The impact of fixed orthodontic appliances and clear aligners on the oral microbiome and the association with clinical parameters: A longitudinal comparative study.

INTRODUCTION: Orthodontic treatment interferes with oral hygiene and promotes plaque retention, which leads to gingival inflammation and enamel demineralization. Although removable clear aligners (CAs) are designed to improve oral hygiene compared with fixed appliances (FAs), comprehensive studies comparing their respective effects on the oral microbiome are limited. This longitudinal study investigated the microbial changes during orthodontic treatment with FA and CA in correlation with clinical parameters. METHODS: Clinical parameters and supragingival plaque were collected from 12 study participants for the FA or CA treatment groups at baseline and at least twice at the 1, 3, 6, and 12-month follow-up appointments. The plaque was also harvested from the aligner tray for the CA group. Microbiome composition was determined via 16S rRNA gene sequencing, compared between groups, and correlated with clinical parameters. RESULTS: Plaque (PI) and gingival indexes (GI) increased significantly in the FA but not the CA group. Beta but not alpha diversities of the microbial communities were distinct between the 2 treatment groups, even though genus-level differences were not significant except for Leptotrichia. The CA tray harbors a unique plaque community. Elevated PI and GI in the FA group correlated with a higher abundance of disease-related genera. CONCLUSIONS: Orthodontic treatments trigger appliance-related plaque community shifts from baseline, and the CA tray environment attracts distinct microbial communities. In comparison with FA, the use of CA resulted in better oral health index outcomes, which is reflected by the corresponding PI and GI-associated oral microbial communities.

Effects of sodium glucose cotransporter 2 inhibitors on risk of dyslipidemia among patients with type 2 diabetes: A systematic review and meta-analysis of randomized controlled trials.

PURPOSE: Sodium glucose cotransporter 2 (SGLT2) inhibitors are shown to cause small, but significant changes of lipid profiles, we aim to investigate whether such altered lipid profiles can be translated into clinically meaningful changes in dyslipidemia. METHODS: PubMed, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) were searched for randomized controlled trials (RCTs) that compared SGLT2 inhibitors with placebo or other oral glucose-lowering drugs in patients with type 2 diabetes mellitus and reported the events of dyslipidemia. A random-effect meta-analysis was performed to calculate the pooled estimates with risk ratio (RR) for dyslipidemia risk and weighted mean difference for lipid profiles with their 95% confidential intervals (CIs). RESULTS: Of 2427 studies identified, 15 RCTs involving 7578 patients were included. This meta-analysis found no association between SGLT2 inhibitors and risk of dyslipidemia (RR: 1.13; 95% CI: 0.91-1.40). However, SGLT2 inhibitors were significantly associated with increases in total cholesterol by 0.15 mmol/L, low-density lipoprotein cholesterol by 0.12 mmol/L, and high-density lipoprotein cholesterol by 0.07 mmol/L while they can significantly decrease triglycerides by -0.12 mmol/L compared to controls. CONCLUSIONS: SGLT2 inhibitors were not associated with increased risk of dyslipidemia. Further trials with longitudinal assessment are needed to assess the effect of SGLT2 inhibitors on trajectories of changes of lipid metabolism.

Orthodontic and surgical treatment of facial asymmetry in a patient with unicoronal craniosynostosis.

This case report presents the unique treatment of a patient with varying asymmetries at different levels within the face. The patient was a 17-year-old male with a diagnosis of right unilateral coronal synostosis. He had frontal and superior orbital retrusion on the fused side, and bossing of the contralateral side. The middle and lower portions of his face were rotated toward the nonfused side. This unique diagnosis presented particular challenges to surgical and orthodontic correction. The treatment approach, which included a combination of Le Fort I and II osteotomies, bilateral sagittal split osteotomy, and orthodontic treatment with 4 premolar extractions, enabled simultaneous correction of nasal, midfacial, lower facial, and dental asymmetries. The orthodontist and surgeon integrated their efforts to correct dentofacial asymmetry in all 3 planes of space. Facial esthetics and dental function were significantly improved with no appreciable relapse occurring over a 2-year retention period.

