Differential Expressions of Inflammatory, Dentinogenic, Regulatory, Proliferative and Stemness Genes in Non-Carious and Carious Human Dental Pulp Tissues: An Ex Vivo Proof-of-Concept Study.

BACKGROUND

Dental caries demineralises the enamel and dentine of the teeth, and as infection progresses it can lead to pulpal inflammation, infection and severe pain.

AIM: To determine and compare the level of mRNA expression of Toll-like receptors ((TLR)-2, TLR-4 and TLR-9), tumour necrosis factor (TNF)-α, interleukins ((IL)-1α, IL-1β, IL-4, IL-6, IL-8, IL-17 and IL-23) as well as markers of dentinogenic (dentine matrix protein (DMP)-1, dentine sialophosphoprotein (DSPP)), regulatory (nuclear factor-kappa B (NF-κB1), mitogen activated protein kinase (MAPK1)), proliferative (mitogen activated protein kinase (MKi)) and stemness (sex determining region Y-box 2 (SOX2)) between non-carious and carious dental pulp tissues.

METHODOLOGY: This study undertook a comprehensive analysis of inflammatory markers including TLR-2, TLR-4, TLR-9, TNF-α, IL-1α, IL-1β, IL-4, IL-6, IL-8, IL-17 and IL-23, as well as markers of dentinogenic DMP-1, DSPP, NF-κB1, MAPK1, proliferative MKi and stemness SOX2 processes in healthy and carious pulp tissues using quantitative real-time reverse-transcription polymerase chain reaction.

RESULTS

We found higher levels of TLR-2, TLR-4, IL-6, IL-8, IL-17A, IL-23A, along with NF-κB1 and MKi67 in the carious pulps (p < 0.05). The concurrent upregulation of IL-17A and IL-23A may suggest the activation of the IL-23/IL-17 signalling axis in the carious pulps, a point underreported in the literature.

CONCLUSION

These findings highlight the crucial role of the immune system in pulpal inflammation and potential implications in developing targeted molecular treatments, supporting the need for further translational research.