Effect of TrisEDTA and Chlorhexidine 0.12% on an In Vitro-Defined Biofilm Representing the Subgingival Plaque Biofilm of the Dog

This study was designed to investigate the effects of chlorhexidine 0.12%, TrisEDTA (tromethamine ethylenediamintetraacetic acid), and a combination of chlorhexidine 0.12% and TrisEDTA on an in vitro plaque biofilm model comprised of three bacterial species commonly found in canine subgingival plaque. Porphyromonas gulae, Actinomyces canis, and Neisseria canis were grown in a biofilm on polished hydroxyapatite coated titanium alloy pucks for 72 h prior to exposure to one of four test solutions: TrisEDTA, chlorhexidine 0.12%, a combination of TrisEDTA and chlorhexidine 0.12%, or sterile deionized water as a control. Following exposure to the test solution, a sample was collected of the biofilm either immediately or following 24 h of additional incubation in a broth medium. Lower numbers of CFU/mL of Porphyromonas gulae resulted when the biofilm was treated with a solution of chlorhexidine 0.12% and TrisEDTA compared to with chlorhexidine 0.12% alone, TrisEDTA alone, or the control and so this solution can be said to be synergistic against Porphyromonas gulae in this controlled in vitro model. Greater reductions in the numbers of CFU/mL of Actinomyces canis and Neisseria canis resulted from treatment with chlorhexidine 0.12% alone than if treated with the combination of TrisEDTA and chlorhexidine 0.12%. When treated biofilm samples were allowed 24 h of additional growth in fresh media, greater variance resulted and this variance highlights the complex dynamics involved in bacterial growth within a biofilm.

Effectiveness of Non-Surgical and Surgical Periodontal Therapy in Lowering HbA1c in Diabetic Patients

Diabetes is global pandemic disease, a metabolic disorder of multiple etiology that is characterized by chronic hyperglycemia resulting from defects in insulin secretion, insulin action, or both. Periodontitis is a chronic inflammatory disease that is initiated by the accumulation of dental plaque biofilm, within which microbial dysbiosis leads to a chronic, non-resolving and destructive inflammatory response. In the last decades, many studies investigated the impact of periodontal treatment on glycemic control in people with diabetes. The aim of this dissertation is to conduct a review of the published literature to understand the association between periodontal therapy and glycated hemoglobin (HbA1c) values. A search was conducted in PUBMED and of the 277 articles found, only 21 were considered for being more relevant. As has been recognized for some time, the results show a correlation between the two diseases and their link lies in the inflammatory process. In the diabetic patient, this results in higher HbA1c values and a situation that is difficult to control. Being able to control the inflammatory state of the periodontium through oral hygiene protocols and periodontal therapy has several benefits in a complicated clinical picture in situations of poor glycemic control. Non-surgical periodontal therapy proves effective in significantly lowering HbA1c levels in diabetic patients.

The feasibility of phage therapy for periodontitis

Periodontitis, a chronic progressive inflammation caused by plaque biofilm, is the main cause of tooth loss in adults. For certain refractory periodontitis cases, it is difficult to achieve a good curative effect using the existing periodontal treatment approaches, which may be due to periodontal pathogenic mechanism in the affected periodontal tissue that the host cannot resist and eliminate. Various pieces of evidence collectively revealed that most studies are focusing on phages in periodontal disease. Several studies have reported periodontitis treatment using phage therapy, highlighting its features including specificity, rapid propagation, and effectiveness on bacteriophage biofilms. In this study, we focus on these reports, aiming to lay the foundation for improved periodontal treatment approaches.

Evaluation of Mouthwash Containing Citrus hystrix DC., Moringa oleifera Lam. and Azadirachta indica A. Juss. Leaf Extracts on Dental Plaque and Gingivitis

Oral hygiene and control of microbial plaque biofilm formation are effective methods for preventing gingivitis. Mouthwashes containing leaf extracts of the medicinal plants Citrus hystrix DC. (KL), Moringa oleifera Lam. (MO) and Azadirachta indica A. Juss. (NE) were assessed for oral healthcare and gingivitis adjunctive treatment. Three types of mouthwash were developed; KL, a combination of KL and MO (KL + MO), and a combination of KL, and NE (KL + NE). The mouthwashes were tested in vivo on 47 subjects with gingivitis who were allocated into five groups as (i) placebo, (ii) KL, (iii) KL + MO, (iv) KL + NE, and (v) 0.12% chlorhexidine gluconate (CHX). Participants were instructed to rinse with herbal mouthwash twice daily for two weeks. Gingival index (GI), plaque index (PI), and oral microbial colonies were measured at baseline and 15 days. Results showed that GI and PI of groups (ii)–(iv) significantly decreased over the placebo group, while accumulative reduction percentages of both Staphylococcus spp. and Candida spp. were found in groups (iii) and (iv). Findings indicated that the herbal mouthwashes reduced GI and PI, and showed potential as oral healthcare products.