Pregnancy-related adverse events associated with statins: a real-world pharmacovigilance study of the FDA Adverse Event Reporting System (FAERS).

BACKGROUND: Statins, previously rated as pregnancy category X agents, were contraindicated during pregnancy due to the teratogenic effects observed in animal studies. However, it is still controversial whether statins have detrimental impact on pregnant women or not, and some studies even suggest a potential benefit of statin use against pregnancy complications. The aim of this study was to explore whether maternal exposure to statins is associated with increased rates of pregnancy-related adverse events (AEs), including abortion, abortion spontaneous, preterm birth, low birth weight, stillbirth/fetal death, and fetal complications. RESEARCH DESIGN AND METHODS: Data from 1 January 2004 to 30 June 2022 were extracted through the U.S. FDA Adverse Event Reporting System (FAERS) database, to conduct disproportionality analysis and Bayesian analysis by reporting odds ratio (ROR) and Bayesian confidence propagation neural network (BCPNN) algorithms. To identify the potential risks of pregnancy-related AEs, each statin was compared to all the other drugs, all the other statins, and the reference drugs (fenofibrate and evolocumab). RESULTS: A total of 477 cases involving pregnancy-related AEs associated with stains were submitted to the FAERS database by healthcare professionals. No obvious disproportionate association of abortion, abortion spontaneous, or stillbirth/fetal death was identified for all statins during gestation. In comparison with all the other drugs, lovastatin showed an increased risk of fetal complications (ROR = 2.45, 95% CI, 1.22-4.95; IC025 = 0.63), and pravastatin demonstrated increased risks of preterm birth (ROR = 4.89, 95% CI, 3.65-6.54; IC025 = 1.69) and low birth weight (ROR = 9.60, 95% CI, 5.56-16.56; IC025 = 1.88). Similar results were found when compared lovastatin or pravastatin with fenofibrate. Furthermore, statins were associated with higher proportion of fetal complications and preterm birth when comparing with evolocumab. CONCLUSIONS: Statins did not increase the risk of pregnancy-related AEs, including abortion, abortion spontaneous, or stillbirth/fetal death. However, we did find significant disproportionality signals for preterm birth and low birth weight associated with pravastatin, and lovastatin was related to a higher proportion of fetal complications. The results in this study may provide evidence on the safety of statins during pregnancy, which need to be verified in further investigations.

A pharmacovigilance study of adverse events associated with polymyxins based on the U.S. Food and Drug Administration Adverse Event Reporting System (FAERS) database.

BACKGROUND: Polymyxins have been regarded as last-line treatment for multidrug-resistant gram-negative bacterial infections. Nonetheless, concerns regarding toxicity persist. This study aimed to explore and compare potential adverse events (AEs) between colistin and polymyxin B (PMB). METHODS: Polymyxins-related AEs were retrieved from the U.S. Food and Drug Administration Adverse Event Reporting System between 2004 and 2022. Potential signals were estimated by the reporting odds ratio (ROR), and subgroup analyses were preformed to adjust for potential factors in AEs with significant disproportionality. RESULTS: Analysis of 3,915 records involving 718 patients revealed a higher disproportionality of renal and urinary disorders (ROR 1.62, 95% CI 1.01-2.59) and acute kidney injury (ROR 1.75, 95% CI 1.07-2.87) with colistin treatment. Conversely, colistin exhibited a lower risk for neurotoxicity (ROR 0.47, 95% CI 0.30-0.73). Seven cases of skin hyperpigmentation were reported with PMB, whereas none were reported with colistin. Over 80% of cases involving polymyxin-related AEs occurred during the first two weeks of therapies, with a median onset time of 4.5 days. CONCLUSIONS: Patients received colistin displayed a higher potential risk of nephrotoxicity but a lower risk of neurotoxicity. Clinicians should be vigilant in monitoring the AEs of hyperpigmentation disorders induced by PMB.

Development of a new model system to study microbial colonization on dentures.

