Subgingival Biofilm Research Articles

Impact of Hyaluronic Acid and Other Re-Epithelializing Agents in Periodontal Regeneration: A Molecular Perspective

This narrative review delves into the molecular mechanisms of hyaluronic acid (HA) and re-epithelializing agents in the context of periodontal regeneration. Periodontitis, characterized by chronic inflammation and the destruction of tooth-supporting tissues, presents a significant challenge in restorative dentistry. Traditional non-surgical therapies (NSPTs) sometimes fail to fully manage subgingival biofilms and could benefit from adjunctive treatments. HA, with its antibacterial, antifungal, anti-inflammatory, angiogenic, and osteoinductive properties, offers promising therapeutic potential. This review synthesizes the current literature on the bioactive effects of HA and re-epithelializing agents, such as growth factors and biomaterials, in promoting cell migration, proliferation, and extracellular matrix (ECM) synthesis. By modulating signaling pathways like the Wnt/β-catenin, TGF-β, and CD44 interaction pathways, HA enhances wound healing processes and tissue regeneration. Additionally, the role of HA in facilitating cellular crosstalk between epithelial and connective tissues is highlighted, as it impacts the inflammatory response and ECM remodeling. This review also explores the combined use of HA with growth factors and cytokines in wound healing, revealing how these agents interact synergistically to optimize periodontal regeneration. Future perspectives emphasize the need for further clinical trials to evaluate the long-term outcomes of these therapies and their potential integration into periodontal treatment paradigms.

The Effect of Xanthohumol and Thymol on Candida albicans Filamentation and Its Impact on the Structure, Size, and Cell Viability of Biofilms Developed over Implant Surfaces

The aim of this in vitro study was to evaluate the effect of xanthohumol and thymol on the impact of Candida albicans on the structure, size and cell viability of subgingival biofilms formed on dental implant surfaces. The structure and microbial biomass of biofilms developed after 72 h, treated and untreated with both extracts, were compared by scanning electron microscopy (SEM) and confocal laser microscopy (CLSM). Quantitative polymerase chain reaction (qPCR) was used to quantify the number of viable and total microorganisms of each of the biofilm-forming strains in each condition. A general linear model was used to compare and validate the CLSM and qPCR results. The presence of xanthohumol and thymol during biofilm development inhibited the filamentous growth of C. albicans. The biofilm incubated with xanthohumol had significantly lower bacterial biomass and cell viability than the biofilm not exposed to the extract (p < 0.05). In contrast, these global parameters showed no differences when the biofilm was incubated with thymol. In the presence of xanthohumol, there was a decrease in counts and cell viability of Fusobacterium nucleatum, Porphyromonas gingivalis, and Aggregatibacter actinomycetemcomitans. Thymol treatment reduced the viability of F. nucleatum and P. gingivalis. The presence of these vegetable extracts during the development of a dynamic in vitro multispecies biofilm model inhibited the filamentous growth of C. albicans, partially reversing the effect that the fungus exerted on the structure, size and vitality of periodontopathogenic bacteria.

Microbiological profile of patients with generalized gingivitis undergoing periodontal therapy and administration of Bifidobacterium animalis subsp. lactis HN019: A randomized clinical trial.

To evaluate the adjunctive use of the probiotic Bifidobacterium animalis subsp. lactis HN019 (B. lactis HN019) to conventional therapy on clinical and microbiological parameters in patients with generalized gingivitis. Sixty systemically healthy individuals with untreated generalized gingivitis were submitted to periodontal therapy and allocated to receive Placebo (n = 30) or Probiotic (n = 30) lozenges, twice a day for 8 weeks. Bleeding on Marginal Probing (BOMP) was evaluated at baseline, after 2 and 8 weeks. Supra and subgingival biofilm were obtained at baseline and 8 weeks post-therapy for analyses by 16S rRNA gene sequencing. Differences between therapeutic groups were analyzed by non-parametric tests (p<0.05). The Placebo and Probiotic groups showed a significant reduction in BOMP at 8 weeks compared to baseline (p<0.05). The Probiotic group had a lower percentage of BOMP when compared with the Placebo group at 8 weeks (p<0.0001). Alpha and beta-diversity showed no statistical significance between groups and time points. At phylum level, no significant differences were observed between groups and time points. At genus level, an increase in the relative abundances of Bergeyella and Corynebacterium were significantly associated with a greater reduction in bleeding in the Placebo group and with less reduction in bleeding in the Probiotic group, respectively. At species level, Schaalia spp., Streptococcus gordonii, and Leptotrichia wadei increased in Placebo and decreased in the Probiotic group after treatment. Granulicatella adiacens decreased significantly after the probiotic therapy, while Saccharibacteria (TM7) spp., Solobacterium moorei, and Catonella morbi increased significantly. In the Placebo group, Bergeyella sp. HMT-322 was associated with a greater percentage of reduction in bleeding. In both groups, Actinomyces species were related to less reduction in bleeding. The adjuvant use of B. lactis HN019 alongside conventional therapy enhanced the reduction in BOMP and promoted greater changes in the microbiological profile of patients with generalized gingivitis. The study was registered at Brazilian Clinical Trials Registry (ReBEC; protocol number: RBR-59v2yb).

