Influence of obesity on subgingival microbiota composition in subjects with different periodontal status: a systematic review.

Objective: This systematic review aimed to investigate the changes in the composition of the subgingival microbiota among subjects with normo-weight, overweight and obesity, in conditions of periodontal health and disease. Materials and Methods: The protocol for this study was designed following PRISMA guidelines. Records were identified using different search engines (PubMed/MedLine, Scopus and Web of Science). Observational studies, in human subjects diagnosed with obesity (BMI >30kg/m2) and periodontal disease (gingivitis and periodontitis), on the analysis of subgingival microbiota were selected. Eight articles were included. Results: The subgingival microbiota of 1,229 subjects (n=894 exposure group and n=335 control group) was analyzed. Periodontal pathogens were the most common bacteria detected in subjects with obesity and periodontitis (Porphyromonas gingivalis, Tannerella forsythia, Campylobacter gracilis, Eubacterium nodatum, Fusobacterium nucleatum spp. vincentii, Parvimonas micra, Prevotella intermedia, Campylobacter rectus, and Aggregatibacter actinomycetemcomitans), as along with some accessory pathogens such as: Streptococcus gordonii, and Veillonella parvula that favor the virulence of late colonizers. Conclusions: Although there are evident alterations in the composition of the subgingival microbiota in subjects with obesity and periodontitis, it is still a challenge to identify a specific pattern of microbiota in these subjects. If associations between subgingival plaque microorganisms and obesity are confirmed, microbiome analysis could be a useful tool to improve preventive measures and the management of people with obesity.

Objetivo: Esta revisión sistemática tuvo como objetivo investigar los cambios en la composición de la microbiota subgingival entre sujetos con normopeso, sobrepeso y obesidad, en condiciones de salud y enfermedad periodontal. Materiales y métodos: El protocolo de este estudio se diseñó siguiendo las directrices PRISMA. Los registros se identificaron utilizando diferentes motores de búsqueda (PubMed/MedLine, Scopus y Web of Science). Se seleccionaron estudios observacionales en sujetos humanos diagnosticados con obesidad (IMC >30kg/m2) y enfermedad periodontal (gingivitis y periodontitis), sobre el análisis de la microbiota subgingival. Se incluyeron ocho artículos. Resultados: Se analizó la microbiota subgingival de 1229 sujetos (n = 894 grupo de exposición y n = 335 grupo de control). Los patógenos periodontales fueron las bacterias más comunes detectadas en los sujetos con obesidad y periodontitis (Porphyromonas gingivalis, Tannerella forsythia, Campylobacter gracilis, Eubacterium nodatum, Fusobacterium nucleatum spp. vincentii, Parvimonas micra, Prevotella intermedia, Campylobacter rectus y Aggregatibacter actinomycetemcomitans), junto con algunos patógenos accesorios, como Streptococcus gordonii y Veillonella parvula, que favorecen la virulencia de los colonizadores tardíos. Conclusiones: Aunque existen alteraciones evidentes en la composición de la microbiota subgingival en sujetos con obesidad y periodontitis, sigue siendo un reto identificar un patrón específico de microbiota en ellos. Si se confirman las asociaciones entre los microorganismos de la placa subgingival y la obesidad, el análisis del microbioma podría ser una herramienta útil para mejorar las medidas preventivas y el manejo de las personas con obesidad.

Effect of mobile app-based oral hygiene instructions on clinical parameters, oral bacterial diversity, and composition of subgingival microbiota in periodontitis patients.

