Metagenomic analysis of black-stained plaques in permanent dentition

Chromogenic bacterial staining of teeth: a scoping review

BACKGROUND

The purpose of this scoping review is to understand the etiological, clinical characteristics and treatment of chromogenic staining of teeth and the various management strategies reported in literature. This SR was performed in accordance with the PRISMA 2022 guidelines and was registered in the PROSPERO database (CRD42024565446).

METHODS

A systematic electronic search on databases like Scopus, Medline, EMBASE, CINAHL, ProQuest and Web of Science from inception to July 2024 was performed. Two independent reviewers ran the search strategy in the mentioned databases.

RESULTS

A total of 989 articles were obtained from various databases. 21 were included for data extraction of which 2 were case reports, 1 was case series and 18 were research articles. The prevalence of staining due to chromogenic bacteria reported from the included studies ranged from 3.1 to 18.5%. All these studies reported on the typical black color of staining of teeth.

CONCLUSION

This scoping review reveals sparsity in existing literature regarding the etiological, clinical characteristics and management of chromogenic staining of teeth. Though the role of peculiar oral microbiota is well established, evidence regarding the management strategies to combat these recalcitrant staining remains a strong research question.

Clinical assessment of various imaging systems for dental plaque scoring after the use of 3 different toothpastes

Purpose

This study was conducted to compare dental plaque scores obtained through clinical examinations and various imaging techniques, as well as to assess the effectiveness of herbal and conventional toothpastes for plaque removal.

Material and Methods

Thirty volunteers were divided into 3 groups. Each group was given a different toothpaste (from 2 herbal toothpastes and a conventional toothpaste) with which to brush their teeth for 21 days. Both initially and after brushing, dental plaque samples were collected, and plaque on the buccal surfaces of anterior teeth was scored using several imaging systems after staining with a disclosing agent. Specifically, digital dental photography, intraoral digital scanning, and FluoreCam imaging were employed to capture intraoral images. The Turesky Modified Quigley-Hein Plaque Index was used for clinical examination and image analysis. Quantitative polymerase chain reaction analyses and correlational assessments between clinical examination and imaging scores were conducted before and after toothpaste use. The Shapiro-Wilk test and Pearson correlations were utilized.

Results

The lowest mean value was observed in the clinical examination without staining, while the highest was obtained using the FluoreCam method. No significant change was found in the level of any microorganism assessed following toothpaste use (P<0.05), with the exception of a decrease in S. mutans levels after using conventional toothpaste (P<0.05).

Conclusion

Herbal toothpaste demonstrated plaque-removal effectiveness comparable to that of conventional toothpaste. The use of imaging methods for measuring plaque index has been suggested as a means to educate patients about plaque control and promote ongoing oral care.

Tomato Plant Microbiota under Conventional and Organic Fertilization Regimes in a Soilless Culture System

Tomato is the main vegetable cultivated under soilless culture systems (SCSs); production of organic tomato under SCSs has increased due to consumer demands for healthier and environmentally friendly vegetables. However, organic tomato production under SCSs has been associated with low crop performance and fruit quality defects. These agricultural deficiencies could be linked to alterations in tomato plant microbiota; nonetheless, this issue has not been sufficiently addressed. Thus, the main goal of the present study was to characterize the rhizosphere and phyllosphere of tomato plants cultivated under conventional and organic SCSs. To accomplish this goal, tomato plants grown in commercial greenhouses under conventional or organic SCSs were tested at 8, 26, and 44 weeks after seedling transplantation. Substrate (n = 24), root (n = 24), and fruit (n = 24) composite samples were subjected to DNA extraction and high-throughput 16S rRNA gene sequencing. The present study revealed that the tomato core microbiota was predominantly constituted by Proteobacteria, Actinobacteria, and Firmicutes. Remarkably, six bacterial families, Bacillaceae, Microbacteriaceae, Nocardioidaceae, Pseudomonadaceae, Rhodobacteraceae, and Sphingomonadaceae, were shared among all substrate, rhizosphere, and fruit samples. Importantly, it was shown that plants under organic SCSs undergo a dysbiosis characterized by significant changes in the relative abundance of Bradyrhizobiaceae, Caulobacteraceae, Chitinophagaceae, Enterobacteriaceae, Erythrobacteraceae, Flavobacteriaceae, Nocardioidaceae, Rhodobacteraceae, and Streptomycetaceae. These results suggest that microbial alterations in substrates, roots, and fruits could be potential factors in contributing to the crop performance and fruit quality deficiencies observed in organic SCSs.