Virtual Screening and Biological Evaluation of Anti-Biofilm Agents Targeting LuxS in the Quorum Sensing System

Biofilm formation is considered as a crucial factor in various oral diseases, such as dental caries. The quorum sensing (QS) signaling system was proved to have a crucial role in the microbial dental plaque biofilm formation of Streptococcus mutans ( S. mutans). LuxS was critical to regulating the QS system and survival of the bacterium, and, therefore, compounds which target LuxS may be a potential therapy for dental caries. The binding activities of 37,170 natural compounds to LuxS were virtually screened in this study. Baicalein and paeonol were chosen for further research of the binding mode and ΔG values with LuxS. Both baicalein and paeonol inhibited the biofilm formation without influence on the growth of S. mutans. Baicalein also distinctly reduced the production of both rhamnolipids and acids. The results provide us with a new approach to combat dental caries instead of the traditional use of antibacterial chemicals.

Parodontitis: Lokale Entzündung mit systemischer Wirkung

SummaryParodontitis zählt zu den 6 häufigsten chronischen nicht-ansteckenden Erkrankungen weltweit. Unbehandeltführt diese zu Zahnverlust. Für die Destruktion des Zahnhalteapparates ist ein komplexes Zusammenspiel zwischen dem dysbiotischen Plaque-Biofilm und der körpereigenen Immunantwort verantwortlich. Lokale Entzündungsreaktionen bleiben jedoch nicht auf die Mundhöhle beschränkt, sondern können auch systemische Auswirkungen zeigen. Moderate bis schwere Parodontitiden erhöhen das Risiko für Typ 2 Diabetes mellitus und kardiovaskuläre Erkrankungen. Umgekehrt modulieren diese systemischen Erkrankungen die Pathogenese parodontaler Entzündungsreaktionen. Verhaltensfaktoren wie Rauchen oder Ernährungsgewohnheiten können modifizierend auf die lokalen und systemischen Entzündungsprozesse einwirken. Die aktuelle Forschung rückt Ernährungsinterventionen bzw. -restriktionen als potenzielle Bestandteile nicht-invasiver Intervention und/oder Präventionsstrategie zur Vermeidung parodontaler Entzündungen und Stoffwechselerkrankungen in den Fokus – ein vielversprechender Ansatz.

Taxonomic and Gene Category Analyses of Subgingival Plaques from a Group of Japanese Individuals with and without Periodontitis

Periodontitis is an inflammation of tooth-supporting tissues, which is caused by bacteria in the subgingival plaque (biofilm) and the host immune response. Traditionally, subgingival pathogens have been investigated using methods such as culturing, DNA probes, or PCR. The development of next-generation sequencing made it possible to investigate the whole microbiome in the subgingival plaque. Previous studies have implicated dysbiosis of the subgingival microbiome in the etiology of periodontitis. However, details are still lacking. In this study, we conducted a metagenomic analysis of subgingival plaque samples from a group of Japanese individuals with and without periodontitis. In the taxonomic composition analysis, genus Bacteroides and Mycobacterium demonstrated significantly different compositions between healthy sites and sites with periodontal pockets. The results from the relative abundance of functional gene categories, carbohydrate metabolism, glycan biosynthesis and metabolism, amino acid metabolism, replication and repair showed significant differences between healthy sites and sites with periodontal pockets. These results provide important insights into the shift in the taxonomic and functional gene category abundance caused by dysbiosis, which occurs during the progression of periodontal disease.

Understanding the Matrix: The Role of Extracellular DNA in Oral Biofilms

Dental plaque is the key etiological agent in caries formation and the development of the prevalent chronic oral inflammatory disease, periodontitis. The dental plaque biofilm comprises a diverse range of microbial species encased within a rich extracellular matrix, of which extracellular DNA (eDNA) has been identified as an important component. The molecular mechanisms of eDNA release and the structure of eDNA have yet to be fully characterized. Nonetheless, key functions that have been proposed for eDNA include maintaining biofilm structural integrity, initiating adhesion to dental surfaces, acting as a nutrient source, and facilitating horizontal gene transfer. Thus, eDNA is a potential therapeutic target for the management of oral disease–associated biofilm. This review aims to summarize advances in the understanding of the mechanisms of eDNA release from oral microorganisms and in the methods of eDNA detection and quantification within oral biofilms.

Arginine induced Streptococcus gordonii biofilm detachment using a novel rotating-disc rheometry method

Oral diseases are one of the most common pathologies affecting human health. These diseases are typically associated with dental plaque-biofilms, through either build-up of the biofilm or dysbiosis of the microbial community. Arginine can disrupt dental plaque-biofilms, and maintain plaque homeostasis, making it an ideal therapeutic to combat the development of oral disease. Despite our understanding of the actions of arginine towards dental plaque-biofilms, it is still unclear how or if arginine effects the mechanical integrity of the dental plaque-biofilm. Here we adapted a rotating-disc rheometry assay, which is routinely used in marine microbial ecology, to study how arginine treatment of Streptococcus gordonii biofilms influences biofilm detachment from surfaces. We demonstrate that the assay is highly sensitive at quantifying the presence of biofilm and the detachment or rearrangement of the biofilm structure as a function of shear stress. We demonstrate that arginine treatment leads to earlier detachment of the biofilm, indicating that arginine treatment weakens the biofilm, making it more suspectable to removal by shear stresses. Our results add to the understanding that arginine targets biofilms by multifaceted mechanisms, both metabolic and physical, further promoting the potential of arginine as an active compound in dentifrices to maintain oral health.