Assessment of the Silver Penetration and Distribution in Carious Lesions of Deciduous Teeth Treated with Silver Diamine Fluoride
The aim of this study was to determine the effects of 38% silver diamine fluoride (SDF) on carious lesions of human deciduous teeth. Ten extracted deciduous incisors with caries were collected and treated with SDF. After the treatment, the teeth were sectioned through the center of the carious lesion. The extent of sliver precipitation was examined using quantitative backscattered electron scanning electron microscopy (qBSE-SEM), energy-dispersive X-ray spectroscopy (EDX), and micro-computed tomography (micro-CT). The qBSE-SEM images revealed that the silver particles could penetrate through the pellicle complex, along with the rod sheaths into the demineralized enamel rods and the dentinal tubules, and form silver-enriched barriers surrounding the carious lesions at depths up to 2,490.2 Î¼m (mean 744.7 Â± 448.7 Î¼m) within the dentinal tubules of the carious lesions, but less likely in the sound enamel. The EDX spectrum analysis revealed that carbon, oxygen, phosphorus, chlorine, silver, and calcium were the main elements detected in the lesions treated with SDF. Additionally, sodium, magnesium, aluminum, silicon, zinc, sulfur, and fluorine were detected as the minor elements within the SDF precipitation "zone." The micro-CT analysis further showed that in the deep cavitated lesions, the silver precipitation could be observed in the pulp chamber. These findings provide new evidence defining the SDF mode of action for arresting caries and suggest that the application of a highly concentrated SDF solution on deciduous teeth should be used with caution for various carious lesions.
Impact of parental migration on oral health outcomes of left-behind school-aged children in Luchuan, southern China
BACKGROUND:With rapid urbanization in China, an increasing number of rural adults have migrated to cities to seek job opportunities, leaving their school-aged children behind. These left-behind children (LBC) without one or both parents usually receive less attention from their caregivers. Whether the parental migration affects the children's oral health is not well understood. This study aimed to explore the differences in dental caries status and oral health-related behaviors between children with different parental migration experiences in a rural area of Southern China. METHODS:A cross-sectional study was conducted in Luchuan County of Guangxi Province in 2015. A total of 1085 school children aged 8-12 participated in this study. Participants' demographic characteristics, parental migration information, and eating and oral hygiene habits were collected using a self-administered questionnaire. Dental caries of permanent teeth was examined using the decayed, missing, and filled tooth (DMFT) index recommended by the World Health Organization. Dental caries experience and oral health-related behaviors were compared between LBC and non-LBC, as well as children with different experiences of parental migrations. The impact of various parental migration attributes on LBC oral health outcomes was examined by univariate and multivariate analyses. RESULTS:Among the school-aged children examined, 60.9% of them were LBC. Only 29.7% of the children brushed their teeth regularly; 86.5% of them did not know what fluoride toothpaste was. Caries prevalence was 51.4% for LBC and 40.8% for non-LBC (pÂ <â€‰0.001). The LBC experienced a greater DMFT mean (1.20â€‰Â±â€‰1.59) compared to the non-LBC (0.85â€‰Â±â€‰1.30) (pÂ <â€‰0.001). Oral health-related behaviors were not significantly different between LBC and non-LBC. Dental caries experience and oral health-related behaviors were not related to the type or duration of parental migration. Multiple regression analyses showed that parental migration was one of significant predictors of children's caries outcome; LBC had a higher risk to caries than non-LBC (95% CI =1.26, 2.09). CONCLUSIONS:These findings indicate that parental migration could be a significant risk factor for caries development among 8- to 12-year-old school children in rural China.
Developmental defects of enamel increase caries susceptibility in Chinese preschool children
OBJECTIVES/OBJECTIVE:The present epidemiological study aimed to compare the prevalence and severity of developmental defects of enamel (DDE) and dental caries between urban and suburban Chinese preschool children. METHODS:A total of 1351 3- to 6-year-old children were invited to participate in this study and received dental examinations. A modified DDE index was used to assess the prevalence and severity of DDE. The dental caries diagnosis was based on the World Health Organization (WHO) health survey methods for field studies and was recorded using the decayed, missing and filled tooth (dmft) index. The caries status was further classified as caries or severe caries according to a modification of the American Academy of Pediatric Dentistry definition. RESULTS:Overall, the DDE prevalence was 48.3% among the 1351 preschool children. The DDE prevalence was higher in innercity children (54.1%) than in suburban children (42.0%; PÂ <Â 0.001). In contrast, the suburban children had a higher prevalence of dental caries (65.2% vs 57.5%; PÂ =Â 0.004) and a higher mean dmft score (3.5Â Â±Â 4.2 vs 2.9Â Â±Â 3.8; PÂ =Â 0.005) than the innercity children. Only 23.9% of the children were free of both DDE and caries. The caries risk increased significantly and independently as DDE severity increased (linear trend, 95% confidence intervalÂ =Â [1.32, 1.69], age [1.60, 1.88], urban residence [1.18, 2.15] and breastfeeding experience [1.04, 1.60]) after controlling for other demographic risk factors. CONCLUSIONS:The study provides new evidence that DDE is a significant contributing factor for the highly prevalent and progressive dental caries observed in Chinese preschool children. These results highlight the importance of including DDE in caries risk assessments.