Introduction: Oral hygiene instruction (OHI) is essential during periodontitis treatment. Various OHI approaches have been explored, including mobile apps. Objective: To evaluate the mobile app-based OHI's effect on periodontitis management by analyzing clinical parameters and subgingival microbiota. Methods: Forty-four periodontitis patients were randomly assigned into two groups. The test group (n = 22) received scaling and root planing (SRP), OHI, and mobile app-based OHI, whereas the control group (n = 22) received SRP and OHI. Full mouth plaque score (FMPS), bleeding on probing (BOP) and probing pocket depth at the sampling sites (site-PPD) were assessed at baseline, one- and three-month visits. The 16S rRNA next-generation sequencing (NGS) was used to analyze subgingival plaque samples. Results: Significant reduction in FMPS, BOP, and site-PPD at one- and three-month visits compared to baseline (p < 0.001) with no significant differences across groups (p > 0.05). In test groups, intra-group analysis showed better improvement in BOP and site-PPD (p < 0.05) than control. The diversity and composition of subgingival microbiota did not differ between groups or timepoints (p > 0.05). Conclusions: Mobile app-based OHI showed no superior effects on improving clinical parameters and subgingival microbiota compared to conventional OHI. Further investigation into its long-term impact on periodontitis treatment is needed.

Distinctive subgingival microbial signatures in older adults with different levels of cognitive function.

AIM: To examine association between subgingival microbial signatures and levels of cognitive impairment in older adults. MATERIALS AND METHODS: We analysed subgingival plaque samples and 16S ribosomal RNA sequences for microbiota among 165 participants (normal controls [NCs]: 40, subjective cognitive decline [SCD]: 40, mild cognitive impairment [MCI]: 49 and dementia: 36). RESULTS: The bacterial richness was lower among individuals with worse cognitive function, and subgingival microbial communities differed significantly among the four groups. Declining cognitive function was associated with decreasing relative abundance of genera Capnocytophaga, Saccharibacteria_genera_incertae_sedis, Lautropia and Granulicatella, and increasing abundance of genus Porphyromonas. Moreover, there were differentially abundant genera among the groups. Random forest model based on subgingival microbiota could distinguish between cognitive impairment and NC (AUC = 0.933, 95% confidence interval 0.873-0.992). Significant correlations were observed between oral microbiota and sex, Montreal Cognitive Assessment (MoCA) score and Mini-Mental State Examination score. Partial correlation analysis showed that Leptotrichia and Burkholderia were closely negatively associated with the MoCA score after adjusting for multiple covariates. Gene function was not significantly different between SCD and NC groups, whereas three homozygous genes were altered in MCI patients and two in dementia patients. CONCLUSIONS: This is the first study to demonstrate an association between the composition, function and metabolic pathways of subgingival microbiota and different levels of cognitive function among older individuals. Future cohort studies should assess its diagnostic usefulness for cognitive impairment.

Analysis of subgingival microbiota and IL-1ß, TNF-α and CX3CL1 levels in gingival crevicular fluid of fixed dental prostheses.

Prosthetic biomaterials can affect the composition of the subgingival microbiota and consequently the production of proinflammatory cytokines, causing damage to the periodontium. A total of 40 patients were divided into two groups: 20 with monolithic zirconia (MZ) prostheses and 20 with porcelain fused to metal (PFM) with nickel-chromium (Ni-Cr) alloy prostheses. Subgingival plaque and gingival crevicular fluid samples were taken. The Checkerboard technique for DNA-DNA hybridization and the enzyme-linked immunosorbent assay technique were performed. Teeth with MZ presented a lower percentage of bleeding on probing and tooth mobility compared to teeth with PFM with Ni-Cr alloy. Prosthodontic teeth harbored higher total levels of the 18 bacterial species than non-prosthodontic teeth. There was a higher prevalence of S. gordonii and V. parvula species in PFM with Ni-Cr alloy compared to MZ. There was an increase in IL-1ß, TNF-α and CX3CL1 levels in PFM with Ni-Cr alloy compared to MZ. MZ is a candidate biomaterial with fewer negative effects on the periodontium, allowing for longer prostheses longevity in the mouth.

Accelerated corrosion of 316L stainless steel in a simulated oral environment via extracellular electron transfer and acid metabolites of subgingival microbiota.

