Genotyping and Association of the Presence of Helicobacter Pylori in Dental Plaque and Gastric Biopsy Specimens in Dyspeptic Patients by PCR-RFLP Technique in Southwest of Iran

The oral cavity can act as an extra gastric reservoir for H pylori, and also the presence of the bacteria in the oral cavity is associated with a higher risk of dental caries development. The aim of this study was to determine the genotype and evaluate the association of the presence of H. pylori in dental plaque and gastric biopsy specimens in dyspeptic patients in Ahvaz, Southwest of Iran. In this study, 106 patients with recruited dyspeptic complaints were selected and from each patient, two gastric antral biopsy specimens and two dental plagues were examined. The presence of H. pylori was identified by the Rapid Urease Test (RUT) and the amplification of ureAB and 16S rRNA genes. Also, to verify a hypothetical mouth-to-stomach infection route, the enzymatic digestions of three genes of cagA, vacA, and ureAB in H. pylori strains isolated from dental plaques and stomach samples were compared for each same case. H. pylori was found in the stomach of 52.8% (56 /106) and the dental plaques of 17.9% (19/106) of the studied cases. On the other hand, H. pylori was recognized in the stomach of all 19 cases with oral colonization. Following a combination of restriction fragment length polymorphism (RFLP) patterns of these three known genes on stomach and dental plague samples, 14 and 11 unique patterns were seen, respectively. However, for all H. pylori-positive cases (19), the comparison of RLFP patterns of these genes in the dental plaque and gastric biopsy specimens was different for the same case. This study showed, no significant association was observed between the presence of H. pylori in dental plaque and the stomach of the same case.

An effective concentration of propolis extract to inhibit the activity of Streptococcus mutans glucosyltransferase enzyme

Background: According to Riset Kesehatan Dasar (Riskesdas) (2013) and the World Health Organisation (WHO), caries is still a global problem and highly prevalent in Indonesia. Caries is mainly caused by Streptococcus mutans with virulence factors known as glucosyltransferase (GTF). The GTF enzyme contribute to the pathogenesis of caries by converting sucrose to fructose and glucan, which are then used in the formation of biofilms and dental plaques. Natural propolis compounds containing flavonoids, terpenoids, saponins and tannins, can inhibit GTF enzyme activity. Purpose: This study aimed to determine an effective concentration of propolis extract for inhibiting the S. mutans GTF enzyme activity. Methods: This study used propolis extract at 14 μg/ mL, 16 μg/m and 1 μg/mL to determine the inhibitory effect on S. mutans GTF enzyme activity. The GTF enzyme were obtained from the supernatant from S. mutans culture centrifugation. The GTF enzyme activity was measured using high-performance liquid chromatography (HPLC) to calculate the fructose level. Results: The mean fructose concentration at 14 μg/mL, 16 μg/mL, and 18μg/mL were 3.31%, 1.56%, and 0.29%, respectively. Conclusion: The most effective concentration of propolis extract for inhibiting the effect of S. mutans GTF enzyme activity is 14 μg/mL.

Function-adaptive clustered nanoparticles reverse Streptococcus mutans dental biofilm and maintain microbiota balance

Dental plaques are biofilms that cause dental caries by demineralization with acidogenic bacteria. These bacteria reside inside a protective sheath which makes any curative treatment challenging. We propose an antibiotic-free strategy to disrupt the biofilm by engineered clustered carbon dot nanoparticles that function in the acidic environment of the biofilms. In vitro and ex vivo studies on the mature biofilms of Streptococcus mutans revealed >90% biofilm inhibition associated with the contact-mediated interaction of nanoparticles with the bacterial membrane, excessive reactive oxygen species generation, and DNA fragmentation. An in vivo examination showed that these nanoparticles could effectively suppress the growth of S. mutans. Importantly, 16S rRNA analysis of the dental microbiota showed that the diversity and richness of bacterial species did not substantially change with nanoparticle treatment. Overall, this study presents a safe and effective approach to decrease the dental biofilm formation without disrupting the ecological balance of the oral cavity.

