Microbial shift and periodontitis

Efficacy of Non-Surgical Periodontal Therapy with Adjunctive Methylene Blue and Toluidine Blue O Mediated Photodynamic in Treatment of Periodontitis: A Randomized Clinical Trial

BACKGROUND

This study aimed to examine the efficacy of methylene blue (MB) and toluidine blue O (TBO) photodynamic therapy (PDT) as adjuncts to root surface debridement (RSD).

METHODS

This split-mouth, randomized, controlled clinical trial included eighteen patients, and a total of 332 sites (control = 102, MB = 124 and TBO = 106) were examined. Two sessions of PDT were completed at baseline and two weeks after RSD. Clinical parameters of bleeding on probing (BOP), plaque index (PI), probing pocket depth (PPD), and clinical attachment level (CAL) were measured pre- and post-treatment.

RESULTS

PPD and BOP reductions in sites treated by RSD with adjunctive photosensitizers (MB and TBO) were significantly higher than in control sites. RSD with MB showed higher efficacy in improving moderately deep pockets (OR 3.350), while adjunctive TBO showed better results in treating deeper pockets (OR 4.643).

CONCLUSIONS

Results suggested that adjunctive use of MB and TBO to RSD could significantly improve periodontal pocket closure and reduce signs of inflammation. In addition, TBO seems to be more efficient in treating deep periodontal pockets than MB, which is more effective in resolving shallower pockets.

Antibiotic resistance in the microbiota of periodontitis patients: an update of current findings

Systemic antibiotics are an effective adjunct in the treatment of periodontitis, but their judicious use is necessary as antimicrobial resistance is a growing global concern. This review aims to explore the current understanding and insight related to antibiotic resistance in the subgingival microbiota of periodontitis patients. A search of MEDLINE (PubMed) was carried out from 1 January 2012 to 25 November 2021 for studies related to antibiotic resistance in periodontitis patients. Of the 90 articles identified, 12 studies were selected for inclusion. A significant incidence of antibiotic resistant isolates was reported for Porphyromonas gingivalis, Prevotella intermedia, Prevotella denticola, Prevotella melaninogenica, Fusobacterium nucleatum, Tanerella forsythia, Aggretibacter actinomycetemcomitans, Streptococcus constellatus, Streptococcus intermedius, and Parvimonas micra, but resistance to specific antibiotics did not reach above 10% of isolates in most studies except for amoxicillin resistance in Aggretibacter actinomycetemcomitans. The highest frequency of resistance across all bacterial species was for amoxicillin, clindamycin, and metronidazole. However, resistance patterns were widely variable across geographical locations, and the high heterogeneity between antibiotic-resistant isolates across studies precludes any clinical recommendations from this study. Although antibiotic resistance has yet to reach critical levels in periodontitis patients, an emphasis on antibiotic stewardship interventions such as point-of-care diagnostics and education for key stakeholders is needed to curb a growing problem.

The Role of Sulfhydryl (Thiols) Groups in Oral and Periodontal Diseases

AIM

The sulfhydryl (thiols) group of glutathione plays an important role in the neutralization of foreign organic compounds and the reduction in peroxides. The purpose of the study is to evaluate the concentration of sulfhydryl groups in the gingival tissue of healthy individuals and those with gingivitis or periodontitis, and to examine the differences between these groups.

MATERIAL AND METHODS

To assess the concentration of sulfhydryl groups (thiols) in the gingival tissue of healthy individuals and those with gingivitis or periodontitis, we used spectrophotometric analysis using dithionitrobenzoate (DTNB) as a reagent to measure the accessible sulfhydryl groups present in gingival tissue proteins. The sample was divided into three distinct groups: individuals with periodontal health, gingivitis, and periodontitis, and different indices were used to assess the periodontal status of the participants. Next, a statistical analysis was conducted to compare the concentrations of sulfhydryl groups among the different groups of patients.

CONCLUSIONS

The results of this study showed significantly decreased levels of sulfhydryl (thiols) groups in gingival tissue from patients with gingivitis and periodontitis, compared with healthy people (control group). These results confirm the role of sulfhydryl (thiols) groups in defense against free radicals. They share a significant role in detoxification, signal transduction, apoptosis, and various other functions at the molecular level.

Oxygen enrichment mediated by calcium peroxide loaded gelatin methacrylate hydrogel eradicates periodontal biofilms

The low oxygen environment of the periodontal pocket favors pathogenic anaerobes' growth, biofilm formation, and quick recurrence after periodontal treatment. In contrast, oxygen is detrimental to anaerobes, such as Porphyromonas gingivalis (P. gingivalis), since they lack a complete anti-oxidation mechanism to detoxify the oxygen challenge. Therefore, consistently feeding pathogenic anaerobes with abundant oxygen would be an effective strategy to combat them. Here, we reported injectable oxygen-generating hydrogels as oxygen mediators to alleviate the local anaerobic environment and eliminate periodontal pathogens. Gelatin methacrylate (GelMA) hydrogels loaded with calcium peroxide (CPO) possessed excellent injectability and exhibited burst releases of oxygen within 24 h with a 40 % oxygen tension peak. CPO-GelMA hydrogels with CPO concentrations of 5, 10, and 15 % reduced 60, 99, and 89.9 % viable P. gingivalis, respectively. Five percentage CPO-GelMA hydrogel downregulated gingipain and fimA gene expression in P. gingivalis without resistance development. Moreover, the CPO-GelMA hydrogels remarkably prevented biofilm formation and eradicated both monospecies and multispecies bacterial biofilms. In conclusion, CPO-GelMA hydrogels exert remarkable antimicrobial and antibiofilm effects on subgingival biofilms, providing a promising strategy for periodontal treatment.

Clinical and Microbiological Evaluation of Diode Laser and Systemic Doxycycline as an Additive to Scaling and Root Planing for Stage II and Stage III Periodontitis Patients

AIM

To assess and contrast the effectiveness of systemic doxycycline and diode laser as supplements to scaling and root planing (SRP) in terms of clinical and microbiological parameters.

MATERIALS AND METHODS

A total of 33 patients diagnosed with periodontitis stages II and III were included and randomized into group A (SRP + diode laser), group B (SRP + doxycycline), and group C (SRP alone). Selected sites were assessed for clinical and microbial parameters-plaque index (PI), gingival index (GI), pocket probing depth (PPD), relative attachment level (RAL), and colony-forming units (CFUs). Every clinical parameter was noted at baseline and after three months. The arithmetic mean, followed by the standard deviation, was calculated for the required assessment intervals. Analysis of variance (ANOVA) was used to compare all parameters between groups, and if the results of the ANOVA test were significant, post hoc analysis was performed. For intragroup comparison, student t-tests were performed.

RESULTS

The clinical parameters significantly improved within three months for all groups. In terms of relative attachment level, a statistically significant difference (P < 0.001) was obtained at the three-month interval compared to the baseline value, with the most statistically significant difference seen in group A (3.36±0.50 to 0.64±0.50), followed by group B (3.18±0.40 to 2.18±0.40). The mean pocket probing depth observed at three months, compared to the baseline value, showed a statistically significant difference (P < 0.001) in group A (5.91±0.70 to 2.18±0.40) compared to group B (6.18±0.75 to 4.36±0.50), followed by group C (5.82±0.75 to 5.27±0.64).

CONCLUSION

The use of diode laser-assisted pocket disinfection and systemic doxycycline, in addition to scaling and root planing, has proven to be efficient for treating periodontal pockets.

The role of probiotics for preventing dysbiosis in periodontal disease: a randomized controlled trial

Background/aim

Scaling and root planing remain inadequate in periodontitis treatment caused by dysbiotic microbial dental plaque. The aim of this clinical trial is to evaluate the effects of probiotics and kefir consumption in initial periodontal therapy (IPT) on oral microbiota composition and treatment outcomes in patients with periodontitis.

Materials and methods

The study was carried out in the Gazi University Department of Periodontology, including a sample size of 36 individuals and utilizing a randomized controlled design. Thirty-six patients with periodontitis were randomly allocated to three groups: one receiving probiotic treatment, another receiving kefir, and a third serving as the control group. Obtaining subgingival microbial samples, we recorded plaque, gingival index, bleeding on probing, periodontal pocket depth, and clinical attachment level (periodontal clinical indices) and then performed IPT. For 14 days, patients took either probiotics, kefir, or no supplements. Data for the first and third months were collected using periodontal clinical indices. DNA sequencing was performed to detect Tannerella forsythia, Porphyromonas gingivalis, and Treponema denticola in subgingival plaque samples collected at baseline and three months.

Results

Significant differences were observed regarding periodontal clinical indices among groups in the intragroup comparisons. Moreover, levels of Tannerella forsythia were significantly decreased in all groups.

