• Journal of Korean society of Dental Hygiene
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• v.8 no.4
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• pp.241-250
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• 2008

In this study, specimens such as tongue, supragingival and subgingival biofilm were taken from total 20 scaling subjects who visited the oral prophylaxis practice lab at department of dental hygienics, J Health College in order to observe bacterial distributions and morphology using scanning electron microscopy(sem). as a result, this study came to the following conclusions: 1. According to observation of tongue, supragingival and subgingival biofilm through sem, it is found that there are round colonies of gram-positive cocci and gram-negative bacilli on blood agar medium. 2. The observation of bacterial morphology on dental biofilm through sem, cocci in chain cocci in cluster and bacillus(rod) respectively. 3. For tongue biofilm, it is found that a variety of bacterial species are detected, such as Granulicatolla adiacens(1), Gemella morbillorum(3), Streptococcus mitis(2), Streptococcus sanguinis(1), Aerococcus viridans (2), Streptococcus equinus(1), Leuconostoc spp.(1), Gemella haemolysans (1) and Lactococcus lactis spp.(1) respectively. 4. For supragingival biofilm, it is found that a variety of bacterial species detected, such as Aerococcus viridans(1), Gemella haemolysans(2), Leuconostoc spp.(2), Gemella morbillorum(1) and Pseudomonas fluoescens (1) respectively. 5. For subgingival biofilm, it is found that a variety of bacterial species detected, such as Leuconostoc spp.(1), Staphylococcus lugdunensis(1) and Streptococcus salivarius(1) respectively.

• Journal of Korean society of Dental Hygiene
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• v.24 no.2
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• pp.131-139
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• 2024

Objectives: Oral bacterial samples included subgingival, supragingival, and saliva plaques. As the diversity and number of microorganisms deffer depending on the area of the oral cavity and the method used, an appropriate and reliable collection method is important. The present study investigated oral bacterial sampling methods. Methods: Supragingival dental plaque was collected from the buccal and lingual tooth surfaces of study participants using sterilized cotton swabs. Plaques were collected from the subgingival area using a sterilized curette. Bacterial genomic DNA was extracted using MagNA Pure 96 DNA and Viral NA low-volume kits. Real-time polymerase chain reaction (PCR) was performed using the PowerCheck^TM Periodontitis Pathogens Multiplex Real-time PCR kit. Results: Aggregatibacter actinomycetemcomitans, Prevotella intermedia, and Fusobacterium nucleatum of the orange complex were not observed in the subgingival biofilms of all study participants. For Porphyromonas. gingivalis, a significant correlation was observed between supragingival, subgingival, and total tooth surface biofilms. Compared to the supragingival and subgingival biofilmss, total tooth surface biofilm exhibited the highest bacterial count when the inswabbing method was used. Conclusions: Based on these findings, the supragingival swab method is recommended for oral bacterial research.

• Journal of dental hygiene science
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• v.19 no.3
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• pp.162-169
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• 2019

Background: Oral diseases are caused by various systemic and local factors, the most closely related being the biofilm. However, the challenges involved in removing an established biofilm necessitate professional care for its removal. This study aimed to evaluate and compare the effects of professional self and professional biofilm care in healthy patients to prevent the development of periodontal diseases. Methods: Thirty-seven patients who visited the dental clinic between September 2018 and February 2019 were included in this study. Self-biofilm care was performed by routine tooth brushing and professional biofilm care was provided using the toothpick method (TPM) or the oral prophylaxis (OP) method using a rubber cup. Subgingival bacterial motility and halitosis (levels of hydrogen sulfide, $H_2S$; methyl mercaptan, $CH_3SH$; and di-methyl sulfide, $(CH_3)_2S$) were measured before, immediately after, and 5 hours after the preventive treatment in the three groups. Repeated measures analysis of variance test was performed to determine significant differences among the groups. Results: TPM was effective immediately after the prevention treatment, whereas OP was more effective after 5 hours (proximal surfaces, F=16.353, p<0.001; smooth surfaces, F=66.575, p<0.001). The three components responsible for halitosis were effectively reduced by professional biofilm care immediately after the preventive treatment; however, self-biofilm care was more effective after 5 hours ($H_2S$, F=3.564, p=0.011; $CH_3SH$, F=6.657, p<0.001; $(CH_3)_2S$, F=21.135, p<0.001). Conclusion: To prevent oral diseases, it is critical to monitor the biofilm. The dental hygienist should check the oral hygiene status and the ability of the patient to administer oral care. Professional biofilm care should be provided by assessing and treating each surface of the tooth. We hope to strengthen our professional in biofilm care through continuous clinical research.

