Prevalence of Porphyromonas gingivalis four rag locus genotypes in patients of orthodontic gingivitis and periodontitis

Exploring the Genetic and Functional Diversity of Porphyromonas gingivalis Survival Factor RagAB

Porphyromonas gingivalis is a key pathogen in periodontitis. Its outer membrane contains the RagAB transport complex, which has been implicated in protein uptake, essential for a proteolytic species. RagA is a 22-stranded β-barrel, and RagB is the corresponding 4-TPR lid, together forming a TonB-dependent system acting as a "pedal bin". Four different alleles were observed, of which ragAB-1 is more virulent than the others. Our aim was to map ragAB in 129 strains of P. gingivalis and related species available in our collection, supported by a newly introduced universal PCR for amplification/sequencing of all four ragA variants and to find reasons for the differences in virulence and/or fitness. Regarding the PCR method, by pairing established Long-PCR primers with our newly designed sequencing primers (ragA-F0, -F1, -R2, -R2a, -R4), it was possible to amplify and sequence all four ragA variants. The same was not possible for ragB due to high heterogeneity. The mapping allowed us to type all strains into ragAB-1-4. For each type, some strains (of mainly animal origin such as Porphyromonas gulae) with slightly different amino acid sequences were identified (designated ragAB-1a to -4a). In terms of function, the transfer of recently discovered SusCD information to the similar RagAB complex provided new insights. Substrate specificity as well as length of pedal could be the route to differential virulence (survival rate, fitness) as Rag-1 (closer related to Rag-3/4) and Rag-2 were found to be massively different here. In general, substrate-ligand-binding sites seem to be quite variable with the exception of Rag-1, probably indicating nutritional preferences. In addition, an insertion (8 aa long) found in loop L7 throughout RagA-2 could not only affect the dynamics of lid opening/closing but might also alter the associated substrate throughput rate.

Effects of Oleanolic Acid Derived from Wine Pomace on Periodontopathic Bacterial Growth in Healthy Individuals: A Randomized Placebo-Controlled Study

Periodontal disease is caused by oral pathogenic bacteria and is associated with systemic disease and frailty. Therefore, its prevention is crucial in extending healthy life expectancy. This study aimed to evaluate the effect of orally administered oleanolic acid, extracted from wine pomace, on periodontopathic bacterial growth in healthy individuals. In this randomized, placebo-controlled, double-blind, parallel-group comparison study, 84 healthy adults were assigned to a placebo (n = 29), low-dose (n = 29, 9 mg oleanolic acid), or high-dose (n = 26, 27 mg oleanolic acid) groups. The number of oral bacteria in their saliva, collected before and 5 h after administration, was determined using the polymerase chain reaction-invader technique. The proportion of periodontopathic bacteria among the total oral bacteria in the saliva was calculated. Oleanolic acid significantly decreased the proportion of Porphyromonas gingivalis among the total oral bacteria in a dose-dependent manner (p = 0.005 (low-dose) and p = 0.003 (high-dose) vs. placebo, Williams' test). Moreover, high-dose oleanolic acid decreased the proportion of Tannerella forsythia (p = 0.064 vs. placebo, Williams' test). Periodontopathic bacteria are closely associated with the development and progression of periodontal disease; thus, the continuous daily intake of oleanolic acid derived from pomace may be helpful in maintaining a healthy oral microbiome by controlling the proportion of periodontopathic bacteria.

Evaluation of loop-mediated isothermal amplification method for efficient detection of the periodontopathic bacteria Porphyromonas gingivalis

Background

Periodontitis is a multifactorial, polymicrobial oral inflammatory illness brought on by oral pathogens. Porphyromonas gingivalis is a Gram-negative, obligatory anaerobic, black-pigmented coccobacillus and is regarded as a primary etiological factor in the progression of periodontitis. Rapid, highly senstitive and specific detection methods are emerging. The present study aimed to evaluate the loop-mediated isothermal amplification (LAMP) technique for efficiently detecting P. gingivalis from subgingival plaque samples of chronic periodontitis patients.

Materials and Methods

This study included 50 subgingival plaque samples from patients suffering from chronic periodontitis. The DNA (Deoxyribonucleic acid) was extracted by the "modified proteinase K" method. A set of six primers, targeting the pepO gene of P. gingivalis, was used for conducting LAMP. The amplification was visualized by naked-eye detection and agarose electrophoresis. Conventional polymerase chain reaction (PCR) and real-time qantitative PCR (qPCR) were carried out by targeting the 16SrRNA (16S ribosomal ribonucleic acid) gene of P. gingivalis.

Results

The results showed that LAMP detected P. gingivalis in 40 out of 50 samples (80%). Whereas, qPCR and conventional PCR technique detected P. gingivalis in 38 (76%) and 33 (66%) samples respectively. The sensitivity and specificity of the LAMP method were 94.87% and 90.90%, respectively. With qPCR, the sensitivity and specificity were found to be 92.30% and 81.81%, respectively, whereas, with conventional PCR, it was found to be 76.92% and 72.72%, respectively.