Conclusion

Kefir can be administered in addition to IPT, providing results similar to those observed with probiotics.

Recent Advances in Functionalized Electrospun Membranes for Periodontal Regeneration

Periodontitis is a global, multifaceted, chronic inflammatory disease caused by bacterial microorganisms and an exaggerated host immune response that not only leads to the destruction of the periodontal apparatus but may also aggravate or promote the development of other systemic diseases. The periodontium is composed of four different tissues (alveolar bone, cementum, gingiva, and periodontal ligament) and various non-surgical and surgical therapies have been used to restore its normal function. However, due to the etiology of the disease and the heterogeneous nature of the periodontium components, complete regeneration is still a challenge. In this context, guided tissue/bone regeneration strategies in the field of tissue engineering and regenerative medicine have gained more and more interest, having as a goal the complete restoration of the periodontium and its functions. In particular, the use of electrospun nanofibrous scaffolds has emerged as an effective strategy to achieve this goal due to their ability to mimic the extracellular matrix and simultaneously exert antimicrobial, anti-inflammatory and regenerative activities. This review provides an overview of periodontal regeneration using electrospun membranes, highlighting the use of these nanofibrous scaffolds as delivery systems for bioactive molecules and drugs and their functionalization to promote periodontal regeneration.

The Role of Dysbiotic Oral Microbiota in Cardiometabolic Diseases: A Narrative Review

Over the past decade, there have been significant advancements in the high-flow analysis of "omics," shedding light on the relationship between the microbiota and the host. However, the full recognition of this relationship and its implications in cardiometabolic diseases are still underway, despite advancements in understanding the pathophysiology of these conditions. Cardiometabolic diseases, which include a range of conditions from insulin resistance to cardiovascular disease and type 2 diabetes, continue to be the leading cause of mortality worldwide, with a persistently high morbidity rate. While the link between the intestinal microbiota and cardiometabolic risks has been extensively explored, the role of the oral microbiota, the second-largest microbiota in the human body, and specifically the dysbiosis of this microbiota in causing these complications, remains incompletely defined. This review aims to examine the association between the oral microbiota and cardiometabolic diseases, focusing on the dysbiosis of the oral microbiota, particularly in periodontal disease. Additionally, we will dive into the mechanistic aspects of this dysbiosis that contribute to the development of these complications. Finally, we will discuss potential prevention and treatment strategies, including the use of prebiotics, probiotics, and other interventions.

Comparative 16S rRNA gene sequencing study of subgingival microbiota of healthy subjects and patients with periodontitis from four different countries

AIM

To investigate the differences between the subgingival microbiota of healthy subjects (HS) and periodontitis patients (PP) from four different countries through a metagenomic approach.

MATERIALS AND METHODS

Subgingival samples were obtained from subjects from four different countries. Microbial composition was analysed through high-throughput sequencing of the V3-V4 region of the 16S rRNA gene. The country of origin, diagnosis and clinical and demographic variables of the subjects were used to analyse the microbial profiles.

RESULTS

In total, 506 subgingival samples were analysed: 196 from HS and 310 from patients with periodontitis. Differences in richness, diversity and microbial composition were observed when comparing samples pertaining to different countries of origin and different subject diagnoses. Clinical variables, such as bleeding on probing, did not significantly affect the bacterial composition of the samples. A highly conserved core of microbiota associated with periodontitis was detected, while the microbiota associated with periodontally HS was much more diverse.

CONCLUSIONS

Periodontal diagnosis of the subjects was the main variable explaining the composition of the microbiota in the subgingival niche. Nevertheless, the country of origin also had a significant impact on the microbiota and is therefore an important factor to consider when describing subgingival bacterial communities.

Saliva as Biomarker for Oral and Chronic Degenerative Non-Communicable Diseases

Saliva is a very complex fluid and it is essential to maintain several physiological processes and functions, including oral health, taste, digestion and immunological defenses. Saliva composition and the oral microbiome can be influenced by several factors, like diet and smoking habits, and their alteration can represent an important access point for pathogens and, thus, for systemic illness onset. In this review, we explore the potentiality of saliva as a new tool for the early detection of some pathological conditions, such as oral diseases, chronic degenerative non-communicable diseases, among these chronic kidney disease (CKD). We also examined the possible correlation between oral and systemic diseases and oral and gut microbiota dysbiosis. In particular, we deeply analyzed the relationship between oral diseases and CKD. In this context, some salivary parameters can represent a new device to detect either oral or systemic pathologies. Moreover, the positive modulation of oral and gut microbiota induced by prebiotics, postbiotics, or symbiotics could represent a new possible adjuvant therapy in the clinical management of oral diseases and CKD.

Nanotechnology for Dentistry: Prospects and Applications

In the XXI century, application of nanostructures in oral medicine has become common. In oral medicine, using nanostructures for the treatment of dental caries constitutes a great challenge. There are extensive studies on the implementation of nanomaterials to dental composites in order to improve their properties, e.g., their adhesive strength. Moreover, nanostructures are helpful in dental implant applications as well as in maxillofacial surgery for accelerated healing, promoting osseointegration, and others. Dental personal care products are an important part of oral medicine where nanomaterials are increasingly used, e.g., toothpaste for hypersensitivity. Nowadays, nanoparticles such as macrocycles are used in different formulations for early cancer diagnosis in the oral area. Cancer of the oral cavity-human squamous carcinoma-is the sixth leading cause of death. Detection in the early stage offers the best chance at total cure. Along with diagnosis, macrocycles are used for photodynamic mechanism-based treatments, which possess many advantages, such as protecting healthy tissues and producing good cosmetic results. Application of nanostructures in medicine carries potential risks, like long-term influence of toxicity on body, which need to be studied further. The introduction and development of nanotechnologies and nanomaterials are no longer part of a hypothetical future, but an increasingly important element of today's medicine.

Periodontal Pathogens and Their Links to Neuroinflammation and Neurodegeneration

Pathogens that play a role in the development and progression of periodontitis have gained significant attention due to their implications in the onset of various systemic diseases. Periodontitis is characterized as an inflammatory disease of the gingival tissue that is mainly caused by bacterial pathogens. Among them, Porphyromonas gingivalis, Treponema denticola, Fusobacterium nucleatum, Aggregatibacter actinomycetemcomitans, and Tannerella forsythia are regarded as the main periodontal pathogens. These pathogens elicit the release of cytokines, which in combination with their virulence factors induce chronic systemic inflammation and subsequently impact neural function while also altering the permeability of the blood-brain barrier. The primary objective of this review is to summarize the existing information regarding periodontal pathogens, their virulence factors, and their potential association with neuroinflammation and neurodegenerative diseases. We systematically reviewed longitudinal studies that investigated the association between periodontal disease and the onset of neurodegenerative disorders. Out of the 24 studies examined, 20 showed some degree of positive correlation between periodontal disease and neurodegenerative disorders, with studies focusing on cognitive function demonstrating the most robust effects. Therefore, periodontal pathogens might represent an exciting new approach to develop novel preventive treatments for neurodegenerative diseases.

Imbalance of Vaginal Microbiota and Immunity: Two Main Accomplices of Cervical Cancer in Chinese Women

Objective

To explore the correlation of female vaginal microbiota and immune factors with cervical cancer.

Methods

The distribution pattern difference of vaginal microbiota of four groups of women (cervical cancer, HPV-positive CIN, HPV-positive non-CIN, and HPV-negative groups) were compared by microbial 16S rDNA sequencing. The protein chip was used to detect the composition and changes of the immune factors in the four groups.

Results

Alpha diversity analysis demonstrated that the diversity of the vaginal microbiota was increased as the disease develops. Among those bacteria abundant in the vaginal microbiota, Lactobacillus, Prevotella, and Gardnerella dominate at the genus level of vaginal flora. Compared with the HPV-negative group, the differentially dominant bacteria, such as Prevotella, Ralstonia, Gardnerella and Sneathia, are enriched in the cervical cancer group. Likewise, Gardnerella, Prevotella, and Sneathia are more in the HPV-positive CIN group, while Gardnerella and Prevotella in the HPV-positive non-CIN group, respectively. In contrast, Lactobacillus and Atopobium are dominant in the HPV-negative group (LDA>4log10). The concentration of inflammatory immune factors IP-10 and VEGF-A were increased in the cervical cancer group (P < 0.05), compared with other groups.

Conclusion

The occurrence of cervical cancer is related to an increase of vaginal microbiota diversity and up-regulation of inflammatory immune factor proteins. The abundance of Lactobacillus was decreased while the one of Prevotella and Gardnerella were increased in the cervical cancer group, compared with other three groups. Moreover, the IP-10 and VEGF-A were also increased in the cervical cancer group. Thus, evaluation of changes in the vaginal microbiota and these two immune factor levels might be a potential non-invasive and simple method to predict cervical cancer. Furthermore, it is significant to adjust and restore the balance of vaginal microbiota and maintain normal immune function in preventing and treating cervical cancer.

