Dysbiosis of oral microbiome persists after dental treatment-induced remission of periodontal disease and dental caries

An overview of the microbiota of the oral cavity of humans and non-human primates with periodontal disease: Current issues and perspectives

OBJECTIVE

To provide a comprehensive summary of the available evidence on the oral microbiota of humans and non-human primates about the etiology of periodontal disease.

DESIGN

An integrative literature review was conducted on 398 clinical and observational articles published between 2010 and 2024 using searches in the MEDLINE/PubMed, Virtual Health Library, and SciELO databases. After the screening, eligibility, data extraction, and methodological quality assessment, 21 studies were selected.

RESULTS

The results, which reveal striking similarities between the pathogens involved in periodontal disease in humans and NHPs, confirm the potential of NHPs as research models and inspire further research in this area.

CONCLUSION

According to these studies, Actinomyces spp., Aggregatibacter actinomycetemcomitans, Campylobacter rectus, Capnocytophaga spp., Eubacterium spp., Filifactor alocis, Fusobacterium spp., Leptotrichia spp., Neisseria mucosa, Parvimonas micra, Porphyromonas spp., Prevotella spp., Selenomonas spp., Streptococcus spp., Treponema spp., Tannerella spp., Veillonella parvula, were the genus and/or species of bacteria found in humans. On the other hand, Aggregatibacter acinomycetemcomitans, Campylobacter rectus, Desulfobulbus spp., Dialister invisus, Eikenella corrodens, Filifactor alocis, Fusobacterium spp., Parvimonas micra, Porphyromonas spp., Prevotella spp., Staphylococcus spp., Streptococcus spp., Treponema spp., Tannerella spp., Veillonella spp., were the most reported in NHPs. No study in non-human primates reported the presence of protozoa, unlike studies in humans that reported the presence of Entamoeba gingivalis and Trichomonas tenax. However, its role in periodontal disease still needs to be elucidated, despite the strong association mainly with severe periodontal disease where protozoa are observed in injured tissues.

Phellodendron bark extract and berberine chloride suppress microbiome dysbiosis in a saliva-derived in vitro microcosm biofilm model

OBJECTIVE

Preventing oral microbiome dysbiosis is crucial for averting the onset and progression of periodontal diseases. Phellodendron bark extract (PBE) and its active component berberine exhibit antibacterial properties against periodontal pathogenic bacteria. Although they inhibit Porphyromonas gingivalis (P. gingivalis)-induced dysbiosis in vitro in multiple species of saliva-derived planktonic cultures, their effects on microcosm biofilm models remain unclear. In this study, we aimed to elucidate the dysbiosis-suppressive effects of PBE and berberine chloride (BC) on biofilm formation.

DESIGN

PBE or BC was added during the formation of in vitro microcosm biofilms containing saliva and P. gingivalis, which were anaerobically cultured for one week. Next-generation sequencing was performed to assess microbiota composition, while quantitative real-time PCR was used to measure bacterial concentrations. Additionally, the butyrate concentration in the culture supernatant was assessed as biofilm pathogenicity.

RESULTS

PBE and BC treatments reduced the relative abundance of periodontal pathogenic bacteria, including P. gingivalis, and significantly increased the relative abundance of the genus Streptococcus and nitrate-reducing bacteria, including the genera of Neisseria and Haemophilus. Moreover, the treatment groups exhibited significantly decreased butyrate concentrations.

CONCLUSIONS

Our findings suggest that PBE and BC could suppress dysbiosis triggered by P. gingivalis in microcosm biofilms in vitro by decreasing the relative abundance and amount of periodontal pathogenic bacteria and enhancing those of nitrate-reducing bacteria that have a high relative abundance in orally healthy individuals. In summary, PBE and BC may contribute to the prevention of periodontal disease through their dysbiosis-suppressive and anti-inflammatory effects.

Involvement of propionate, citrulline, homoserine, and succinate in oral microbiome metabolite-driven periodontal disease progression

Dysbiosis of the oral microbiome has been implicated in the onset and progression of periodontal diseases. An altered oral microbiome can significantly affect the concentration and composition ratio of bacterial-derived metabolites, thereby contributing to disease development. However, there is limited research on the role of metabolites derived from the oral microbiota. This study aimed to identify specific bacteria-derived metabolites and their contributions to pathogenicity. Mouth-rinsed water was collected from 24 patients with periodontal disease and 22 healthy individuals. We conducted a correlation analysis between periodontal disease-associated bacteria and metabolites present in mouth-rinsed water. We evaluated the effects of these metabolites on human gingival epithelial cells analysis of oral bacteria culture supernatants confirmed the origin of these metabolites. We identified 20 metabolites associated with bacteria that are significantly more prevalent in periodontal disease. Notably, propionate, succinate, citrulline, and homoserine-metabolites derived from the oral microbiome-were identified as being associated with periodontal disease. These results suggested that metabolites derived from the oral microbiota are involved in periodontal disease.

