Post hoc pairwise comparisons revealed that CD31+ vessel density was significantly higher in the symptomatic irreversible pulpitis samples compared to both the asymptomatic irreversible pulpitis (50.3 vs. 39.2, p = 0.031) and control (50.3 vs. 25.8, p = 0.001) samples. This evidence concerns the gene PECAM1 and pulpitis.