Microbiota Regulates Pancreatic Cancer Carcinogenesis through Altered Immune Response

The microbiota is present in many parts of the human body and plays essential roles. The most typical case is the occurrence and development of cancer. Pancreatic cancer (PC), one of the most aggressive and lethal types of cancer, has recently attracted the attention of researchers. Recent research has revealed that the microbiota regulates PC carcinogenesis via an altered immune response. Specifically, the microbiota, in several sites, including the oral cavity, gastrointestinal tract, and pancreatic tissue, along with the numerous small molecules and metabolites it produces, influences cancer progression and treatment by activating oncogenic signaling, enhancing oncogenic metabolic pathways, altering cancer cell proliferation, and triggering chronic inflammation that suppresses tumor immunity. Diagnostics and treatments based on or in combination with the microbiota offer novel insights to improve efficiency compared with existing therapies.

Efficacy of surgical periodontal treatment with and without photobiomodulation in the treatment of severe periodontitis: An evaluation of periodontal, microbiological, and cytokine levels

AIM

To compare the efficacy of surgical periodontal treatment (SPT) alone and PDT-assisted surgery in participants with severe periodontitis MATERIAL AND METHODS: The present clinical trial was completed by 64 participants (n=32 each). The selection was made according to predefined inclusion and exclusion criteria. Patients in group A were treated with SPT only and participants in group B were treated with SPT adjunct to PDT. Microbiological assessment of P.Gingivalis; T. Forsythia and T.Denticola were evaluated using cultural analysis and periodontal parameters plaque score (PSc), bleeding on probing (BoP) periodontal depth (PD), and clinical attachment loss (CAL) at baseline and post-treatment at 6 months and 12 months were performed. The gingival crevicular fluid (GCF) was collected for the estimation of IL-1β and tumor necrosis factor-alpha (TNF-α) using an enzyme-linked immunosorbent assay (ELISA). For intra-group comparison and post hoc correction, Student's t-test along with Bonferroni was used. For the difference between follow-ups, an analysis of variance (ANOVA) multiple rank tests were incorporated.

RESULTS

The mean age of participants in the SPT group was 55.25±4.6yrs. Whereas, participants treated with PDT adjunct to SPT were 54.88±3.6yrs. Periodontal parameters (BoP, PD, PSc, CAL) showed no significant difference at baseline. At 6 months and 12 months follow-up, a significant difference in all parameters (BoP, PD, PSc, and CAL) was found in participants treated with SPT alone and PDT adjunct to SPT (p<0.05). Inflammatory biomarkers at 6-month and 12-month follow-ups, a statistically significant difference in the level of biomarkers (IL-1β and TNF-α) were observed in both groups from baseline (p<0.05). However, at baseline, no significant difference was noted in both groups (p> 0.05). The microbiological assessment showed a significant drop in the bacterial count in participants treated with both regimes i.e., SPT alone and PDT adjunct to SPT.

CONCLUSION

Photodynamic therapy (PDT) adjunct to surgical periodontal treatment (SPT) in severe periodontitis improves microbiological and periodontal parameters and lowers the level of proinflammatory cytokines.

Non-Surgical Therapy and Oral Microbiota Features in Peri-Implant Complications: A Brief Narrative Review

The therapeutic discretion in cases of peri-implantitis should take into account the limits and advantages of specific therapeutic itineraries tailored according to each clinical case and each individual patient. This type of oral pathology emphasizes the complex classification and diagnostic issues coupled with the need for targeted treatments, in light of the oral peri-implant microbiota changes. This review highlights the current indications for the non-surgical treatment of peri-implantitis, describing the specific therapeutic efficacy of different approaches and discussing the more appropriate application of single non-invasive therapies The non-surgical treatment choice with antiseptics or antibiotics (single or combined, local, or systemic) for short courses should be considered on a case-by-case basis to minimize the incidence of side effects and concomitantly avoid disease progression.

Local and Systemic Effects of Porphyromonas gingivalis Infection

Porphyromonas gingivalis, a gram-negative anaerobe, is a leading etiological agent in periodontitis. This infectious pathogen can induce a dysbiotic, proinflammatory state within the oral cavity by disrupting commensal interactions between the host and oral microbiota. It is advantageous for P. gingivalis to avoid complete host immunosuppression, as inflammation-induced tissue damage provides essential nutrients necessary for robust bacterial proliferation. In this context, P. gingivalis can gain access to the systemic circulation, where it can promote a prothrombotic state. P. gingivalis expresses a number of virulence factors, which aid this pathogen toward infection of a variety of host cells, evasion of detection by the host immune system, subversion of the host immune responses, and activation of several humoral and cellular hemostatic factors.

Bleaching Effect of Ozonized Substances on Resin Composite: A New Potentiality for Ozone Therapy in Dentistry

Composite resins are commonly used in dentistry for direct restorations. The color stability of these materials still represents a major concern for both the clinician and the patient. In recent years, ozone therapy has been extensively used in dentistry to manage wounds healing, dental caries, oral lichen planus, gingivitis and periodontitis, halitosis, osteonecrosis of the jaw, post-surgical pain, plaque and biofilms, root canal treatment, dentin hypersensitivity, temporomandibular joint disorders, and teeth whitening. To date, several studies have evaluated the bleaching effect exerted by ozone on natural teeth, but no studies have been conducted to determine the effect on the color of composite resins. The aim of the present study is to determine whether ozonized oils/gels could determine a color change on composite resin. A total of 40 discs of an A3 shade restorative composite were divided into two groups, respectively exposed to a pigmentation treatment consisting of 10 applications of 10 min each of a 1% chlorhexidine-based gel (trial group) and to storage into physiological solution (control group). The samples of both groups were respectively subdivided into four subgroups which underwent four different protocols, three of which were based on the exposure to different ozonized products and the latter representing the control. A colorimetric analysis with the CIELAB method was conducted with the following timing: after 24 h of storage in physiological solution (before the experimental procedures) (T0), after the subdivision into groups A and B (corresponding to the pigmentation for samples of group A and storage in physiological solution for samples of group B) (T1), and after subdivision into subgroups 1–4 (corresponding to the application of the ozonized products vs. control) (T2). No statistically significant difference was found between the samples at T0. The 20 samples of group A, exposed to the colorant agent, underwent a color change from T0 to T1, whereas the 20 samples exposed to the physiologic solution did not undergo any significant color change. A positive but moderate influence was assessed for E and L values, whereas no significant change occurred for A and B values. Therefore, dental ozonized oils/gels could be valuable in restorative dentistry as bleaching agents of resin composites exposed to discoloration, an alternative to the traditional hydrogen peroxide and carbamide peroxide, but further studies are required to confirm these findings.

A Novel Antimicrobial Hydrogel for the Management of Periodontal Diseases

OBJECTIVES

This study aimed to synthesise a drug-delivery system based on a porous polymer hydrogel, with antimicrobial properties against Porphyromonas gingivalis and potential to be used in tissue regeneration.

MATERIAL AND METHODS

2-Hydroxyethyl methacrylate monomers were polymerised using thermal and photoactivation in the presence of silver nitrate (AgNO₃) and/or chlorhexidine digluconate. Poly-2-hydroxyethyl methacrylate (pHEMA) hydrogels containing silver nanoparticles (AgNPs) and/or 0.12% chlorhexidine (CHX) were produced and characterised using cryo-SEM and confocal microscopy. Hydrogel degradation and leaching of AgNP were tested for 1.5 months. The antimicrobial properties were tested against P. gingivalis using broth culture system and disk diffusion tests.

RESULTS

Our methodology manufactured porous polymeric hydrogels doped with AgNPs and CHX. Hydrogels showed a successful delivery of CHX and sustainable release of AgNPs in a steady hydrogel degradation rate determined based on the weight loss of samples. Hydrogels with AgNPs or CHX had a significant antimicrobial effect against P. gingivalis, with CHX-hydrogels exhibiting a stronger effect than AgNP-hydrogels in the short-term assessment. AgNP-CHX hydrogels showed a compounded antimicrobial effect, whereas control hydrogels containing neither AgNPs nor CHX had no influence on bacterial growth (P < .05).

CONCLUSIONS

The dual-cured pHEMA hydrogel loaded with antimicrobial agents proved to be an efficient drug-delivery system against periodontopathogens, with the potential to be used as a scaffold for tissue regeneration.