PURPOSE: Dentures are often colonized with a variety of microorganisms, including Candida albicans, that contribute to denture stomatitis. Several in vitro models have been previously established to study denture-related microbial colonization and evaluate treatment efficacy of denture cleansers; however, those models typically fail to appreciate the complex topology and heterogeneity of denture surfaces and lack effective ways to accurately measure microbial colonization. The purpose of this study was to study microbial colonization with a new model system based on real dentures, to more realistically mimic in vivo conditions. MATERIALS AND METHODS: Scanning electron microscopy was used to observe topological structures among surfaces from different parts of the denture. Employing C. albicans as a model microorganism, we established microbial colonization on different denture surfaces. Moreover, we applied a modified MTT (3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide) colorimetric assay to quantify C. albicans colonization on dentures without the necessity of biofilm removal and to evaluate treatment efficacy of denture cleansers. RESULTS: There were significant variations in topological structures among surfaces from different parts of the denture, with the unpolished side having the highest amounts of indentations and pores. The distinct denture surfaces support microbial colonization differently, with the unpolished side containing the highest level of microbial colonization and biofilm formation. Furthermore, the modified MTT colorimetric assay proved to be an accurate assay to measure biofilm formation on dentures and evaluate treatment efficacy of denture cleansers. CONCLUSION: This new denture model system in conjunction with the MTT colorimetric assay is a valuable tool to study denture-related microbiology and treatment approaches.

Treatment of anterior open bite and an ankylosed incisor by applying multiloop edgewise archwire, mini-implants, and dentoalveolar distraction.

An 18.7-year-old female patient with an anterior open bite and an ankylosed left maxillary central incisor was referred from a private orthodontic clinic. Canine relationships were Class II and molar relationships were Class I. The open bite was closed with the multiloop edgewise archwire and up-and-down elastics. The maxillary left central incisor was extruded by dentoalveolar distraction assisted with mini-implants. Active treatment took 2 years and 1 month, and the treatment result remained stable 14 months after debonding.

Antagonistic interaction between two key endodontic pathogens Enterococcus faecalis and Fusobacterium nucleatum.

Background: Endodontic infections are known to be caused by pathogenic bacteria. Numerous previous studies found that both Fusobacterium nucleatum and Enterococcus faecalis are associated with endodontic infections, with Fusobacterium nucleatum more abundant in primary infection while Enterococcus faecalis more abundant in secondary infection. Little is known about the potential interactions between different endodontic pathogens. Objective: This study aims to investigate the potential interaction between F. nucleatum and E. faecalis via phenotypical and genetic approaches. Methods: Physical and physiological interactions of F. nucleatum and E. faecalis under both planktonic and biofilm conditions were measured with co-aggregation and competition assays. The mechanisms behind these interactions were revealed with genetic screening and biochemical measurements. Results: E. faecalis was found to physically bind to F. nucleatum under both in vitro planktonic and biofilm conditions, and this interaction requires F. nucleatum fap2, a galactose-inhibitable adhesin-encoding gene. Under our experimental conditions, E. faecalis exhibits a strong killing ability against F. nucleatum by generating an acidic micro-environment and producing hydrogen peroxide (H2O2). Finally, the binding and killing capacities of E. faecalis were found to be necessary to invade and dominate a pre-established in vitro F. nucleatum biofilm. Conclusions: This study reveals multifaceted mechanisms underlying the physical binding and antagonistic interaction between F. nucleatum and E. faecalis, which could play a potential role in the shift of microbial composition in primary and secondary endodontic infections.

Safety of Glucagon-Like Peptide-1 Receptor Agonists: A Real-World Study Based on the US FDA Adverse Event Reporting System Database.