Oral Microbiome Dynamics in Treated Childhood Caries: A Comparative Study

BACKGROUND

Dental caries is a multifactorial disease that results from interactions of susceptible host, cariogenic microorganisms, and fermentable carbohydrate sources. Our study explored oral microbiome shifts in children before and after dental treatment.

METHODS

Initial saliva samples were collected from caries free, moderate caries, and severe caries children based on the decayed, missing, and filled teeth index (DMFT/dmft) index. After three months of dental treatment, second saliva samples were gathered from the moderate and severe caries groups. The microbiota was analyzed by 16S rRNA gene-based high-throughput sequencing.

RESULTS

Most children with caries were between seven and eight years of age (40%), from middle-income group families (61%), highly educated parents (18% secondary level and 75% tertiary level) with good oral hygiene practices. There was a significant increase in alpha-diversity post-dental intervention. Firmicutes, Bacteroidota, and Proteobacteria were abundant across all samples. Post-treatment, Actinobacteria, and Firmicutes significantly decreased (p < 0.05) while Fusobacteria, Proteobacteria, Spirochaetota, and Synergistota significantly increased (p < 0.05). At genus level, a decreased trend was seen in Streptococcus, Prevotella_7, and Rothia and an increased trend was seen in Fusobacterium, Neisseria, Haemophilus, and Leptotrichia, but was not statistically significant.

CONCLUSIONS

This study on Malaysian children highlights that dental caries are influenced by factors like age, socioeconomic status, and diet, with oral microbiome diversity increasing post-treatment, though some harmful bacteria persist, indicating a need for targeted oral health education and further research on probiotics' role in caries prevention.

Oral Microbiota Development in the First 60 Months: A Longitudinal Study

Childhood is considered crucial in the establishment of future oral microbiota. However, the precise period of oral microbiota development remains unclear. This study aimed to identify the progression of oral microbiota formation in children. We longitudinally investigated the salivary microbiota of 54 children across 13 time points from 1 wk to 60 mo (5 y) old and their parents at 2 time points as a representative sample of the adult microbiota. Using next-generation sequencing, we obtained 10,000 gene sequences of the 16s rRNA V1-V2 region for each sample. The detection rate in children of 110 operational taxonomic units commonly detected in more than 85% of mothers and fathers, defined as the main constituent bacteria, was 25% at 1 wk old, increased to 80% between 6 and 18 mo old, and reached approximately 90% by 36 mo old. Early main constituent bacteria detected at 1 wk old were limited to Streptococcus, Rothia, and Gemella. At 6 to 18 mo old, the detection rates of various main constituent bacteria, including Neisseria, Haemophilus, and Fusobacterium, increased. UniFrac distance analysis showed that the oral microbiota of children approached that of adults at 6 to 18 mo old. In the weighted UniFrac distance index, unlike the unweighted index, there were no significant changes in children between 36 and 60 mo old from adults, and microbiota formation at 60 mo old was sufficiently advanced to be included within the range of adult individual differences. Our findings suggest that the initial 36 mo, particularly the period from 6 to 18 mo old, consists of a time window for oral microbiota maturation. In addition, the development of microbiota during this period may be critical for future oral disease prevention.

Dipotassium glycyrrhizate prevents oral dysbiosis caused by Porphyromonas gingivalis in an in vitro saliva-derived polymicrobial biofilm model

OBJECTIVES

Oral microbiome dysbiosis prevention is important to avoid the onset and progression of periodontal disease. Dipotassium glycyrrhizate (GK2) is a licorice root extract with anti-inflammatory effects, and its associated mechanisms have been well-reported. However, their effects on the oral microbiome have not been investigated. This study aimed to elucidate the effects of GK2 on the oral microbiome using an in vitro polymicrobial biofilm model.

METHODS

An in vitro saliva-derived polymicrobial biofilm model was used to evaluate the effects of GK2 on the oral microbiome. One-week anaerobic culture was performed, in which GK2 was added to the medium. Subsequently, microbiome analysis was performed based on the V1-V2 region of the 16 S rRNA gene, and pathogenicity indices were assessed. We investigated the effects of GK2 on various bacterial monocultures by evaluating its inhibitory effects on cell growth, based on culture turbidity.

RESULTS

GK2 treatment altered the microbiome structure and decreased the relative abundance of periodontal pathogenic bacteria, including Porphyromonas. Moreover, GK2 treatment reduced the DPP4 activity -a pathogenicity index of periodontal disease. Specifically, GK2 exhibited selective antibacterial activity against periodontal pathogenic bacteria.