Conclusion

LAMP is an efficient technique for quick, accurate, and reliable identification of P. gingivalis from subgingival plaque samples. The technique needs to be validated analytically, and further studies can be conducted by taking saliva and/or gingival crevicular fluid samples from periodontitis patients.

Prevalence and Phylogenetic Analysis of Lipoprotein-Gene ragB-1 of Porphyromonas gingivalis-A Pilot Study

Porphyromonas gingivalis (P.g.) is a key pathogen involved in periodontal diseases. The aim of this study was to investigate the prevalence and phylogenetic origin of the lipoprotein-gene ragB in its most virulent variant, ragB-1 (co-transcribed with ragA-1 as locus rag-1), in different P.g. strains collected worldwide. A total of 138 P.g. strains were analyzed for the presence of ragB-1 by pooled analysis and subsequently individual PCRs. Sequencing a core fragment of ragB-1 of the individual strains made it possible to carry out a phylogenetic classification using sequence alignment. In total, 22 of the 138 P.g. strains tested positive for ragB-1, corresponding to a prevalence of 16%. The fragment investigated was highly conserved, with variations in the base sequence detected in only three strains (OMI 1072, OMI 1081, and OMI 1074). In two strains, namely OMI 1072 (original name: I-433) and OMI 1081 (original name: I-372), which originate from monkeys, two amino-acid alterations were apparent. Since ragB-1 has also been found in animal strains, it may be concluded that rag-1 was transferred from animals to humans and that this originally virulent variant was weakened by mutations over time so that new, less virulent, adapted commensal versions of rag (rag-2, -3, and -4), with P.g. as the host, evolved.

A comprehensive review on human disease-causing bacterial proteases and their impeding agents

Proteases are enzymes that catalyze the amide bond dissociation in polypeptide and protein peptide units. They are categorized into seven families and are responsible for a wide spectrum of human ailments, such as various types of cancers, skin infections, urinary tract infections etc. Specifically, the bacterial proteases cause a huge impact in the disease progression. Extracellular bacterial proteases break down the host defense proteins, while intracellular proteases are essential for pathogens virulence. Due to its involvement in disease pathogenesis and virulence, bacterial proteases are considered to be potential drug targets. Several studies have reported potential bacterial protease inhibitors in both Gram-positive and Gram-negative disease causing pathogens. In this study, we have comprehensively reviewed about the various human disease-causing cysteine, metallo, and serine bacterial proteases as well as their potential inhibitors.

Cytotoxicity Test of Active Compounds Natural Ingredients of Snail Mucus (Achatina fulica) Against BHK-21 Fibroblast Cells

Snails are unpleasant yet beneficial. Rural people have used one to treat illnesses like toothache for years. We will test snail's mucus Achatina fulica's cytotoxic activity against Baby Hamster Kidney (BHK-21) fibroblast cells at 12.5%, 25%, 50%, 100% and its resistance to Phorpyromonas gingivalis, Fusobacterium nucleatum, E. Faecalis, and S. aureus using Microtetrazolium (MTT) assay. The test and comparison solution was incubated with 5x103/100 l cells in 96-well plates. 5 mg/mL MTT completed the solution's incubation. ELISA readers measured purple color intensity. The formula transformed absorbance data at 595 nm into percent alive cells. ELISA readers read data. ANOVA, parametric Kolmogorov-Smirnov data normality test were performed. The cytotoxicity statistical test shows the following results: 12.5 % (0.76875 ±0.01117), 25% (0.49350 ±0.004796), 50% (0.30250 ±0.006658) and 100% (0.171 ±0.10488). The lowest cytotoxicity of Achatina fulica snail mucus is 12.5% with an average of 0.768. Achatina fulica snail mucus resists Phorpyromonas gingivalis, Fusobacterium nucleatum, E. Faecalis, and S. aureus at 12.5%.

Modulatory Mechanisms of Pathogenicity in Porphyromonas gingivalis and Other Periodontal Pathobionts

The pathogenesis of periodontitis depends on a sustained feedback loop where bacterial virulence factors and immune responses both contribute to inflammation and tissue degradation. Periodontitis is a multifactorial disease that is associated with a pathogenic shift in the oral microbiome. Within this shift, low-abundance Gram-negative anaerobic pathobionts transition from harmless colonisers of the subgingival environment to a virulent state that drives evasion and subversion of innate and adaptive immune responses. This, in turn, drives the progression of inflammatory disease and the destruction of tooth-supporting structures. From an evolutionary perspective, bacteria have developed this phenotypic plasticity in order to respond and adapt to environmental stimuli or external stressors. This review summarises the available knowledge of genetic, transcriptional, and post-translational mechanisms which mediate the commensal-pathogen transition of periodontal bacteria. The review will focus primarily on Porphyromonas gingivalis.