Correlation between caries activity and salivary microbiota in preschool children

Early childhood caries (ECC) is the most common chronic infectious oral disease in preschool children worldwide. It is closely related to the caries activity (CA) of children. However, the distribution characteristics of oral saliva microbiomes in children with different CA are largely underexplored. The aim of this study was to investigate the microbial community in saliva of preschool children with different CA and caries status, and to analyze the difference of microbial community in saliva of children with different CA and its correlation with ECC. Subjects were divided into 3 groups based on the Cariostat caries activity test: Group H, high CA (n=30); Group M, medium CA (n = 30); Group L, low CA (n=30). Questionnaire survey was used to explore the related influencing factors of CA. According to the caries status (on the basis of decayed mising filled teeth), these subjects were divided into caries-free group (dmft=0, n=19), caries-low group (0 < dmft ≤ 4, n=27) and caries-high group (dmft > 4, n=44). Microbial profiles of oral saliva were analyzed using 16S rRNA gene sequencing. There were significant differences in the microbial structure (P < 0.05). Scardovia and Selenomonas were the biomarkers of both H group and high caries group. The genus Abiotrophia and Lautropia were the biomarkers of both the L group and the low caries group, while the Lactobacillus and Arthrospira spp. were significantly enriched in the M group. The area under the ROC curve of the combined application of dmft score, age, frequency of sugary beverage intake, and the genus Scardovia, Selenomonas, and Campylobacter in screening children with high CA was 0.842. Moreover, function prediction using the MetaCyc database showed that there were significant differences in 11 metabolic pathways of salivary microbiota among different CA groups. Certain bacteria genera in saliva such as Scardovia and Selenomonas may be helpful in screening children with high CA.

Epidemiological and Microbiome Characterization of Black Tooth Stain in Preschool Children

OBJECTIVE

To assess the epidemiologic attributes and microbial variations associated with extrinsic black tooth stain (BTS) among Chinese preschool children.

METHODS

This cross-sectional study included 250 preschool children (3-4 years) from three kindergartens in Shanghai, China. Following clinical examination, and using a case-control design, saliva and dental plaque specimens were collected from caries-free participants with (n = 21, BTS group) and without (n = 48, control group) BTS. The chi-square test and logistic regression model were used to evaluate factors associated with BTS. 16S rRNA sequencing were used to characterize the associated microbial communities.

RESULTS

BTS was detected in 12.4% of participants, with a mean of 13.7 black-stained teeth. Participants with BTS had a lower caries burden and better oral hygiene (P = 0.003). Children with less frequent intake of marmalade or honey (P = 0.033) and regular application of fluoride (P = 0.007) had a lower likelihood of having BTS. Microbiota analysis revealed 14 phyla, 35 classes, 63 orders, 113 families, 221 genera, 452 species, and 1,771 operational taxonomic units (OTUs). In terms of microbial diversity, no significant differences were observed in the saliva of the two groups (P > 0.05). Dental plaque from the BTS group exhibited higher OTU richness but lower evenness than that from the control group (Chao P = 0.006, Shannon P = 0.007, respectively) and showed a significant difference in β diversity (P = 0.002). The microbiome in the two groups was characterized by various microbial biomarkers, such as Pseudomonas fluorescens, Leptotrichia sp._HMT_212, Actinomyces sp._HMT_169, and Aggregatibacter sp._HMT_898 in plaques from the BTS group. Functional analysis of the microbial species suggested the existence of a hyperactive metabolic state on teeth surfaces with BTS plaques and revealed that ferric iron, the iron complex transport system, and the iron (III) transport system were more abundant in BTS plaque samples.

CONCLUSIONS

This study provides insights into the epidemiologic and microbial features of BTS in preschool children. The microbiome in BTS is characterized by various microbial biomarkers, which can serve as indicators for BTS diagnosis and prognosis.

Metagenomic Analysis of Dental Plaque on Pit and Fissure Sites With and Without Caries Among Adolescents

Caries is one of the most prevalent infectious diseases worldwide and is driven by the dysbiosis of dental biofilms adhering to tooth surfaces. The pits and fissured surfaces are the most susceptible sites of caries. However, information on the taxonomic composition and functional characteristics of the plaque microbiota in the pit and fissure sites is very limited. This study aimed to use metagenomic sequencing analyses to investigate the relationship between the plaque microbiome in the pit and fissure site and caries in adolescents. A total of 20 adolescents with active pit and fissure surface caries were involved as well as 20 age-matched, caries-free teenagers for control tests. Plaque samples were collected from the pit and fissure site and were subjected to metagenomic analyses, in which the microbial communities were investigated. Our results showed that the microbiota diversity was similar between those two groups. At the species level, the relative abundances of A. gerencseriae, P. acidifaciens, P. multisaccharivorax, S. oralis, S. mutans, and P. denticolens were higher in the caries-active group. N. elongata, C. hominis, and A. johnsonii were relatively more abundant in the caries-free groups. Functional analysis suggested that the metabolic pathway was the most abundant pathway, and the functional traits of the level 2 pathways included amino acid metabolism, metabolism of cofactors, and vitamins and carbohydrate metabolism. Our results also revealed that the caries group displayed several alterations in metabolic pathways, including enriched functions in carbohydrate digestion and absorption. This study suggested that in addition to the specific anatomical structures of the pit and fissured surfaces, the fundamental differences in the plaque microbiome may also be related to the susceptibility of pit and fissure caries.