Porphyromonas gingivalis impairs glucose uptake in skeletal muscle associated with altering gut microbiota.

Skeletal muscles have a high metabolic capacity, which play key roles in glucose metabolism. Although periodontal disease increases the risk of metabolic syndrome, the relationship between periodontal bacterial infection and skeletal muscle metabolic dysfunction is unclear. We found that anti-Porphyromonas gingivalis (Pg) antibody titers positively correlated with intramuscular adipose tissue content (IMAC), fasting blood glucose, and HOMA-IR in metabolic syndrome patients. In C57BL/6J mice fed a high-fat diet, recipients of oral Pg (HFPg) had impaired glucose tolerance, insulin resistance, and higher IMAC compared to recipients of saline (HFco). The soleus muscle in HFPg mice exhibited fat infiltration and lower glucose uptake with higher Tnfa expression and lower insulin signaling than in HFco mice. Gene set enrichment analysis showed that TNFα signaling via NFκB gene set was enriched in the soleus muscle of HFPg mice. Moreover, TNF-α also decreased glucose uptake in C2C12 myoblast cells in vitro. Based on 16S rRNA sequencing, Pg administration altered the gut microbiome, particularly by decreasing the abundance of genus Turicibacter. Microbial network of the gut microbiome was dramatically changed by Pg administration. Our findings suggest that infection with Pg is a risk factor for metabolic syndrome and skeletal muscle metabolic dysfunction via gut microbiome alteration.

High-frequency pulsed diode laser irradiation inhibits bone resorption in mice with ligature-induced periodontitis.

AIM: The purpose of this study was to elucidate the suppressive effect of high-frequency pulsed diode laser irradiation on bone resorption and its biological effects on gene expression and microbiome composition on the gingival tissue in ligature-induced periodontitis in mice. MATERIALS AND METHODS: Ligating ligature around the teeth and/or laser irradiation was performed on the gingival tissue in mice as follows: Co (no ligature and no laser irradiation), Li (ligation without laser irradiation), La (no ligature but with laser irradiation), and LiLa (ligation with laser irradiation). Bone resorption was evaluated using micro-computed tomography. RNA-seq analysis was performed on gingival tissues of all four groups at 3 days after ligation. The differences in microbial composition between Li and LiLa were evaluated based on the number of 16S rRNA gene sequences. RESULTS: Bone resorption caused by ligation was significantly suppressed by laser irradiation. RNA-seq in Co and La gingival tissue revealed many differentially expressed genes, suggesting diode laser irradiation altered gene expression. Gene set enrichment analysis revealed mTORC1 signalling and E2F target gene sets were enriched in gingival tissues both in La and LiLa compared with that in Co and Li, respectively. The amount of extracted DNA from ligatures was reduced by laser irradiation, and bacterial network structure was altered between the Li and LiLa. CONCLUSIONS: High-frequency pulsed diode laser irradiation showed biological effects and suppressed bone resorption in ligature-induced periodontitis.

Application of digital prosthodontics and connective tissue grafting in the management of peri-implant mucosal recession around a malpositioned 1-piece implant: A clinical report.

This clinical report describes a conservative approach to improve an unesthetic implant-supported crown and peri-implant mucosal recession around a malpositioned, 1-piece implant in the maxillary right central incisor region by using digital technology. In such clinical situations, the implants are usually removed because of an unpredictable definitive esthetic outcome. However, this clinical report describes the preservation of such a compromised implant by improving the esthetic outcome with a connective-tissue graft, and a digital approach used a 1-step preformed zirconia coping technique with an appropriate emergence profile.

Patient-specific establishment of bacterial composition within the peri-implant microbiota during the earliest weeks after implant uncovering.