Self-ligating brackets exhibit accumulation of high levels of periodontopathogens in gingival crevicular fluid

Different types of brackets seem to influence the disruption of the oral microbial environment. Therefore, the aim of this study was to evaluate the influence of self-ligating brackets on the gingival crevicular fluid levels of the putative periodontal pathogens Aggregatibacter actinomycetemcomitans sorotype a (Aaa), Tannerella forsythia, Fusobacterium nucleatum, and Porphyromonas gingivalis. Sixty samples of crevicular fluid of twenty patients (11 boys and 9 girls) were analysed at baseline (T0) and after 30 (T1) and 60 (T2) days of bonding of the self-ligating (In-Ovation^®R, Dentsply, GAC or SmartClip™, 3 M Unitek, Monrovia, CA, USA) and of one conventional bracket (Gemini™, 3 M Unitek, Monrovia, CA, USA) used with elastomeric ligatures. Total DNA from samples was extracted using CTAB-DNA precipitation method and Real-time PCR was performed to analyse bacterial level. Non-parametric Friedman and Wilcoxon tests were used for data analysis (p value of < 0.05). F. nucleatum presented a different level among the different brackets at T1 (p = 0.025), the highest level in the Gemini™ bracket when compared to the SmartClip™ bracket (p = 0.043). P. ginigvalis levels increased in the In-Ovation^®R (p = 0.028) at T1. The subgingival levels of bacterial species associated with periodontal disease P. ginigvalis increased in the self-ligating brackets In-Ovation^®R.Clinical Relevance: Some kinds of brackets could provide more retentive sites than others, and it seems to modulate the subgingival microbiota, since, in this study, we could observe the increase of the species associated with periodontal disease. Preventive protocols should be adopted in the use of self-ligating brackets.

Systemic immune response against the oral pathogens Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans is associated with the formation and rupture of intracranial aneurysms

BACKGROUND AND PURPOSE

Periodontal infections are associated with the formation and rupture of intracranial aneurysms (IAs). This study investigated the role of two key periodontal pathogens, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans.

METHODS

Immunoglobulin A (IgA) and IgG antibodies against P. gingivalis and A. actinomycetemcomitans were measured with enzyme immune assay from the serum of 227 IA patients, of whom 64 also underwent clinical oral examination. As a control group, 1096 participants in a cross-sectional health survey, Health 2000, underwent serological studies and oral examination. Logistic regression was used for multivariate analysis. Immunohistochemistry was performed to demonstrate bacteria-derived epitopes in the IA wall.

RESULTS

Widespread gingivitis and severe periodontitis were more common in IA patients than in controls (2× and 1.5×, respectively). IgA antibodies against P. gingivalis and A. actinomycetemcomitans were 1.5× and 3-3.4× higher, respectively, in both unruptured and ruptured IA patients compared to controls (p ≤ 0.003). IgG antibodies against P. gingivalis were 1.8× lower in unruptured IA patients (p < 0.001). In multivariate analysis, high IgA, but low IgG, antibody levels against P. gingivalis (odds ratio [OR] = 1.4, 95% confidence interval [Cl] = 1.1-1.8 and OR = 1.5, 95% Cl = 1.1-1.9; OR = 0.6, 95% Cl = 0.4-0.7 and OR = 0.5, 95% Cl = 0.4-0.7) and against A. actinomycetemcomitans (OR = 2.3, 95% Cl = 1.7-3.1 and OR = 2.1, 95% Cl = 1.5-2.9; OR = 0.6, 95% Cl = 0.4-0.8 and OR = 0.6, 95% Cl = 0.5-0.9) were associated with the risk of IA formation and rupture. Immunohistochemistry showed P. gingivalis epitopes in the IA wall.

CONCLUSIONS

Exposure to the periodontal pathogens P. gingivalis and A. actinomycetemcomitans and dysfunctional acquired immune response against them may increase the risk of IA formation and IA rupture.

The RagA and RagB proteins of Porphyromonas gingivalis

RagA and RagB proteins are major components of the outer membrane of the oral pathogen Porphyromonas gingivalis and, while recently suggested to represent a novel peptide uptake system, their full function is still under investigation. Herein, we (a) discuss the evidence that the rag locus contributes to P. gingivalis virulence; (b) provide insight to Rag protein potential biological function in macromolecular transport and other aspects of bacterial physiology; (c) address the host response to Rag proteins which are immunodominant and immunomodulatory; and (d) review the potential of Rag-focused therapeutic strategies for the control of periodontal diseases.

Effect of Chlorhexidine Varnish and Fluoride Varnish on White Spot Lesions in Orthodontic Patients- a Systematic Review

Aim:

The aim of this study is to critically review the studies that studied the effect of Chlorhexidine varnish and fluoride varnish on White Spot Lesion (WSL) in patients undergoing orthodontic treatment.

Materials and Methods:

The electronic database PubMed, The Cochrane Library, Medline, Embase, Google Scholar, Web of Knowledge along with a complimentary manual search of all orthodontic journals till the first week of December 2019 was searched. English language study performed on humans, randomized or nonrandomized clinical trials, comparing the effect of fluoride and chlorhexidine varnish on WSL was included in the review. Quality assessment of included studies was performed.