Clinical and Microbiological Periodontal Biofilm Evaluation of Patients with Type I Diabetes

Background/Objectives: The purpose of this study was to assess the microbial composition and density of subgingival plaque samples for periodontal pathogens while correlating the values with glycemic control levels via glycated hemoglobin (HbA1c), a type of hemoglobin that has chemically linked glucose, in type I diabetes individuals who will undergo complex oral rehabilitation through orthodontic treatment and implant surgery. Methods: A cohort of 42 adults with type I diabetes were included in this study. The subjects sustained a comprehensive periodontal clinical examination as well as microbiological assessments of their subgingival plaque samples through quantitative real-time PCR. The samples were collected from the two deepest pockets of each subject. Results: The highest number of periodontopathogenic bacteria was observed in the pockets of 5–7 mm. T. forsythia showed the highest prevalence (20.48%), with decreasing numbers as follows: T. denticola (13.31%), P. gingivalis (11.26%), A. actinomycetemcomitans (7%), and P. intermedia (4.9%). T. denticola and T. forsythia were significantly more commonly observed in individuals with elevated HbA1c serum levels. No correlation was observed between P. gingivalis, A. actinomycetemcomitans, P. intermedia presence, and the HbA1c value. Conclusions: Periodontopathogenic agents’ presence in subgingival biofilm samples varied in accordance with the pocket probing depth and metabolic control of the diabetic individuals. In our study, the appearance of these periodontopathogenic agents was linked to lowered metabolic control in patients with type I diabetes mellitus.

Applications Of Photodynamic Therapy In Periodontal Diseases

Background: According to A. Marcacci et al (1888), when many reports emerged on light absorbing properties and of fluorescence of various dyes, it became clear that dye excitation by light exerts destructive action in biological systems. This so-called photodynamic action was described as a process in which light, after being absorbed by dyes sensitizes organisms for visible light inducing cell damage. The supra- and subgingival plaque biofilm on tooth surfaces should easily be accessible for flushing with the dye and for activating them by light. Thus, periodontal diseases are promising applications of Photodynamic Therapy. Introduction: Chronic periodontitis is the most common periodontal disease which is related to the chronic accumulation of bacterial plaque. Since mechanical methods are not sufficient in the treatment of this disease, administration of local/systemic antibiotic is recommended following mechanical debridement. However, side effects of antibiotics such as microbial resistance and patient allergy led to development of alternative methods. One of these suggested methods is the antimicrobial photodynamic therapy (aPDT). PDT is a local noninvasive treatment modality without the side effects caused by antibiotics. Objectives: In this review, the mechanism of action of PDT and its application in the treatment of various periodontal conditions along with its future trends are discussed. Conclusion: Even though PDT is still in experimental stages of development and testing, the method may be an adjunct to conventional antibacterial measures in periodontology and Implant related perspectives.