Comprehensive analysis of bacteriocins in Streptococcus mutans

Streptococcus mutans produces bacteriocins that show antibacterial activity against several bacteria. However, comprehensive analysis of these bacteriocins has not been well done. In this study, we isolated 125 S. mutans strains from volunteers and determined their whole genome sequence. Based on the genome analysis, the distribution of each bacteriocin gene (mutacins I-IV, K8 and Smb) was investigated. We found 17, 5, and 2 strains showing 100% matches with mutacin I, mutacin II and mutacin III, respectively. Five mutacin III-positive strains had 2 mismatches compared to mature mutacin III. In 67 mutacin IV-positive strains, 38 strains showed 100% match with mutacin IV, while 29 strains showed some variations. In 23 mutacin K8- and 32 mutacin Smb-positive strains, all except one mutacin K8-positive strain showed 100% match with the mature peptides. Among 125 strains, 84 (65.1%), 26 (20.2%), and 5 (3.9%) strains were positive for one, two and three bacteriocin genes, respectively. Then, the antibacterial activity against oral streptococci and other oral bacterial species was investigated by using bacteriocin gene single-positive strains. Each bacteriocin gene-positive strain showed a different pattern of antibacterial activity. These results speculate that individual S. mutans strains may affect the bacterial composition of dental plaques.

Biofilm formation by Streptococcus mutans and its inhibition by green tea extracts

Dental Caries is considered one of the most existing and worldwide common diseases related to the oral cavity affecting both children and adults. Streptococcus mutans is the main cariogenic microorganism involved in the dental caries progression. Natural products such as herbal plants were found to have less side effects and economic value than those of the chemically synthesized antibiofilm agents. This study aimed to isolate Streptococcus mutans from different oral samples taken from saliva and dental plaques specimens to determine their capability for biofilm formation and to evaluate the antibiofilm activity of aqueous and alcoholic green tea extracts. The results revealed that 35, 4 and 1% of recovered dental plaque isolates exhibited strong, moderate and weak biofilm formation capabilities versus 26, 12 and 2% for those recovered from saliva. Two green tea extracts (aqueous and alcoholic) were tested for their antibiofilm formation activity against some selected S. mutans isolates. The results showed that the minimum biofilm inhibitory concentrations (MBICs) of the alcoholic and aqueous green tea extracts were in the range of 3.1 to 12.5 mg/ml and 6.5 to 50 mg/ml, respectively. Accordingly, green tea extracts can be incorporated in various oral preparations for preventing dental caries.

Epidemiological and etiological aspects of dental caries development

The infectious factor is etiological in the caries development. Early colonization of S. mutans is considered as a key point; another important caries-associated microorganism is Lactobacillus, which colonizes carious lesions later. Ecological shifts in the dental plaques against the background of weakened local immunity increase their cariogenicity and lead to the caries progression. The data obtained confirm the key importance of the oral colonization resistance in initiating dental caries and its progression. Thus, the biological status of dental plaque and the activity of cariogenic bacteria are regarded as the key mechanisms for the emergence of dental caries. Therefore, the in-depth study of oral microbial homeostasis, the factors supporting its dynamic balance, is extremely important for modern cariology that will greatly contribute to developing programs and recommendations for prevention of dental caries and its early detection in order to improve the general health of population.