Clinical Significance:

The need for an adjunct oral hygiene aid to reduce the incidence and prevalence of white spot lesions in orthodontic patients is necessary. The use of these varnishes will aid in the same and thus make the adverse effects of fixed orthodontic treatment negligible.

Review of Literature:

Enamel demineralization is a significant risk associated with orthodontic treatment when oral hygiene is poor. Prevention of demineralization during orthodontic treatment is one of the greatest challenges faced by clinicians despite modern advances in caries prevention. The development of White Spot Lesions (WSLs) is attributed to prolonged plaque accumulation around the brackets.

Results:

The search identified a total of 3 studies that were included in this review. One study had Low risk of bias and the remaining 2 studies had moderate overall risk. Results showed that there was a reduction in the incidence of white spot lesions in orthodontic patients after application of chlorhexidine and Fluoride varnish.

Conclusion:

Low level evidence is available to conclude that the use of chlorhexidine varnishes and fluoride varnishes reduces the prevalence of white spot lesions in patients undergoing fixed orthodontic treatment. Due to its limitations, the results of this systematic review should be handled with caution and further well-planned Randomized Clinical Trial (RCT) are needed to provide a discrete conclusion.

Clinical significance of ragA, ragB, and PG0982 genes in Porphyromonas gingivalis isolates from periodontitis patients

Consistent detection of ragA, ragB, and PG0982 in the genome of Porphyromonas gingivalis (P. gingivalis) isolates from periodontitis patients suggests that genotypes containing these genes may influence virulence and P. gingivalis-associated periodontitis progression. This study evaluated the prevalence of these genes in P. gingivalis isolates from periodontitis patients (n = 28) and in isolates from periodontally healthy P. gingivalis carriers (n = 34). The association of these genes with progression of periodontitis, in vitro cell invasiveness, and bacterial survival following periodontal therapy was also assessed. Periodontal charting and microbiological sampling were done at baseline, and at 6, 12, and 24 months following subgingival debridement of the periodontitis patients. Healthy controls were assessed at baseline for comparison. P. gingivalis isolates were analysed by ragA, ragB, and PG0982 specific polymerase chain reaction (PCR) and Sanger sequencing. Primary human gingival fibroblasts were used for invasion experiments. Results showed that 25% of the tested isolates from the periodontitis group had ragB detected, whereas this gene was undetected in isolates from healthy participants. However, none of the selected genes was associated with an increased cell invasiveness in vitro, with bacterial survival, or with significant clinical periodontal parameter changes. Identification of genes that influence P.gingivalis virulence and therapeutic outcome may have a diagnostic or prognostic value.

Oral dysbiosis induced by Porphyromonas gingivalis is strain-dependent in mice

Background:Porphyromonas gingivalis strain W83, one of the most widely investigated, is considered virulent in the context of periodontitis. The recently isolated P. gingivalis TDC60 has been reported to be highly pathogenic, although it has not yet been investigated in a mouse periodontitis model by oral gavage.

Aim: Our aim was to compare the virulence of both strains by evaluating their impact on alveolar bone loss and the composition of oral microbiota.

Methods: We inoculated by oral gavage C57BL/6 mice with either one of the two P. gingivalis strains and compared to a sham-treated group, without antibiotics pre-treatment. The mandibular alveolar bone of treated mice and controls were assessed, one month after the final inoculation, by microCT measurements. Moreover, at this time, we characterized their oral microbiota by 16S rRNA gene sequencing.

Results: While P. gingivalis W83 successfully initiated periodontitis, TDC60-treated mice only experienced moderate lesions. Furthermore, only W83-treated mice exhibited a specific distinct microbiota, with significantly lower richness and evenness than other samples, and decreased proportions of taxa usually found in healthy individuals.

Conclusion: This association between alveolar bone loss and a major persistent shift of the oral microbiota gives insights into virulence discrepancies among these bacterial strains.

Gingipain R1 and Lipopolysaccharide From Porphyromonas gingivalis Have Major Effects on Blood Clot Morphology and Mechanics

Background:Porphyromonas gingivalis and its inflammagens are associated with a number of systemic diseases, such as cardiovascular disease and type 2 diabetes (T2DM). The proteases, gingipains, have also recently been identified in the brains of Alzheimer's disease patients and in the blood of Parkinson's disease patients. Bacterial inflammagens, including lipopolysaccharides (LPSs) and various proteases in circulation, may drive systemic inflammation.

Methods: Here, we investigate the effects of the bacterial products LPS from Escherichia coli and Porphyromonas gingivalis, and also the P. gingivalis gingipain [recombinant P. gingivalis gingipain R1 (RgpA)], on clot architecture and clot formation in whole blood and plasma from healthy individuals, as well as in purified fibrinogen models. Structural analysis of clots was performed using confocal microscopy, scanning electron microscopy, and AFM-Raman imaging. We use thromboelastography® (TEG®) and rheometry to compare the static and dynamic mechanical properties of clots.