Regulation of the Host Immune Microenvironment in Periodontitis and Periodontal Bone Remodeling

The periodontal immune microenvironment is a delicate regulatory system that involves a variety of host immune cells including neutrophils, macrophages, T cells, dendritic cells and mesenchymal stem cells. The dysfunction or overactivation of any kind of local cells, and eventually the imbalance of the entire molecular regulatory network, leads to periodontal inflammation and tissue destruction. In this review, the basic characteristics of various host cells in the periodontal immune microenvironment and the regulatory network mechanism of host cells involved in the pathogenesis of periodontitis and periodontal bone remodeling are summarized, with emphasis on the immune regulatory network that regulates the periodontal microenvironment and maintains a dynamic balance. Future strategies for the clinical treatment of periodontitis and periodontal tissue regeneration need to develop new targeted synergistic drugs and/or novel technologies to clarify the regulatory mechanism of the local microenvironment. This review aims to provide clues and a theoretical basis for future research in this field.

Effects of green tea extract epigallocatechin-3-gallate (EGCG) on oral disease-associated microbes: a review

For thousands of years, caries, periodontitis and mucosal diseases, which are closely related to oral microorganisms, have always affected human health and quality of life. These complex microbiota present in different parts of the mouth can cause chronic infections in the oral cavity under certain conditions, some of which can also lead to acute and systemic diseases. With the mutation of related microorganisms and the continuous emergence of drug-resistant strains, in order to prevent and treat related diseases, in addition to the innovation of diagnosis and treatment technology, the development of new antimicrobial drugs is also important. Catechins are polyphenolic compounds in green tea, some of which are reported to provide health benefits for a variety of diseases. Studies have shown that epigallocatechin-3-gallate (EGCG) is the most abundant and effective active ingredient in green tea catechins, which acts against a variety of gram-positive and negative bacteria, as well as some fungi and viruses. This review aims to summarize the research progress on the activity of EGCG against common oral disease-associated organisms and discuss the mechanisms of these actions, hoping to provide new medication strategies for the prevention and treatment of oral infectious diseases, the future research of EGCG and its translation into clinical practice are also discussed.

Feasibility of oral microbiome profiles associated with oral squamous cell carcinoma

Objective

Recently, the possibility that oral microbiomes is associated with oral squamous cell carcinoma (OSCC) initiation and progression has attracted attention; however, this association is still unclear. Here, we comprehensively analyze the microbiome profiles of saliva samples using next-generation sequencing followed by determining the association between oral microbiome profiles and OSCC.

Materials and Methods

Microbiome profiles in saliva samples from patients with OSCC, oral leukoplakia (OLK), and postoperative OSCC (Post) were analyzed. Candidate OSCC-associated bacteria were identified by comparing the bacterial diversity and relative abundance of each group based on these microbiome profiles, and their applicability as OSCC detection tools were evaluated.

Results

There were significant differences in genus abundances (Streptococcus, Aggregatibacter, and Alloprevotella) among the groups from saliva samples. In the OSCC group, compared with the OLK and Post groups, abundances of the genus Fusobacterium, phylum Fusobacteria and phylum Bacteroidetes were markedly increased and that of the genus Streptococcus and phylum Firmicutes were decreased.

Conclusion

The results suggested a strong association of these bacteria with OSCC. Especially, phylum Fusobacterium was significantly associated with early recurrence of OSCC. Thus, oral microbiome analysis may have a potential of novel OSCC detection and prognostic tool.

Comparative evaluation of postoperative pain and tissue response in patients undergoing conventional flap surgeries with or without 940 nm diode laser exposure - A randomized clinical study

BACKGROUND

Over the past few years, a growing body of evidence has allowed us to ascertain that the initiation of periodontitis stems from the existence of oral microbial biofilm and that this requires definitive treatment. Owing to its exceptional usability, affordability, and antibacterial activity, the "diode laser" (DL) has increasingly become a popular and important tool in a dentist's armamentarium. However, there is a scarcity of scientific evidence on the utility and advantages of using "diode laser" in periodontal flap surgery. The study aimed to determine the efficacy of 940 nm diode laser exposure in combination with conventional periodontal flap surgery for the treatment of chronic periodontitis to evaluate postoperative discomfort and clinical parameters.

MATERIALS AND METHODS

A total of 10 subjects (7 males and 3 females) with generalized chronic periodontitis were recruited and completed the study without any dropouts. For this split-mouth study, 40 sample sites with pocket probing depth (PPD) 5-7 mm post periodontal Phase I therapy were selected. The quadrants were randomly allocated to Groups A, B, C, and D using the fish bowl lottery method. Kirkland flap surgery with laser and modified Widman flap (MWF) with laser were performed in Group A and C, respectively, while Kirkland flap surgery and MWF surgery were performed in Group B and Group D. Clinical parameters including visual analog scale (VAS) score and gingival inflammation were determined at 3^rd and 7^th day postoperatively while PPD, clinical attachment level (CAL), and sulcus bleeding index (SBI) were recorded at baseline and 6 months following treatment. Wilcoxon signed-rank test and Kruskal-Wallis test were used for intra-group and inter-group comparison of parameters, respectively.

RESULTS

Statistically significant difference was attained with postoperative discomfort in laser-assisted groups on 1^st and 3^rd day postoperatively (P < 0.001). There was no significant difference in the proportion of subjects with gingival inflammation. A statistically significant reduction in mean PPD at 6 months postoperatively was seen among all study groups (P < 0.05) but the inter-group difference was not statistically significant. SBI score reduced significantly from baseline to 6 months follow-up among all four groups (P < 0.05). However, we did not find the inter-group difference to be statistically non-significant.

CONCLUSION

Diode laser as an adjunct to the surgical procedure can demonstrate appreciable benefits by increasing the CAL and minimizing the postoperative pain and the probing pocket, but such additional effects were not observed with gingival inflammation.

Probiotics in Periodontal and Peri-Implant Health Management: Biofilm Control, Dysbiosis Reversal, and Host Modulation

Periodontitis and peri-implantitis are microbially associated diseases of the tissues supporting the teeth and dental implants that are mediated by host inflammation and eventually lead to tooth and dental implant loss. Given the probiotics' role in biofilm control, dysbiosis reversal, and host modulation, their potential beneficial effects on the improvement of periodontitis and peri-implantitis have been recently investigated. Moreover, probiotics use has also been proposed in periodontal health management in patients undergoing fixed orthodontic therapy. Therefore, the present study aimed to review, considering the periodontal microbiome composition around teeth and dental implants in healthy and pathological conditions, the putative favorable effects of probiotics on gingivitis, periodontitis, and peri-implantitis. The secondary aim of the present narrative review was to synthesize the supporting evidence and proposed protocols for probiotics use as adjuncts in periodontitis and peri-implantitis treatment and the periodontal health management of orthodontic patients with fixed appliances. Contrasting findings from the literature may be due to the different methods, posology, and duration of probiotics prescriptions and due to the heterogeneous biological and clinical measurement methods employed. Thus, no definitive conclusions could be drawn about the effectiveness of probiotics in periodontal management, both in healthy and pathological conditions. Further studies are needed to validate probiotics for periodontal management and provide recommended protocols.

Evaluating clinical utility of subgingival and salivary endotoxin activity levels as periodontal biomarkers

Objectives

The use of periodontal biomarkers for identification and monitoring of unique patient populations could foster better stratification of at-risk groups, increase access to treatment for those most in need, facilitate preventive measures and improve personalised care plans. The aim of this study was to examine the diagnostic and prognostic utility of oral lipopolysaccharides as bacterially-derived periodontal biomarkers.

Methods

Periodontal parameters were recorded, and saliva and subgingival plaque samples were collected at the beginning of the study from periodontally healthy volunteers and periodontitis patients, and three months after completion of conventional periodontal treatment in the periodontitis group. Endotoxin activity in the samples was measured using the recombinant factor C assay. Associations between clinical periodontal parameters and subgingival and salivary endotoxin activities were analysed using a multivariate regression model, while the ROC curve was applied to estimate the sensitivity, specificity and c-statistics for salivary and subgingival endotoxin activities as diagnostic biomarkers for periodontitis.

Results

Significant correlations were found between subgingival endotoxin activities, probing pocket depth and periodontal diagnosis, which were independent from patients' age, gender and smoking status. In addition, subgingival endotoxin levels had high specificity and sensitivity in detecting periodontal health and disease (0.91 and 0.85 respectively). Salivary endotoxin activity was positively associated with periodontal diagnosis, mean probing pocket depth, percentages of sites over 4 mm and full mouth bleeding score. However, it was inferior in discriminating patients with stable periodontium from those with periodontitis (sensitivity = 0.69, specificity = 0.61) compared to subgingival endotoxin activity.

Conclusions

Subgingival endotoxin activity has good diagnostic and prognostic values as a site-specific periodontal biomarker and is not influenced by the patient's age, gender or smoking status. In contrast, salivary endotoxin activity, as a patient-level biomarker, is dependent on patient's age, has poorer diagnostic and prognostic capability, but shows good correlations with disease susceptibility and both its extent and severity.