BACKGROUND AND OBJECTIVE: Dysbiosis, a loss of balance in the microbiota, is a potential factor of peri-implantitis. However, compositional change of the peri-implant microbiota soon after implant uncovering is still unknown. In this study, bacterial composition in the peri-implant sulcus was examined to understand the establishment of bacterial composition within the peri-implant microbiota during the earliest weeks after implant uncovering. METHODS: Microbiota samples were collected at weeks 1, 2, 4, and 6 after stage-two surgery. Bacterial DNA was isolated from the samples, and a 16S rRNA gene library was constructed. Sequence reads were obtained using a high-throughput sequencing platform and were taxonomically assigned at the phylum and genus levels. RESULTS: Alpha diversity indices, which did not include taxonomic information, were at similar levels throughout the four time points. At 1 and 2 weeks, the bacterial composition was similar among patients with the predominance of Firmicutes and Proteobacteria. However, the composition was diverse at 4 and 6 weeks and significantly dissimilar to the composition at 1 week. CONCLUSIONS: At 1 week, the peri-implant microbiota was already formed with alpha diversity as high as that at the later time points. However, the bacterial composition was not highly dissimilar among patients at 1 week. The composition changed over the passage of several weeks and was specific for each patient.

Application of Ligature-Induced Periodontitis in Mice to Explore the Molecular Mechanism of Periodontal Disease.

Periodontitis is an inflammatory disease characterized by the destruction of the periodontium. In the last decade, a new murine model of periodontitis has been widely used to simulate alveolar bone resorption and periodontal soft tissue destruction by ligation. Typically, 3-0 to 9-0 silks are selected for ligation around the molars in mice, and significant bone loss and inflammatory infiltration are observed within a week. The ligature-maintained period can vary according to specific aims. We reviewed the findings on the interaction of systemic diseases with periodontitis, periodontal tissue destruction, the immunological and bacteriological responses, and new treatments. In these studies, the activation of osteoclasts, upregulation of pro-inflammatory factors, and excessive immune response have been considered as major factors in periodontal disruption. Multiple genes identified in periodontal tissues partly reflect the complexity of the pathogenesis of periodontitis. The effects of novel treatment methods on periodontitis have also been evaluated in a ligature-induced periodontitis model in mice. This model cannot completely represent all aspects of periodontitis in humans but is considered an effective method for the exploration of its mechanisms. Through this review, we aimed to provide evidence and enlightenment for future studies planning to use this model.

Accuracy of cone beam computed tomography in evaluation of palatal mucosa thickness.

AIM: The purpose of this study was to investigate the accuracy of the measurement of palatal mucosa thickness using cone beam computed tomography (CBCT) and to create a conversion formula to evaluate palatal mucosa thickness more accurately. We then evaluated the palatal mucosa thickness in a Japanese population using CBCT and the conversion formula. MATERIALS AND METHODS: We evaluated palatal mucosa thickness in 10 healthy subjects at 15 sites using CBCT, digital impression, and K file. Multiple regression analysis was performed to create a conversion formula to measure thickness accurately. We then obtained CBCT data from 174 patients retrospectively, applied the conversion formula, and evaluated palatal mucosa thickness. RESULTS: Sites of measurement affected measurement error. Measurement using CBCT was 0.34 ± 0.04 mm smaller than actual measurement; therefore, a conversion formula was created. Male, age ≥60 years, and probing pocket depth ≥4 mm had significant and positive associations with palatal mucosa thickness; however, no association was observed between bleeding on probing and palatal mucosa thickness. CONCLUSION: CBCT is useful for the noninvasive and accurate measurement of palatal mucosa thickness.

Japanese subgingival microbiota in health vs disease and their roles in predicted functions associated with periodontitis.

The present study aimed to identify and compare the microbial signatures between periodontally healthy and periodontitis subjects using 454 sequences of 16S rRNA genes. Subgingival plaque samples were collected from ten periodontally healthy subjects and ten matched chronic periodontitis patients. Bacterial DNA was extracted and next-generation sequencing of 16S rRNA genes was performed. The microbial composition differed between healthy subjects and periodontitis patients at all phylogenetic levels. Particularly, 16 species, including Lautropia mirabilis and Neisseria subflava predominated in healthy subjects, whereas nine species, including Porphyromonas gingivalis and Filifactor alocis predominated in periodontitis. UniFrac, a principal coordinate and network analysis, confirmed distinct community profiles in healthy subjects and periodontitis patients. Using predicted function profiling, pathways involved in phenylpropanoid, GPI-anchor biosynthesis, and metabolism of alanine, arginine, aspartate, butanoate, cyanoamino acid, fatty acid, glutamate, methane, proline, and vitamin B6 were significantly over-represented in periodontitis patients. These results highlight the oral microbiota alterations in microbial composition in periodontitis and suggest the genes and metabolic pathways associated with health and periodontitis. Our findings help to further elucidate microbial composition and interactions in health and periodontitis.