Results: We found that these inflammagens may interact with fibrin(ogen) and this interaction causes anomalous blood clotting.

Conclusions: These techniques, in combination, provide insight into the effects of these bacterial products on cardiovascular health, and particularly clot structure and mechanics.

Clinical, microbiological, and immunological evaluation of patients in corrective orthodontic treatment

Background

The objective was to analyze clinical, microbiological, and immunological periodontal parameters in patients in corrective orthodontic treatment.

Materials and methods

Twenty-eight patients were selected. Plaque index (PI), bleeding on probing (BOP), width of keratinized gingiva, levels of 40 bacterial species, and of 3 cytokines (IL-1β, MMP-8, and TNF-α) in gingival crevicular fluid (GCF) were evaluated at T0, before orthodontic treatment; T1, 6 months; and T2, 12 months post-treatment. Non-parametric, Friedman, Wilcoxon, ANOVA, and Spearman correlation coefficient tests were used for statistical analyses, with the significance level of 5%.

Results

No significant difference was found for the width of keratinized gingiva, but PI presented a significant increase at T1 and T2 (p < 0.05) when compared with T0. The percentage of sites with BOP increased significantly from T0 to T1 (p < 0.05); however, at T2, the values decreased and did not differ anymore from T0 (p > 0.05). In the microbiological analysis, red complex pathogens were in significantly greater proportions in T2 compared with T0 (p < 0.05). There was no statistically significant difference in the cytokine levels between the periods but there was a positive correlation between BOP and IL-1β (r = 0.49 p = .01) and TNF-α (r = 0.39 and p = .05).

Conclusion

In conclusion, corrective orthodontic treatment caused clinical periodontal alterations regarding biofilm accumulation and gingival bleeding, with alteration of periodontopathogens.

Prevalence of Anaerobic Bacteria (P.gingivalis) as Major Microbial Agent in the Incidence Periodontal Diseases by Meta-analysis

STATEMENT OF THE PROBLEM

Periodontal diseases are complex oral diseases characterized by bacterial-induced inflammatory destruction of tooth-supporting tissues. Porphyromonas gingivalis (P. gingivalis) is a common gram-negative anaerobic oral bacteria strongly associated with periodontal disease.

PURPOSE

The present study was conducted to estimate prevalence of P. gingivalis in patients with periodontal diseases by using meta-analysis method.

MARTIALS AND METHOD

Different databases including PubMed, EmBase, Scopus, the Institute for Scientific Information (ISI) Web of Science, and the Cochrane Library were searched to identify original English-language studies addressing prevalence of P. gingivalis in periodontal diseases up to December 2014. The random effects model was applied in the meta-analysis and the heterogeneity between studies was assessed using a Cochran test and the I² index. Funnel plots and Egger test were used to examine publication bias. Statistical analyses were performed using STATA version 12.

RESULTS

Forty-two eligible studies published during 1993- 2016 were selected for meta-analysis. Considering all the included studies, the total sample size was 5,884 individuals containing 2,576 healthy people with a mean age of 37.21±7.45 years and 3,308 periodontal patients with a mean age of 44.16±8.35 years. Overall, the prevalence of P. gingivalis was 78% [95% CI: 74-81] in periodontal diseases group and 34% [95% CI: 26-41] in healthy individuals. There was a significantly higher prevalence of P.gingivalis in individuals with periodontal diseases compared to healthy subjects [78% versus 34%, respectively].

CONCLUSION

This study indicates that P. gingivalis is highly present in subjects with periodontal diseases and it also appears in periodontally healthy people, although to a lesser extent. Thus, the presence of P. gingivalis increases the chance of periodontal disease and it can be considered as a main potential risk factor.

Distribution of Porphyromonas gingivalis fimA and mfa1 fimbrial genotypes in subgingival plaques

Background

Strains of periodontal disease-associated bacterium Porphyromonas gingivalis have different pathogenicity, which can be attributed to clonal genetic diversity. P. gingivalis typically expresses two types of fimbriae, FimA and Mfa1, which comprise six (I, Ib, II, III, IV, and V) and two (mfa⁵³ and mfa⁷⁰) genotypes, respectively. This study was conducted to investigate the distribution of the two fimbrial genotypes of P. gingivalis in clinical specimens.

Methods

Subgingival plaques were collected from 100 participants during periodontal maintenance therapy and examined for P. gingivalis fimbrial genotypes by direct polymerase chain reaction and/or DNA sequencing. We also analyzed the relationship between fimbrial genotypes and clinical parameters of periodontitis recorded at the first medical examination.

Results

Both fimbrial types could be detected in 63 out of 100 samples; among them, fimA genotype II was found in 33 samples (52.4%), in which the mfa⁷⁰ genotype was 1.75 times more prevalent than mfa⁵³. The total detection rate of fimA genotypes I and Ib was 38.1%; in these samples, the two mfa1 genotypes were observed at a comparable frequency. In two samples positive for fimA III (3.2%), only mfa⁵³ was detected, whereas in four samples positive for fimA IV (6.3%), the two mfa1 genotypes were equally represented, and none of fimA V-positive samples defined the mfa1 genotype. No associations were found between clinical parameters and fimbrial subtype combinations.

