Altered peripheral blood mRNA and salivary biomarkers in dental anxiety: a cross-sectional study

Previous studies indicate that dental anxiety (DA) is associated with increased salivary cortisol and alpha-amylase, biomarkers of hypothalamic-pituitary-adrenal (HPA) axis and sympathetic-adrenal-medullary (SAM) activation. However, underlying molecular mechanisms remain unclear. This study aimed to explore whether peripheral blood mRNA expression levels of glucocorticoid receptor (GR), GR transcripts containing exons 1B (GR-1B), glutamate ionotropic receptor AMPA type subunit 1 (GRIA1), oxytocin (OT), oxytocin receptor (OTR), and Poly ADP-Ribose Polymerase 1 (PARP1), together with salivary cortisol and alpha-amylase levels, are associated with dental anxiety.

In this cross-sectional study, a total of 30 DA patients and 28 non-DA patients were included. The mRNA expression levels of GR, GR-1B, GRIA1, OT, OTR, and PARP1 in peripheral blood were determined by real-time quantitative polymerase chain reaction. Salivary cortisol and alpha-amylase concentrations were determined by enzyme-linked immunosorbent assay.

The expression levels of GR-1B mRNA were significantly higher in the DA group than in the non-DA group, whereas GRIA1 and OT mRNA expression levels were lower in the DA group. Concurrently, salivary cortisol and alpha-amylase levels were significantly higher in the DA group.

Dental anxiety may be associated with altered stress-related molecular expression and salivary biomarkers. These findings provide preliminary evidence of peripheral molecular and salivary changes associated with dental anxiety and may contribute to understanding its biological correlates.