• International Journal of Oral Biology
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• v.43 no.4
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• pp.171-175
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• 2018

Quorum sensing (QS) is a cell density-dependent communication mechanism between bacteria through small signaling molecules. When the number of QS signaling molecules reaches a threshold, they are transported back into the cells or recognized by membrane-bound receptors, triggering gene expression which affects various phenotypes including bioluminescence, virulence, adhesion, and biofilm formation. These phenotypes are beneficial for bacterial survival in harsh environments. This review summarizes the application of QS inhibitors for control of biofilm formation and virulence expression of periodontal pathogens.

• Journal of Periodontal and Implant Science
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• v.52 no.1
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• pp.77-87
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• 2022

Purpose: This pilot study assessed the immediate in vivo effect of high peak pulse power neodymium-doped yttrium aluminum garnet (Nd:YAG) laser monotherapy on selected red/orange complex periodontal pathogens in deep human periodontal pockets. Methods: Twelve adults with severe periodontitis were treated with the Laser-Assisted New Attachment Procedure (LANAP®) surgical protocol, wherein a free-running, digitally pulsed, Nd:YAG dental laser was used as the initial therapeutic step before mechanical root debridement. Using a flexible optical fiber in a handpiece, Nd:YAG laser energy, at a density of 196 J/cm² and a high peak pulse power of 1,333 W/pulse, was directed parallel to untreated tooth root surfaces in sequential coronal-apical passes to clinical periodontal probing depths, for a total applied energy dose of approximately 8-12 joules per millimeter of periodontal probing depth at each periodontal site. Subgingival biofilm specimens were collected from each patient before and immediately after Nd:YAG laser monotherapy from periodontal pockets exhibiting ≥6 mm probing depths and bleeding on probing. Selected red/orange complex periodontal pathogens (Porphyromonas gingivalis, Tannerella forsythia, Prevotella intermedia/nigrescens, Fusobacterium nucleatum, Parvimonas micra, and Campylobacter species) were quantified in the subgingival samples using established anaerobic culture techniques. Results: All immediate post-treatment subgingival biofilm specimens continued to yield microbial growth after Nd:YAG laser monotherapy. The mean levels of total cultivable red/orange complex periodontal pathogens per patient significantly decreased from 12.0% pretreatment to 4.9% (a 59.2% decrease) immediately after Nd:YAG laser monotherapy, with 3 (25%) patients rendered culture-negative for all evaluated red/orange complex periodontal pathogens. Conclusions: High peak pulse power Nd:YAG laser monotherapy, used as the initial step in the LANAP® surgical protocol on mature subgingival biofilms, immediately induced significant reductions of nearly 60% in the mean total cultivable red/orange complex periodontal pathogen proportions per patient prior to mechanical root instrumentation and the rest of the LANAP® surgical protocol.

• Journal of Periodontal and Implant Science
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• v.31 no.4
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• pp.661-668
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• 2001