Discussion

Both P. gingivalis fimbrial types were detected at various ratios in subgingival plaques, and a tendency for fimA and mfa1 genotype combinations was observed. However, there was no association between P. gingivalis fimbrial genotypes and periodontitis severity.

New Application of Psoralen and Angelicin on Periodontitis With Anti-bacterial, Anti-inflammatory, and Osteogenesis Effects

Psoralen and angelicin are two effective compounds isolated from psoraleae, a traditional Chinese medicine. They have a wide range of applications for bone disease treatment and immune modulation. In this study, we explored their new applications for the treatment of periodontal diseases. This study aimed to investigate the effects of psoralen and angelicin on Porphyromonas gingivalis growth and P. gingivalis-derived lipopolysaccharide (Pg-LPS)-induced inflammation, and further to evaluate their effects on osteogenesis. Finally, the effects of angelicin on a mouse model of periodontitis were also investigated. The results showed that psoralen and angelicin had beneficial dose-dependent effects regarding the inhibition of planktonic P. gingivalis and biofilms of P. gingivalis. There were no significant differences in the viability of monocyte-like THP-1 cells and human periodontal ligament cells (hPDLCs) treated with either psoralen or angelicin compared to the untreated control cells. Psoralen and angelicin also markedly decreased the mRNA expression and release of inflammatory cytokines (interleukin [IL]-1β and IL-8) by THP-1 cells in a dose-dependent manner. They significantly enhanced the alkaline phosphatase (ALP) activity of hPDLCs and up-regulated the expression of osteogenic proteins (runt-related transcription factor 2 [RUNX2], distal-less homeobox 5 [DLX5], and osteopontin [OPN]). Angelicin significantly attenuated alveolar bone loss and inflammation response in the mice with periodontitis. In conclusion, our data demonstrated that psoralen and angelicin could inhibit the growth of planktonic P. gingivalis and P. gingivalis biofilm. It is also the first report on the anti-inflammatory effect of psoralen and angelicin against Pg-LPS. They also had an osteogenesis-potentiating effect on hPDLCs. The in vivo study also indicated the effect of angelicin regarding protection against periodontitis. Our study highlighted the potential ability of psoralen and angelicin to act as novel natural agents to prevent and treat periodontitis.

Prevalence of fimA genotypes of Porphyromonas gingivalis in adolescent orthodontic patients

Background

The placement of fixed orthodontic appliances may alter the composition of oral microbiota and has the potential risk of periodontal complication. Porphyromonas gingivalis fimbriae play a critical role in colonization of P. gingivalis in subgingival regions. In this study, we investigated the association between the prevalence of P. gingivalis-specific fimA genotypes and periodontal health status in adolescent orthodontic patients, to identify the pathogencity of P. gingivalis during orthodontic therapy.

Methods

Sixty-one adolescent orthodontic patients were enrolled in the case group, while the control group consisted of 56 periodontally healthy adolescents. At baseline (T0), clinical parameter (gingival index) was tested, and subgingival plaque samples were obtained from the lower incisors. The incidences of P. gingivalis and fimA genotypes were detected by polymerase chain reaction. All parameters were reassessed after 1 month (T1), 2 months (T2), 3 months (T3), and 6 months (T4) in the case group and then compared with those of the controls.

Results

Both microbiological and clinical parameters from orthodontic patients started to increase after placement of fixed appliances. Maximum values were reached at 3 months after placement and followed by their decreases at six months. However, the microbiological and clinical parameters in the case group were significantly higher than those of the control group. The GI of fimA II, IV-positive samples was significantly higher than that of negative samples.

Conclusion

P. gingivalis carrying fimA II or IV was closely related to orthodontic gingivitis. In addition, proper oral hygiene control could lead to little increase in dental plaque accumulation, and exert a beneficial effect to periodontal tissues.

Study of Porphyromonas gingivalis in periodontal diseases: A systematic review and meta-analysis

Background: The mouth cavity hosts various types of anaerobic bacteria including Porphyromonas gingivalis, which causes periodontal inflammatory diseases. P. gingivalis is a gram-negative oral anaerobe and is considered as a main etiological factor in periodontal diseases. Several studies have reported a relationship between P. gingivalis in individuals with periodontal diseases and a critical role of this bacterium in the pathogenesis of periodontal diseases. The present study aimed at estimating this probability using a meta-analysis.

Methods: We searched several databases including PubMed, Scopus, Google Scholar, and Web of Science to identify case-control studies addressing the relationship between P. gingivalis with periodontal diseases. A total of 49 reports published from different countries from 1993 to 2014 were included in this study. I² (heterogeneity index) statistics were calculated to examine heterogeneity. Data were analyzed using STATA Version 11.