The effect of Er,Cr:YSGG laser on periodontopathic bacteria elimination: an in vitro study

In vitro bacterial elimination using the erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser against periodontopathic bacteria was investigated. Bacterial suspensions of Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis were spread on agar plates and the Er,Cr:YSGG laser was applied at 40 mJ pulse energy for durations of 30 s, 60 s, and 90 s. The agar plates were incubated, and growth inhibition zones were assessed. Optimal laser irradiation durations to achieve maximal bacterial elimination were evaluated using laser ablation on the bacterial colonies. The remaining viable bacteria were determined by the colony-forming unit (CFU) counting method. Growth inhibition zones were observed at all irradiation durations for both A. actinomycetemcomitans and P. gingivalis. Mean logarithmic values of CFU/ml after bacterial colony irradiation for 0 s (control), 12 s × 1 lap, 24 s × 1 lap, 48 s × 1 lap, and 24 s × 2 laps were 8.82 ± 0.35, 7.31 ± 0.94, 6.32 ± 0.61, 3.17 ± 2.90, and 0.00, respectively, for A. actinomycetemcomitans and 9.83 ± 0.50, 9.42 ± 0.11, 6.90 ± 1.60, 2.33 ± 3.19, and 0.00 for P. gingivalis. Significant differences were found between the control group and the two irradiated groups 48 s × 1 lap and 24 s × 2 laps (p < 0.05), and also between irradiated groups 12 s × 1 lap and 24 s × 2 laps (p < 0.05). An Er,Cr:YSGG laser with power setting 1.5 W and 30 Hz frequency showed potential for bacterial elimination against A. actinomycetemcomitans and P. gingivalis in vitro. Significant bacterial elimination (> 99.99%) was observed after 48 s of irradiation.

Effects of Traumatic Brain Injury on the Gut Microbiota Composition and Serum Amino Acid Profile in Rats

Traumatic brain injury (TBI) heavily impacts the body: it damages the brain tissue and the peripheral nervous system and shifts homeostasis in many types of tissue. An acute brain injury compromises the “brain–gut-microbiome axis”, a well-balanced network formed by the brain, gastrointestinal tract, and gut microbiome, which has a complex effect: damage to the brain alters the composition of the microbiome; the altered microbiome affects TBI severity, neuroplasticity, and metabolic pathways through various bacterial metabolites. We modeled TBI in rats. Using a bioinformatics approach, we sought to identify correlations between the gut microbiome composition, TBI severity, the rate of neurological function recovery, and blood metabolome. We found that the TBI caused changes in the abundance of 26 bacterial genera. The most dramatic change was observed in the abundance of Agathobacter species. The TBI also altered concentrations of several metabolites, specifically citrulline and tryptophan. We found no significant correlations between TBI severity and the pre-existing gut microbiota composition or blood metabolites. However, we discovered some differences between the two groups of subjects that showed high and low rates of neurological function recovery, respectively. The present study highlights the role of the brain–gut-microbiome axis in TBI.

Oral Microbiome Using Colocasia antiquorum var. esculenta Extract Varnish in a Mouse Model with Oral Gavage of P. gingivalis ATCC 53978

Background and Objective: There is increasing interest in preventing periodontitis using natural products. The purpose of this study was to investigate the effect of Colocasia antiquorum var. esculenta (CA) varnish on the oral microbiome and alveolar bone loss in a mouse periodontitis model. Materials and Methods: Antibacterial activity against Porphyromonas gingivalis (P. gingivalis) ATCC 53978 and cell cytotoxicity using CCK-8 on L929 cells were measured. Balb/c mice were assigned into five groups (negative control, positive control, CA in drinking water, varnish, and CA varnish). P. gingivalis was administered to the mice by oral gavage three times. After sacrifice, the oral microbiome and the levels of the inflammatory cytokine IL-1β and matrix metalloproteinase-9 were analyzed. Alveolar bone loss was measured using micro-computed tomography. Results: CA extract showed an antibacterial effect against P. gingivalis (p < 0.05) and showed no cytotoxicity at that concentration (p > 0.05). Although alpha diversity of the oral microbiome did not statistically differ between the groups (p > 0.05), the relative abundance of dominant bacteria tended to be different between the groups. The inflammatory cytokine IL-1β was reduced in the CA varnish group (p < 0.05), and no difference was observed in MMP-9 expression and alveolar bone loss (p > 0.05). Conclusions: CA varnish did not affect the overall microflora and exhibited an anti-inflammatory effect, suggesting that it is possibility a suitable candidate for improving periodontitis.

Microbial differences between active and remission peri-implantitis

Peri-implantitis has a polymicrobial etiology and is a major cause of dental implant loss. Various clinical protocols for its prevention and treatment have been proposed; however, some cases show a rapid progression with non-resolving clinical symptoms. To clear a means of differentiating between such cases, the implants with peri-implantitis in this study were categorized as the active group and the remission group and that two kinds of samples were obtained from the same subjects (n = 20). The microbiome was analyzed through pyrosequencing of the 16S rRNA gene. From LEfSe results, Porphyomonas, Fusobacterium, Treponema, Tannerella, and other periodontal pathogens were abundant in the active group, while lactic acid bacteria (Lactobacillales and Bifidobacterium) were abundant in the remission group.

Comparison Between Different Delivery Vehicles for the Probiotic Bifidobacterium animalis subsp. lactis HN019 on Experimental Periodontitis in Rats

This study aimed to assess the effects of the probiotic (PROB) Bifidobacterium animalis subsp. lactis HN019 in two different delivery vehicles in experimental periodontitis (EP), including the gene expression for IL-10, IFN-γ, and FOXP3. In total, 32 rats were assigned into groups (n=8): C (control), EP, EP-PROB/Water, and EP-PROB/Milk. The probiotic was administered for 4 weeks, from baseline to euthanasia. Periodontitis was induced by ligatures 14 days after baseline. Data were statistically analyzed (p<0.05). Both probiotic groups presented decreased alveolar bone loss and increased interproximal attachment level than group EP. Also, these parameters were significantly improved in the Milk group when compared with the Water group. EP-PROB/Milk showed higher gene expression for IL-10 and lower for FOXP3 in relation to EP-PROB/Water and EP groups. The use of milk was able to potentiate the protective effects of B. lactis HN019 in rats under EP.

Relationship between Undernutrition and Periodontal Diseases among a Sample of Yemeni Population: A Cross-Sectional Study

Undernutrition is an inadequate supply of energy and nutrients. Periodontal diseases (PDs) are defined as a broad form of chronic inflammatory disease of the gingiva, bone, and ligaments supporting the teeth. This study aimed to reveal the relationship between undernutrition, using body mass index (BMI) and serum albumin level (Alb), and PDs in a sample of Yemeni population. A cross-sectional study was conducted at dental teaching clinics at the Faculty of Dentistry, Sana’a University. Of 1920 patients who attended clinics, only 229 matched the study criteria. Oral examination was performed to assess the periodontal clinical parameter measurements. BMI and Alb were measured. Participants of both genders were involved, with a slight increase in males (n = 134, 58.5%), and most of the study sample was in the age group of 18–35 years (n = 209, 91.3%). Regarding habits, only 18.2% (n = 43) of patients were smokers and about half of the participants (n = 136, 59.4%) were khat chewers. Most cases had mild undernutrition according to BMI (n = 139, 60.7%) and normal Alb level (n = 213, 93%). Regarding the periodontal diagnosis, most of the participants were diagnosed with gingivitis (n = 186, 81.2%). BMI and albumin level were nonsignificantly associated with PDs. PDs were statistically significant with the participant’s age, gender, level of education, and smoking ( $P>0.05$ ). However, BMI, khat chewing, and albumin level were nonsignificant factors of periodontal diseases among Yemeni participants ( $P>0.05$ ). In both genders, variables such as age of the patients, smoking, khat chewing, and PDs were nonsignificantly associated with BMI. This study showed that the majority of the participants had been diagnosed with gingivitis, but there was not an association between PDs and undernutrition. This paper is presented on research square URL // https://www.researchsquare.com/article/rs-429796/v1 with DOI 10.21203/rs.3.rs-429796/v1.

