# Using Spatial Transcriptomics to Identify a Diagnostic Molecular Signature Associated with Reversible Dental Pulpitis

## TL;DR

This study uses spatial transcriptomics to uncover molecular signatures in dental pulpitis, offering a more accurate way to distinguish reversible from irreversible cases.

## Contribution

The paper introduces a novel transcriptomic framework for classifying pulpitis based on immune-fibroblast interactions and gene expression patterns.

## Key findings

- Reversible and irreversible pulpitis share immune-fibroblast ratios and TLR4/neuroinflammation activation.
- Genes like PTN and CXCL14 are upregulated in irreversible pulpitis, suggesting residual healing potential.
- Immune-fibroblast interactions, not just macrophage shifts, influence pulpitis progression.

## Abstract

Diagnostic protocols in endodontics rely heavily on subjective pain assessments and sensibility testing, which often fail to reflect the true histopathological and molecular state of the dental pulp. This limitation can result in misdiagnosis of reversible pulpal inflammation (pulpitis) as irreversible, leading to unnecessary devitalization of teeth that might otherwise respond to more conservative treatments. Improved understanding of pulp biology is essential to refine case selection and maintain tooth vitality.

We aim to investigate the transcriptomic profiles of pulpitis, identify inflammation subtypes, and improve classification beyond the traditional reversible/irreversible framework.

Spatial transcriptomics (Visium-CytAssist-V2) was used to analyze four dental pulp tissues. Cell deconvolution and differential gene expression analyses were performed to characterize transcriptomic signatures of healthy pulp (HL), reversible pulpitis (RP), and irreversible pulpitis (IP), with specific attention to coronal regions adjacent to carious lesions.

Clinically diagnosed IP samples, presenting with deep caries, percussion sensitivity, and lingering cold pain, shared molecular features with RP, including a similar immune-fibroblast ratio and activation of TLR4 and neuroinflammation pathways. IP samples showed upregulation of genes involved in immune signaling, cell migration, and tissue repair. Notably, increased PTN and CXCL14, along with decreased ENG (CD105), SELE, COL4A1, CXCL1, and CXCL13, may indicate residual healing potential. Immune-fibroblast interactions, rather than macrophage shifts alone, appear to influence pulpitis progression.

Our data suggest a distinct transcriptomic profile associated with pulp healing. These findings support a more nuanced diagnostic approach that emphasizes immune-fibroblast dynamics, with implications for improving pulp preservation through appropriate vital pulp therapy.