Cariogenic properties of Streptococcus mutans clinical isolates with sortase defects

Remineralization potential of apacider mangosteen adhesive pastes on artificial carious lesions

Background/purpose

Attention to caries administration has altered toward an early finding of lesions and targeted to noninvasive management with a remineralizing agent. This study compared the remineralization potential of apacider mangosteen adhesive pastes (AMAP), 500-ppm fluoride toothpaste (FT500), and 1000-ppm fluoride toothpaste (FT1000) on artificial caries.

Materials and methods

Artificial caries were generated to enamel of eighty extracted human premolars. The specimens were allocated to four groups and subjected to pH-cycling with the application of testing agents (2 min each, for 10 days): (1) AMAP, dairy, (2) FT500, twice a day, (3) FT1000, twice a day, and (4) no treatment (NT). The surface microhardness was determined before demineralization, after demineralization, and after application of pH-cycling. The hardness, percent of hardness recovery (%HR), and percent of remineralization potential (%RP) were analyzed with ANOVA and Bonferroni's test (α = 0.05). Polarized light microscopy (PLM) was assessed for lesion depth.

Results

Significant differences in remineralization were observed upon various agents compared to NT (P < 0.05). A significant difference in remineralization was found among AMAP, FT1000, and FT500 (P < 0.05). No significant difference in %HR and %RP was observed between AMAP and FT1000 (P > 0.05). PLM signified greater decrease in depth for AMAP, compared to FT1000 and FT500, but no depth reduction for NT.

Conclusion

AMAP possesses comparable remineralization ability to FT1000. However, decreasing in depth of carious lesions was evinced with using AMAP more than FT1000 and FT500. AMAP was recommended as a potential remineralization material for handling initial caries.

Isolation and Identification of Potentially Pathogenic Microorganisms Associated with Dental Caries in Human Teeth Biofilms

Dental caries is attributed to the predominance of cariogenic microorganisms. Cariogenic microorganisms are pathological factors leading to acidification of the oral microenvironment, which is related to the initiation and progression of caries. The accepted cariogenic microorganism is Streptococcus mutans (S. mutans). However, studies have found that caries could occur in the absence of S. mutans. This study aimed to assess the presence of potentially cariogenic microorganisms in human teeth biofilm. The microorganisms were isolated from human mouth and freshly extracted human maxillary incisors extracted for reasons of caries. The isolates were sorted based on their acidogenic and aciduric properties, and the S. mutans was used as the reference strain. Four potentially cariogenic strains were selected. The selected strains were identified as Streptococcus salivarius (S. salivarius), Streptococcus anginosus (S. anginosus), Leuconostoc mesenteroides (L. mesenteroides), and Lactobacillus sakei (L. sakei) through morphological analysis followed by 16S rRNA gene sequence analysis. The cariogenicity of isolates was analyzed. We show, for the first time, an association between L. sakei (present in fermented food) and dental caries. The data provide useful information on the role of lactic acid bacteria from fermented foods and oral commensal streptococci in dental caries.

The enhancing antibiofilm activity of curcumin on Streptococcus mutans strains from severe early childhood caries

BACKGROUND

Streptococcus mutans (S. mutans) is one of the main cariogenic bacteria for caries. It was found that the clinical strains of S. mutans isolated from caries active population have stronger cariogenic ability than the isolates from caries-free (CF) people. Previous studies have found that curcumin can inhibit biofilm formation of S. mutans UA159. The objective of this study is to explore the antibiofilm effect of curcumin on the clinical isolates of S. mutans from severe early childhood caries(SECC).

RESULTS

The isolates from SECC group had more biomass than CF group (t = 4.296, P < 0.001). The acidogenicity and aciduricity of the strains from two groups showed no significant difference. After treatment with curcumin, the viability of biofilm was reduced to 61.865% ± 7.108% in SECC and to 84.059% ± 10.227% in CF group at 24 h (P < 0.05). The net reduction of live bacteria and total bacteria in the SECC group was significantly higher than that of the CF group (live bacteria t = 3.305, P = 0.016; total bacteria t = 2.378, P = 0.045) at 5 min. For 24 h, the net reduction of live bacteria and total bacteria in the SECC group was significantly higher than that of the CF group (live bacteria t = 3.305, P = 0.016; total bacteria t = 2.378, P = 0.045). The reduction of biofilm thickness reduced significantly in 5 min (t = 4.110, P = 0.015) and in 24 h (t = 3.453, P = 0.014). Long-term (24 h) curcumin treatment inhibited the amount of EPS in SECC group from (25.980 ± 1.156) μm³/μm² to (20.136 ± 1.042) μm³/μm², the difference was statistically significant (t = 7.510, P < 0.001). The gene of gtfC, gtfD, ftf, gbpB, fruA and srtA in the CF group and the gtfB, gtfC, gtfD, ftf, gbpB, srtA in SECC group were respectively reduced after 5 min curcumin treatment. After 24 h treatment, the gtfB, gtfC, gtfD, ftf, gbpB, fruA and srtA in both two groups were downregulation, all the differences were statistically significant.

CONCLUSIONS

Curcumin has antibiofilm activity on clinical strains of S. mutans, especially for those isolated from SECC.