Results: After a detailed analysis of the selected articles, 49 case-control studies with 5924 individuals fulfilled the inclusion criteria for the meta-analysis. The healthy controls included 2600 healthy individuals with a Mean±SD age of 36.56±7.45 years. The periodontal diseases group included 3356 patients with a mean age of 43.62±8.35 years. There was a statistically significant difference between P. gingivalis in periodontal patients and healthy controls; 9.24 (95% CI: 5.78 to 14.77; P = 0.000). In the other word, there was a significant relationship between the presence of P. gingivalis and periodontal diseases.

Conclusion: Analyzing the results of the present study, we found a strong association between the presence of P. gingivalis and periodontal diseases. This result suggests that another research is needed to further assess this subject.

Profiling of subgingival plaque biofilm microbiota in adolescents after completion of orthodontic therapy

Background

Fixed orthodontic treatment is the most common method for malocclusion but has the potential risk of periodontal complication with unclear outcomes of whether microbiologic and clinical changes could be reversible in adolescents after orthodontic therapy.

Methods

Twenty adolescents with orthodontic treatment were enrolled in the study as the case group at end of the therapy, while 19 periodontally healthy adolescents were involved in the control group. At baseline (T₀), clinical parameters including gingival index, probing depth and sulcus bleeding index were tested, and subgingival plaque samples were collected from the lower incisors. The counts of A. actinomycetemcomitans, P. gingivalis, P. intermedia, T. forsythia and total bacteria were determined by real-time PCR. All parameters were reassessed after 1 month (T₁) and 3 months (T₂) in the case group and compared with that of the controls.

Results

At baseline (T₀), clinical parameters (including GI, PD, SBI) of the test sites in the case group were significantly higher than that of the control group (P<0.05 or P<0.01). At 3 months (T₂), no differences were noticed in GI and SBI between two groups. The prevalence and counts of periodontopathogens tend to be normal (P>0.05), while PD and the amount of P.intermedia were still significantly higher compared with that of the control group (P<0.05 or P<0.01).

Conclusion

After removal of appliances, the periodontal changes induced by orthodontic therapy are only partially reversible at 3 months after removal.

Control of White Spot Lesions with Use of Fluoride Varnish or Chlorhexidine Gel During Orthodontic Treatment A Randomized Clinical Trial

OBJECTIVE

To compare the effectiveness of fluoride varnish and 2% chlorhexidine gel for controlling active white spot lesions (WSLs) adjacent to orthodontic brackets.

STUDY DESIGN

Thirty-five orthodontic patients (17.2 ± 2.3 years old) presenting 60 WSLs adjacent to orthodontic brackets were enrolled in this randomized, blind, 3-armed and controlled clinical trial. The patients were randomly allocated to 1 of 3 arms: (1) two applications of 5% NaF varnish- F, with one-week interval, (2) two applications of 2% chlorhexidine gel-CHX, with one-week interval and (3) usual home care-control (CO). The WSLs were scored by using a DIAGNOdent pen. An independent examiner scored the surfaces using Nyvad criteria for caries assessment.

RESULTS

A total of thirty patients presenting 51 lesions completed the study. All treatments reduced the fluorescence values during the experimental period; however, F induced faster remineralization than CHX. After 3 months, 70.58 % were inactive considering all groups. DIAGNOdent pen and Nyvad presented a significant correlation.

CONCLUSION

After 3 months of treatment, F, CHX and CO were capable of controlling the WSLs adjacent to the orthodontic brackets. However, the treatment with F was capable of controlling the progression of the WSLs in a shorter period of time.

Consequences of orthodontic treatment in malocclusion patients: clinical and microbial effects in adults and children

BACKGROUND

Malocclusion is a common disease of oral and maxillofacial region. The study was aimed to investigate levels changes of periodontal pathogens in malocclusion patients before, during and after orthodontic treatments, and to confirm the difference between adults and children.

METHOD

One hundred and eight malocclusion patients (46 adults and 62 children at the school-age) were randomly selected and received orthodontic treatment with fixed orthodontic appliances. Subgingival plaques were Porphyromonas gingivalis (P.gingivalis), Fusobacterium nucleatum (F. nucleatum), Prevotella intermedia (P. intermedia) and Tannerella forsythensis (T. forsythensis) collected from the observed regions before and after treatment. Clinical indexes, including plaque index (PLI), gingival index (GI), sulcus bleeding index (SBI), probing depth (PD) and attachment loss (AL) of observed teeth were examined.

RESULTS

The detection rates of P.gingivalis, F. nucleatum, P. intermedia and T. forsythensis increased from baseline to the third month without significant difference, and then returned to pretreatment levels 12 month after applying fixed orthodontic appliances. Adults' percentage contents of P.gingivalis, F. nucleatum, P. intermedia and T. forsythensis were significantly higher than those of children at baseline and the first month, but not obvious at the third month. PLI and SBI were increased from baseline to the first and to the third month both in adults and children groups. Besides, PD were increased from baseline to first month, followed by a downward trend in the third month; however, all patients were failed to detect with AL.

