Porphyromonas gingivalis infection in the oral cavity is associated with elevated galactose-deficient IgA1 and increased nephritis severity in IgA nephropathy.

BACKGROUND: The relationship between the major periodontal bacteria, Porphyromonas gingivalis, and the pathogenesis of IgA nephropathy (IgAN)-particularly with respect to galactose-deficient IgA1 (Gd-IgA1)-has not been fully elucidated. METHODS: Saliva samples from 30 IgAN patients and 44 patients with chronic kidney disease (CKD) were subjected to analysis of P. gingivalis status via polymerase chain reaction using a set of P. gingivalis-specific primers. The associations between P. gingivalis presence and clinical parameters, including plasma Gd-IgA1, were analyzed in each group. RESULTS: Compared with the CKD group, the IgAN group demonstrated significantly higher plasma Gd-IgA1 levels (p < 0.05). Compared with the P. gingivalis-negative subgroup, the P. gingivalis-positive subgroup exhibited significantly higher plasma Gd-IgA1 levels in both IgAN and CKD patients (p < 0.05). Additionally, among IgAN patients, the P. gingivalis-positive subgroup displayed significantly higher plasma Gd-IgA1 and urine protein levels, compared with the P. gingivalis-negative subgroup (p < 0.05). With respect to renal biopsy findings, the frequencies of segmental glomerulosclerosis and tubular atrophy/interstitial fibrosis were significantly greater in the P. gingivalis-positive subgroup than in the P. gingivalis-negative subgroup, according to the Oxford classification of IgAN (p < 0.05). CONCLUSION: Our findings suggest an association between the presence of P. gingivalis in the oral cavity and the pathogenesis of IgAN, mediated by increased levels of Gd-IgA1.

Inhibitory Effects of Shikonin Dispersion, an Extract of Lithospermum erythrorhizon Encapsulated in ß-1,3-1,6 Glucan, on Streptococcus mutans and Non-Mutans Streptococci.

Shikonin is extracted from the roots of Lithospermum erythrorhizon, and shikonin extracts have been shown to have inhibitory effects on several bacteria. However, shikonin extracts are difficult to formulate because of their poor water solubility. In the present study, we prepared a shikonin dispersion, which was solubilized by the inclusion of ß-1,3-1,6 glucan, and analysed the inhibitory effects of this dispersion on Streptococcus mutans and non-mutans streptococci. The shikonin dispersion showed pronounced anti-S. mutans activity, and inhibited growth of and biofilm formation by this bacterium. The shikonin dispersion also showed antimicrobial and antiproliferative effects against non-mutans streptococci. In addition, a clinical trial was conducted in which 20 subjects were asked to brush their teeth for 1 week using either shikonin dispersion-containing or non-containing toothpaste, respectively. The shikonin-containing toothpaste decreased the number of S. mutans in the oral cavity, while no such effect was observed after the use of the shikonin-free toothpaste. These results suggest that shikonin dispersion has an inhibitory effect on S. mutans and non-mutans streptococci, and toothpaste containing shikonin dispersion may be effective in preventing dental caries.

Inhibitory Effect of Adsorption of Streptococcus mutans onto Scallop-Derived Hydroxyapatite.

Hydroxyapatite adsorbs various substances, but little is known about the effects on oral bacteria of adsorption onto hydroxyapatite derived from scallop shells. In the present study, we analyzed the effects of adsorption of Streptococcus mutans onto scallop-derived hydroxyapatite. When scallop-derived hydroxyapatite was mixed with S. mutans, a high proportion of the bacterial cells adsorbed onto the hydroxyapatite in a time-dependent manner. An RNA sequencing analysis of S. mutans adsorbed onto hydroxyapatite showed that the upregulation of genes resulted in abnormalities in pathways involved in glycogen and histidine metabolism and biosynthesis compared with cells in the absence of hydroxyapatite. S. mutans adsorbed onto hydroxyapatite was not killed, but the growth of the bacteria was inhibited. Electron microscopy showed morphological changes in S. mutans cells adsorbed onto hydroxyapatite. Our results suggest that hydroxyapatite derived from scallop shells showed a high adsorption ability for S. mutans. This hydroxyapatite also caused changes in gene expression related to the metabolic and biosynthetic processes, including the glycogen and histidine of S. mutans, which may result in a morphological change in the surface layer and the inhibition of the growth of the bacteria.