Influence of Porphyromonas gingivalis in gut microbiota of streptozotocin-induced diabetic mice.

OBJECTIVES: Increasing evidence suggests that periodontitis can exacerbate diabetes, and gut bacterial dysbiosis appears to be linked with the diabetic condition. The present study examined the effects of oral administration of the periodontopathic bacterium, Porphyromonas gingivalis, on the gut microbiota and systemic conditions in streptozotocin-induced diabetic mice. MATERIALS AND METHODS: Diabetes was induced by streptozotocin injection in C57BL/6J male mice (STZ). STZ and wild-type (WT) mice were orally administered P. gingivalis (STZPg, WTPg) or saline (STZco, WTco). Feces were collected, and the gut microbiome was examined by 16S rRNA gene sequencing. The expression of genes related to inflammation, epithelial tight junctions, and glucose/fatty acid metabolism in the ileum or liver were examined by quantitative PCR. RESULTS: The relative abundance of several genera, including Brevibacterium, Corynebacterium, and Facklamia, was significantly increased in STZco mice compared to WTco mice. The relative abundances of Staphylococcus and Turicibacter in the gut microbiome were altered by oral administration of P. gingivalis in STZ mice. STZPg mice showed higher concentrations of fasting blood glucose and inflammatory genes levels in the ileum, compared to STZco mice. CONCLUSIONS: Oral administration of P. gingivalis altered the gut microbiota and aggravated glycemic control in streptozotocin-induced diabetic mice.

Deep sequencing reveals specific bacterial signatures in the subgingival microbiota of healthy subjects.

OBJECTIVES: This study aimed to define the comprehensive bacterial flora of the healthy oral cavity by identifying and comparing bacterial species in different subgingival sites using 454 sequencing of 16S rRNA genes. MATERIALS AND METHODS: Subgingival plaque samples were taken from six target teeth (central incisor, first premolar, and first molar in both the maxilla and mandible) of 10 periodontally healthy patients. Bacterial DNA was extracted and next-generation sequencing of 16S rRNA genes was performed. RESULTS: Bacterial composition in phylum level was similar for all sites within the same individual irrespective of tooth location. Unweighted UniFrac distance values of microbiome also showed that average distance was significantly larger between subjects than between tooth locations of the same subjects. CONCLUSIONS: The present results clarify the lack of effect of tooth location in the healthy subgingival microbiota. Results may suggest that any subgingival site can demonstrate similar subject-specific microbiota. CLINICAL RELEVANCE: This investigation offers a better understanding of the uniqueness of the oral microbiome. The present study will facilitate sampling in future subgingival microbiological studies.

Effect of Porphyromonas gingivalis infection in the placenta and umbilical cord in pregnant mice with low birth weight.

OBJECTIVE: Growing evidence indicates an association between periodontitis and delivery outcome; however, the mechanism is unclear. This study aimed to investigate the influence of Porphyromonas gingivalis (Pg) infection on delivery outcome in mice. MATERIALS AND METHODS: Bacteremia was induced in pregnant Slc:ICR mice (8 weeks old) by intravenous injection of Pg. Mice were randomly divided into a control group (CO), and those receiving Pg injection at gestational day 1 (GD1), gestational day 15 (GD15) or every day (ED). Delivery outcome, Pg infection, and gene expression in the placenta and umbilical cord were evaluated. RESULTS: Birth weight was lower in the ED and GD15 groups than in the CO group. A remarkable increase in anti-Pg IgG antibody was observed in the ED and GD1 groups, although Pg was not detected in the placenta or umbilical cord. mRNA expression of Tnfα and Il6 in the placenta, and Hif1α in the umbilical cord, was significantly increased in the ED group. Microarray analysis of the umbilical cord revealed increased expression of several genes including Orm1, Mgl2, Rps6ka3 and Trim15 in the ED group. CONCLUSIONS: Pg infection during the third trimester caused low birth weight and inflammation in the placenta and umbilical cord.

A dual composite resin injection molding technique with 3D-printed flexible indices for biomimetic replacement of a missing mandibular lateral incisor.