Anti-P. gingivalis immune sera were obtained from mice immunized with either P. gingivalis alone, or F. nucleaturm followed by P. gingivalis. Two groups of immune sera were examined for binding capacity to P. gingivalis biofilm by confocal laser scanning microscope, Antibody avidity index was also determined for each immune sera. The results indicated that prior immunization of mice with F. nucleaturm impaired P. gingivalis-specific immune sera in binding capacity to biofilm and antibody avidity to P. gingivalis. Elevated antibody responses in patients with destructive periodontal disease has often been related to suboptimal level of protective antibody $(opsonophagocytosis)^{1-3)}$ while post-immune sera obtained with experimental animals using a single periodontal pathogen demonstrated satisfactory levels of protective function against the homologous bacterial $challenge^{4,5)}$.The reason is unclear why elevated IgG responses in periodontal patients to periodontal pathogens do not necessarily reflect their protective function. Such an immune deviation might be derived from the fact that destructive periodontal disease is cumulative result of immunopathologic processes responding to an array of different colonizing microorganisms sequentially infecting in the subgingival environmental niche. Fusobacterium nucleaturm is one of the key pathogens in gingivitis, in the transitional phase of conversion of gingivitis into destructive periodontitk, and in adult $periodontitis^{6-8)}$. It also plays a central role in coaggregation with other important microbial species in subgingival $area^{6,9,10)}$ as well as in $biofilm^{11)}$, especially with Porphyromonas gingjvalis in synergism of virulence in human periodontal disease or in animal $models^{12-14)}$. This organism has also been reported to have immune modulating activity for secondary immune response to Actinobacillus $actinomycetemcomitans^{15)}$. It is presumed that sequential colonization and intermicrobial coaggregation between intermediate and late colonizers could potentially modulate the immune responses and development of specific T cell phenotypes in periodontal lesions. We have recently demonstrated the skewed polarization of P. gingivalis-specific helper T cell clones in mice immunized with F. nucleaturm followed by P. $gingivalis.^{16)}$. Consequently F. nucleaturm may initially prime the immune cells and modify their responses to the successive organism, P. gingivalis. This could explain why one frequently observes non-protective serum antibodies to P. gingivalis in periodontal patients in contrast with those obtained from animals that were immunized with $P.gingivalis\;alone^{17)}$. The present study was performed to investigate the immune modulating effect of F. nucleatum on serum binding to experimental biofilms and the avidity of anti-P. gingivalis antibody.

• Journal of Periodontal and Implant Science
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• v.52 no.4
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• pp.282-297
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• 2022

Purpose: To explore differences in the subgingival microbiome according to the presence of periodontitis and/or type 2 diabetes mellitus (T2D), a metagenomic sequencing analysis of the subgingival microbiome was performed. Methods: Twelve participants were divided into 4 groups based on their health conditions (periodontitis, T2D, T2D complicated with periodontitis, and generally healthy). Subgingival plaque was collected for metagenomic sequencing, and gingival crevicular fluids were collected to analyze the concentrations of short-chain fatty acids. Results: The shifts in the subgingival flora from the healthy to periodontitis states were less prominent in T2D subjects than in subjects without T2D. The pentose and glucuronate interconversion, fructose and mannose metabolism, and galactose metabolism pathways were enriched in the periodontitis state, while the phosphotransferase system, lipopolysaccharide (LPS) and peptidoglycan biosynthesis, bacterial secretion system, sulfur metabolism, and glycolysis pathways were enriched in the T2D state. Multiple genes whose expression was upregulated from the red and orange complex bacterial genomes were associated with bacterial biofilm formation and pathogenicity. The concentrations of propionic acid and butyric acid were significantly higher in subjects with periodontitis, with or without T2D, than in healthy subjects. Conclusions: T2D patients are more susceptible to the presence of periodontal pathogens and have a higher risk of developing periodontitis. The pentose and glucuronate interconversion, fructose and mannose metabolism, galactose metabolism, and glycolysis pathways may represent the potential microbial functional association between periodontitis and T2D, and butyric acid may play an important role in the interaction between these 2 diseases. The enrichment of the LPS and peptidoglycan biosynthesis, bacterial secretion system, and sulfur metabolism pathways may cause T2D patients to be more susceptible to periodontitis.

• Journal of Periodontal and Implant Science
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• v.51 no.4
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• pp.276-284
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• 2021