316L stainless steel (SS) is widely applied as microimplant anchorage (MIA) due to its excellent mechanical properties. However, the risk that the oral microorganisms can corrode 316L SS is fully neglected. Microbiologically influenced corrosion (MIC) of 316L SS is essential to the health and safety of all patients because the accelerated corrosion caused by the oral microbiota can trigger the release of Cr and Ni ions. This study investigated the corrosion behavior and mechanism of subgingival microbiota on 316L SS by 16S rRNA and metagenome sequencing, electrochemical measurements, and surface characterization techniques. Multispecies biofilms were formed by the oral subgingival microbiota in the simulated oral anaerobic environment on 316L SS surfaces, significantly accelerating the corrosion in the form of pitting. The microbiota samples collected from the subjects differed in biofilm compositions, corrosion behaviors, and mechanisms. The oral subgingival microbiota contributed to the accelerated corrosion of 316L SS via acidic metabolites and extracellular electron transfer. Our findings provide a new insight into the underlying mechanisms of oral microbial corrosion and guide the design of oral microbial corrosion-resistant materials.

Periodontal diseases in Thai schoolchildren. Clinical and microbiological observations.

The prevalence of periodontitis among Thai schoolchildren is unknown. In a cross-sectional study, the prevalence and severity of periodontal diseases, in a group of Thai schoolchildren, along with the presence and numbers of bacterial species commonly associated with periodontitis were investigated. A consent form was sent out to 192 schoolchildren in one school (Chanachanupathom School) in Chana, Southern Thailand (in the age range of 12-18 years) and 119 attended for a clinical and microbiological examination. Clinical recordings included number of teeth present, DMFT, plaque index, bleeding index, clinical attachment loss (CAL), and probing pocket depth (PPD). Pooled plaque samples were analyzed with culture and qPCR against bacteria associated with periodontitis. The children had low caries experience (DMFT = 3.2 ± 2.3), poor oral hygiene, high bleeding scores, and 67 (56.3%) had at least one interproximal site with CAL ≥ 1 mm. Thirty-seven (31.1%) of the children were diagnosed with periodontitis stage I, and sixteen (13.4%) were classified as periodontitis Stage II. Aggregatibacter actinomycetemcomitans was sparsely found in all but the healthy clinical groups (gingivitis, periodontitis Stage I and II), while the groups showed a high prevalence of Fusobacterium spp., Prevotella intermedia/nigrescens, and Campylobacter species as well as of the periodontitis-associated species Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia. Thai schoolchildren have poor oral hygiene with abundant amounts of plaque and high presence of bleeding. Early onset periodontitis is common but mostly in its mild form and is not associated with the presence of A. actinomycetemcomitans.

Assessment of Subgingival Biofilm and its Relationship with the Status of Tumors in a Population with Breast Cancer

This study aimed to compare the subgingival microbiota of subjects with and without breast cancer (BC). Patients with BC (Group 1; n= 50) and without BC (Group 2; n=50) with periodontitis (A) and without periodontitis (B). The study was conducted in two phases (P1 and P2). One biofilm sample was collected from each subject and analyzed by DNA-DNA Hybridization (Checkerboard DNA-DNA). The relative abundance of the subgingival microbiota differed between the Case and Control groups. However, some species were higher in patients in the Case than in Control subjects and differed between the groups in both phases. Composition of the subgingival microbial community according to the Socransky complex was related to periodontal disease, followed by clinical attachment of level (CAL ≥4mm), age, and tooth loss, which were found to be abundant in Cases when compared with controls. Patients with Tumor Grade II and III had a higher prevalence of tooth loss and CAL≥4mm. It was concluded that in individuals with BC, the sub-gingival microbiota exhibited atypical changes, but they developed periodontal disease.