Contribution of Severe Dental Caries Induced by Streptococcus mutans to the Pathogenicity of Infective Endocarditis.

Streptococcus mutans, a major pathogen of dental caries, is regarded as a causative agent of infective endocarditis (IE), which mainly occurs in patients with underlying heart disease. However, it remains unknown whether severe dental caries that extend to pulp space represent a possible route of infection. In the present study, we evaluated the virulence of S. mutans for IE development using rats with concurrent severe dental caries and heart valve injury. Dental caries was induced in rats through the combination of a caries-inducing diet and the administration of S. mutans into the oral cavity. Then, the heart valves of a subset of rats were injured using a sterile catheter and wire under general anesthesia. The rats were euthanized at various times with various stages of dental caries. The number of teeth affected by dental caries with pulp exposure was increased in the rats in a time-dependent manner. S. mutans was recovered from injured heart tissue, which was mainly observed in rats with higher number of S. mutans bacteria in mandibular bone and a larger number of teeth in which caries extended to pulp. Dental caries was more severe in rats with heart injury than in rats without heart injury. Sequencing analysis targeting 16S rRNA revealed that specific oral bacteria appeared only in rats with heart injury, which may be related to the development of dental caries. Our findings suggest that dental caries caused by the combination of S. mutans infection and sucrose intake may contribute to S. mutans colonization in injured heart tissue.

Effects of Enzyme Replacement Therapy for Primary Teeth in a Patient with Infantile Hypophosphatasia.

Hypophosphatasia (HPP) is a skeletal disorder characterized by hypomineralization of bone, with early exfoliation of primary teeth. Alkaline phosphatase enzyme replacement therapy (ERT) has been shown to improve bone hypomineralization for patients with HPP, although its dental effects are unknown. A 20-month-old Japanese boy diagnosed with infantile HPP was referred to our clinic because of early exfoliation of primary teeth. The patient had been followed by a pediatrician since the age of 3 months, due to slow weight gain. At the age of 12 months, primary incisors showed sudden exfoliation; at the age of 19 months, a diagnosis of HPP was made based on bone and dental manifestations. ERT was initiated at the age of 21 months. The patient demonstrated stable periodontal conditions of primary molars that erupted after initiation of ERT, due to improved alveolar bone and tooth mineralization. Thus, ERT may improve both dental and systemic conditions.

Molecular and clinical analyses of Helicobacter pylori colonization in inflamed dental pulp.

BACKGROUND: Recently, dental pulp has been considered a possible source of infection of Helicobacter pylori (H. pylori) in children. We previously developed a novel PCR system for H. pylori detection with high specificity and sensitivity using primer sets constructed based on the complete genome information for 48 H. pylori strains. This PCR system showed high sensitivity with a detection limit of 1-10 cells when serial dilutions of H. pylori genomic DNA were used as templates. However, the detection limit was lower (102-103 cells) when H. pylori bacterial DNA was detected from inflamed pulp specimens. Thus, we further refined the system using a nested PCR method, which was much more sensitive than the previous single PCR method. In addition, we examined the distribution and virulence of H. pylori in inflamed pulp tissue. METHODS: Nested PCR system was constructed using primer sets designed from the complete genome information of 48 H. pylori strains. The detection limit of the nested PCR system was 1-10 cells using both H. pylori genomic DNA and bacterial DNA isolated from inflamed pulp specimens. Next, distribution of H. pylori was examined using 131 inflamed pulp specimens with the nested PCR system. In addition, association between the detection of H. pylori and clinical information regarding endodontic-infected teeth were investigated. Furthermore, adhesion property of H. pylori strains to human dental fibroblast cells was examined. RESULTS: H. pylori was present in 38.9% of inflamed pulp specimens using the nested PCR system. H. pylori was shown to be predominantly detected in primary teeth rather than permanent teeth. In addition, samplings of the inflamed pulp were performed twice from the same teeth at 1- or 2-week intervals, which revealed that H. pylori was detected in most specimens in both samplings. Furthermore, H. pylori strains showed adhesion property to human dental fibroblast cells. CONCLUSION: Our results suggest that H. pylori colonizes inflamed pulp in approximately 40% of all cases through adhesion to human dental fibroblast cells.