Peri-implant clinical profile and subgingival yeasts carriage among cigarette-smokers with peri-implant mucositis

BackgroundThe present observational clinical investigation is based on the hypothesis that subgingival yeast carriage (SYC) is higher in cigarette-smokers with peri-implant mucositis (PM) than non-smokers with and without PM.ObjectiveThe aim was to assess peri-implant clinical profile and SYC among cigarette-smokers with PM.MethodologyParticipants were divided into four groups: Group-1—Cigarette-smokers with PM; Group-2—Cigarette-smokers without PM; Group-3—Non-smokers with PM; and Group-4—Non-smokers without PM. Information on duration and daily frequency of cigarette smoking (pack years), age, gender, familial history of smoking and most recent visit to a dentist and/or dental hygienist was collected. The following information was retrieved from healthcare records: implant dimensions, implant insertion torque, depth of insertion (credidastal or subcrestal), implant abutment connection, jaw location, implant surface characteristic, and mode of implant prosthesis retention. Peri-implant modified plaque and gingival indices (mPI and mGI), probing depth (PD) and crestal bone loss were recorded. Subgingival biofilm samples were collected, and SYC was recorded in colony forming units per milliliter (CFU/ml). P < 0.05 were considered statistically significant.ResultsEighty male individuals (20, 19, 21 and 20 individuals were included in groups 1, 2, 3 and 4, respectively) were included. The mPI was higher in Group-1 than groups 2 (P < 0.05) and 4 (P < 0.05). The mPI was higher in Group-3 than groups 2 (P < 0.05) and 4 (P < 0.05). The mGI was higher in Group-3 than groups 1 (P < 0.05), 2 (P < 0.05) and 4 (P < 0.05). The PD was higher in Group-1 than groups 2 (P < 0.05) and 4 (P < 0.05). The PD was higher in Group-3 than Groups 2 (P < 0.05) and 4 (P < 0.05). The CFU/ml were higher in Group-1 than groups 2 (P < 0.05) and 4 (P < 0.05). The CFU/ml were higher in Group-3 than groups 2 (P < 0.05) and 4 (P < 0.05).ConclusionPeri-implant soft-tissue inflammatory parameters are worse and SYC is higher in moderate smokers than light smokers with PM and non-smokers without PM.

Prognostic Impact of Microbiome Dysbiosis: A Prospective Study.

To determine the relationship between microbiome dysbiosis indices and biofilm immunogenicity and their prognostic implications on periodontal treatment response. Thirty periodontally healthy controls and 30 periodontitis cases (stage III) were recruited. Cases received non-surgical periodontal therapy (NSPT), and their treatment response at 6 months was evaluated using a treat-to-target endpoint (≤ 4 sites with probing depths ≥ 5 mm). Pooled subgingival biofilm samples were obtained from controls and cases. The V3-4 hypervariable region of the 16S rRNA gene was sequenced and two compositional indices (subgingival microbiome dysbiosis index, SMDI, and dysbiosis ratio, DR) were calculated. Nuclear factor kappa-B (NF-κB) activation elicited by biofilm samples in monocytic reporter cells was quantified to assess biofilm immunogenicity. SMDI, DR and biofilm immunogenicity were highly diagnostic for periodontitis (area under curves [AUC] > 0.90, p < 0.001). Among periodontitis cases, all three microbial parameters were significantly reduced after NSPT (p < 0.001). Cases achieving the treat-to-target endpoint had lower pre-treatment SMDI and biofilm immunogenicity (p < 0.05) and different microbial recolonization patterns from poor responders. Both measures predicted treatment response (AUC of 0.767 and 0.835, respectively, p < 0.05). Subgingival biofilm dysbiosis quantified using SMDI and biofilm immunogenicity was diagnostic of periodontitis and predictive of NSPT outcomes.

Periodontal Evaluation for a New Alkasite Restorative Material in Noncarious Cervical Lesions: A Randomized-Controlled Clinical Trial.

This study aims to evaluate the periodontal condition adjacent to Cention N (CN) restorations applied for noncarious cervical lesions (NCCL) compared with resin-modified glass ionomer cement (RM-GIC) restorations in terms of plaque accumulation, attachment loss, and gingival inflammation. This is a double-blind split-mouth three-armed randomized-controlled clinical trial. The study arms are RM-GIC (FUJI II LC), CN + adhesive system, and CN + retentive groove. The study included 25 restorations per arm. Follow-ups were performed at 1 week, 3, 6, and 9 months after the application of the restorations. The periodontal condition was evaluated using the plaque index (PI), the bleeding on probing index (BOP), and the probing depth (PD). Appropriate tests were used to perform statistical analyses (α = 0.05). There was no significant difference between Cention N and RM-GIC regarding the studied variables. However, after the application of the restorations, it was noted that the PI and the PD mean values increased. The average increase after 9 months was 0.06 and 0.34 for PI and PD, respectively, with that of PD being significant. It was also noted that the percentage of positive BOP sites increased at the 1-week follow-up for all study groups and afterward dropped to near preintervention values at the 3-month and later follow-ups. The two ion-releasing materials Cention N and RM-GIC have a comparable and clinically acceptable effect on the gingival tissue when restoring NCCLs. The combined effect of the gingival retraction cord and the rubber dam clamp on the periodontal tissues might be more important to consider, especially in relation to the probing depth. Future long-term studies are needed to evaluate the effect of Cention N on the subgingival biofilm in comparison with nonion-releasing restorative materials, and subsequently, its effect on gingival inflammation. This clinical trial was registered in clinicaltrial.gov clinical registry under protocol #NCT05593159.