PATIENTS: This case report presents a minimally invasive approach to replace a missing mandibular lateral incisor using a dual-injection molding technique with flowable composite resins. Integrated with a comprehensive digital workflow, this method achieves a structurally and esthetically biomimetic, bi-layered prosthetic solution. A 34-year-old woman with congenital absence of a mandibular lateral incisor was successfully rehabilitated using a direct composite resin-bonded fixed partial denture (RBFPD). DISCUSSION: Two specialized three-dimensional (3D)-printed flexible indices stabilized by a custom-designed 3D-printed rigid holder were employed to ensure the meticulous injection molding of flowable composite resins formulated to emulate the inherent chromatic gradations between dentin and enamel. The inherent flexibility of the indices, combined with the holder, facilitated accurate and seamless adaptation to the complex morphological features of the dental arch, thereby mitigating the challenges commonly associated with rigid 3D-printed resin indices. CONCLUSIONS: The bilayered direct composite RBFPD using 3D printed flexible indices prepared with a full digital workflow has several advantages over other dental prosthetic solutions, including noninvasiveness, cost-effectiveness, biomimetic esthetics, repairability, and shortened treatment times. Although the initial results are promising, further longitudinal studies with larger patient cohorts are required to confirm the long-term efficacy of this approach.

Novel Flowchart Guiding the Non-Surgical and Surgical Management of Peri-Implant Complications: A Narrative Review.

Peri-implant diseases, such as peri-implant mucositis and peri-implantitis, are induced by dysbiotic microbiota resulting in the inflammatory destruction of peri-implant tissue. Nonetheless, there has yet to be an established protocol for the treatment of these diseases in a predictable manner, although many clinicians and researchers have proposed various treatment modalities for their management. With the increase in the number of reports evaluating the efficacy of various treatment modalities and new materials, the use of multiple decontamination methods to clean infected implant surfaces is recommended; moreover, the use of hard tissue laser and/or air abrasion techniques may prove advantageous in the future. Limited evidence supports additional effects on clinical improvement in antimicrobial administration for treating peri-implantitis. Implantoplasty may be justified for decontaminating the implant surfaces in the supracrestal area. Surgical treatment is employed for advanced peri-implantitis, and appropriate surgical methods, such as resection therapy or combination therapy, should be selected based on bone defect configuration. This review presents recent clinical advances in debridement methods for contaminated implant surfaces and regenerative materials for treating peri-implant bone defects. It also proposes a new flowchart to guide the treatment decisions for peri-implant disease.

Periodontal treatment and microbiome-targeted therapy in management of periodontitis-related nonalcoholic fatty liver disease with oral and gut dysbiosis.

A growing body of evidence from multiple areas proposes that periodontal disease, accompanied by oral inflammation and pathological changes in the microbiome, induces gut dysbiosis and is involved in the pathogenesis of nonalcoholic fatty liver disease (NAFLD). A subgroup of NAFLD patients have a severely progressive form, namely nonalcoholic steatohepatitis (NASH), which is characterized by histological findings that include inflammatory cell infiltration and fibrosis. NASH has a high risk of further progression to cirrhosis and hepatocellular carcinoma. The oral microbiota may serve as an endogenous reservoir for gut microbiota, and transport of oral bacteria through the gastro-intestinal tract can set up a gut microbiome dysbiosis. Gut dysbiosis increases the production of potential hepatotoxins, including lipopolysaccharide, ethanol, and other volatile organic compounds such as acetone, phenol and cyclopentane. Moreover, gut dysbiosis increases intestinal permeability by disrupting tight junctions in the intestinal wall, leading to enhanced translocation of these hepatotoxins and enteric bacteria into the liver through the portal circulation. In particular, many animal studies support that oral administration of Porphyromonas gingivalis, a typical periodontopathic bacterium, induces disturbances in glycolipid metabolism and inflammation in the liver with gut dysbiosis. NAFLD, also known as the hepatic phenotype of metabolic syndrome, is strongly associated with metabolic complications, such as obesity and diabetes. Periodontal disease also has a bidirectional relationship with metabolic syndrome, and both diseases may induce oral and gut microbiome dysbiosis with insulin resistance and systemic chronic inflammation cooperatively. In this review, we will describe the link between periodontal disease and NAFLD with a focus on basic, epidemiological, and clinical studies, and discuss potential mechanisms linking the two diseases and possible therapeutic approaches focused on the microbiome. In conclusion, it is presumed that the pathogenesis of NAFLD involves a complex crosstalk between periodontal disease, gut microbiota, and metabolic syndrome. Thus, the conventional periodontal treatment and novel microbiome-targeted therapies that include probiotics, prebiotics and bacteriocins would hold great promise for preventing the onset and progression of NAFLD and subsequent complications in patients with periodontal disease.