Contribution of Streptococcus mutans Strains with Collagen-Binding Proteins in the Presence of Serum to the Pathogenesis of Infective Endocarditis.

Streptococcus mutans, a major pathogen of dental caries, is considered one of the causative agents of infective endocarditis (IE). Recently, bacterial DNA encoding 120-kDa cell surface collagen-binding proteins (CBPs) has frequently been detected from S. mutans-positive IE patients. In addition, some of the CBP-positive S. mutans strains lacked a 190-kDa protein antigen (PA), whose absence strengthened the adhesion to and invasion of endothelial cells. The interaction between pathogenic bacteria and serum or plasma is considered an important virulence factor in developing systemic diseases; thus, we decided to analyze the pathogenesis of IE induced by S. mutans strains with different patterns of CBP and PA expression by focusing on the interaction with serum or plasma. CBP-positive (CBP+)/PA-negative (PA-) strains showed prominent aggregation in the presence of human serum or plasma, which was significantly greater than that with CBP+/PA-positive (PA+) and CBP-negative (CBP-)/PA+ strains. Aggregation of CBP+/PA- strains was also observed in the presence of a high concentration of type IV collagen, a major extracellular matrix protein in serum. In addition, aggregation of CBP+/PA- strains was drastically reduced when serum complement was inactivated. Furthermore, an ex vivo adherence model and an in vivo rat model of IE showed that extirpated heart valves infected with CBP+/PA- strains displayed prominent bacterial mass formation, which was not observed following infection with CBP+/PA+ and CBP-/PA+ strains. These results suggest that CBP+/PA-S. mutans strains utilize serum to contribute to their pathogenicity in IE.

Investigation of periodontal disease development and Porphyromonas gulae FimA genotype distribution in small dogs.

In dogs, Porphyromonas gulae is a major periodontal pathogen with 41-kDa proteins polymerizing to form a filamentous structure called fimbriae or pili, termed FimA. FimA is classified into three genotypes: A, B, and C, and there are combinations of types A, B, C, A/B, A/C, B/C, and A/B/C. Periodontal disease is the most common oral disease in small dogs, but the periodontal disease status and P. gulae colonization at each dog age and breed remain unclear. In this study, we stratified 665 small dogs and analyzed the periodontal status and distribution of P. gulae with each FimA genotype. Dogs with periodontal disease and FimA genotype tended to increase with age. The dogs with at least one FimA genotype had significantly more severe periodontal disease compared with P. gulae-negative dogs (P < 0.01). Additionally, periodontal status was significantly associated with specific FimA genotype distribution in Toy Poodles and Chihuahuas (P < 0.05), whereas there was no such association in Dachshunds. These results suggest that the onset of periodontal disease and P. gulae colonization are related and progress with age. The relationship between periodontal disease and FimA genotype may differ depending on the dog breeds.

Effects of mouthwash on periodontal pathogens and glycemic control in patients with type 2 diabetes mellitus.

Periodontitis is known to be associated with type 2 diabetes mellitus (T2DM), and gargling with mouthwash is known to reduce the incidence of periodontitis by inhibiting periodontal pathogens. However, the effects of mouthwash on oral and systemic conditions in patients with T2DM remain unknown. In this study, we investigated the effects of gargling with mouthwash on the number of red complex species, including Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia, and HbA1c levels in patients with T2DM. Patients were instructed to gargle with water for 6 months, followed by gargling with mouthwash containing chlorhexidine gluconate for the subsequent 6 months. At each clinic visit, saliva was collected and bacterial DNA was extracted to detect red complex species using the polymerase chain reaction technique. The HbA1c level was determined using a blood sample. The number of red complex species significantly decreased in younger or male patients who gargled with mouthwash. Furthermore, HbA1c levels significantly decreased in younger patients or patients with higher HbA1c levels who gargled with mouthwash. These results suggest that gargling with mouthwash reduces the number of red complex species and improves the hyperglycemic status in patients with T2DM, especially younger patients.

A Case of X-Linked Hypophosphatemic Rickets with Dentin Dysplasia in Mandibular Third Molars.