Subgingival Yeasts Species Amongst Smokers and Nonsmokers With Peri-implantitis

There is a dearth of studies that have assessed yeast species in the subgingival biofilm (SB) samples collected from smokers and nonsmokers with peri-implantitis. This study assesses peri-implant clinical and radiographic profiles and yeasts species in the subgingival SB of cigarette smokers and nonsmokers with peri-implantitis. Participants were divided into 3 groups: group 1, cigarette smokers with peri-implantitis; group 2, nonsmokers with peri-implantitis; and group 3, nonsmokers without peri-implantitis. Information on smoking pack-years and patient demographics was collected. Implant-related parameters were retrieved from health care records. Peri-implant modified plaque and gingival indices (mPI and mGI, respectively), probing depth (PD), and crestal bone loss (CBL) were recorded. The SB samples were collected, subgingival yeasts colonisation was recorded, and yeasts species were identified. P < .05 was considered statistically significant. Respectively, 22, 22, and 24 individuals were included in groups 1, 2, and 3. In group 1, cigarette smokers had a smoking history of 29.7 ± 7.9 pack-years. The PD, mPI, and mesial and distal CBL were higher in groups 1 (P < .01) and 2 (P < .01) than in group 3. The mGI was higher in group 2 (P < .01) than in groups 1 and 3. The total number of implants in groups 1, 2, and 3 were 22, 22, and 24, respectively. In group 3, implants were in function for a longer duration (12.2 ± 2.3 years; P < .05) than in groups 1 (5.6 ± 1.9 years) and 2 (5.1 ± 0.7 years). Yeasts levels in CFU/mL were higher in group 1 than in groups 2 (P < .05) and 3 (P < .05); they were also higher in group 2 than in group 3 (P < .05). Candida albicans was the most isolated yeasts species, followed by Candida tropicalis, in all groups. Cigarette smokers and nonsmokers present similar peri-implant clinicoradiographic profiles, and oral yeasts (predominantly C albicans) seem to play a role in the progression of peri-implant disease in these individuals.

Effectiveness of supplementary antimicrobial procedures in disinfecting lateral canals as evaluated by a novel ex vivo analytical approach

This ex vivo study devised an analytical ex vivo method for infection/disinfection of simulated lateral canals located in the middle and apical segments of the root. The antibacterial effects of supplementary approaches were tested in this model. Extracted mandibular premolars had their main root canals enlarged and then two lateral canals (100 μm in diameter) were created in the root, one in the apical and the other in the middle portion. Micro-computed tomography was used for specimen selection and to confirm the quality of the simulated ramifications. The specimens were contaminated with a mixed bacterial culture from subgingival bacterial biofilm added to pure Enterococcus faecalis strain ATCC 29212 grown overnight, using special strategies to facilitate culture medium penetration within the lateral canals. The following procedures were tested for disinfection: NaOCl/passive ultrasonic irrigation (PUI), NaOCl/XP-endo Finisher, ozonated water/continuous ultrasonic irrigation (CUI), and NaOCl/conventional irrigation with 30-G needles (control). Bacteriological samples were taken from the main canal before (S1) and after (S2) each supplementary protocol, and also from each lateral canal after treatment (S3). DNA extracted from the samples was subjected to quantitative real-time polymerase chain reaction. All S1 main canal samples were positive for bacterial presence. Bacterial counts in the main root canal substantially decreased by 99.2% after PUI, 99.1% after ozone/CUI, 99% after XP-endo Finisher, and 96% in the control group (P < 0.01 for all groups). There were no significant differences between groups (P > 0.05). The same was observed when comparing the effects of the supplementary approaches in the apical and middle lateral canals (P > 0.05). Only a few lateral canals showed no detectable bacteria. The method proposed here proved effective for ex vivo infection/disinfection studies. All supplementary approaches induced a substantial bacterial reduction in the main canal, with no significant differences between them. However, in terms of lateral canal disinfection, none of the tested approaches showed significant effects when compared to the control group.