El objetivo de este estudio fue comparar la microbiota subgingival de sujetos con y sin cáncer de mama (CM). Pacientes con CM (Grupo 1; n= 50) y sin CM (Grupo 2; n=50) con periodontitis (A) y sin periodontitis (B). El estudio se realizó en das fases (P1 y P2). Se recogió una muestra de biopelícula de cada sujeto y se analizó mediante hibridación ADN-ADN (tablero de ajedrez ADN-ADN). La abundancia relativa de la microbiota subgingival difirió entre los grupos de Caso y Control. Sin embargo, algunas especies fueron más altas en los pacientes del Caso que en los sujetos del Control y difirieron entre los grupos en ambas fases. La composición de la comunidad microbiana subgingival según el complejo de Socransky se relacionó con la enfermedad periodontal, seguida por el nivel de inserción clínica (CAL≥4mm), la edad y la pérdida de dientes, que se mostró abundante en los casos en comparación con los controles. Los pacientes con Tumor Grado II y III tuvieron mayor prevalencia de pérdida dental y CAL≥4mm. Se concluyó que en individuos con CM la microbiota subgingival presentó cambios atípicos, pero sin embargo, desarrollaron enfermedad periodontal.

Antimicrobial peptides in treatment of Stage III Grade B periodontitis: A randomized clinical trial.

BACKGROUND: To evaluate the effects of antimicrobial peptides (AMPs) on Stage III Grade B periodontitis. METHODS: This trial abided by the principle of consistency test, approved by ethics committee and registered in clinical trials. All qualified 51 patients with Stage III Grade B periodontitis were randomly divided into three groups: SRP group, SRP with minocycline hydrochloride (Mino group) as Control groups, and SRP with AMPs (AMP group) as the Test group. Clinical examinations and subgingival plaques were monitored at baseline and at 7 and 90 days after treatment in the SRP, SRP with AMP and Mino groups. RESULTS: The AMP group (Test group) had a reduced PD (Periodontal probing depth) and an attachment gain significantly higher than SRP and Mino groups (Control groups) at day 90. The abundance of periodontal pathogens was decreased in the AMP group at 7 and 90 days compared with the SRP group and Mino group. Only the AMP group showed an increase the abundance of periodontal probiotics including Capnocytophaga, Gemella, and Lactobacillus at 7 and 90 days. CONCLUSIONS: This study shows that AMPs as an adjunct to SRP promote additional clinical and microbiological benefits in the treatment of Stage III Grade B periodontitis.

Obesity Is Associated with the Severity of Periodontal Inflammation Due to a Specific Signature of Subgingival Microbiota.

The aim of this study was to analyze the link between periodontal microbiota and obesity in humans. We conducted a cohort study including 45 subjects with periodontitis divided into two groups: normo-weighted subjects with a body mass index (BMI) between 20 and 25 kg/m2 (n = 34) and obese subjects with a BMI > 30 kg/m2 (n = 11). Our results showed that obesity was associated with significantly more severe gingival inflammation according to Periodontal Inflamed Surface Area (PISA index). Periodontal microbiota taxonomic analysis showed that the obese (OB) subjects with periodontitis were characterized by a specific signature of subgingival microbiota with an increase in Gram-positive bacteria in periodontal pockets, associated with a decrease in microbiota diversity compared to that of normo-weighted subjects with periodontitis. Finally, periodontal treatment response was less effective in OB subjects with persisting periodontal inflammation, reflecting a still unstable periodontal condition and a risk of recurrence. To our knowledge, this study is the first exploring both salivary and subgingival microbiota of OB subjects. Considering that OB subjects are at higher periodontal risk, this could lead to more personalized preventive or therapeutic strategies for obese patients regarding periodontitis through the specific management of oral microbiota of obese patients.

Effects of modified triangular flap for third molar extraction on distal periodontal health of second molar: A randomized controlled study.