X-linked hypophosphatemic rickets (XLH) is a disease characterized by impaired bone mineralization, and its dental features include gingival abscesses and large pulp spaces due to dentin dysplasia. A 20-year-old woman with XLH was referred to oral surgery for extraction of mandibular third molars. She was diagnosed with XLH at approximately 1 year of age and was treated thereafter. There was no history of gingival abscesses, and panoramic radiographic and computed tomographic examinations revealed no evidence of dentin dysplasia. However, histopathological examination of the extracted teeth showed dentin dysplasia, including interglobular dentin. In this XLH patient, dentin dysplasia was revealed histologically even though no obvious abnormality was found on visual and radiographic examinations. These findings suggest that in patients with XLH, oral management must take dentin dysplasia of the permanent teeth into consideration even if the patient's general condition is well controlled with conventional therapy.

Evaluation of alveolar bone hypomineralization in pediatric hypophosphatasia using orthopantomography.

Hypophosphatasia (HPP) is a metabolic disease characterized by impaired bone mineralization and early exfoliation of primary teeth. This study was performed to develop a method for quantitatively evaluating alveolar bone hypomineralization using orthopantomographic images. Alveolar bone density was defined according to the pixel values and corrected by brightness shown by an indicator applied to the orthopantomographic device. Images of 200 healthy subjects (aged 2-15 years) were classified into five age groups. The corrected pixel values were significantly lower in the younger group than in those aged 14-15 years (2-4, 5-7, and 8-10 years versus 14-15 years: P < 0.0001, 11-13 years versus 14-15 years: P < 0.01). Orthopantomographic images of 17 patients with HPP were evaluated. The corrected pixel values of three-fourths of the patients with odonto type HPP were lower than the mean values of the healthy group. One-third of patients treated with enzyme replacement therapy showed higher corrected pixel values than the healthy group. Our results suggest that odonto type HPP without skeletal problems is occasionally accompanied by hypomineralization of alveolar bone and that alveolar bone hypomineralization in patients with severe HPP is possibly improved by enzyme replacement therapy.

Estimation of dental age based on the developmental stages of permanent teeth in Japanese children and adolescents.

Assessment of children's growth and development based on general and oral developmental status and dental age is important in pediatric dentistry for appropriate diagnosis and treatment. Teeth are a useful maturation index because they are unlikely to be affected by exogenous factors such as disease. We examined the correlation between chronological and dental age of permanent teeth in Japanese children and adolescents using orthopantomography. The sample comprised 1024 orthopantomographs from individuals aged 3-18 years, which were stored in an electronic media database for 10 years (2009-2019). We classified the developmental stages of each permanent tooth were classified into 11 stages, clarified the dental age for each developmental stage, and prepared a conversion table. Using the results, we compared the sequence and rate of development of each permanent tooth. We clarified the dental age of each permanent tooth from childhood to mid-adolescence and established a method for calculating the dental age of the whole jaw that is appropriate for modern Japanese individuals. We found that girls tended to form teeth at a faster rate than boys until puberty, but boys caught up with girls after puberty, suggesting that secondary sexual characteristics are involved in the rate of tooth formation.

Detection of Helicobacter pylori from Extracted Teeth of a Patient with Idiopathic Thrombocytopenic Purpura.

Immune thrombocytopenic purpura (ITP) is an autoimmune disease characterized by isolated cryptogenic thrombocytopenia due to a transient or persistent reduction in platelet count. Many patients with ITP have shown improved platelet count after Helicobacter pylori eradication therapy. However, there have been no studies regarding H. pylori in the oral cavity of patients with ITP. Here, we describe a patient with ITP whose oral samples exhibited H. pylori. A 64-year-old woman with ITP came to our hospital with chief complaints that required oral surgery, including tooth extraction and cystectomy. Bacterial DNA from H. pylori was confirmed on the extracted tooth, but was not detected in the saliva taken at the time. Bacterial DNA from H. pylori was detected on the suture around the extraction socket, which was removed at 10 days post-operation. However, H. pylori DNA was not detected in other oral samples at 10 or 30 days post-operation. A urea breath test was carried out in the gastrointestinal clinic at 60 days post-operation, which revealed no presence of H. pylori in the gastrointestinal tract. These results suggest that teeth with severe bacterial infections may be a potential reservoir of H. pylori for patients with ITP.

