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.