Objective: The aim of this study was to assess the effect of flap design for impacted mandibular third molar extraction on the distal periodontal tissue of their neighbors clinically, immunologically, and microbiologically. Study design: This randomized controlled study comprised 100 patients who were allocated randomly to receive either a triangular flap or a modified triangular flap. The distal periodontal pocket depth, plaque index, bleeding on probing, the presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia, and the level of interleukin-1ß, interleukin-8 and matrix metalloproteinase-8 of adjacent second molars were measured at baseline, and 1, 4 and 8 weeks after surgery. Results: After 1 and 4 weeks, distal periodontal conditions of adjacent second molars deteriorated, along with an increase in subgingival microbiota and inflammatory factors in both groups. And compared to the modified triangular flap group, the triangular flap group significantly increased (p < 0.05). Prevotella intermedia, interleukin-1ß and probing depth were positively correlated in both groups. After 8 weeks, they returned to the preoperative level. Conclusions: In this study, both flap designs for impacted mandibular third molar extractions was associated with worse clinical periodontal indices, increased inflammatory biomarkers of gingival crevicular fluid, and more subgingival pathogenic microbiota within 4 weeks. But compared with the triangular flap, the modified triangular flap was better for distal periodontal health of adjacent second molars, which provides certain directions for clinical treatment.

Metabolism of periodontal pathobionts: Their regulatory roles in the dysbiotic microbiota.

The onset and development of periodontitis centers around microbiota dysbiosis and disrupted host responses. Dynamic metabolic activities of the subgingival microbiota modify the polymicrobial community, shape the microenvironment, and modulate the host response. A complicated metabolic network exists in interspecies interactions between periodontal pathobionts and commensals, which can lead to the development of dysbiotic plaque. Dysbiotic subgingival microbiota undergo metabolic interactions with the host and disrupt host-microbe equilibrium. In this review, we discuss the metabolic profiles of the subgingival microbiota, the metabolic crosstalk in polymicrobial communities, including pathobionts and commensals, and the metabolic interactions between microbes and the host.

Potential Impact of Prosthetic Biomaterials on the Periodontium: A Comprehensive Review.

The success of a prosthetic treatment is closely related to the periodontal health of the individual. The aim of this article was to review and present the importance of prosthetic restorative materials on the condition of the periodontium, the changes that occur in the composition of the subgingival microbiota and the levels of inflammatory markers in gingival crevicular fluid. Articles on the influence of different prosthetic restorative materials on subgingival microbiota and proinflammatory cytokines were searched for using the keywords "prosthetic biomaterials", "fixed prosthesis", "periodontal health", "subgingival microbiota", "periodontal biomarkers" and "gingival crevicular fluid" in PubMed/Medline, Science Direct, Scopus and Google Scholar. The type of material used for prosthesis fabrication together with poor marginal and internal fit can result in changes in the composition of the subgingival microbiota, as well as increased accumulation and retention of dentobacterial plaque, thus favoring the development of periodontal disease and prosthetic treatment failure. Biological markers have helped to understand the inflammatory response of different prosthetic materials on periodontal tissues with the main purpose of improving their clinical application in patients who need them. Metal-free ceramic prostheses induce a lower inflammatory response regardless of the fabrication method; however, the use of CAD/CAM systems is recommended for their fabrication. In addition, it is presumed that metal-ceramic prostheses cause changes in the composition of the subgingival microbiota producing a more dysbiotic biofilm with a higher prevalence of periodontopathogenic bacteria, which may further favor periodontal deterioration.

Comparative analysis of subgingival microbiota in patients with mild, moderate, and severe chronic periodontitis.

In this study, we explored the suspected pathogens of chronic periodontitis at different stages of occurrence and development. We collected 100 gingival crevicular fluid samples, 27, 27, and 26 from patients with mild, moderate, and severe chronic periodontitis, respectively, and 20 from healthy individuals. Pathogens were detected using a 16S rRNA metagenomic approach. Quantitative Insights in Microbial Ecology, Mothur, and other software were used to analyze the original data, draw relative abundance histograms and heat maps, and calculate flora abundance and diversity indexes. We identified 429 operational taxonomic units, covering 13 phyla, 20 classes, 32 orders, 66 families, and 123 genera from the four groups of samples. Each group showed microbial diversity, and the number of new species of bacterial flora in the gingival crevicular fluid samples gradually increased from the healthy to the severe chronic periodontitis group. There was a significant difference in the relative abundance of the core flora at the phylum, class, order, family, and genus classification levels. Our data indicated a certain correlation between the changes in the subgingival microbial structure and the occurrence and development of chronic periodontitis, which might be able to provide a reference for the diagnosis, treatment and prevention of chronic periodontitis.