Management of Periodontal Disease with Adjunctive Therapy with Ozone and Photobiomodulation (PBM): A Randomized Clinical Trial

Periodontitis is an inflammatory condition of the soft and hard tooth-supporting tissues, representing the first cause of tooth loss. In addition to standard mechanical debridement (Scaling and Root Planing, SRP), further approaches have been proposed as adjuncts. The aim of the present randomized clinical trial is to compare the efficacy of ozone or photobiomodulation (PBM) therapy in addition to SRP to treat periodontal disease. According to a split-mouth design, 240 pathological sites, corresponding to 30 periodontal patients, were randomly divided according to the professional oral hygiene protocol performed at baseline (T0) and after 1 (T1), 2 (T2), 3 (T3), 4 (T4), 5 (T5), and 6 (T6) months. A total of 120 sites underwent an ozonized water administration (ozone group), whereas the other 120 sites were treated with photobiomodulation (PBM group), both in addition to SRP. At every timepoint, the following clinical indexes were assessed: Probing Pocket Depth (PPD) (measured on six sites per element), Plaque Index (PI), and Bleeding on Probing (BOP). As regards PPD, significant intergroup differences were noticed from T5, with significantly lower values in the PBM group (p < 0.05), where values further decreased at T6 (p < 0.05). Both PI and BoP generally decreased from baseline to T6 in both groups; a significant difference was found between T0 and T1 among the groups (p < 0.05), with a progressively higher reduction in the PBM group among the time frames of the study, despite intergroup comparisons not being significant (p > 0.05). Both ozone and PBM appear to be effective adjuvant treatments to SRP, obtaining a slightly better outcome for the latter in the long term, with significant differences at T5 and T6 for PPD. However, because of the absence of standardized protocols for PBM considering both therapeutic and research purposes, no definitive conclusions can be reached, and further studies are required.

Potential Treponema denticola-based periodontal vaccine to resolve a global public health challenge: a narrative literature review

INTRODUCTION

Periodontitis is a diseased condition of the gum which imposes considerable costs on healthcare systems. It progresses further beyond the inflammation of supportive tissues of the teeth, and the collateral damages are closely associated with Alzheimer's disease, cardiovascular disease, and diabetes mellitus.

AREAS COVERED

A comprehensive literature review was performed to summarize published studies in English during the period of 1990-2021 to discuss the rationales for developing periodontal vaccine, cost-effectiveness analyses on the prevention of periodontitis, Treponema denticola-based vaccine candidates, as well as immunological mechanisms in animal models.

EXPERT OPINION

Preventive strategies against periodontitis may halt the onset of gum inflammation itself and the consequent chronic diseases. Considering the multi-microbial condition of periodontitis, an ideal periodontal vaccine should target multiple pathological pathways. Preventive approaches compared to surgical treatments evidently have significant impact on the healthcare budget and long-term health of the individuals in different communities. Despite many advances in periodontal vaccine research, there are still significant hurdles to overcome in developing a vaccine. Investment in research and development activities on key periodontal pathogens including Treponema denticola and Porphyromonas gingivalis in the foreseeable future is a worthy and cost-effective approach for the policymakers to prevent deleterious impacts of periodontitis.

Paraprobiotics in Non-Surgical Periodontal Therapy: Clinical and Microbiological Aspects in a 6-Month Follow-Up Domiciliary Protocol for Oral Hygiene

Periodontal disease represents a progressive destruction of tooth-supporting tissues. Recently, paraprobiotics are regarded as an adjunctive therapy to the non-surgical Scaling-and-Root-Planing (SRP). The aim of this study is to evaluate the efficacy of two new formulations of paraprobiotics, a toothpaste and a mouthwash, respectively, for the domiciliary hygiene. A total of 40 patients were randomly assigned to the following domiciliary treatments: Group 1 (SRP + Curasept Intensive Treatment 0.2% chlorhexidine) (control) and Group 2 (SRP + Biorepair Peribioma toothpaste + Biorepair Peribioma Mousse mouthwash) (trial). At baseline (T₀) and after 3 and 6 months (T₁–T₂), periodontal clinical (Bleeding on Probing, Probing Pocket Depth, Clinical Attachment Loss, Bleeding Score, Sulcus Bleeding Index, Plaque Index, Approximal Plaque Index, Adherent Gingiva, Gingival Recession, and Pathological Sites) and microbiological parameters (Pathological Bacteria, Saprophytic Bacteria, Enlarged Red Complex, Red Complex, Orange Complex, and counts of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythensys, Treponema denticola, Prevotella intermedia, and Fusobacterium nucleatum). The use of the experimental products resulted in a significant reduction of most of the clinical indices assessed, which occurred at a major degree with respect to the conventional chlorhexidine considered as control. Additionally, after 6 months of use, the abovementioned products significantly decreased the percentage of pathological bacteria and the counts of those bacteria constituting the “Red Complex”, more related to the periodontal disease. Accordingly, the paraprobiotics-based products tested in this study seem to represent a valid support to SRP with a benefit on both clinical indices and on specific periodontopathogens.

Home Oral Care of Periodontal Patients Using Antimicrobial Gel with Postbiotics, Lactoferrin, and Aloe Barbadensis Leaf Juice Powder vs. Conventional Chlorhexidine Gel: A Split-Mouth Randomized Clinical Trial

Periodontitis is a progressive destruction of both soft and hard tooth-supporting tissues. In the last years, probiotics have been proposed as a support to the gold standard treatment scaling and root planing (SRP), but no extensive literature is present as regards the effect of the more recent postbiotics. Thirty patients subjected to SRP were randomly assigned to two domiciliary hygiene treatments based on the following oral gels: the postbiotics-based Biorepair Parodontgel Intensive (Group 1) and the chlorhexidine-based Curasept Periodontal Gel (Group 2). At baseline (T₀) and after 3 and 6 months (T₁–T₂), the following periodontal clinical parameters were recorded: Probing Pocket Depth (PPD), recession, dental mobility, Bleeding on Probing (BoP), and Plaque Control Record (PCR). A significant intragroup reduction was assessed in both groups for PPD, BoP, and PCR; conversely, recession significantly increased in both groups, whereas dental mobility did not vary. As regards intergroup comparisons, no statistically significant differences were assessed. Both gels, respectively, containing antioxidant natural ingredients and chlorhexidine, are effective for the domiciliary treatment of periodontitis. Further studies are required to evaluate the singular chemical compounds of the gels expected to exert the beneficial action assessed in this preliminary study.

Alterations of the Oral Microbiota Profiles in Chinese Patient With Oral Cancer

Oral cancer is the most common malignant tumor in the oral and maxillofacial region, of which more than 90% is squamous cell carcinoma. The incidence of oral cancer is on the rise worldwide. An imbalance between the microorganism composition and its host may lead to the occurrence of oral malignant tumors. Accumulating evidence suggests that the oral microbiota plays an important role in oral cancer; however, the association between oral microbiota and oral cancer has not yet been comprehensively studied. In this study, metagenomic sequencing was used to compare the microbial composition of three groups of samples from Chinese patients with oral cancer, patients with precancerous lesion, and normal individuals. In terms of microbiota richness, the oral microbiota of patients with precancerous lesions was richer than that of oral cancer patients and healthy controls, whereas in terms of microbiota diversity, there was little difference between the three groups. The three groups of samples exhibited statistically significant differences in microbiota composition and metabolic function at the family, genus, and species levels (P < 0.05). The differentially enriched phylum in oral cancer samples was Bacteroidetes (P < 0.05). At the genus level, the main differentially enriched taxa were Prevotella, Peptostreptococcus, Carnobacterium, and Diastella (P < 0.05). The species level was differentially enriched in Prevotella intermedia and Peptostreptococcus stomatis (p < 0.05). The prediction of microbiota function shows that oral cancer is mainly associated with coenzyme A biosynthesis, phosphopantothenic acid biosynthesis, inosine 5’-phosphate degradation, and riboflavin biosynthesis. Furthermore, the increase in C-reactive protein level in oral cancer patients was found to be closely related to P. intermedia. Overall, oral bacterial profiles showed significant differences between the oral cancer group and normal group. Hence, microbes can be employed as diagnostic markers and treatment targets for oral cancer.

Chemomechanical preparation influences the microbial community and the levels of LPS, LTA and cytokines in combined endodontic-periodontal lesions: A clinical study

BACKGROUND

This study was conducted to compare the microbiomes, the levels of lipopolysaccharides (LPS), lipoteichoic acid (LTA), and cytokines (interleukin [IL]-1β and tumor necrosis factor-alpha [TNF-α]), before and after chemomechanical preparation (CMP) of the root canals (RC) and their associated periodontal pockets (PP) in teeth with combined EPL.

MATERIALS

Samples were taken from 10 RC and PP, before and after CMP. The microbiomes (next-generation sequencing, V3-V4 hypervariable region of the 16S rRNA gene), microbiome diversity (bioinformatics analyses), LPS (limulus amebocyte lysate), LTA, IL-1β, and TNF-α (ELISA) were evaluated. A statistical analysis was performed with significance level set at 5%.