An integrated preventive and therapeutic magnetic nanoparticle loaded with rhamnolipid and vancomycin for combating subgingival biofilms

ObjectivesMechanical debridement supplemented with antibacterial agents effectively eradicates subgingival biofilms formed in the periodontal pockets of severe periodontitis patients. However, the available antimicrobial agents have limited penetrating ability to kill the bacteria encased in the deep layers of biofilms. This study aimed to fabricate a novel magnetic nanoparticle (MNP) loaded with rhamnolipid (RL) and vancomycin (Vanc, Vanc/RL-Ag@Fe3O4) to combat subgingival biofilms. MethodsThe multispecies subgingival biofilm was formed by periodontal pathogens, including Streptococcus oralis (S. oralis), Streptococcus sanguinis (S. sanguinis), Actinomyces naeslundii (A. naeslundii), Porphyromonas gingivalis (P. gingivalis) and Fusobacterium nucleatum (F. nucleatum). Scanning electron microscope (SEM), confocal laser scanning microscopy (CLSM), and quantitative real-time polymerase chain reaction (qRT-PCR) were used to determine the anti-biofilm efficacy of Vanc/RL-Ag@Fe3O4 with or without a magnetic field on multispecies subgingival biofilms. ResultsThe minimal inhibitory concentration (MIC) values of Vanc/RL-Ag@Fe3O4 on S. oralis, S. sanguinis, A. naeslundii, P. gingivalis, and F. nucleatum were 25, 50, 100, 50, and 25 μg/mL, respectively. Vanc/RL-Ag@Fe3O4 (200 μg/mL) reduced the 7-d biofilm thickness from 22 to 13 µm by degrading extracellular polymeric substance (EPS) and killing most bacteria except for tolerant F. nucleatum. A magnetic field enhanced the anti-biofilm effect of Vanc/RL-Ag@Fe3O4 by facilitating its penetration into the bottom layers of biofilms and killing tolerant F. nucleatum. SignificanceVanc/RL-Ag@Fe3O4 MNPs can release RL, Vanc, and Ag and eradicate subgingival biofilms by disrupting EPS and killing bacteria. Vanc/RL-Ag@Fe3O4 combined with a magnetic force is a promising approach for combating periodontal infection.

Choline and geranate ionic liquid for subgingival biofilm control

Periodontitis is a chronic inflammatory disease that causes destruction of the periodontium and eventual tooth loss. The priority in the periodontal treatment is to remove the subgingival biofilm. Chemical removal of biofilms using antimicrobial agents has been applied in clinical practice. However, their clinical effect is still limited because the agents must overcome biofilm’s significant drug tolerance, which is primarily caused by the extracellular matrix, a physical barrier that attenuates drug diffusion. This study aimed to study the use of ionic liquids (ILs), a new class of biocompatible materials, for controlling subgingival biofilms because of their excellent permeability. Choline and geranate (CAGE) IL was tested for its highly potent antiseptic behavior and permeability. Antibacterial tests revealed that the significant efficacy of CAGE against periodontopathic microorganisms was derived from their ability to destroy cell membrane, as demonstrated by membrane permeability assay and transmission electron microscopy imaging. Antibiofilm tests using two pathogenic biofilm models revealed that CAGE exerted efficacy against the biofilm-embedded bacteria, conspicuously neutralized the biofilms, and eventually destroyed the biofilm structure. Furthermore, the penetration of CAGE into the biofilm was visually confirmed using confocal laser scanning microscopy. This study highlighted the potential of CAGE as a powerful antibiofilm therapeutic.

Microbiological and Salivary Biomarkers Successfully Predict Site-Specific and Whole-Mouth Outcomes of Nonsurgical Periodontal Treatment.

