Effectiveness of a nanoemulsion‑containing Nigella sativa nanoparticles encapsulated in propolis nanomicelles on dentin tubule occlusion: An scanning electron microscopy study

Abstract

Background: Dentin hypersensitivity (DH) is a prevalent clinical condition, occurring when exposed
dentin reacts to various thermal, chemical, or mechanical stimuli. Although different interventions such as
fluoride varnish, adhesives, and natural bioactive compounds have been tested, there is still a demand for
more effective and durable solutions.This study aimed to evaluate the ability of a nanoemulsion containing
Nigella sativa nanoparticles encapsulated in propolis nanomicelles to occlude dentinal tubules and to
compare its performance with fluoride varnish under the simulated acidic and mechanical challenges.
Materials and Methods: In this in vitro study, hydroethanolic extract of Nigella sativa was
encapsulated in propolis‑based micelles to prepare the nanoemulsion. Thirty‑six extracted human
third molars were sectioned at the mid‑crown and randomly assigned to four groups (n = 9): (1)
normal saline, (2) nanoemulsion (15‑min immersion), (3) nanoemulsion (30‑min immersion), and (4)
5% fluoride varnish. Each group was further divided into three subgroups: control (no challenge), acid
challenge, and simulated toothbrushing. Scanning electron microscopy at × 4000 magnification was
used to quantify the percentage of occluded dentinal tubules. Data were analyzed with the two‑way
analysis of variance and least significant difference post hoc tests at a significance level of P ≤ 0.05.
Results: Material type (P = 0.018), challenge regimen (P < 0.001), and their interaction (P < 0.001) significantly
influenced occlusion percentage. The highest occlusion was observed with nanoemulsion (30‑min
immersion) in the acid challenge subgroup (46.78%), followed by nanoemulsion (15‑min immersion)
after toothbrushing (41.85%), and fluoride varnish in the acid challenge subgroup (37.19%). Acidic and
brushing challenges significantly reduced occlusion in all groups (P < 0.001).
Conclusion: Nanoemulsion containing Nigella sativa nanoparticles within propolis nanomicelles
demonstrated superior dentinal tubule occlusion compared to fluoride varnish, with notable
resistance to acid and brushing challenges. Given their natural origin, anti‑inflammatory, and
remineralizing properties, such nanoformulations may offer an effective and biocompatible alternative
for managing DH. Clinical studies are recommended to validate these findings in vivo.
Key Words: Dentin‑desensitizing agents, dentin sensitivity, electron, microscopy, nanoparticles,Nigella sativa, propolis, scanning

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 Mahsa Fatahi: Pubmed,Google Scholar