Peri-implantitis management by resective surgery combined with implantoplasty and Er:YAG laser irradiation, accompanied by free gingival graft: a case report.

The optimal method for decontamination of implant surfaces for peri-implantitis treatment remains controversial. In recent years, erbium-doped yttrium aluminum garnet (Er:YAG) laser irradiation and implantoplasty (IP) (i.e. mechanical modification of the implant) have been reported to be effective in decontaminating implant surfaces during the surgical treatment. Also, a lack of adequate keratinized mucosa (KM) around the implant is known to be associated with more plaque accumulation, tissue inflammation, attachment loss, and mucosal recession, increasing the risk of peri-implantitis. Therefore, free gingival graft (FGG) has been recommended for gaining adequate KM around the implant. However, the necessity of acquiring KM for the treatment of peri-implantitis using FGG remains unclear. In this report, we applied the apically positioned flap (APF) as resective surgery for peri-implantitis treatment in conjunction with IP and Er:YAG laser irradiation to polish/clean the implant surface. Furthermore, FGG was conducted simultaneously to create additional KM, which increased the tissue stability and contributed to the positive results. The two patients were 64 and 63 years old with a history of periodontitis. The removal of granulation tissue and debridement of contaminated implant surfaces were performed with Er:YAG laser irradiation post flap elevation and then modified smooth surfaces mechanically using IP. Er:YAG laser irradiation was also utilized to remove the titanium particles. In addition, we performed FGG to increase the width of KM as a vestibuloplasty. Peri-implant tissue inflammation and progressive bone resorption were not observed, and both patients maintained good oral hygiene conditions until the 1-year follow-up appointment. Bacterial analysis via high-throughput sequencing revealed proportional decreases in bacteria associated with periodontitis (Porphyromonas, Treponema, and Fusobacterium). To the best of our knowledge, this study is the first to describe peri-implantitis management and bacterial change before and after procedures by resective surgery combined with IP and Er:YAG laser irradiation for peri-implantitis treatment, accompanied by FGG for increasing KM around the implants.

Blue Light-Emitting Diode Irradiation Without a Photosensitizer Alters Oral Microbiome Composition of Ligature-Induced Periodontitis in Mice.

Objective: This study investigated the suppressive effects of blue light-emitting diode (LED) irradiation on bone resorption and changes in the oral microbiome of mice with ligature-induced periodontitis. Background: Wavelength of blue light has antimicrobial effects; however, whether blue LED irradiation alone inhibits the progression of periodontitis remains unclear. Methods: Nine-week-old male mice ligated ligature around the right maxillary second molar was divided into ligation alone (Li) and ligation with blue LED irradiation (LiBL) groups. The LiBL group underwent blue LED (wavelength, 455 nm) irradiation four times in a week at 150 mW/cm2 without a photosensitizer on the gingival tissue around the ligated tooth at a distance of 5 mm for 5 min. The total energy density per day was 45 J/cm2. Bone resorption was evaluated using micro-computed tomography at 8 days. Differences in the oral microbiome composition of the collected ligatures between the Li and LiBL groups were analyzed using next-generation sequencing based on the 16S rRNA gene from the ligatures. Results: Blue LED irradiation did not suppress bone resorption caused by ligature-induced periodontitis. However, in the LiBL group, the α-diversity, number of observed features, and Chao1 were significantly decreased. The relative abundances in phylum Myxococcota and Bacteroidota were underrepresented, and the genera Staphylococcus, Lactococcus, and Lactobacillus were significantly overrepresented by blue LED exposure. Metagenomic function prediction indicated an increase in the downregulated pathways related to microbial energy metabolism after irradiation. The co-occurrence network was altered to a simpler structure in the LiBL group, and the number of core genera decreased. Conclusions: Blue LED irradiation altered the composition and network of the oral microbiome of ligature-induced periodontitis in mice.