Background/Objectives: Nonsurgical periodontal treatment (NSPT) is the gold-standard technique for treating periodontitis. However, an individual's susceptibility or the inadequate removal of subgingival biofilms could lead to unfavorable responses to NSPT. This study aimed to assess the potential of salivary and microbiological biomarkers in predicting the site-specific and whole-mouth outcomes of NSPT. Methods: A total of 68 periodontitis patients exhibiting 1111 periodontal pockets 4 to 6 mm in depth completed the active phase of periodontal treatment. Clinical periodontal parameters, saliva, and subgingival biofilm samples were collected from each patient at baseline and three months after NSPT. A quantitative PCR assay was used to detect the presence of Fusobaterium nucleatum and Porphyromonas gingivalis in the biofilm samples. Salivary biomarkers including matrix metalloproteinase (MMP)-9, glutathione S-transferase (GST), and Annexin-1 were assayed both qualitatively (Western blot analysis) and quantitively (ELISA). Results: NSPT yielded significant improvements in all clinical parameters, including a reduction in bacterial load and decreased levels of MMP-9 together with increased concentrations of GST and Annexin-1. The binary logistic regression suggested that the overall accuracy of P. gingivalis identification, probing pocket depth, and interproximal sites was 71.1% in predicting successful site-specific outcomes. The salivary biomarker model yielded an overall accuracy of 79.4% in predicting whole-mouth outcomes following NSPT. Conclusions: At baseline, the presence of shallow periodontal pockets at interdental locations with a lower abundance of P. gingivalis is predictive of a favorable response to NSPT at the site level. Decreased salivary MMP-9 associated with increased GST and Annexin-1 levels can predict successful whole-mouth outcomes following NSPT.

Quantifying periodontitis-associated oral dysbiosis in tongue and saliva microbiomes-An integrated data analysis.

Periodontitis is primarily driven by subgingival biofilm dysbiosis. However, the quantification and impact of this periodontal dysbiosis on other oral microbial niches remain unclear. This study seeks to quantify the dysbiotic changes in tongue and salivary microbiomes resulting from periodontitis by applying a clinically relevant dysbiosis index to an integrated data analysis. The National Center for Biotechnology Information (NCBI) database was searched to identify BioProjects with published studies on salivary and tongue microbiomes of healthy and periodontitis subjects. Raw sequence datasets were processed using a standardized bioinformatic pipeline and categorized by their ecological niche and periodontal status. The subgingival microbial dysbiosis index (SMDI), a dysbiosis index originally developed using the subgingival microbiome, was computed at species and genus levels and customized for each niche. Its diagnostic accuracy for periodontitis was evaluated using receiver operating characteristic curves. Four studies, contributing 328 microbiome samples, were included. At both species and genus levels, periodontitis samples had a higher SMDI, but the differences were only significant for subgingival biofilm and saliva (p<0.001). However, SMDI showed good diagnostic accuracy for periodontitis status for all three niches (area under curve ranging from 0.76 to 0.90, p<0.05). The dysbiosis index of subgingival biofilm was positively correlated with saliva consistently (p<0.001) and with the tongue at the genus level (p=0.036). While the impact on the tongue microbiome requires further investigation, periodontitis-associated dysbiosis affects the salivary microbiome and is quantifiable using the dysbiosis index. The diagnostic potential of salivary microbial dysbiosis as a convenient periodontal biomarker for assessing periodontal status has potential public health and clinical applications. Periodontitis, a severe inflammation of the gums which causes bone loss, is a disease caused by an imbalance of good and bad bacteria under the gums. However, it is unclear how this bacterial imbalance in the gums affects the bacterial balance of other distinct parts of the mouth, such as the saliva and tongue. This study uses bacteria datasets of four previously published studies, contributing a total of 328 bacterial samples. The data were processed using a uniform data analysis workflow, and a bacterial score, the subgingival microbial dysbiosis index (SMDI), previously shown to capture periodontitis-associated bacteria imbalance, was calculated separately for samples from under the gums, the saliva, and the tongue. The SMDI was able to distinguish between health and periodontitis within each oral location, and in general, the scores were higher for periodontitis samples, though this difference was significant only for bacteria under the gums and in saliva. Saliva scores were also consistently correlated with bacteria under the gums. This study shows that periodontitis-associated bacterial imbalances are observed in oral locations beyond just under the gums, particularly the saliva. Thus, saliva bacteria may be used as a convenient biomarker for assessing gum disease, allowing for potential public health and clinical applications.

Supportive periodontal care with or without subgingival instrumentation: Microbiological results of a 2-year randomized clinical trial.