Purpose: The aim of this randomized clinical trial was to assess whether chemical cleansing using a sulfonic/sulfuric acid gel solution (HBX) as an adjunct to scaling and root planing (SRP) resulted in a decrease in residual plaque and calculus in deep periodontal pockets compared to SRP alone. Methods: Fifty-six patients with 56 hopeless posterior teeth, scheduled for extraction due to severe periodontitis, were enrolled in this study. Each tooth was randomly assigned to 1 of the 2 experimental procedures. The test teeth were subjected to the irrigation of the subgingival area with HBX for 2 minutes, followed by SRP with hand and ultrasonic instruments for 14 minutes, and then extracted. The control teeth received only mechanical instrumentation before extraction. Residual biofilm was evaluated on photographs and measured as total area and percentage of root surface covered by remaining plaque (RP) or calculus (RC) after treatment. Results: The initial pocket depth (PD) and total subgingival root surface area were similar between the 2 treatment groups. After treatment, the total subgingival root area covered by RP and RC was statistically significantly larger (P<0.001) in the control group than in the test group. The test teeth showed a lower percentage of RP, but a higher percentage of RC than the control teeth (both P<0.001). Complete calculus removal was achieved in 42% of the control teeth surfaces and in 25% of the test teeth surfaces for a PD of 4 mm. Conclusions: The additional chemical cleansing with HBX resulted in a statistically significant improvement in bacterial plaque removal during SRP of deep pockets, but it was not effective in reducing calculus deposits.

• Journal of Periodontal and Implant Science
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• v.40 no.4
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• pp.153-163
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• 2010

Periodontal disease, as a polymicrobial disease, is globally endemic as well as being a global epidemic. It is the leading cause for tooth loss in the adult population and has been positively related to life-threatening systemic diseases such as atherosclerosis and diabetes. As a result, it is clear that more sophisticated therapeutic modalities need to be developed, which may include vaccines. Up to now, however, no periodontal vaccine trial has been successful in satisfying all the requirements; to prevent the colonization of a multiple pathogenic biofilm in the subgingival area, to elicit a high level of effector molecules such as immunoglobulin sufficient to opsonize and phagocytose the invading organisms, to suppress the induced alveolar bone loss, or to stimulate helper T-cell polarization that exerts cytokine functions optimal for protection against bacteria and tissue destruction. This article reviews all the vaccine trials so as to construct a more sophisticated strategy which may be relevant in the future. As an innovative strategy to circumvent these barriers, vaccine trials to stimulate antigen-specific T-cells polarized toward helper T-cells with a regulatory phenotype (Tregs, $CD_{4+}$, $CD_{25+}$, $FoxP_{3+}$) have also been introduced. Targeting not only a single pathogen, but polymicrobial organisms, and targeting not only periodontal disease, but also periodontal disease-triggered systemic disease could be a feasible goal.

• International Journal of Oral Biology
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• v.41 no.1
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• pp.17-23
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• 2016

Chronic/cyclic neutropenia, leukocyte adhesion deficiency syndrome, Papillon-$Lef{\grave{e}}vre$ syndrome, and $Ch{\grave{e}}diak$-Higashi syndrome are associated with severe periodontitis, suggesting the importance of neutrophils in the maintenance of periodontal health. Various Toll-like receptor (TLR) ligands are known to stimulate neutrophil function, including FcR-mediated phagocytosis. In the present study, the effect of TLR2 activation on the non-opsonic phagocytosis of oral bacteria and concomitant production of reactive oxygen species (ROS) by human neutrophils was evaluated. Neutrophils isolated from peripheral blood were incubated with Streptococcus sanguinis or Porphyromonas gingivalis in the presence of various concentrations of $Pam_3CSK_4$, a synthetic TLR2 ligand, and analyzed for phagocytosis and ROS production by flow cytometry and chemiluminescence, respectively. $Pam_3CSK_4$ significantly increased the phagocytosis of both bacterial species in a dose-dependent manner. However, the enhancing effect was greater for S. sanguinis than for P. gingivalis. $Pam_3CSK_4$ alone induced ROS production in neutrophils and also increased concomitant ROS production induced by bacteria. Interestingly, incubation with P. gingivalis and $Pam_3CSK_4$ decreased the amounts of ROS, as compared to $Pam_3CSK_4$ alone, indicating the possibility that P. gingivalis survives within neutrophils. However, neutrophils efficiently killed phagocytosed bacteria of both species despite the absence of $Pam_3CSK_4$. Although P. gingivalis is poorly phagocytosed even by the TLR2-activated neutrophils, TLR2 activation of neutrophils may help to reduce the colonization of P. gingivalis by efficiently eliminating S. sanguinis, an early colonizer, in subgingival biofilm.