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Dentin from deep carious lesions treated with PACT showed a decrease in cariogenic microbial load.

The application was successful regarding the following three assessed attributes: (1) effectiveness, (2) efficiency, and (3) satisfaction. However, dietary education was observed to be necessary for the children and their guardians.

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Photodynamic therapy decreased the diameter of S. mutans cells and AFM may be used as a technique for bacterial cell analysis.

Cariogenic oral biofilms cause recurrent dental caries around composite restorations, resulting in unprosperous oral health and expensive restorative treatment. Quaternary ammonium monomers that can be copolymerized with dental resin systems have been explored for the modulation of dental plaque biofilm growth over dental composite surfaces. Here, for the first time, we investigated the effect of bis(2-methacryloyloxyethyl) dimethylammonium bromide (QADM) on human overlying mature oral biofilms grown intra-orally in human participants for 7–14 days. Seventeen volunteers wore palatal devices containing composite specimens containing 10% by mass of QADM or a control composite without QADM. After 7 and 14 days, the adherent biofilms were collected to determine bacterial counts via colony-forming unit (CFU) counts. Biofilm viability, chronological changes, and percentage coverage were also determined through live/dead staining. QADM composites caused a significant inhibition of Streptococcus mutans biofilm formation for up to seven days. No difference in the CFU values were found for the 14-day period. Our findings suggest that: (1) QADM composites were successful in inhibiting 1–3-day biofilms in the oral environment in vivo; (2) QADM significantly reduced the portion of the S. mutans group; and (3) stronger antibiofilm activity is required for the control of mature long-term cariogenic biofilms. Contact-killing strategies using dental materials aimed at preventing or at least reducing high numbers of cariogenic bacteria seem to be a promising approach in patients at high risk of the recurrence of dental caries around composites.

This study utilized the confocal Raman microspectroscopy (CRM) technique for the first time to investigate the degree of the penetration of toluidine blue-orto (TBO) in artificial caries lesions produced by two distinct caries-inducing models. The dentin specimens (n = 10) were divided into three groups: control, in vitro and in situ. Thereafter, the lesion depth and the demineralization level were evaluated by cross-sectional microhardness (CSMH). CRM mapping across the dentin surface was assessed after the dye application. The CSMH and CRM data were analyzed by t-test and ANOVA, respectively (P < 0.05). The values of the lesion depth and the demineralization areas were higher for in situ samples (P < 0.05). The TBO penetration values (μm) for the control, in vitro and in situ groups were 44.8 ± 5.6, 46.1 ± 4.5 and 51.2 ± 8.5, respectively. There were no statistically significant differences among the groups (P > 0.05). The rate of TBO penetration was detected up to about <50 μm and the demineralization level did not influence the results. These results have showed promising parameters to develop new protocols for deep caries lesions management using photodynamic antimicrobial chemotherapy.

Bacterial biofilms play a key role in the pathogenesis of major oral diseases. Nanoparticles open new paths for drug delivery in complex structures such as biofilms. This study evaluated the antimicrobial effect of zein nanoparticles containing anacardic acid (AA) extracted from cashew shells of Anacardium occidentale on in vitro Streptococcus mutans biofilm formation and mature biofilms. The minimum inhibitory concentration (MIC), minimum bacterial concentration (MBC), and antibiofilm assays were performed. Streptococcus mutans UA159 biofilms were formed on saliva-coated hydroxyapatite disk for 5 days. To evaluate the preventive effect on biofilm formation, before contact with the inoculum, the disks were immersed once for 2 min in (1) hydroethanolic solution; (2) blank zein nanoparticles; (3) zein nanoparticles containing AA; and (4) 0.12% chlorhexidine gluconate. To determine the effect against mature biofilms, the disks containing 5-day preformed biofilms were further treated using the same procedure. The bacterial viability and dry weight were determined for both assays and used to compare the groups using ANOVA followed by Tukey's test (p < 0.05). Both MIC and MBC for AA-loaded zein nanoparticles were 0.36 μg/mL. Groups 3 and 4 were very effective in inhibiting S. mutans biofilm formation, as no colony-forming units were detected. In contrast, for mature biofilms, no difference in bacterial viability (p = 0.28) or dry weight (p = 0.09) was found between the treatments. Therefore, the AA-based nanoformulation presented very high inhibitory and bactericidal activities against planktonic S. mutans, and the results indicate a strong antiplaque effect. However, the formulation showed no antimicrobial effect on the established biofilm.