BACKGROUND AND OBJECTIVE: Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are used as adjunctive therapy to lifestyle intervention and metformin treatment in type 2 diabetes mellitus patients, as most GLP-1RAs have cardiovascular benefits; however, a number of adverse events (AEs) have been reported in postmarketing surveillance. OBJECTIVE: The aim of this study was to describe the AEs associated with GLP-1RA monotherapy and identify important medical event (IME) signals for GLP-1RAs. METHODS: Data from 1 April 2005 to 31 December 2021 from the US FDA Adverse Event Reporting System (FAERS) database were extracted to conduct disproportionality analysis and Bayesian analysis. AEs and IMEs were classified by system organ classes (SOCs) and preferred terms (PTs) according to the Medical Dictionary for Regulatory Activities (MedDRA®). The reporting odds ratio (ROR) and information component (IC) were used to indicate the disproportionality. RESULTS: A total of 71,515 records involving GLP-1RA monotherapy were submitted to the database, of which 16,350 records were GLP-1RA/IME pairs. Significant disproportionality emerged in five SOCs: 'gastrointestinal disorders' (n = 13,104; lower end of the 95% confidence interval (CI) of the IC [IC025] = 1.34), 'investigations' (n = 6889; IC025 = 0.64), 'metabolism and nutrition disorders' (n = 2943; IC025 = 0.44), 'neoplasms benign/malignant' (n = 1989; IC025 = 0.01), and 'hepatobiliary disorders' (n = 1497; IC025 = 0.38). The most common AEs were pancreatitis, nausea, and weight decrease. Unexpected significant AEs were detected, such as ileus, osteomyelitis, renal cell carcinoma, nephrolithiasis, and drug-induced liver injury. CONCLUSION: The majority of AEs have been listed in the prescribing information or reported in previous studies, however we found significant disproportionality in some specific tumor- and liver-related AEs. Clinicians should pay more attention to the newly detected disproportionality that may be triggered by GLP-1RAs, especially in the vulnerable population after long-term use. Considering the limitations of the FAERS database, there is a need for additional pharmacoepidemiological approaches to validate the results of this study.

Strain-Level Variation and Diverse Host Bacterial Responses in Episymbiotic Saccharibacteria.

Saccharibacteria (TM7), which are obligate episymbionts growing on the surface of host bacteria, may play an important role in oral disease, such as periodontitis (1, 2). As TM7 is a newly cultured lineage of bacteria, its research is limited by the small number of isolated representatives relative to the number of TM7 genomes assembled from culture-independent studies (3-5). A comprehensive view of both TM7 taxa and TM7 strain-level variations remains opaque. In this study, we expanded our previously developed TM7 baiting method into using many host bacteria in parallel, which allowed us to obtain 37 TM7 strains from the human oral cavity. These strains were further classified into low-enrichment (LE, n = 24) and high-enrichment (HE, n = 13) groups based on their proficiency at propagating on host bacteria. Of the 13 HE strains, 10 belong to "Candidatus Nanosynbacter sp." strain HMT-352 (human microbial taxon) (6), enabling us to explore both the phenotypic and genomic strain variations within a single TM7 species. We show that TM7 HMT-352 strains exhibit a diverse host range and varied growth dynamics during the establishment of their episymbiotic relationship with host bacteria. Furthermore, despite HMT-352 strains sharing a majority of their genes, we identified several gene clusters that may play a pivotal role in host affinity. More importantly, our comparative analyses also provide TM7 gene candidates associated with strain-level phenotypic variation that may be important for episymbiotic interactions with host bacteria. IMPORTANCE Candidate phylum radiation (CPR) bacteria comprise a poorly understood phylum that is estimated to encompass ∼26% of all diversity of domain bacteria. Among CPR bacteria, the Saccharibacteria lineage (TM7) is of particular interest, as it is found in high abundance in the mammal microbiome and has been associated with oral disease. While many CPR genomes, TM7 included, have been acquired through culture-independent methods, only a small number of representatives have been isolated. Such isolated representatives, however, shed light on the physiology, pathogenesis, and episymbiotic interactions of TM7. Combined with genomic analyses, experiments involving isolated representatives can distinguish phylogenetic to phenotypic discrepancies and better identify genes of importance. In this study, we utilized multiple host bacteria in parallel to isolate TM7 bacteria and examined strain-level variation in TM7 to reveal key genes that may drive TM7-host interactions. Our findings accentuate that broad phylogenetic characterization of CPR is the next step in understanding these bacteria.

Levels of Fibrin Degradation Products at Admission With Acute Ischemic Stroke Correlate With the NIH Stroke Scale Score 1 h After Intravenous Thrombolysis.