Nonsurgical Periodontal Treatment Options and Their Impact on Subgingival Microbiota.

BACKGROUND: Different periodontal treatment methods (quadrant-wise debridement, scaling and root planing (Q-SRP), full-mouth scaling (FMS), full-mouth disinfection (FMD), and FMD with adjuvant erythritol air-polishing (FMDAP)) were applied in periodontitis patients (stage III/IV). The study objective (substudy of ClinicalTrials.gov Identifier: NCT03509233) was to compare the impact of treatments on subgingival colonization. METHODS: Forty patients were randomized to the treatment groups. Periodontal parameters and subgingival colonization were evaluated at baseline and 3 and 6 months after treatment. RESULTS: Positive changes in clinical parameters were recorded in every treatment group during the 3-month follow-up period, but did not always continue. In three groups, specific bacteria decreased after 3 months; however, this was associated with a renewed increase after 6 months (FMS: Porphyromonas gingivalis; FMD: Eubacterium nodatum, Prevotella dentalis; and FMDAP: uncultured Prevotella sp.). CONCLUSIONS: The benefit of all clinical treatments measured after 3 months was associated with a decrease in pathogenic bacteria in the FMS, FMD, and FMDAP groups. However, after 6 months, we observed further improvement or some stagnation in clinical outcomes accompanied by deterioration of the microbiological profile. Investigating the subgingival microbiota might help appraise successful periodontal treatment and implement individualized therapy.

Subgingival Microbiota and Cytokines Profile Changes in Patients with Periodontitis: A Pilot Study Comparing Healthy and Diseased Sites in the Same Oral Cavities.

Periodontitis is a common condition characterized by an exacerbated pro-inflammatory response, which leads to tissue destruction and, ultimately, alveolar bone loss. In this pilot study, we assess the microbiota composition and cytokine profile changes in patients with stage III/IV, grade B/C periodontitis, specifically by comparing healthy and diseased sites in the same oral cavity. Overall, we found that microbiota architecture was significantly disrupted between diseased and healthy sites, and that the clustering was driven, in part, by the increased relative abundances of Synergistetes in diseased sites, as well as the increased abundances of Firmicutes in healthy sites. We also observed that diseased sites were enriched in Synergistetes, TM7, SR1, Spirochaetes, Bacteroidetes and Fusobacteria, and depleted in Firmicutes, Proteobacteria, Tenericutes and Actinobacteria compared to healthy sites. We found that Interleukin-1b, Interleukin-4, Interleukin-10, and Interleukin-17A were significantly overexpressed in diseased sites, whereas Interleukin-6 and TNF-alpha do not differ significantly between healthy and diseased sites. Here, we observed concomitant changes in the subgingival plaque microbiota and cytokines profile, suggesting that this combined alteration could contribute to the pathobiology of periodontitis.

Characterization of the Subgingival Cultivable Microbiota in Patients with Different Stages of Periodontitis in Spain and Colombia. A Cross-Sectional Study.