Light-Induced Fluorescence-Based Device and Hybrid Mobile App for Oral Hygiene Management at Home: Development and Usability Study

Background Dental diseases can be prevented through the management of dental plaques. Dental plaque can be identified using the light-induced fluorescence (LIF) technique that emits light at 405 nm. The LIF technique is more convenient than the commercial technique using a disclosing agent, but the result may vary for each individual as it still requires visual identification. Objective The objective of this study is to introduce and validate a deep learning–based oral hygiene monitoring system that makes it easy to identify dental plaques at home. Methods We developed a LIF-based system consisting of a device that can visually identify dental plaques and a mobile app that displays the location and area of dental plaques on oral images. The mobile app is programmed to automatically determine the location and distribution of dental plaques using a deep learning–based algorithm and present the results to the user as time series data. The mobile app is also built with convergence of naive and web applications so that the algorithm is executed on a cloud server to efficiently distribute computing resources. Results The location and distribution of users’ dental plaques could be identified via the hand-held LIF device or mobile app. The color correction filter in the device was developed using a color mixing technique. The mobile app was built as a hybrid app combining the functionalities of a native application and a web application. Through the scrollable WebView on the mobile app, changes in the time series of dental plaque could be confirmed. The algorithm for dental plaque detection was implemented to run on Amazon Web Services for object detection by single shot multibox detector and instance segmentation by Mask region-based convolutional neural network. Conclusions This paper shows that the system can be used as a home oral care product for timely identification and management of dental plaques. In the future, it is expected that these products will significantly reduce the social costs associated with dental diseases.

Molecular Identification of Helicobacter pylori and IceA Genes Frequency from Dental Plaques Isolated from People Using PCR Method

Background and Aims: Helicobacter pylori (H. pylori) is a gram-negative, microaerophilic, spiral-shaped flagellated bacterium that is urease, catalase and oxidase positive. One of its pathogenicity factors is the iceA gene. H. pylori has recently been recognized as a genetic indicator for the development and evolution of duodenal ulcer disease in the East. This study aimed to determine the presence of this bacterium in gingival plaques in non-endocrine patients in Bojnourd city, and the polymerase chain reaction technique examined the percentage of iceA gene. Materials and Methods: A total of 100 samples of dental plaque were taken and transferred to a tube that has been physiologically placed. After DNA extraction, primer design was performed, and then the polymerase chain reaction was performed for the whole sample. Results: Of 100 samples examined in this study, two samples of H. pylori were positive (2%), and the frequency of the iceA gene of two samples was positive (100%). Conclusion: In the Bojnord city, the frequency of iceA gene in people is high, and the frequency of H. pylori in tooth plaques is low. Also, iceA gene can be considered as an indicator for predicting the contamination and risk of H. pylori infection in the region. To confirm the results, more molecular studies are required in other populations.

Suppressive Effects of Hainosan (Painongsan) against Biofilm Production by Streptococcus mutans

Streptococcus mutans, a bacterium that causes dental plaques, forms a biofilm on tooth surfaces. This biofilm can cause gingivitis by stimulating the gingival margin. However, there is no established treatment for biofilm removal. Hainosan (Painongsan), a traditional Japanese Kampo formula, has been used to treat gingivitis. Therefore, we investigated the biofilm suppressive effects of the hainosan extract (HNS) and its components on S. mutans. We conducted scanning electron microscopy and confocal laser microscopy analyses to clarify the anti-biofilm activities of HNS and its crude drugs. We also performed a quantitative RT-PCR assay to assess the biofilm-related gene expression. HNS showed a significant dose-dependent suppressive effect on biofilm formation. Both the scanning electron microscopy and confocal laser microscopy analyses also revealed the significant inhibitory effects of the extract on biofilm formation. Transmission electron microscopy analysis showed that HNS disrupted the surface of the bacterial wall. Furthermore, HNS reduced the hydrophobicity of the bacteria, and suppressed the mRNA expression of β-glucosyltransferase (gtfB), glucosyltransferase-SI (gtfC), and fructosyltransferase (ftf). Among the constituents of hainosan, the extract of the root of Platycodon grandiflorum (PG) showed the strongest biofilm suppression effect. Platycodin D, one of the constituent natural compounds of PG, inhibited S. mutans-associated biofilm. These findings indicate that hainosan eliminates dental plaques by suppressing biofilm formation by S. mutans.