Background: Fibrin degradation products (FDPs) are fragments released by the plasmin-mediated degradation of fibrinogen or fibrin. Whether plasma levels of these fragments can predict the thrombolytic effect of recombinant tissue plasminogen activator (r-tPA) remains unknown. Methods: We performed a hospital-based study of patients with acute ischemic stroke (AIS) to explore the relationship between FDP levels at admission and the NIH Stroke Scale (NIHSS) score 1 h after thrombolysis treatment. In this retrospective, single-center study, the data of all patients with AIS who received r-tPA treatment at Beijing Tiantan Hospital from January 2019 to October 2020 were collected and analyzed. Demographic and clinical data, including laboratory examinations, were also analyzed. Results: A total of 339 patients with AIS were included in this study. Of these, 151 showed favorable effects of r-tPA, and 188 showed unsatisfactory effects at 1 h after thrombolysis. Overall, we found an inverse relationship between the FDPs levels at admission and the NIHSS score. A significant difference was observed when using the interquartile range of the FDPs levels (1.31 µg/mL) as a cutoff value (P = 0.003, odds ratio [OR] = 1.95, 95% confidence interval [CI]: 1.26-3.01), even after adjusting for confounding factors (P = 0.003, OR = 2.23, 95% CI: 1.31-3.77). In addition, significant associations were observed in the tertile (T3) and quartile (Q3, Q4) FDP levels when compared with T1 or Q1. A nomogram was also employed to create a model to predict an unsatisfactory effect of r-tPA. We found that FDP levels, white blood cell count, age, D-dimer level, and body mass index could influence the thrombolytic effect of r-tPA. Conclusion: In conclusion, the present study demonstrated that the levels of FDPs at admission can be used as a prognostic factor to predict the curative effect of r-tPA.

Predicting 1-Hour Thrombolysis Effect of r-tPA in Patients With Acute Ischemic Stroke Using Machine Learning Algorithm.

Background: Thrombolysis with r-tPA is recommended for patients after acute ischemic stroke (AIS) within 4.5 h of symptom onset. However, only a few patients benefit from this therapeutic regimen. Thus, we aimed to develop an interpretable machine learning (ML)-based model to predict the thrombolysis effect of r-tPA at the super-early stage. Methods: A total of 353 patients with AIS were divided into training and test data sets. We then used six ML algorithms and a recursive feature elimination (RFE) method to explore the relationship among the clinical variables along with the NIH stroke scale score 1 h after thrombolysis treatment. Shapley additive explanations and local interpretable model-agnostic explanation algorithms were applied to interpret the ML models and determine the importance of the selected features. Results: Altogether, 353 patients with an average age of 63.0 (56.0-71.0) years were enrolled in the study. Of these patients, 156 showed a favorable thrombolysis effect and 197 showed an unfavorable effect. A total of 14 variables were enrolled in the modeling, and 6 ML algorithms were used to predict the thrombolysis effect. After RFE screening, seven variables under the gradient boosting decision tree (GBDT) model (area under the curve = 0.81, specificity = 0.61, sensitivity = 0.9, and F1 score = 0.79) demonstrated the best performance. Of the seven variables, activated partial thromboplastin clotting time (time), B-type natriuretic peptide, and fibrin degradation products were the three most important clinical characteristics that might influence r-tPA efficiency. Conclusion: This study demonstrated that the GBDT model with the seven variables could better predict the early thrombolysis effect of r-tPA.

Smoking May Lead to Marginal Bone Loss Around Non-Submerged Implants During Bone Healing by Altering Salivary Microbiome: A Prospective Study.