The objective was to characterize and compare the subgingival microbiota in patients diagnosed according to the World Workshop on the Classification of Periodontal and Peri-Implant Diseases and Conditions 2018. For this cross-sectional study, Spanish and Colombian subjects (characterized as health/gingivitis, periodontitis in stages I-II or stages III-IV) were clinically assessed, and subgingival samples were taken and processed by culture. The comparisons among patients with periodontal status (and between countries) was made using Mann-Whitney, Kruskal-Wallis, ANOVA and chi-square tests. The final sample consisted of 167 subjects. Eikenella corrodens and Parvimonas micra were more frequently detected in health/gingivitis and Porphyromonas gingivalis in periodontitis (p < 0.05). Higher total counts were observed in Colombia (p = 0.036). In Spain, significantly higher levels of P. gingivalis and Campylobacter rectus were observed, and of Tannerella forsythia, P. micra, Prevotella intermedia, Fusobacterium nucleatum, Actinomyces odontolyticus and Capnocytophaga spp. in Colombia (p < 0.001). P. micra was more prevalent in health/gingivitis and stage I-II periodontitis in Colombia, and P. gingivalis in all periodontitis groups in Spain (p < 0.05). As conclusions, significant differences were detected in the microbiota between health/gingivitis and periodontitis, with minor differences between stages of periodontitis. Differences were also relevant between countries, with Colombia showing larger counts and variability of bacterial species.

Effect of Full-mouth Disinfection Protocol on Glycaemic Control and Subgingival Microbiota in Patients with Type 1 and Type 2 Diabetes.

PURPOSE: To evaluate the effect of a full-mouth disinfection protocol (FMD) on periodontal parameters, glycaemic control and subgingival microbiota of periodontal patients with type 1 and type 2 diabetes, as well as those without diabetes. MATERIALS AND METHODS: This study included 33 patients with periodontitis. Eleven of them were type 1 diabetes patients, 11 were type 2 diabetes patients, and 11 were non-diabetics. At baseline and 3 months after the FMD, the periodontal parameters of each patient were recorded, samples of capillary blood for the chairside assessment of HbA1c were taken, and plaque samples from the two deepest periodontal pockets were collected to test for the presence of Aggregatibacter actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi), Tannerella forsythia (Tf) and Treponema denticola (Td). RESULTS: Bleeding on probing (BOP), probing pocket depth (PPD), clinical attachment level (CAL) and glycated haemoglobin (HbA1c) decreased statistically significantly (p < 0.05) in all three groups 3 months after FMD. Only the proportion of Pg in the control group decreased statistically significantly (p < 0.05), while the proportion of other bacteria decreased or remained the same, whereby the differences were not statistically significant. Moreover, the proportion of Aa in type 1 diabetics increased statistically significantly (p < 0.05). CONCLUSION: The FMD protocol improves periodontal parameters and glycaemic control of type 1 and type 2 diabetes patients with periodontitis.

High-throughput sequencing analysis of the microbiota of subgingival plaque in patients with periodontitis / 口腔疾病防治

Objective @# To detect the composition of the subgingival microbiota in generalized aggressive periodontitis (GAgP) and severe chronic periodontitis (SCP) patients tested by high-throughput sequencing (HTS) technologies, analyze its diversity and function by using bioinformatics, and observe changes in the subgingival microbiota before and after periodontal initial therapy.@* Methods@#Eleven patients with GAgP and 14 patients with SCP who visited the Department of Periodontics in Stomatological Hospital of Kunming Medical University from September 2018 to May 2019 were recruited, and subgingival plaque samples were collected at baseline and 6 weeks after initial therapy. Then, the genomic DNA was distracted and sequenced by the Illumina MiSeq high-throughput sequencing platform. QIIME (quantitative insights in microbial ecology), Mothur, SPSS and other software were used to analyze community information. LEfSe difference analysis (linear discriminant analysis effect size), network analysis, and the KEGG PATHWAY database (https://www.kegg.jp/kegg/pathway.html) were used to predict community function. @* Results @# At baseline, the dominant microbiota of GAgP and SCP patients were similar, including Bacteroidetes, Porphyromonas and Porphyromonas endodontalis. Six weeks after initial therapy, as the periodontal pocket became shallower, the variation trend of the microbiota of GAgP and SCP patients was similar. The relative abundance of gram-negative bacteria, such as Bacteroidetes, Porphyromonas and Porphyromonas endodontalis, decreased, while the relative abundance of gram-positive bacteria, such as Proteobacteria, Actinomyces and Rothia aeria, increased. Actinobacteria were significantly increased biomarkers of the subgingival microbiota in GAgP after treatment. Streptococcus is an important genus that connects the microbiota related to periodontitis and the microbiota related to periodontal health. Community function prediction result showed that initial treatment can reduce the functions of amino acid metabolism, methane metabolism, and peptidase in GAgP and SCP patients.@*Conclusion@#The subgingival microbiota of GAgP and SCP patients are similar. Streptococcus, as an early colonizer, may play an important role in promoting plaque biofilm formation and maturation in the process of subgingival flora from health to imbalance. Initial therapy can change the composition and structure of the subgingival microbiota, reduce community diversity, and reduce the functions of amino acid metabolism, methane metabolism, and peptidase in GAgP and SCP patients.