To compare the subgingival microbiota of patients receiving supportive periodontal care (SPC) with and without subgingival instrumentation, over 2 years. This study was a randomized clinical trial that included 62 participants (50.97 ± 9.26 years old; 40 females) who completed non-surgical periodontal therapy. Participants were randomly assigned to receive oral prophylaxis with oral hygiene instructions alone (test) or in combination with subgingival instrumentation (control) during SPC. Pooled subgingival biofilm samples were obtained from four sites per patient at SPC baseline and at 3, 6, 12, 18, and 24 months. Real-time polymerase chain reaction was used for absolute quantification of Eubacteria and the target bacteria Porphyromonas gingivalis, Tannerella forsythia, and Treponema denticola. Data were analysed using generalized estimating equations, taking into consideration the clustering of observations within individuals. No significant differences were found between the experimental groups regarding the mean counts of Eubacteria and target bacteria, as well as the periodontal parameters at the sampled sites. Although significant variability in bacterial counts was present during SPC, all counts after 2 years were not statistically different from those at baseline. Bacterial counts were associated with the presence of plaque, bleeding on probing, mean probing depth ≥3 mm, and follow-up period. SPC with or without subgingival instrumentation can result in comparable subgingival microbiological outcomes. clinicaltrials.gov: NCT01598155 (https://clinicaltrials.gov/study/NCT01598155?intr=supragingival%20control&rank=4#study-record-dates).

Periodontal and microbiological data in patients with mucous membrane pemphigoid in a French population in 2021-2022: A pilot cross-sectional study.

In the case of mucous membrane pemphigoid with gingival expression (gMMP), the complete healing of the gingiva is generally not achieved despite medical treatment. Therefore, patients' oral comfort is impaired. The dysbiotic periodontal microbiota, generated by a lack of oral hygiene associated with persistent gingival pain, could the immunopathological mechanism to persist. The main objective of this study was to characterize the subgingival microbiota of the gMMP patients, and to highlight a potential link between this microbiological data and the clinical data. Subgingival biofilm was collected from 15 gMMP patients, medically treated or not, but not receiving periodontal treatment. The usual clinical periodontal parameters were recorded. The biofilm was analyzed by polymerase chain reaction quantitative. The risk factors of severe erosive gingivitis and severe periodontitis were assessed using Chi-square or Fischer's exact test were used. Whatever the medical and periodontal conditions of the patients, the results showed the existence of three main communities of periodontopathic, dysbiotic bacteria. The first including Tannnerella forsythia, Peptostreptococcus micros, Fusobacterium nucleatum, and Campylobacter rectus, was found in 100% of the patients, the second enriched with Treponema denticola in 60% and the third enriched with Porphyromonas gingivalis and Prevotella intermedia in 26%. Furthermore, there was a significant positive link between the duration of gMMP and the severity of erosive gingivitis (p = 0.009), and the loss of deep periodontal tissue (p = 0.04). This pilot study suggests a high periodontal risk in gMMP patients. The pathological processes, autoimmune on the one hand and plaque-induced on the other, may amplify each other. The application of periodontal therapy is therefore necessary in parallel with medical treatment. Nevertheless, further controlled studies are required to validate and complement these preliminary results.

Does Exposure to Burning and Heated Tobacco Affect the Abundance of Perio-Pathogenic Species in the Subgingival Biofilm?

This study investigated the impact of tobacco exposure, specifically through heating and burning, on periodontopathogens in the subgingival microbiome among clinically healthy individuals and those diagnosed with periodontitis. The sample comprised 66 subjects (26–56 years, median 38 yrs; 64% females) classified as non-smokers, classic cigarette smokers, and tobacco heating system (THS) smokers (each N = 22). Full-mouth periodontal examination was performed, and 330 paper-point samples from periodontal pockets were collected. Next-generation sequencing of 16S rRNA genes was conducted to identify the composition of subgingival microbiome. Periodontitis prevalence among the groups was ranked as THS (41%) &lt; non-smokers (44%) &lt; cigarette smokers (68%), without statistically significant differences between the groups. The number of perio-pathogenic species was higher in subjects with periodontitis compared to those without (median 7 vs. 6 species; p = 0.005) but without significant differences between exposure groups: non-smokers (6) = smokers (6) &lt; THS (6.5). When combining exposure and periodontal status, each smoker group had more perio-pathogenic species than non-smokers: non-smokers without periodontitis (5) &lt; smokers without periodontitis (5.5) &lt; THS without periodontitis (6); non-smokers with periodontitis (6.5) &lt; THS with periodontitis (7) = smokers with periodontitis (7). Multiple linear regression indicated periodontitis as the sole predictor of perio-pathogenic species quantity, irrespective of the type of tobacco consumption, sex, age, or oral hygiene (R2 = 0.163; p = 0.005). In conclusion, the quantity of perio-pathogenic species in the subgingival microbiome was more influenced by periodontitis than by exposure to tobacco smoke, regardless of whether it was heated or burned.