Homemade blenderized tube feeding improves gut microbiome communities in children with enteral nutrition.

Enteral nutrition for children is supplied through nasogastric or gastrostomy tubes. Diet not only influences nutritional intake but also interacts with the composition and function of the gut microbiota. Homemade blenderized tube feeding has been administered to children receiving enteral nutrition, in addition to ready-made tube feeding. The purpose of this study was to evaluate the oral/gut microbial communities in children receiving enteral nutrition with or without homemade blenderized tube feeding. Among a total of 30 children, 6 receiving mainly ready-made tube feeding (RTF) and 5 receiving mainly homemade blenderized tube feeding (HBTF) were analyzed in this study. Oral and gut microbiota community profiles were evaluated through 16S rRNA sequencing of saliva and fecal samples. The α-diversity representing the number of observed features, Shannon index, and Chao1 in the gut were significantly increased in HBTF only in the gut microbiome but not in the oral microbiome. In addition, the relative abundances of the phylum Proteobacteria, class Gammaproteobacteria, and genus Escherichia-Shigella were significantly low, whereas that of the genus Ruminococcus was significantly high in the gut of children with HBTF, indicating HBTF altered the gut microbial composition and reducing health risks. Metagenome prediction showed enrichment of carbon fixation pathways in prokaryotes at oral and gut microbiomes in children receiving HBTF. In addition, more complex network structures were observed in the oral cavity and gut in the HBTF group than in the RTF group. In conclusion, HBTF not only provides satisfaction and enjoyment during meals with the family but also alters the gut microbial composition to a healthy state.

Association between periodontal disease and chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) and periodontal disease are chronic inflammatory conditions that significantly affect an individual's overall health and well-being. Generally, the prevalence of periodontitis is higher in patients with COPD than those without COPD, which may partly be attributed to common risk factors in COPD, such as smoking, respiratory infections, and inflammation. In particular, periodontitis may exacerbate the progression of COPD and further deteriorate the respiratory system by promoting inflammatory responses and bacterial infections. Immunocytes, including neutrophils, and microorganisms such as Fusobacterium nucleatum originating from oral biofilms are believed to be crucial factors influencing to COPD. Furthermore, the potential benefits of treating periodontal disease in COPD outcomes have been investigated. Although the relationship between COPD and periodontal disease has been preliminarily studied, there is currently a lack of large-scale clinical studies to validate this association. In addition to clinical examinations, investigating biomarkers and microbiology may contribute to explore the underlying mechanisms involved in the management of these conditions. This review aims to contribute to a better understanding of the clinical and basic research aspects of COPD and periodontitis, allowing for potential therapeutic approaches and interdisciplinary management strategies.

Novel and Efficient Method for Diagnosing Infective Endocarditis Using 16S Ribosomal RNA Gene Amplicon Sequence.

We present 2 cases that both developed infective endocarditis and underwent mitral valve replacement. In addition to positive blood culture and echocardiographic findings, such as vegetation or mitral valve perforation, the 16S ribosomal RNA gene amplicon sequence approach used was helpful for disease diagnosis. (Level of Difficulty: Intermediate.).

Treatment of Peri-implantitis Caused by Malpositioning and an Extra Implant: A Case Report.

The number of complications related to dental implants has been increasing, as implant therapy has grown to become the most popular treatment choice for replacing missing teeth. Various cases of implant complications have been reported, particularly biologic complications caused by inadequate surgical techniques, including malpositioned implants, that are difficult to solve. In the present case, two malpositioned implants with peri-implantitis were placed in the maxillary right first molar area of a 64-year-old woman. To treat the peri-implant infection and facilitate self-plaque control, one malpositioned implant was removed, and the other was treated with open flap debridement using an erbium-doped yttrium aluminum garnet (Er:YAG) laser. The implant suprastructure was then changed adequately to recover oral function. This case report demonstrates the clinical steps, healing process, and 6-month follow-up of peri-implantitis caused by malpositioned implants.

Corrigendum: Comparison of Periodontal Bacteria of Edo and Modern Periods Using Novel Diagnostic Approach for Periodontitis With Micro-CT.

[This corrects the article DOI: 10.3389/fcimb.2021.723821.].