RESULTS

The most abundant phyla in both sites were Firmicutes and Proteobacteria. Comparative studies of bacterial genera species revealed that some increased and others decreased after CMP at both sites. A 3% reduction in Gram-negative bacteria (RC) and a 4% increase in Gram-positive bacteria (PP) were detected. LPS levels were 4.4 times higher in PP than in the RC. LTA was detected in all samples investigated. Higher levels of IL-1β and TNF-α were detected in both sites at baseline. After CMP, LPS, LTA, IL-1β and TNF-α were reduced in both sites.

CONCLUSION

The microbial community in the RC and PP in teeth with combined EPL indicated a similarity between both sites. CMP effectively reduced the microbial load and the LPS levels from teeth with EPL, and consequently diminished the cytokine levels. The reduction in LTA levels in the RC and PP proved challenging.

Differential Signature of the Microbiome and Neutrophils in the Oral Cavity of HIV-Infected Individuals

HIV infection is associated with a wide range of changes in microbial communities and immune cell components of the oral cavity. The purpose of this study was to evaluate the oral microbiome in relationship to oral neutrophils in HIV-infected compared to healthy individuals. We evaluated oral washes and saliva samples from HIV-infected individuals (n=52) and healthy controls (n=43). Using 16S-rRNA gene sequencing, we found differential β-diversity using Principal Coordinate Analysis (PCoA) with Bray-Curtis distances. The α-diversity analysis by Faith’s, Shannon, and observed OTUs indexes indicated that the saliva samples from HIV-infected individuals harbored significantly richer bacterial communities compared to the saliva samples from healthy individuals. Notably, we observed that five species of Spirochaeta including Spirochaetaceae, Spirochaeta, Treponema, Treponema amylovorum, and Treponema azotonutricum were significantly abundant. In contrast, Helicobacter species were significantly reduced in the saliva of HIV-infected individuals. Moreover, we found a significant reduction in the frequency of oral neutrophils in the oral cavity of HIV-infected individuals, which was positively related to their CD4⁺ T cell count. In particular, we noted a significant decline in CD44 expressing neutrophils and the intensity of CD44 expression on oral neutrophils of HIV-infected individuals. This observation was supported by the elevation of soluble CD44 in the saliva of HIV-infected individuals. Overall, the core oral microbiome was distinguishable between HIV-infected individuals on antiretroviral therapy compared to the HIV-negative group. The observed reduction in oral neutrophils might likely be related to the low surface expression of CD44, resulting in a higher bacterial diversity and richness in HIV-infected individuals.

A potential pathogenic association between periodontal disease and Crohn's disease

Oral conditions are relatively common in patients with inflammatory bowel disease (IBD). However, the contribution of oral maladies to gut inflammation remains unexplored. Here, we investigated the effect of periodontitis on disease phenotypes of patients with IBD. In all, 60 patients with IBD (42 with ulcerative colitis [UC] and 18 with Crohn’s disease [CD]) and 45 healthy controls (HCs) without IBD were recruited for this clinical investigation. The effects of incipient periodontitis on the oral and gut microbiome as well as IBD characteristics were examined. In addition, patients were prospectively monitored for up to 12 months after enrollment. We found that, in both patients with UC and those with CD, the gut microbiome was significantly more similar to the oral microbiome than in HCs, suggesting that ectopic gut colonization by oral bacteria is increased in patients with IBD. Incipient periodontitis did not further enhance gut colonization by oral bacteria. The presence of incipient periodontitis did not significantly affect the clinical outcomes of patients with UC and CD. However, the short CD activity index increased in patients with CD with incipient periodontitis but declined or was unchanged during the study period in patients without periodontitis. Thus, early periodontitis may associate with worse clinically symptoms in some patients with CD.

Management of Gingival Bleeding in Periodontal Patients with Domiciliary Use of Toothpastes Containing Hyaluronic Acid, Lactoferrin, or Paraprobiotics: A Randomized Controlled Clinical Trial

Periodontitis is an irreversible oral disease causing the destruction of tooth-supporting tissues. In addition to scaling and root planing (SRP) procedures, patients should achieve a correct domiciliary oral hygiene in order to maintain a healthy status. The aim of the present study was to evaluate the efficacy of different toothpastes in reducing gingival bleeding in periodontal patients. In addition to a professional treatment of SRP, 80 patients were randomly divided into four groups according to the toothpaste assigned for the daily domiciliary use using an electric toothbrush: Group 1 (Biorepair Gum Protection), Group 2 (Biorepair Plus Parodontgel), Group 3 (Biorepair Peribioma PRO), and Group 4 (Meridol Gum Protection) (control group). After baseline (T0), patients were visited after 15 days (T1), 3 months (T2), and 6 months (T3). At each appointment, the following periodontal indexes were assessed: bleeding on probing (BoP), full-mouth bleeding score (FMBS), and modified sulcus bleeding index (mSBI). All the experimental toothpastes caused an immediate significant modification of the three clinical indexes measured, except for the control product. Biorepair Peribioma PRO, with its paraprobiotic content, was also the only toothpaste causing a prolonged effect, reducing BoP even at T3. Accordingly, both hyaluronic acid and lactoferrin appear as reliable supports for the domiciliary management of periodontal disease. In spite of this, paraprobiotics are likely to show the most important benefit thanks to their immunomodulating mechanism of action.

Gut Microbial Diversity in Female Patients With Invasive Mole and Choriocarcinoma and Its Differences Versus Healthy Controls

Objective

To investigate variation in gut microbiome in female patients with invasive mole (IM) and choriocarcinoma (CC) and compare it with healthy controls.

Methods

Fecal microbiome of 12 female patients with IM, 9 female patients with CC, and 24 healthy females were analyzed based on 16s rDNA sequencing. Alpha (α) diversity was evaluated using Shannon diversity index and Pielou evenness index, while beta (β) diversity was assessed using principle coordinate analysis (PCoA) of unweighted Unifrac distances. The potential functional changes of microbiomes were predicted using Tax4Fun. The relative abundance of microbial taxa was compared using Welch’s t test. The role of varied gut microbiota was analyzed via receiver operating characteristic (ROC) curve.

Results

The α diversity and β diversity were significantly different between IM patients and controls, but not between CC patients and controls. In addition, the abundance of cancer-related genes was significantly increased in IM and CC patients. Notably, a total of 19 families and 39 genera were found to have significant differences in bacterial abundance. ROC analysis indicated that Prevotella_7 may be a potential biomarker among IM, CC, and controls.

Conclusion

Our study demonstrated that the diversity and composition of gut microbiota among IM patients, CC patients, and healthy females were significantly different, which provides rationale for using gut microbiota as diagnostic markers and treatment targets, as well as for further study of gut microbiota in gestational trophoblastic neoplasia (GTN).

Association Between Tumor Necrosis Factor-α (G-308A) Polymorphism and Chronic Periodontitis, Aggressive Periodontitis, and Peri-implantitis: A Meta-analysis

OBJECTIVE

Chronic periodontitis (CP), aggressive periodontitis (AP), and peri-implantitis (PI) are chronic inflammatory diseases. Tumor necrosis factor-α (TNF-a) is an effective immune inflammatory mediator. Several studies have been conducted to explore the association between the TNF-α (G-308A) polymorphism and susceptibility to CP, AP, and PI. Our objective was to examine whether the TNF-α (G-308A) polymorphism is related to these diseases.

METHODS

We conducted a meta-analysis to investigate the association between the TNF-α (G-308A) polymorphism and CP, AP, and PI. The PubMed, Embase, CNKI, and Web of Science electronic databases were searched for studies published from inception to August 11, 2020; the reference lists of included studies were also searched. The included studies were assessed in the following genetic models: dominant model, recessive model, allelic model, heterozygous model, and homozygous model.

RESULTS

Forty articles (50 comparisons) with 2243 CP, 824 AP, 615 PI, 795 healthy peri-implant, and 3575 healthy controls were considered for the TNF-α (G-308A) polymorphism in this meta-analysis. Variant A of TNF-α (G-308A) was associated with increased AP risk in the general population, especially in Asians, and this polymorphism was significantly associated with elevated risk of CP in Asians and Caucasians. There was no association between the A allele and PI risk. None of the contrasts of the genetic model yielded a significant finding in Latin Americans. Different genotyping methods may affect the association between the TNF-α (G-308A) polymorphism and these diseases.

CONCLUSION

These findings supported that variant A of the TNF-α (G-308A) polymorphism may contribute to CP and AP susceptibility, particularly in Asians and Caucasians. More efforts and further studies with larger sample sizes will be required to validate the risk of CP, AP, and PI.

