The Effect of Probiotic Lactobacillus acidophilus and Ethanolic Propolis Compound toward Nucleic Acid Deposition in the Extracellular Polymeric Substance of Root Canal Bacteria.

OBJECTIVE: This study aimed to evaluate the effects of Apis trigona ethanolic propolis and probiotic bacteria Lactobacillus acidophilus on the nucleic acid concentration in the extracellular polymeric substances (EPS) derived from biofilm of root canal bacteria. MATERIALS AND METHODS: Clinical bacteria of the root canal were cultured with ethanolic extract of propolis (EEP; 10 or 0.1%) and L. acidophilus. After the formation of biofilm was observed in the monolayer bacterial culture under several conditions, the enzymatic treatment and nucleic acid quantification were sequentially performed. STATISTICAL ANALYSIS: Independent t-test and Mann-Whitney were performed following data normality to analyze the significant differences of the treatment effect on the nucleic acid concentration in EPS from the isolated biofilm. RESULTS: The results showed that the nucleic acid concentration in EPS biofilm were not increased by coculture with L. acidophilus as probiotics. However, the treatment with 10% EEP could significantly increase nucleic acid concentration. CONCLUSION: This study suggested that the biosurfactants from probiotic bacteria L. acidophilus might be a promising candidate for endodontic treatment, arguably better than EEP in inhibiting biofilm maturation and complexity.

Evaluation of International Caries Detection and Assessment System (ICDAS)-related Caries Severity among Caries Risk Groups in Pendul District: An Observational Study.

AIM: The aim of this study was to evaluate the difference in severity of caries code 5 or 6 according to the International Caries Detection and Assessment System (ICDAS) among caries risk groups in Pendul district. MATERIALS AND METHODS: This was an observational study with a cross-sectional design. A total of 730 people who were residing in Pendul district belonged to population of this study. One of the inclusion criteria of this study was the people who were ≥5 years old according to World Health Organization. On the basis of our preliminary survey, we confirmed 660 people who fulfilled the inclusion criteria. The subjects were selected using the accidental simple random sampling. Slovin's formula was used with margin of error 8% to obtain the 138 subjected people. Of the 138 subjects studied, there were only 87 people who could be included in the further inclusion criteria by having dental caries code 5 or 6 according to ICDAS. The Kruskal-Wallis statistical test was used to analyze the differences as the data belong to nonparametric and there were three variable groups. Next, the Mann-Whitney U was used to test the differences between these variables. RESULTS: The results of this study showed that there was a significant difference in the severity of caries among caries risk groups (P < 0.05). CONCLUSION: The higher the caries risk the higher the caries severity that was observed. This result supported the potential use of caries risk assessment as a predictive and supportive tool to prevent the increasing caries severity in the community.

Sp6 regulation of Rock1 promoter activity in dental epithelial cells.

Sp6 is a transcription factor of the SP/KLF family and an indispensable regulator of the morphological dynamics of ameloblast differentiation during tooth development. However, the underlying molecular mechanisms remain unclear. We have previously identified one of the Sp6 downstream genes, Rock1, which is involved in ameloblast polarization. In this study, we investigated the transcriptional regulatory mechanisms of Rock1 by Sp6. First, we identified the transcription start sites (TSS) and cloned the 5'-flanking region of Rock1. Serial deletion analyses identified a critical region for Rock1 promoter activity within the 249-bp upstream region of TSS, and chromatin immunoprecipitation assays revealed Sp6-binding to this region. Subsequent transient transfection experiments showed that Rock1 promoter activity is enhanced by Sp6, but reduced by Sp1. Treatment of dental epithelial cells with the GC-selective DNA binding inhibitor, mithramycin A, affected Rock1 promoter activity in loss of enhancement by Sp6, but not repression by Sp1. Further site-directed mutagenesis indicated that the region from -206 to -150 contains responsive elements for Sp6. Taken together, we conclude that Sp6 positively regulates Rock1 transcription by direct binding to the Rock1 promoter region from -206 to -150, which functionally distinct from Sp1.

Ctip2-mediated Sp6 transcriptional regulation in dental epithelium-derived cells.

Tooth development relies on the interaction between the oral ectoderm and underlying mesenchyme, and is regulated by a complex genetic cascade. This transcriptional cascade is regulated by the spatiotemporal activation and deactivation of transcription factors. The specificity proteins 6 (Sp6) and chicken ovalbumin upstream promoter transcription factor-interacting protein 2 (Ctip2) were identified in loss-of-function studies as key transcription factors required for tooth development. Ctip2 binds to the Sp6 promoter in vivo; however, its role in Sp6 expression remains unclear. In this study, we investigated Sp6 transcriptional regulation by Ctip2. Immunohistochemical analysis revealed that Sp6 and Ctip2 colocalize in the rat incisor during tooth development. We examined whether Ctip2 regulates Sp6 promoter activity in dental epithelial cells. Cotransfection experiments using serial Sp6 promoter-luciferase constructs and Ctip2 expression plasmids showed that Ctip2 significantly suppressed the Sp6 second promoter activity, although the Sp6 first promoter activity was unaffected. Ctip2 was able to bind to the proximal region of the Sp6 first promoter, as previously demonstrated, and also to the novel distal region of the first, and second promoter regions. Our findings indicate that Ctip2 regulates Sp6 gene expression through direct binding to the Sp6 second promoter region. J. Med. Invest. 61: 126-136, February, 2014.