CONCLUSIONS

Periodontal and microbiological statuses of malocclusion patients may be influenced by fixed orthodontic appliances in both adults and children, more significant in children than in adults. Some microbiological indexes have synchronous trend with the clinical indexes. Long-term efficacy of fixed orthodontic appliances for malocclusion should be confirmed by future researches.

Control of white spot lesion adjacent to orthodontic bracket with use of fluoride varnish or chlorhexidine gel

The aims of this study were to compare the effectiveness of fluoride varnish and chlorhexidine gel in controlling white spot lesions (WSLs) adjacent to orthodontic brackets and to compare the ability of Quantitative Light-Induced Fluorescence (QLF) to measure mineral uptake with that of transverse microradiography (TMR). Thirty premolars with artificially induced WSLs were randomly assigned to three groups: (1) two applications of 5% NaF-varnish (F), with one-week interval, (2) two applications of 2% chlorhexidine gel (CHX), with one-week interval, and (3) control (CO), no treatment. QLF was used to measure changes in fluorescence before and after caries induction, 1 week after each application and 1, 2, and 3 months after the last application of F or CHX. TMR was performed to quantify lesion depth and mineral content after caries induction to evaluate the effects of F, CHX, and CO 3 months after the last application of agents. The data were analyzed by repeated measures ANOVA and Tukey's test. All treatments increased the mineral content during the experimental period; however, F induced faster remineralization than CHX. The correlation between QLF and TMR was significantly moderate. Two applications of fluoride varnish or 2% chlorhexidine gel at one-week intervals were effective in controlling WSLs.

Detection of fusobacterium nucleatum and fadA adhesin gene in patients with orthodontic gingivitis and non-orthodontic periodontal inflammation

Fusobacterium nucleatum is one of the most abundant gram-negative bacilli colonizing the subgingival plaque and closely associated with periodontal disease. However it is unclear whether F. nucleatum is involved in gingival inflammation under orthodontic appliance. A novel adhesin, FadA, which is unique to oral Fusobacteria, is required for F. nucleatum binding and invasion to epithelial cells and thus may play an important role in colonization of Fusobacterium in the host. In this study, we evaluated the prevalence of F. nucleatum and its virulence factor FadA adhesion gene (fadA) in 169 subgingival biofilm samples from 55 cases of gingivitis patients with orthodontic appliances, 49 cases of gingivitis patients without orthodontic treatment, 35 cases of periodontitis patients and 30 cases of periodontally healthy people via PCR. The correlations between the F. nucleatum/fadA and gingivitis index(GI)was also analyzed. The detection rate of F. nucleatum/fadA in periodontitis group and non-orthodontic gingivitis group was higher than the other two groups (p<0.01) while it was higher in orthodontic gingivitis group than in health people (p<0.05). An obviously positive correlation was observed between the prevalence of F. nucleatum/fadA and GI. F. nucleatum carrying fadA may be more closely related to the development of gingivitis and periodontal disease compared with orthodontic gingivitis.

Investigating the biological properties of carbohydrate derived fulvic acid (CHD-FA) as a potential novel therapy for the management of oral biofilm infections

Background

A number of oral diseases, including periodontitis, derive from microbial biofilms and are associated with increased antimicrobial resistance. Despite the widespread use of mouthwashes being used as adjunctive measures to control these biofilms, their prolonged use is not recommended due to various side effects. Therefore, alternative broad-spectrum antimicrobials that minimise these effects are highly sought after. Carbohydrate derived fulvic acid (CHD-FA) is an organic acid which has previously demonstrated to be microbiocidal against Candida albicans biofilms, therefore, the aims of this study were to evaluate the antibacterial activity of CHD-FA against orally derived biofilms and to investigate adjunctive biological effects.

Methods

Minimum inhibitory concentrations were evaluated for CHD-FA and chlorhexidine (CHX) against a range of oral bacteria using standardised microdilution testing for planktonic and sessile. Scanning electron microscopy was also employed to visualise changes in oral biofilms after antimicrobial treatment. Cytotoxicity of these compounds was assessed against oral epithelial cells, and the effect of CHD-FA on host inflammatory markers was assessed by measuring mRNA and protein expression.

Results

CHD-FA was highly active against all of the oral bacteria tested, including Porphyromonas gingivalis, with a sessile minimum inhibitory concentration of 0.5%. This concentration was shown to kill multi-species biofilms by approximately 90%, levels comparable to that of chlorhexidine (CHX). In a mammalian cell culture model, pretreatment of epithelial cells with buffered CHD-FA was shown to significantly down-regulate key inflammatory mediators, including interleukin-8 (IL-8), after stimulation with a multi-species biofilm.

Conclusions

Overall, CHD-FA was shown to possess broad-spectrum antibacterial activity, with a supplementary function of being able to down-regulate inflammation. These properties offer an attractive spectrum of function from a naturally derived compound, which could be used as an alternative topical treatment strategy for oral biofilm diseases. Further studies in vitro and in vivo are required to determine the precise mechanism by which CHD-FA modulates the host immune response.