Clinical characteristics of children and guardians possessing CBP-positive Streptococcus mutans strains: a cross-sectional study.

Streptococcus mutans is a major etiological agent for dental caries. We previously demonstrated that S. mutans strains expressing collagen-binding proteins (CBPs) were related to the pathogenesis of systemic diseases. However, their acquisition and colonization remain unknown. Here, we investigated the detection rates of CBP-positive S. mutans strains in children and their guardians to clarify the background for the acquisition and colonization in children. Saliva samples were collected from children and their mothers, and detection of S. mutans and collagen-binding genes (cnm, cbm) was performed by PCR after DNA extraction. The oral status of each child was examined, and their mothers were asked to complete a questionnaire. The isolation rate of Cnm-positive S. mutans was significantly higher in mothers than in children. Notably, the possession rates of CBP-positive strains in children were significantly higher in children whose mothers had CBP-positive strains than in children whose mothers did not have these strains. Furthermore, children with CBP-positive strains had a significantly shorter breastfeeding period than children without these strains. The present results suggest that nutritional feeding habits in infancy are one of the factors involved in the acquisition and colonization of CBP-positive S. mutans strains.

Evaluation of the collagen-binding properties and virulence of killed Streptococcus mutans in a silkworm model.

Streptococcus mutans, a major pathogen of dental caries, is also known as a causative agent of cardiovascular disease. A 120 kDa collagen-binding protein (Cnm) of S. mutans is an important contributor to the pathogenicity of cardiovascular disease. Although dead bacteria have been detected in cardiovascular specimens by molecular biological methods, the pathogenicity of the bacteria remains unknown. Here, we analyzed the pathogenicity of killed S. mutans by focusing on collagen-binding ability and the effects on silkworms. In live S. mutans, Cnm-positive S. mutans had high collagen-binding activity, while Cnm-negative S. mutans had no such activity. After treatment with killed Cnm-positive S. mutans, amoxicillin-treated bacteria still had collagen-binding ability, while lysozyme-treated bacteria lost this ability. When live and amoxicillin-treated S. mutans strains were administered to silkworms, the survival rates of the silkworms were reduced; this reduction was more pronounced in Cnm-positive S. mutans infection than in Cnm-negative S. mutans infection. However, the administration of any of the lysozyme-treated bacteria did not reduce the survival rate of the silkworms. These results suggest that amoxicillin-killed Cnm-positive S. mutans strains maintain collagen-binding properties and pathogenicity in the silkworm model, and are possibly associated with pathogenicity in cardiovascular diseases.

Inhibitory effect of toothbrush monofilament containing surface pre-reacted glass-ionomer (S-PRG) filler on Streptococcus mutans.

The oral environment affects not only oral health, but also general health, and the importance of oral self-care has recently been recognised. Although toothbrushes are the most important self-care product, there are few toothbrushes that have an inhibitory effect on oral bacteria. In the present study, monofilaments used for toothbrushes containing surface pre-reacted glass-ionomer (S-PRG) filler (a component recently applied to various dental materials) were developed. Among nylon and polyester monofilaments commonly used for toothbrushes, nylon monofilaments can accommodate more S-PRG filler than polyester monofilaments, resulting in greater release of ions from the S-PRG filler. These monofilaments containing S-PRG filler formed less biofilm containing Streptococcus mutans, a major pathogen of dental caries, than monofilaments without S-PRG filler. Moreover, S. mutans adhering to monofilaments containing S-PRG filler were more easily exfoliated and eliminated than those adhering to monofilaments without S-PRG filler. Such inhibitory effects on S. mutans were more marked in nylon monofilaments than in polyester monofilaments. These findings that monofilaments containing S-PRG filler can release ions and have an inhibitory effect on S. mutans suggest that they may be an effective material for toothbrushes.

Inhibitory effect of a gel paste containing surface pre-reacted glass-ionomer (S-PRG) filler on the cariogenicity of Streptococcus mutans.

