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.

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.

Sublingual Dermoid Cyst in Young Child.

A dermoid cyst is a benign congenital lesion of ectodermal origin that can arise in any region of the body, though occurrence is rare. A young girl aged 2 years 4 months was referred to our hospital because of a painless mass in the floor of the mouth. Intraoral examination findings revealed a painless movable elastic soft mass on the floor of the mouth measuring approximately 15 mm in diameter. Magnetic resonance imaging indicated a cystic lesion, with low signal intensity shown in T1-weighted and extremely high signal intensity in T2-weighted images. These clinical findings indicated the presence of a dermoid cyst and removal was planned. Under general anesthesia with nasal intubation, surgical removal was performed through an incision on the floor of the mouth. Blunt dissection exposed the integrity of the cyst capsule, which was weakly attached to adjacent tissue. The excised mass was 19 mm × 14 mm × 11 mm in size. Histological examination findings confirmed a diagnosis of dermoid cyst. The operation was successfully completed without any complications and the postoperative course was good. It is important to properly evaluate cysts in children and provide proper treatment with appropriate timing.

Large-Scale Survey of Missing Deciduous Anterior Teeth on Medical Examination at the Age of 3.5 Years.

Tooth anomalies in childhood may negatively affect the healthy development of the dentition and occlusion; hence, it is important to examine the actual oral condition at an early stage. The present study was performed to understand the state of missing deciduous anterior teeth in children aged 3.5 years who underwent dental checkups in Matsubara City. In total, 3508 children received oral examinations, and items such as erupted deciduous teeth and teeth anomalies were recorded. Among these children, those with missing anterior deciduous teeth were selected, and their details were analyzed. In the 216 children, there were 266 missing anterior deciduous teeth. Congenitally missing anterior deciduous teeth were observed in 80 children, and fused teeth were observed in 128 children. The missing teeth were predominantly located in the mandible and occurred more frequently on the right side. The most common reason for acquired missing teeth was trauma, and no cases of spontaneous loss due to systemic disease were found in this study. Screening for various tooth anomalies is expected to play an important role in cultivating a better understanding of the oral cavity of children, developing healthy dentitions, and contributing to the early detection of some systemic diseases.

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 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.

Oral management with mouthguards during the mixed dentition period: A case report.

Custom-made mouthguards are widely used by athletes during training and sporting events for the prevention of oral injuries. However, even though the prevalence of dental injuries in children in the primary or mixed dentition stages is high, few reports have focused on mouthguard use for such cases due to the difficulties associated with adapting them as teeth are lost and replaced. This report presents a case of a Japanese boy in the mixed dentition stage with a custom-made mouthguard. For fabrication, self-curing acrylic resin was used to fill portions of a working model to keep space for the later eruption of permanent teeth. However, adjustment was necessary when gingival swelling occurred in association with maxillary canine eruption, after which refabrication was necessary. Regular management of a custom-made mouthguard by the attending dentist is important for children in the mixed dentition period, especially during maxillary canine eruption, which causes drastic dentition changes. In the present case, custom-made mouthguards were fully effective based on the prediction of changes in the dentition and with regular dental management.