BACKGROUND: This prospective and controlled study elucidates the impact of smoking on the salivary microbiome and its further influence on marginal bone loss (MBL) around an implant during a 3-month bone-healing period. METHODS: Saliva samples were collected preoperatively from 20 periodontally healthy patients with single-tooth replacement in the posterior mandible (smokers [n = 10] and non-smokers [n = 10]). Sequencing of 16S recombinant RNA gene amplicons was used to characterize the salivary microbiome. Each patient received implant surgery after oral clinical assessment, and MBL around the implant was measured during a 3-month healing period. RESULTS: In total, 871,389 sequences were compared against the Human Oral Microbiome Database for bacterial identification. Microbial signatures of smokers exhibited lower diversity and richness, with a significant decrease in uncultured species. The phyla Gracilibacteria and Saccharibacteria showed a significant decrease in smokers. The genera Streptococcus, Lachnoanaerobaculum, Stomatobaculum, and Eubacterium were significantly increased in smokers, whereas Selenomonas, Selenomonas [G-3], and Catonella were significantly decreased. Specifically, Porphyromonas gingivalis was significantly more abundant in smokers, which was positively related to the severity of MBL during bone healing. CONCLUSIONS: Smoking shapes the salivary microbiome in states of clinical health, and further may influence MBL during bone healing by creating high at-risk-for-harm communities. Understanding of the distinctly divergent oral microbiome in smokers and non-smokers is a base for personalized therapeutics for this high-risk cohort and also a base for further study on the pathologic mechanisms.

Effect of gelatin sponge with colloid silver on bone healing in infected cranial defects.

Oral infectious diseases may lead to bone loss, which makes it difficult to achieve satisfactory restoration. The rise of multidrug resistant bacteria has put forward severe challenges to the use of antibiotics. Silver (Ag) has long been known as a strong antibacterial agent. In clinic, gelatin sponge with colloid silver is used to reduce tooth extraction complication. To investigate how this material affect infected bone defects, methicillin-resistant Staphylococcus aureus (MRSA) infected 3-mm-diameter cranial defects were created in adult female Sprague-Dawley rats. One week after infection, the defects were debrided of all nonviable tissue and then implanted with gelatin sponge with colloid silver (gelatin/Ag group) or gelatin alone (gelatin group). At 2 and 3days after debridement, significantly lower mRNA expression levels of IL-6 and TNF-α and lower plate colony count value were detected in gelatin/Ag group than control. Micro-CT analysis showed a significant increase of newly formed bone volume fraction (BV/TV) in gelatin/Ag treated defects. The HE stained cranium sections also showed a faster rate of defect closure in gelatin/Ag group than control. These findings demonstrated that gelatin sponge with colloid silver can effectively reduce the infection caused by MRSA in cranial defects and accelerate bone healing process.

Marginal bone loss around non-submerged implants is associated with salivary microbiome during bone healing.

Marginal bone loss during bone healing exists around non-submerged dental implants. The aim of this study was to identify the relationship between different degrees of marginal bone loss during bone healing and the salivary microbiome. One hundred patients were recruited, and marginal bone loss around their implants was measured using cone beam computed tomography during a 3-month healing period. The patients were divided into three groups according to the severity of marginal bone loss. Saliva samples were collected from all subjected and were analysed using 16S MiSeq sequencing. Although the overall structure of the microbial community was not dramatically altered, the relative abundance of several taxonomic groups noticeably changed. The abundance of species in the phyla Spirochaeta and Synergistetes increased significantly as the bone loss became more severe. Species within the genus Treponema also exhibited increased abundance, whereas Veillonella, Haemophilus and Leptotrichia exhibited reduced abundances, in groups with more bone loss. Porphyromonasgingivalis, Treponemadenticola and Streptococcus intermedius were significantly more abundant in the moderate group and/or severe group. The severity of marginal bone loss around the non-submerged implant was associated with dissimilar taxonomic compositions. An increased severity of marginal bone loss was related to increased proportions of periodontal pathogenic species. These data suggest a potential role of microbes in the progression of marginal bone loss during bone healing.

The Denture-Associated Oral Microbiome in Health and Stomatitis.