Probiotics for periodontal health-Current molecular findings

Dysbiosis of the oral microbiome is associated with a variety of oral and systemic diseases, including periodontal disease. Oral dysbiosis in periodontal disease leads to an exacerbated host immune response that induces progressive periodontal tissue destruction and ultimately tooth loss. To counter the disease‐associated dysbiosis of the oral cavity, strategies have been proposed to reestablish a “healthy” microbiome via the use of probiotics. This study reviews the literature on the use of probiotics for modifying the oral microbial composition toward a beneficial state that might alleviate disease progression. Four in vitro and 10 preclinical studies were included in the analysis, and these studies explored the effects of probiotics on cultured biofilm growth and bacterial gene expressions, as well as modulation of the host response to inflammation. The current molecular findings on probiotics provide fundamental evidence for further clinical research for the use of probiotics in periodontal therapy. They also point out an important caveat: Changing the biofilm composition might alter the normal oral flora that is beneficial and/or critical for oral health.

Ozone Gel in Chronic Periodontal Disease: A Randomized Clinical Trial on the Anti-Inflammatory Effects of Ozone Application

Simple Summary

The search for new topical antimicrobial treatments represents an actual challenge both in orthopedics and in dentistry. As regards the latter, antiseptics represent an aid to the non-surgical treatment commonly employed to contrast periodontitis. This study aims to assess the efficacy of an ozone-based gel with respect to the more common chlorhexidine gels. Ten participants were treated by means of nonsurgical periodontal therapy, with, in addition, a chlorhexidine gel and an ozone one, both, respectively, used in half of the oral sites. Patients were visited at baseline, after one month, and after three months, and at each time point clinical indexes were assessed. This study revealed that the use of the ozonized gel in addition to the standard non-surgical therapy generally did not significantly differ if compared to the use of chlorhexidine. Based on this, ozone deserves consideration for its wide applicability in several clinical fields, especially considering the reduced number of shortcomings with respect to those generally related to chlorhexidine.

Abstract

The search for new topical treatments able to display not only antimicrobial properties but also a multiplicity of other beneficial effects while expressing safe cytocompatibility toward host tissues is being progressively developed. Antiseptics represent an aid to the gold standard nonsurgical treatment Scaling-and-Root-Planing (SRP) for periodontal disease. This split-mouth study aims to assess the efficacy of the ozonized gel GeliO₃ (Bioemmei Srl, Vicenza, Italy) plus SRP (experimental treatment), with respect to SRP + chlorhexidine gel. Ten participants were treated with SRP + chlorhexidine gel (control sites) and with SRP + ozone gel (trial sites). After 1 (T₁) and 3 months (T₂) from baseline (T₀), patients were revisited. At each time-point, the following indexes were assessed: probing pocket depth (PPD), clinical attachment level (CAL), gingival index (GI), plaque index (PI), and bleeding on probing (BoP). It has been assessed that the use of the ozonized gel in addition to SRP did not show significant differences if compared to conventional SRP + chlorhexidine. Chlorhexidine was found to be more effective than ozone in reducing CAL and GI at T₂. Ozone deserves consideration for its wide applicability in several clinical fields. In this connection, we also glance at the latest research on ozone therapy.

Mendelian randomization analysis identified genes potentially pleiotropically associated with periodontitis

OBJECTIVE

To prioritize genes that were pleiotropically or potentially causally associated with periodontitis.

METHODS

We applied the summary data-based Mendelian randomization (SMR) method integrating genome-wide association study (GWAS) for periodontitis and expression quantitative trait loci (eQTL) data to identify genes that were pleiotropically associated with periodontitis. We performed separate SMR analysis using CAGE eQTL data and GTEx eQTL data. SMR analysis were done for participants of European and East Asian ancestries, separately.

RESULTS

We identified multiple genes showing pleiotropic association with periodontitis in participants of European ancestry and participants of East Asian ancestry. PDCD2 (corresponding probe: ILMN_1758915) was the top hit showing pleotropic association with periodontitis in the participants of European ancestry using CAGE eQTL data, and BX093763 (corresponding probe: ILMN_1899903) and AC104135.3 (corresponding probe: ENSG00000204792.2) were the top hits in the participants of East Asian ancestry using CAGE eQTL data and GTEx eQTL data, respectively.

CONCLUSION

We identified multiple genes that may be involved in the pathogenesis of periodontitis in participants of European ancestry and participants of East Asian ancestry. Our findings provided important leads to a better understanding of the mechanisms underlying periodontitis and revealed potential therapeutic targets for the effective treatment of periodontitis.

Microbial transitions from health to disease

Recent advances in our understanding of the microbial populations that colonize the human mouth, their acquisition, interdependency, and coevolution with the host, bring a different perspective to the mechanisms underpinning the maintenance of periodontal health and the development of disease. In this work we suggest that our knowledge map of the etiology of periodontal health and disease can be viewed as a broad, highly connected, and integrated system that spans the entire spectrum of microbe/host/clinical interactions. The overall concept of present Periodontology 2000, that the microbial biofilm can be considered a human tissue of bacteriological origin, is entirely consistent with this integrated system view. The health-associated community structure of microbial biofilms can be considered a system that is normally resilient to perturbation. Equally, there is evidence to suggest that the dysbiotic community structure in disease may share similar resilience properties. In both instances, the resilience may be governed by the precise makeup of the acquired microbiome and by the genetics of the host. Understanding the mechanisms that enable the resistance to change of healthy and dysbiotic microbial populations may be important in the development of approaches to prevent the progression of disease and to restore health in diseased individuals.

Association between Appendicitis and Incident Systemic Sclerosis

Objective: This nationwide study aimed to investigate the association between newly diagnosed systemic sclerosis (SSc) and previous appendicitis history. Methods: A total of 1595 patients who were newly diagnosed with SSc were recruited as the SSc cases from the 2003 to 2012 claims data of the entire population in Taiwan. The other 15,950 individuals who had never been diagnosed with SSc during 2003 and 2012 were selected as the non-SSc controls to match the SSc cases. We defined that the index date as the first date of SSc diagnosis of SSc cases and the first date of ambulatory visit for any reason of non-SSc controls. Conditional logistic regression analysis was applied for the association between appendicitis and the risk of the incident SSc, tested by estimating odds ratios (ORs) with 95% confidence intervals (CIs). Potential confounders, including the Charlson comorbidity index (CCI), a history of periodontal disease, salmonella infection, and intestinal infection, were controlled. We further designed sensitivity analyses by varying the definition of appendicitis according to the status of receiving primary appendectomy. Results: The mean age was 51 years in the case and control groups. Females accounted for 77.5%. A total of 17 (1.1%) out of 1595 SSc cases and 81 (0.5%) out of 15,950 non-SSc controls had a history of appendicitis before the index date had a history of appendicitis. A significant association between appendicitis and the risk of SSc was confirmed (OR, 2.03; 95% CI, 1.14–3.60) after adjusting potential confounders. CCI ≥ 1 (OR, 8.48; 95% CI, 7.50–9.58) and periodontal disease (OR, 1.55; 95% CI, 1.39–1.74) were also significantly associated with the risk of SSc. The association between appendicitis and SSc risk remained robust using various definitions of appendicitis. Conclusion: Our study demonstrated appendicitis was associated with the incident SSc. CCI ≥ 1 and periodontal disease also contributed to the risk of developing SSc.

The prevalence of novel periodontal pathogens and bacterial complexes in Stage II generalized periodontitis based on 16S rRNA next generation sequencing

Objective:

To define the subgingival microbial profile associated with Stage II generalized periodontitis using next-generation sequencing and to determine the relative abundance of novel periodontal pathogens and bacterial complexes.

Methodology:

Subgingival biofilm samples were collected from 80 subjects diagnosed with Stage II generalized periodontitis. Bacterial DNA was extracted, and 16S rRNA-based bacterial profiling via next-generation sequencing was carried out. The bacterial composition and diversity of microbial communities based on the age and sex of the patients were analyzed. The bacterial species were organized into groups: bacterial complexes (red, orange, purple, yellow, and green), novel periodontal pathogens, periodontal health-related species, and unclassified periodontal species. The results were analyzed and statistically evaluated.

Results:

The highest number of bacteria belonged to the phylum Bacteroidetes and Firmicutes. In terms of relative abundance, the orange complex represented 18.99%, novel bacterial species (Fretibacterium spp. and Saccharibacteria spp.) comprised 17.34%, periodontal health-related species accounted for 16.75% and unclassified periodontal species represented (Leptotrichia spp. and Selenomonas spp.) 15.61%. Novel periodontal pathogens had outweighed the periodontal disease-related red complex (5.3%). The one-sample z-test performed was statistically significant at p<0.05. The Beta diversity based on the unweighted UniFrac distance at the species level demonstrated a total variance of 15.77% based on age and 39.19% on sex, which was not statistically significant.

Conclusion:

The bacterial species corresponding to the disease-related orange complex and novel periodontal pathogens are predominant in Stage II generalized periodontitis.