AgNPs: The New Allies Against S. Mutans Biofilm - A Pilot Clinical Trial and Microbiological Assay.

Priscila L.L Freire,André Galembeck,Fabio C Sampaio,Aronita Rosenblatt,Miguel A P Flores,Thayza C M Stamford,Allan J.R Albuquerque

doi:10.1590/0103-6440201600994

Abstract

The purpose of this study was to evaluate the antimicrobial properties of a new formulation containing silver nanoparticles, named Nano Silver Fluoride (NSF), to inhibit Streptococcus mutans biofilm formation on children's dental enamel. The variations in dental biofilm pH and in the Simplified-Oral-Hygiene-Index (OHI-S) also were evaluated after the treatment with NSF. This was a randomized, double-blind, crossover and prospective pilot clinical trial study in which 12 schoolchildren, aged between 7-8 years, had their dental enamel treated with two solutions: S1 - Nano Silver Fluoride and S2 - negative control (saline solution), in different experimental moments. The dental biofilm adhered to enamel treated with NSF had lower values of S. mutans viability (absorbance) and colony forming units (CFU) than the S0 (baseline) and S2. There was a statistically significant difference between the OHI-S mean values of S0 and S1. There were no differences between the biofilm pH (both before and after the use of the test substances) and among the different groups. These properties suggest that NSF has bactericidal effect against S. mutans biofilm and it may be used for clinical control and prevention of dental biofilm formation.

Highlights

Dental caries remain a major public health issue that affects 95% of the world’s population, mostly in developing countries, which lack access to dental care [1]
This study evaluated the antimicrobial efficacy of Nano Silver Fluoride on S. mutans growth in children’s dental biofilms, variations in dental biofilm pH after product application and the Simplified-Oral-Hygiene-Index (OHI-S) of the treated tooth surfaces
The samples treated with Nano Silver Fluoride (NSF) revealed lower colony forming units (CFU) counts compared to the other groups (Table 1)

Summary

Introduction

Dental caries remain a major public health issue that affects 95% of the world’s population, mostly in developing countries, which lack access to dental care [1]. Owing to its acidogenic and aciduric characteristics that contribute to colonization of the tooth surface, dental plaque formation and to demineralization of hard dental tissues, Streptococcus mutans is regarded as the main bacterium related to the initiation of dental caries [2]. Laboratory studies have reported that SDF prevents the formation of Streptococcus mutans, Streptococcus sobrinus, Actinomyces naeslundii, Lactobacillus acidophilus and Lactobacillus rhamnosus biofilms [5], but its use for dental purposes is generally not encouraged, because it induces black tooth discoloration. The use of nanoscale has eliminated this problem, either in caries lesion or in healthy dental tissue, in addition to enhancing chemical and antimicrobial properties and reducing cell toxicity [6,7,8,9,10,11]. AgNPs have little or no cytotoxicity [6,7] and clinical application has become possible without risks

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