While investigation of the microbiome on natural oral surfaces has generated a wealth of information, few studies have examined the microbial communities colonizing dentures and their relationship to oral health. To address this knowledge gap, we characterized the bacterial community associated with dentures and remaining teeth in healthy individuals and patients with denture stomatitis. The microbiome compositions of matched denture and tooth plaque samples of 10 healthy individuals and 9 stomatitis patients were determined by 16S rRNA gene pyrosequencing. The microbial communities colonizing dentures and remaining teeth in health and disease were very similar to each other. Matched denture and tooth samples from the same individuals shared a significantly higher percentage of identical phylotypes than random pairs of samples from different study participants. Despite these overall similarities, several bacterial phylotypes displayed discrete health- and stomatitis-associated denture colonization, while others were distinct in health and disease independently of the surface. Certain phylotypes exhibited differential colonization of dentures and teeth independently of denture health status. In conclusion, denture and natural tooth surfaces in health and stomatitis harbor similar bacterial communities. Individual-related rather than surface-specific factors play a significant role in the bacterial phylotype composition colonizing dentures and teeth. This individual-specific mutual influence on denture and tooth surface colonization could be an important factor in maintaining oral health in denture wearers. Discrete differences in colonization patterns for distinct genera and phylotypes warrant further studies regarding their potential involvement or utility as specific indicators of health and disease development in denture-wearing individuals. IMPORTANCE Denture stomatitis is a prevalent inflammatory condition of the mucosal tissue in denture wearers that is triggered by microorganisms. While Candida has been extensively studied for its role in stomatitis etiology, the bacterial component largely remains to be investigated. Our data show that certain types of bacteria are significantly associated with denture health and disease. Furthermore, the bacterial communities residing on the teeth and dentures of the same person are similar to each other independently of the surface, and thus, denture health could impact the maintenance of remaining teeth and vice versa.

Development of In Vitro Denture Biofilm Models for Halitosis Related Bacteria and their Application in Testing the Efficacy of Antimicrobial Agents.

OBJECTIVE: Since dentures can serve as a reservoir for halitosis-causing oral bacteria, halitosis development is a concern for denture wearers. In this study, we surveyed the prevalence of four selected halitosis-related species (Fusobacterium nucleatum, Tannerella forsythia, Veillonella atypica and Klebsiella pneumoniae) in clinical denture plaque samples, and developed denture biofilm models for these species in vitro to facilitate assessment of antimicrobial treatment efficacy. Design : Denture plaque from ten healthy and ten denture stomatitis patients was screened for the presence of aforementioned four species by PCR. Biofilm formation by these halitosis-associated species on the surfaces of denture base resin (DBR) discs was evaluated by crystal violet staining and confocal laser scanning microscopy. The efficacy of denture cleanser treatment on these mono-species biofilms was evaluated by colony counting. Results : 80% of the subjects in the denture stomatitis group and 60% in the healthy group contained at least one of the targeted halitosis-related species in their denture plaque. All halitosis species tested were able to form biofilms on DBR disc surfaces to varying degrees. These in vitro mono-species resin biofilm models were used to evaluate the efficacy of denture cleansers, which exhibited differential efficacies. When forming biofilms on resin surfaces, the halitosis-related species displayed enhanced resistance to denture cleansers compared with their planktonic counterparts. Conclusion : The four selected halitosis-related bacterial species examined in this study are present on the majority of dentures. The mono-species biofilm models established on DBR discs for these species are an efficient screening tool for dental product evaluation.

Effects of ginkgoneolic acid on the growth, acidogenicity, adherence, and biofilm of Streptococcus mutans in vitro.

Ginkgo biloba has long been used in traditional Chinese medicine. In this study, ginkgoneolic acid, a kind of compound extracted from G. biloba, was investigated for its effects on growth, acid production, adherence, biofilm formation, and biofilm morphology of Streptococcus mutans. The results showed that ginkgoneolic acid inhibited not only the growth of S. mutans planktonic cells at minimum inhibitory concentration (MIC) of 4 µg/mL and minimum bactericidal concentration (MBC) of 8 µg/mL but also the acid production and adherence to saliva-coated hydroxyapatite of S. mutans at sub-MIC concentration. In addition, this agent was effective in inhibiting the biofilm formation of S. mutans (MBIC(50) = 4 µg/mL), and it reduced 1-day-developed biofilm of S. mutans by 50 % or more at low concentration (MBRC(50) = 32 µg/mL). Furthermore, the present study demonstrated that ginkgoneolic acid disrupted biofilm integrity effectively. These findings suggest that ginkgoneolic acid is a natural anticariogenic agent in that it exhibits antimicrobial activity against S. mutans and suppresses the specific virulence factors associated with its cariogenicity.