Surface pre-reacted glass-ionomer (S-PRG) filler is a bioactive functional glass that releases six different ions. Although several dental materials containing S-PRG filler have been developed, few self-care products containing S-PRG filler have been reported. We investigated the inhibitory effects of PRG gel paste containing S-PRG filler on Streptococcus mutans, a major pathogen of dental caries. PRG gel paste inhibited bacterial growth of S. mutans in a concentration-dependent manner, and all S. mutans were killed in the presence of ≥ 1% PRG gel paste. Additionally, it was difficult for S. mutans to synthesize insoluble glucan from sucrose in the presence of 0.1% PRG gel paste. A biofilm formation model was prepared in which slices of bovine enamel were infected with S. mutans after treatment with or without PRG gel paste. Biofilm formation was inhibited significantly more on the enamel treated with PRG gel paste than on enamel without PRG gel paste (P < 0.001). The inhibitory effects on bacterial growth and biofilm formation were more prominent with PRG gel paste than with S-PRG-free gel paste, suggesting that PRG gel paste may be effective as a self-care product to prevent dental caries induced by S. mutans.

Dental Manifestations Leading to the Diagnosis of Hypophosphatasia in Two Children.

Hypophosphatasia (HPP) is an inherited bone disease caused by mutation of the alkaline phosphatase, biomineralization associated (ALPL) gene and is characterized by bone hypomineralization and/or early exfoliation of primary teeth. Dental manifestations can lead to the diagnosis of milder types of HPP. The purpose of this paper is to report the case of two patients with growth and development problems who were referred to a dental clinic due to early exfoliation of primary teeth and were subsequently diagnosed with childhood HPP with bone symptoms. Early diagnosis of HPP and management of growth and development are important, as HPP is a progressive disease. When dentists detect early exfoliation of the mandibular incisors before four years of age, they should refer the patient for investigation of HPP. Growth and development should be closely monitored in patients with early primary tooth exfoliation.

Ankylosed Primary Molar in a Japanese Child with Hypophosphatasia.

Hypophosphatasia (HPP) is a rare genetic disorder; affected patients may experience early exfoliation of primary teeth, especially anterior teeth. However, there have been few reports regarding longitudinal follow-up for primary teeth, especially posterior teeth, until their replacement with permanent teeth. Here, we describe a patient with HPP who underwent follow-up from 1 to 9 years of age. A 14-month-old boy was referred to our hospital with the chief complaint of early loss of primary anterior teeth. He was diagnosed with odonto-type HPP by his pediatrician, due to low serum alkaline phosphatase concentration and early exfoliation of primary teeth with bone hypomineralization. The patient experienced exfoliation of three additional primary anterior teeth by 4 years and 1 month of age. Partial dentures were applied for space maintenance; there were no problems regarding subsequent replacement with permanent teeth in the anterior region. However, the primary mandibular right first molar appeared to be submerged when the patient was 8 years and 3 months of age; the severity of submergence was greater when the patient was 9 years of age. The affected primary molar was considered to be ankylosed; it was extracted when the patient was 9 years and 4 months of age. Histopathological analysis of the tooth revealed disturbed cementum formation, which is a typical characteristic of teeth in patients with HPP. On the basis of these findings, we hypothesize that the disturbed cementum formation could lead to susceptibility to early exfoliation of anterior teeth, as well as occurrence of ankylosis involving posterior teeth.

Contribution of Streptococcus mutans to Helicobacter pylori colonisation in oral cavity and gastric tissue.

Helicobacter pylori is presumed to infect gastric tissue via the oral cavity in childhood, whereas risk factors for H. pylori infection in the oral cavity are unknown. In this study, we analysed the effects of Streptococcus mutans, a major cariogenic bacterial species, on H. pylori colonisation in the oral cavity, as well as gastric tissue. Rats in the weaning period were infected with S. mutans in the oral cavity, then fed a caries-inducing diet to facilitate S. mutans colonisation. One month after S. mutans infection, rats were infected with H. pylori in the oral cavity; rats were then euthanised at 1 month after H. pylori infection. H. pylori was detected in the oral cavities of rats infected with both S. mutans and H. pylori, but not in rats infected with H. pylori alone. In addition, H. pylori colonisation in the gastric tissue and typical gastrointestinal damage were observed in rats infected with both S. mutans and H. pylori. When H. pylori was co-cultured with in vitro biofilm formed by S. mutans, a large number of H. pylori bacteria invaded the biofilm formed by S. mutans. Our results suggest that S. mutans is involved in the establishment of H. pylori infection.