CONCLUSIONS

These findings suggest that GK2 has a selective antibacterial effect against periodontal pathogenic bacteria; thus, preventing oral microbiome dysbiosis. Therefore, GK2 is expected to contribute to periodontal disease prevention by modulating the oral microbiome toward a state with low inflammatory potential, thereby utilizing its anti-inflammatory properties on the host.

Intensive oral prophylaxis does not alter the tongue microbiome in young patients with chronic kidney disease: longitudinal, randomized, controlled study

Introduction

Gingivitis is a common intraoral disease in patients with chronic kidney disease (CKD), which poses a particular interdisciplinary challenge. We aimed to determine the influence of an intensive oral prophylaxis program (OPP) compared to standard prevention measures on the tongue microbiome of young patients with CKD.

Methods

Thirty patients with CKD (mean age 14.2 ± 5.2 years) and generalized gingivitis were included. The effects of the intensive OPP were compared with standard prophylaxis according to statutory health insurance (treatment as usual, TAU) as a control. Tongue swabs were taken from the patients at baseline (t1) and after 3 (t2) and 6 (t3) months. Next-generation sequencing of 16S rDNA genes was used to quantitatively characterize microbial communities.

Results

There were no differences in the abundance, richness, or diversity of the observed genera and species between the two study groups at baseline or after 3 or 6 months. Furthermore, no change in predefined gingivitis and oral health bacterial clusters were found. At the phylum level, Firmicutes were decreased after intervention in the TAU group (t2TAU 42.9 ± 7.1 to t3TAU 34.8 ± 4.7 (npairs=14), p=0.003; false discovery rate 0.02). The decrease of Firmicutes was not significant in the OPP group.

Conclusions

Despite the intensity of dental prophylaxis and decreasing clinical signs of inflammation and decreasing plaque amount, no clinically relevant changes in the tongue microbiome were observed. Our results confirm the conserved and stable nature of the tongue microbiome, even in children with CKD.

Oral microbiome, periodontal disease and systemic bone-related diseases in the era of homeostatic medicine

BACKGROUND

Homeostasis is a state of self-regulation and dynamic equilibrium, maintaining the good physiological functions of each system in living organisms. In the oral cavity, the interaction between the host and the oral microbiome forms oral microbial homeostasis. Physiological bone remodeling and renewal can occur under the maintenance of oral microbial homeostasis. The imbalance of bone homeostasis is a key mechanism leading to the occurrence of systemic bone-related diseases. Considering the importance of oral microbial homeostasis in the maintenance of bone homeostasis, it still lacks a complete understanding of the relationship between oral microbiome, periodontal disease and systemic bone-related diseases.

AIM OF REVIEW

This review focuses on the homeostatic changes, pathogenic routes and potential mechanisms in the oral microbiome in periodontal disease and systemic bone-related diseases such as rheumatoid arthritis, osteoarthritis, osteoporosis and osteomyelitis. Additionally, this review discusses oral microbiome-based diagnostic approaches and explores probiotics, mesenchymal stem cells, and oral microbiome transplantation as promising treatment strategies.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This review highlights the association between oral microbial homeostasis imbalance and systemic bone-related diseases, and highlights the possibility of remodeling oral microbial homeostasis for the prevention and treatment of systemic bone-related diseases.

Effects of Sjogren's syndrome and high sugar diet on oral microbiome in patients with rampant caries: a clinical study

OBJECTIVE

The purpose of this study was to assess the composition of the oral microbial flora of adults with rampant caries in China to provide guidance for treatment.

PATIENTS AND METHODS

Sixty human salivary and supragingival plaque samples were collected. They were characterized into four groups: patients with rampant caries with Sjogren's syndrome (RC-SS) or high-sugar diet (RC-HD), common dental caries (DC), and healthy individuals (HP). The 16S rRNA V3-V4 region of the bacterial DNA was detected by Illumina sequencing. PCoA based on OTU with Bray-Curtis algorithm, the abundance of each level, LEfSe analysis, network analysis, and PICRUSt analysis were carried out between the four groups and two sample types. Clinical and demographic data were compared using analysis of variance (ANOVA) or the nonparametric Kruskal-Wallis rank-sum test, depending on the normality of the data, using GraphPad Prism 8 (P < 0.05).

RESULTS

OTU principal component analysis revealed a significant difference between healthy individuals and those with RC-SS. In the saliva of patients with rampant caries, the relative abundance of Firmicutes increased significantly at the phylum level. Further, Streptocpccus, Veillonella, Prevotella, and Dialister increased, while Neisseria and Haemophilus decreased at the genus level. Veillonella increased in the plaque samples of patients with rampant caries.

CONCLUSION

Both salivary and dental plaque composition were significantly different between healthy individuals and patients with rampant caries. This study provides a microbiological basis for exploring the etiology of rampant caries.

CLINICAL RELEVANCE

This study provides basic information on the flora of the oral cavity in adults with rampant caries in China. These findings could serve as a reference for the treatment of this disease.