Digital Quantitative Analysis of the Relationship Between Periodontitis and Porphyromonas gingivalis

Porphyromonas gingivalis (P. gingivalis) constitutes an essential part of the subgingival dental plaque biofilm, serving as a significant factor in the development of periodontitis. Therefore, establishing a rapid and highly sensitive detection method for P. gingivalis is crucial to effectively manage periodontitis and its associated complications. In this study, droplet digital PCR (ddPCR) technology was employed for the detection of P. gingivalis, with a detection limit of 101 CFU/mL, exhibiting a 10-fold higher sensitivity compared to qPCR (with a sensitivity of 102 CFU/mL). Furthermore, no cross-reactivity was observed with four other bacterial species. In comparison to real-time quantitative PCR, ddPCR demonstrated enhanced sensitivity in detecting P. gingivalis at lower concentrations in 16 simulated samples, indicating its applicability for rapid detection of P. gingivalis.

Combination of Neovestitol and Vestitol Modifies the Profile of Periodontitis-Related Subgingival Multispecies Biofilm.

The aim of this study was to evaluate the effect of the combination of neovestitol-vestitol (CNV) compounds obtained from Brazilian red propolis on the microbiological profile of a mature multispecies subgingival biofilm. The biofilm with 32 bacterial species associated with periodontitis was formed for seven days using a Calgary device. Treatment with CNV (1600, 800, 400, and 200 μg/mL), amoxicillin (54 μg/mL), and vehicle control was performed for 24 h on the last day of biofilm formation. Biofilm metabolic activity and DNA-DNA hybridization (checkerboard) assays were performed. The groups treated with CNV 1600 and amoxicillin reduced 25 and 13 species, respectively, compared to the control vehicle treatment (p ≤ 0.05); both reduced P. gingivalis, while only CNV reduced T. forsythia. When the data from the two treatments (CNV and AMOXI) were compared, a statistically significant difference was observed in 13 species, particularly members of Socransky's orange complex. Our results showed that CNV at 1600 μg/mL showed the best results regarding the metabolic activity of mature biofilms and obtained a reduction in species associated with the disease, such as T. forsythia, showing a better reduction than amoxicillin. Therefore, CNV seems to be a promising alternative to eradicate biofilms and reduce their pathogenicity.

Sinensetin protects against periodontitis through binding to Bach1 enhancing its ubiquitination degradation and improving oxidative stress

Periodontitis is a chronic inflammatory and immune reactive disease induced by the subgingival biofilm. The therapeutic effect for susceptible patients is often unsatisfactory due to excessive inflammatory response and oxidative stress. Sinensetin (Sin) is a nature polymethoxylated flavonoid with anti-inflammatory and antioxidant activities. Our study aimed to explore the beneficial effect of Sin on periodontitis and the specific molecular mechanisms. We found that Sin attenuated oxidative stress and inflammatory levels of periodontal ligament cells (PDLCs) under inflammatory conditions. Administered Sin to rats with ligation-induced periodontitis models exhibited a protective effect against periodontitis in vivo. By molecular docking, we identified Bach1 as a strong binding target of Sin, and this binding was further verified by cellular thermal displacement assay and immunofluorescence assays. Chromatin immunoprecipitation-quantitative polymerase chain reaction results also revealed that Sin obstructed the binding of Bach1 to the HMOX1 promoter, subsequently upregulating the expression of the key antioxidant factor HO-1. Further functional experiments with Bach1 knocked down and overexpressed verified Bach1 as a key target for Sin to exert its antioxidant effects. Additionally, we demonstrated that Sin prompted the reduction of Bach1 by potentiating the ubiquitination degradation of Bach1, thereby inducing HO-1 expression and inhibiting oxidative stress. Overall, Sin could be a promising drug candidate for the treatment of periodontitis by targeting binding to Bach1.