The Impact of Smoking on Subgingival Plaque and the Development of Periodontitis: A Literature Review.

Smoking seriously affects oral health and causes a variety of oral diseases. Numerous clinical data show that smoking significantly increases the risk of periodontitis, and the duration and amount of smoking are positively correlated with the severity of periodontitis. In fact, smoking creates an environment conducive to the colonization of periodontopathogens, which affects the process of periodontitis. Since subgingival plaque which harbors periodontopathogens is the initiation factor of periodontitis, it is critical to study the impact of smoking on subgingival microbiota for understanding the relationship between smoking and periodontitis. Continuous advances have been made on the understanding of effects of smoking on subgingival plaque and the development of periodontitis. Smoking is observed to enhance the pathogenicity of periodontopathogens, especially the red complex microorganisms, via promoting their colonization and infection, and regulating the expression and function of multiple virulence factors. Furthermore, smoking has a negative impact on periodontal microecological homeostasis, which is reflected in the decrease of commensal bacteria and the increase of periodontopathogens, as well as the changes in the interaction between periodontopathogens and their commensal microbes in subgingival biofilm, thus influencing the pathogenicity of the subgingival plaque. In summary, the mechanism of smoking on subgingival plaque microorganisms represented by the red complex and its effect on the periodontal microecology still need to be further explored. The relevant research results are of great significance for guiding the periodontal clinical treatment of smoking population. This review summarizes the effects and relevant mechanisms of smoking on subgingival plaque and the development of periodontitis.

Short-term variation in the subgingival microbiota in two groups of patients treated with clear aligners and vestibular fixed appliances: A longitudinal study.

OBJECTIVE: To evaluate the subgingival microbiological changes during the first six months of therapy with clear aligners (CAs) and fixed appliances (FAs). The null hypothesis was that there would be no microbiological differences between the two. SETTING/SAMPLE: Two groups of patients to be treated, respectively, with CAs (14 patients; 9 females and 5 males; mean age 21 years ± 0.25) and FAs (13 patients; 8 females and 5 males; mean 14 years ± 0.75) were consecutively recruited. MATERIALS AND METHODS: Subgingival microbiological samples were obtained at the right upper central incisor and right first molar at four different time points: before appliance fitting (T0), and at 1 month (T1), 3 months (T3) and 6 months (T6) thereafter. Total bacterial load (TBL) and counts of the bacteria Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Fusobacterium nucleatum, Campylobacter rectus, Treponema denticola and Tannerella forsythia were determined using real-time PCR. RESULTS: Total bacterial load did not vary in the CA group, while a significant increase was detected after 3 and 6 months of treatment in the FA group. Unlike red complex species, C rectus and F nucleatum were often detected: levels remained stable in the CA group but increased progressively in the FA group. CONCLUSION: The type of orthodontic appliance influences the subgingival microbiota. TBL increased in the FA group but not in the CA group, although the levels of the individual periodontal pathogenic bacteria species did not significantly increase during the observation period.