the a* value increased (P < 0.05). Compared to Group 1, the levels of MMP-9, IL-1β, osteoactivin, OPN, IL-8 and the IL-8/IL-10 and IL-6/IL-10 ratios in pulp blood were significantly higher in Group 2, 3 and 4 (P < 0.05), while the levels of TGF-β1 presented with the opposite trend (P < 0.01).

Color characteristics and molecular biomarkers in pulp blood could serve as objective indicators for assessing pulp inflammation degree and may further provide a basis for selecting vital pulp therapy strategies.

These findings have the potential to enhance the diagnostic accuracy of pulpitis and support clinical decision-making in vital pulp therapy, ultimately improving clinical outcomes and tooth survival.