Active Probiotic Therapeutics may Prevent Oral Candida Infections inÂ the Elderly Population, but theÂ Evidence is Insufficient
ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION/BACKGROUND:A meta-analysis of randomized trials assessing the effects of probiotic preparations on oral candidiasis in the elderly. Ai R, Wei J, Ma D, etÂ al. Arch Oral Biol 2017;83:187-92. SOURCE OF FUNDING/BACKGROUND:Chinese government research foundation funds. TYPE OF STUDY/DESIGN/METHODS:Systematic review with meta-analysis of data.
Caries outcome following an intensive fluoride varnish treatment regimen for children at high risk for early childhood caries
PURPOSE/OBJECTIVE:To evaluate the caries relapse rate for a cohort of 2- to 4-year-old children at high risk of early childhood caries when treated with an intensive fluoride varnish (FV) regimen. METHODS:Eighty paediatric patients were recruited. Forty of these patients were high risk and received the FV treatment (three applications within 2Â weeks and additional applications at 1 and 3Â months) during 2009-2010. Mutans streptococci (MS) levels in the saliva were evaluated during the treatment period. A comparative group of 40 children, selected from an electronic record search at the New York University College of Dentistry to be of similar age, gender, and ethnicity, but not at elevated risk for ECC, received the standard of care (semi-annual FV treatment). Detailed caries examination and treatment records were obtained for all patients from 2009 to 2014. RESULTS:A significant reduction (PÂ <Â 0.001) in MS levels was observed in the intensive FV treatment group at the 3-month visit compared with baseline. There was no effect of the intensive FV treatment on caries outcome in the anterior teeth, and the overall caries scores were significantly increased on the posterior teeth. CONCLUSION/CONCLUSIONS:The intensive FV regimen appears insufficient to prevent caries relapse in children at high risk for caries.
A screening method for gastric cancer by oral microbiome detection
Gastric cancer is the second most common malig-nancy and one of the principal causes of cancerâ€‘related mortality worldwide. Early diagnostic and screening methods for gastric cancer are limited at present, most of them involving invasive procedures. We aimed to investigate the characteristics of the oral microbiome in gastric cancer individuals and to conduct a screening method for gastric cancer by oral microbiome detection. We used highâ€‘throughput sequencing to examine the total bacterial profile of saliva and plaque samples of 50Â subjects, including 37Â individuals with gastric cancer and 13Â controls. The Venn diagram and species abundance clusters were generated from the data. The results indicated that the oral bacteria were more complex in patients with gastric cancer. Based on the characteristics of the oral microbiome in individuals with gastric cancer, a scoring system was designed to screen gastric cancer. In the present study, 36 out of 37Â individuals in the gastric cancer group were identified as a highâ€‘risk population, giving a sensitivity rate of 97%. One out of 13Â individuals in the control group was identified as a highâ€‘risk population, providing a false-positive rate of 7.7%. The scoring system we designed may be a potential method for screening suspected gastric cancer patients by oral microbiome detection. Further calibration of this scoring system is needed by recruiting a larger study population.
Diagnosing Developmental Defects of Enamel: Pilot Study of Online Training and Accuracy
PURPOSE/OBJECTIVE:The purpose of this study was to assess dentists' ability to correctly identify and classify development defects of enamel (DDE). METHODS:The modified DDE (MDDE) index was used to classify enamel defects into two types: (1) enamel hypoplasia-pitted, grooved, or missing enamel; or (2) enamel opacity-translucency of enamel not caused by dental caries or fluorosis (can be either demarcated or diffuse). A panel of six experts selected and scored 36 images using the MDDE, and the consensus score was used as the gold standard score in the evaluation of survey respondents. A short training table was developed to match training images to descriptors for the MDDE. A survey, including the training table, was then distributed electronically to 2,036 U.S. dentists and expanded function dental assistants from the Indian Health Service and 6,174 members of American Academy of Pediatric Dentistry. The percent of correct responses was evaluated for each image. RESULTS:Survey respondents (348 total) showed great variability in correct responses for each image, ranging from 41 to 97 percent, for each category of the MDDE. CONCLUSIONS:Enhanced training and calibration on the ability of dental providers is needed to identify the different types of development defects of enamel.
