Evaluating the cytotoxicity and efficacy of nanoemulsion containing propolis plus Nigella sativa nanoparticles for pulpotomy of primary teeth: randomised split-mouth clinical trial pilot study.

Purpose: Due to strong suggestions about natural compounds, we evaluated the cytotoxicity of propolis and Nigella sativa nanoemulsion (NEPNS) and its effect for direct pulp capping of primary teeth.

Methods: After preparing the NEPS extract, the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) cytotoxicity test was performed. Then amongst children referred to the paediatric department, those whose healthy canines had to be extracted for orthodontic reasons were chose. Subsequent to pulpotomy of both canines, NEPNS were placed on one side and calcium-enriched mixture (CEM) on the other as pulp capping. Finally, after 30 days, the teeth were extracted and a blind pathologist examined the histopathology sections of the samples. Statistical analysis was performed using one-way ANOVA, Tukey post hoc, and Fisher exact test (α = 0.05).

Results: Cytotoxicity test showed that cell viability exposed to 25 and 50 ppm of NEPNS were similar to the control group in 24 and 48 h. The histopathology showed that there was no significant difference between two groups in dentin bridge formation, pre-dentin production, foreign body reaction, and presence of dentin chips (P = 0.0242, 0.567, 0.098, and 0.999 respectively). Meanwhile, the inflammation was significantly lower (P = 0.0313) and odontoblastic differentiation was significantly higher in the CEM group (P = 0.015).

Conclusion: Incorporating NEPNS for direct pulp capping of primary teeth leads to mild inflammation comparing to CEM, but dentine bridge formation and developing pre-dentin was similar to the control group after 30 days.

Trial registration: This prospective study was registered at the national clinical trials registry virtual platform as IRCT20230312057689N1 on 2 April 2023.