The Effect of Green-Synthesized Nanoparticles on Dental Caries-Causing Bacteria: A Systematic Review
Authors: Sepahdar Asma , Selahbarzin Behnoush , Naini Atoosa Vaez , Jafari Samira , Moradi Mehrnaz , Shakib Pegah 
Published: December 2024

Introduction:
In this study, a comprehensive search was conducted across multiple databases,
including PubMed, Google Scholar, SID, Scopus, Medline, and Web of Science, as well as
selected herbal medicine journals. The inclusion of herbal medicine journals was justified by the
growing interest in green-synthesized nanoparticles derived from plant extracts, which are relevant
to the focus of this review. Articles published between 2015 and 2023 were evaluated. To ensure a
robust selection process, studies were assessed for quality using specific criteria beyond the AXIS
checklist, including study design, sample size, and methodological rigor. Any discrepancies between
reviewers were resolved through discussion or consultation with a third reviewer. This approach
aimed to minimize bias and ensure the inclusion of high-quality studies that contribute
meaningfully to the review’s objectives.

Objective:
The primary objective of this review was to investigate the therapeutic implications of
green-synthesized metallic nanoparticles, such as silver and zinc nanoparticles, in addressing dental
caries, with a focus on their antibacterial properties and potential to improve current treatment
modalities.

Materials and Methods:
In this study, PubMed, Google Scholar, SID, Scopus, Medline, Web of Science,
and herbal medicine journals were searched, and articles from 2015 to 2023 were evaluated.

Results:
In this study, 22 clinical trials were reviewed, and the effectiveness of synthesized nanoparticles
was demonstrated in nearly all of them. The nanoparticles found to be most effective
against tooth decay-causing bacteria include silver, zinc, selenium, nickel, and copper nanoparticles.
To provide greater clarity, key findings, such as nanoparticle size, minimum inhibitory concentration
(MIC) values, and specific antibacterial effects, are presented in a table. Additionally, a
more in-depth comparison was made between these nanoparticles, focusing on their relative effectiveness
under different conditions. For example, silver nanoparticles were consistently effective
across various trials due to their strong antimicrobial properties, while zinc and copper nanoparticles
showed efficacy in specific concentrations and against particular bacterial strains. Furthermore,
green-synthesized nanoparticles were compared with those produced using traditional methods,
evaluating factors, such as effectiveness, scalability, and safety, to provide a comprehensive
understanding of their potential in dental caries treatment.

Conclusion:
According to the literature review, nanoparticles with antibacterial properties have the
potential to serve as an alternative or complement to conventional chemical treatments for combating
tooth decay. Future research should focus on exploring specific types of nanoparticles, such as
green-synthesized metallic nanoparticles (e.g., silver and zinc), which have shown promising antibacterial
effects. Additionally, more emphasis should be placed on optimizing synthesis methods
that enhance biocompatibility and scalability for clinical use. The development of affordable
treatment options using medicinal plants for green synthesis is particularly promising and should
be further explored to make nanoparticle-based therapies more accessible in clinical settings.