Chronic Periodontal Disease, Periodontal Pathogen Colonization, and an Increased Risk of Precancerous Gastric Lesions
BACKGROUND: The present study assessed the association between periodontal pathogen colonization and the potential risk of developing precancerous lesions of gastric cancer (PLGC) in a clinical setting. METHODS: The present study included 35 newly diagnosed patients with PLGC and 70 age-matched individuals without PLGC. A full-mouth intra-oral examination was performed to assess the periodontal conditions. Stimulated whole saliva and pooled plaque samples were collected to evaluate colonization by Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia and Actinobacillus actinomycetemcomitans and to characterize the oral microbial diversity in the saliva and dental plaque. RESULTS: Compared with the control group, the patients with PLGC experienced a higher prevalence of bleeding on probing (BOP; 31.5% vs. 22.4%, P < 0.05), higher levels of T. denticola (P < 0.01) and A. actinomycetemcomitans (P <0.01), and less bacterial diversity in their saliva (P < 0.01). The final multivariate logistic regression model comprising all key socio-demographic characteristics, oral health behavioral factors and periodontal assessments revealed that elevated colonization with periodontal pathogens, specifically T. forsythia, T. denticola, and A. actinomycetemcomitans, decreased bacterial diversity in the dental plaque, and not flossing teeth regularly were significant predictors of an increased risk of PLGC (P = 0.022). CONCLUSION: The findings of the present study provide new evidence suggesting that periodontal pathogen burdens and bacterial diversity in the oral cavity are important factors contributing to a potential increased risk of developing precancerous gastric lesions.
Midgut bacterial communities in the giant Asian honeybee (Apisdorsata) across four developmental stages: a comparative study
Bacterial communities are known to play important roles during the developmental stages of insects, but current knowledge of bacteria associated with the midgut of Apisdorsata,the giant Asian honeybee, is limited.Using polymerase chain reaction-denaturing gradient gel electrophoresis analysis (PCR-DGGE) and 16S rRNA sequencing, the aim of this study was to determine the dynamics of bacterialcommunity structure across four A. dorsata life stages in different geographical locations. The results reveal that bacterial diversity increased as the bee progressed through larval stage to newly emerged worker and oldworker. However, in the pupal stage, no bands identified as bacteria couldbe observed. Overall, twobacterial phyla (Proteobacteria and Firmicutes) and four classes (Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Bacilli) were identified, but the frequency varied among the different stages and locations. The classes of Gammaproteobacteria and Bacilli dominated among larval, newly emerged worker and old worker developmental stages
Streptococcus mutans Displays Altered Stress Responses While Enhancing Biofilm Formation by Lactobacillus casei in Mixed-Species Consortium
Like Streptococcus mutans, lactobacilli are commonly isolated from carious sites, although their exact role in caries development remains unclear. This study used mixed-species models to analyze biofilm formation by major groups of oral lactobacilli, including L. casei, L. fermentum, L. rhamnosus, L. salivarius ssp. salivarius, and L. gasseri. The results showed that lactobacilli did not form good biofilms when grown alone, although differences existed between different species. When grown together with S. mutans, biofilm formation by L. gasseri and L. rhamnosus was increased by 2-log (P < 0.001), while biofilms by L. fermentum reduced by >1-log (P < 0.001). L. casei enhanced biofilm formation by ~2-log when grown with S. mutans wild-type, but no such effects were observed with S. mutans deficient of glucosyltransferase GtfB and adhesin P1. Both S. mutans and L. casei in dual-species enhanced resistance to acid killing with increases of survival rate by >1-log (P < 0.001), but drastically reduced the survival rates following exposure to hydrogen peroxide (P < 0.001), as compared to the respective mono-species cultures. When analyzed by RNA-seq, more than 134 genes were identified in S. mutans in dual-species with L. casei as either up- or down-regulated when compared to those grown alone. The up-regulated genes include those for superoxide dismutase, NADH oxidase, and members of the mutanobactin biosynthesis cluster. Among the down-regulated genes were those for GtfB and alternative sigma factor SigX. These results further suggest that interactions between S. mutans and oral lactobacilli are species-specific and may have significant impact on cariogenic potential of the community.