Background and Objectives: Streptococcus mutans (S. mutans) is the main microorganism associated with the presence of dental caries and specific serotypes of this bacteria have been related to several systemic diseases limiting general health. In orthodontics, white spot lesions (WSL), represent a great challenge for clinicians due to the great fluctuation of their prevalence and incidence during conventional orthodontic treatments. Although silver nanoparticles (AgNP) have been demonstrated to have great antimicrobial properties in several microorganisms, including S. mutans bacteria, there is no available information about anti adherence and antimicrobial properties of AgNP exposed to two of the most relevant serotypes of S. mutans adhered on orthodontic materials used for conventional therapeutics. The objective of this study was to determine anti-adherence and antimicrobial levels of AgNP against serotypes c and k of S. mutans on conventional orthodontic appliances. Materials and Methods: An AgNP solution was prepared and characterized using dispersion light scattering (DLS) and transmission electron microscopy (TEM). Antimicrobial and anti-adherence activities of AgNP were determined using minimal inhibitory concentrations (MIC) and bacterial adherence testing against serotypes c and k of S. mutans clinically isolated and confirmed by PCR assay. Results: The prepared AgNP had spherical shapes with a good size distribution (29.3 ± 0.7 nm) with negative and well-defined electrical charges (−36.5 ± 5.7 mV). AgNP had good bacterial growth (55.7 ± 19.3 µg/mL for serotype c, and 111.4 ± 38.6 µg/mL for serotype k) and adherence inhibitions for all bacterial strains and orthodontic wires (p < 0.05). The serotype k showed statistically the highest microbial adherence (p < 0.05). The SS wires promoted more bacterial adhesion (149.0 ± 253.6 UFC/mL × 10⁴) than CuNiTi (3.3 ± 6.0 UFC/mL × 10⁴) and NiTi (101.1 ± 108.5 UFC/mL × 10⁴) arches. SEM analysis suggests CuNiTi wires demonstrated better topographical conditions for bacterial adherence while AFM evaluation determined cell wall irregularities in bacterial cells exposed to AgNP. Conclusions: This study suggests the widespread use of AgNP as a potential anti-adherent and antimicrobial agent for the prevention of WSL during conventional orthodontic therapies and, collaterally, other systemic diseases.

It has been reported that patients with rheumatoid arthritis (RA) are more likely to exhibit periodontitis than patients without RA. However, the frequency and severity of dental caries in patients with RA is still unknown. The aim of the study was to investigate whether higher counts of cariogenic bacteria are present in RA patients in contrast to healthy subjects, and to ascertain whether the frequency and severity of dental caries are increased in RA patients. The study involved 160 adults: an RA group (n = 80) and a control group matched by age and gender (n = 80). The participants' dental status scores were determined based on the following indices: the Decayed, Missing and Filled Teeth (DMFT) index, the Filled and Sound Teeth (FS-T) index, Treatment Needs Index (TNI), Care Index (CI), and Integrative Dental Caries Index (IDCI). DNA copies of Streptococcus mutans (S. mutans) and Streptococcus sobrinus (S. sobrinus) were quantified using realtime polymerase chain reaction (PCR). The IDCI showed that the RA group was more affected, mainly presenting moderate to severe dental caries. The RA group also had higher global DMFT scores than the control group and scored higher on the decayed component of the DMFT index. The TNI and CI indicated that RA patients required more dental attention and appropriate treatment. The Streptococcus mutans count was significantly higher in the RA group. A complete basic oral examination, along with oral health instruction including adequate oral and dental hygiene, is crucial to prevent dental caries and associated complications in RA patients, since they appear to be more vulnerable than the non-RA population.

Dental caries is an infectious oral disease originated by the presence of different microorganisms from well-defined biofilms. Many treatments for dental caries have been demonstrated to be successful protocols; however, incidence and prevalence remain still high. Although silver nanoparticles (AgNPs) have shown excellent antimicrobial properties, even against different oral bacteria, there is no available scientific information that has evaluated the antimicrobial activity of AgNPs against oral biofilms from subjects with active dental caries. The objective of this research was to evaluate the inhibitory effect of AgNPs in dental biofilms from subjects with and without dental caries. Two sizes of AgNPs were prepared and characterized. Dental plaque samples were collected from 30 subjects with dental caries and 30 subjects with no dental caries. Microbiological analysis was determined by the minimum inhibitory concentration (MIC) of nanoparticles, and the presence and distribution of microbial strains were identified by polymerase chain reaction (PCR) assay. AgNPs had significant antimicrobial effects against all samples of dental plaque; however, the physical properties of AgNPs, as well as specific sociodemographic and clinical conditions from patients, were also associated with bacterial growth inhibition of Ag particles ( ). PCR confirmed the presence of oral bacteria associated with dental caries, such as S. mutans and S. sobrinus strains, principally. The AgNPs exhibited great potential to be used as an antimicrobial therapy for the control and prevention of dental caries.

Objective: To determine and compare the distribution of Porphyromonas gingivalis fimA genotypes in patients affected by Rheumatoid arthritis (RA) and periodontitis (PE). Materials and methods: This study involved 394 subjects divided into four groups, RA, PE, RA and PE and healthy subjects. PE was diagnosed by using clinical attachment loss (CAL) and probing depth (PD) indexes. Presence of P. gingivalis and its genotypes was identified by polymerase chain reaction in subgingival biofilm. Results: P. gingivalis was more frequent in patients with RA (82.69%), and fimA II genotype was the most frequent in all groups, especially in PE/RA (76.71%). There was statistical difference (p < .05) regarding the frequency of P. gingivalis genotypes such as fimA Ib, II and III. Conclusions: Distribution of P. gingivalis fimA II genotypes was different among groups, it could play a critical role in the presence of PE in RA patients.

Filifactor alocis and Dialister pneumosintes have been associated with the initiation and progression of periodontitis (PE). We determined and compared the frequency of both bacteria in patients with PE, rheumatoid arthritis (RA), and PE/RA simultaneously. Detection was performed by polymerase chain reaction in the subgingival biofilm. Bacteria were more frequent in patients with PE, and clinical periodontal parameters such as pocket depth (PD) and clinical attachment loss (CAL) were significantly higher in patients with PE/RA. F. alocis and D. pneumosintes could influence PD and CAL, hence participating in the initiation and progression of PE in patients with RA.