Tissue Biocompatibility and Antimicrobial Properties of Sympathomimetic Nasal Solutions for Potential Use in Dental Pulpal Management.

OBJECTIVES: Sympathomimetic nasal solutions (SNS), containing oxymetazoline or phenylephrine, may be used directly onto dental pulp tissue and initiate hemostasis via activation of alpha-receptors that innervate arteriole smooth muscles. The aim of this study was to assess these SNS's biocompatibility with human dental pulp stem cells (hDPSCs) and ability to kill a deep caries-associated pathogen, Rothia dentocariosa. MATERIALS AND METHODS: A Kirby-Bauer disk diffusion susceptibility test assessed SNS zones of inhibition (ZOI) toward R. dentocariosa growth on agar plates. Over-the-counter (OTC) SNS containing 0.025% and 0.05% oxymetazoline (NS-OXY-kids, NS-OXY-original) and 1% phenylephrine (NS-PHE) were tested along with ingredients found in these nasal solutions: 0.025%, 0.05% oxymetazoline; 0.0125%, 0.025% benzalkonium chloride; and 0.2%, 1% phenylephrine (PHE). A second antimicrobial broth inhibition assay examined effects on R. dentocariosa planktonic growth. A 24-h recovery biocompatibility assay with resazurin (alamarBlue) was performed on hDPSC that were exposed to pure respective compound solutions, NS-OXY-kids, NS-PHE, and 1% PHE for 10 min. RESULTS: NS-OXY-kids, NS-OXY-original, NS-PHE, and 0.025% BKC were bactericidal toward R. dentocariosa with an average ZOI of (16.33 ± 2.22 [average ± SD] mm). NS-PHE had a small but statistically significant difference (17.83 ± 3.189 mm) between NS-OXY-kids (14.67 ± 1.033 mm); 0.0125% BKC had a smaller (p < 0.05) ZOI of 10.5 ± 0.837 mm. Solutions containing solely OXY (0.025%, 0.05%) and PHE (0.2%, 1%) demonstrated no bactericidal activity but had a slight bacteriostatic inhibition in the broth inhibition assay. The commercial OTC formulations of NS-PHE and NS-OXY-kids needed to be diluted 1:10 to have near 50% metabolic activity of hDPSCs normalized to untreated control cells. CONCLUSIONS: NS-PHE and NS-OXY (both original and kids) had antimicrobial activity toward R. dentocariosa and comparable biocompatibility with hDPSCs. SNS may have both hemostatic and antimicrobial properties if used as pulpal medicaments.