Search

Introduction Elucidating the microbial ecology of endodontic infections (EIs) is a necessary step in developing effective intracanal antimicrobials. The aim of the present study was to investigate the bacterial composition of symptomatic and asymptomatic primary and persistent infections in a Greek population using high-throughput sequencing methods. Methods 16S amplicon pyrosequencing of 48 root canal bacterial samples was conducted, and sequencing data were analyzed using an oral microbiome-specific and a generic (Greengenes) database. Bacterial abundance and diversity were examined by EI type (primary or persistent), and statistical analysis was performed by using non-parametric and parametric tests accounting for clustered data. Results Bacteroidetes was the most abundant phylum in both infection groups. Significant, albeit weak associations of bacterial diversity were found, as measured by UniFrac distances with infection type (analyses of similarity, R = 0.087, P =.005) and symptoms (analyses of similarity, R = 0.055, P =.047). Persistent infections were significantly enriched for Proteobacteria and Tenericutes compared with primary ones; at the genus level, significant differences were noted for 14 taxa, including increased enrichment of persistent infections for Lactobacillus, Streptococcus, and Sphingomonas. More but less abundant phyla were identified using the Greengenes database; among those, Cyanobacteria (0.018%) and Acidobacteria (0.007%) were significantly enriched among persistent infections. Persistent infections showed higher phylogenetic diversity (PD) (asymptomatic: PD = 9.2, standard error [SE] = 1.3; symptomatic: PD = 8.2, SE = 0.7) compared with primary infections (asymptomatic: PD = 5.9, SE = 0.8; symptomatic: PD = 7.4, SE = 1.0). Conclusions The present study revealed a high bacterial diversity of EI and suggests that persistent infections may have more diverse bacterial communities than primary infections. © 2015 American Association of Endodontists.

Recent genome-wide association studies (GWAS) of chronic periodontitis (CP) offer rich data sources for the investigation of candidate genes, functional elements, and pathways. We used GWAS data of CP (n = 4,504) and periodontal pathogen colonization (n = 1,020) from a cohort of adult Americans of European descent participating in the Atherosclerosis Risk in Communities study and employed a MAGENTA approach (i.e., meta-analysis gene set enrichment of variant associations) to obtain gene-centric and gene set association results corrected for gene size, number of single-nucleotide polymorphisms, and local linkage disequilibrium characteristics based on the human genome build 18 (National Center for Biotechnology Information build 36). We used the Gene Ontology, Ingenuity, KEGG, Panther, Reactome, and Biocarta databases for gene set enrichment analyses. Six genes showed evidence of statistically significant association: 4 with severe CP (NIN, p = 1.6 × 10−7; ABHD12B, p = 3.6 × 10−7; WHAMM, p = 1.7 × 10−6; AP3B2, p = 2.2 × 10−6) and 2 with high periodontal pathogen colonization (red complex–KCNK1, p = 3.4 × 10−7; Porphyromonas gingivalis–DAB2IP, p = 1.0 × 10−6). Top-ranked genes for moderate CP were HGD (p = 1.4 × 10−5), ZNF675 (p = 1.5 × 10−5), TNFRSF10C (p = 2.0 × 10−5), and EMR1 (p = 2.0 × 10−5). Loci containing NIN, EMR1, KCNK1, and DAB2IP had showed suggestive evidence of association in the earlier single-nucleotide polymorphism–based analyses, whereas WHAMM and AP2B2 emerged as novel candidates. The top gene sets included severe CP (“endoplasmic reticulum membrane,” “cytochrome P450,” “microsome,” and “oxidation reduction”) and moderate CP (“regulation of gene expression,” “zinc ion binding,” “BMP signaling pathway,” and “ruffle”). Gene-centric analyses offer a promising avenue for efficient interrogation of large-scale GWAS data. These results highlight genes in previously identified loci and new candidate genes and pathways possibly associated with CP, which will need to be validated via replication and mechanistic studies.

Despite the concerted efforts of research and professional and advocacy stakeholders, recent evidence suggests that improvements in the oral health of young children in the United States has not followed the prevailing trend of oral health improvement in other age groups. In fact, oral health disparities in the youngest children may be widening, yet efforts to translate advances in science and technology into meaningful improvements in populations’ health have had limited success. Nevertheless, the great strides in genomics, biological, behavioral, social, and health services research in the past decade have strengthened the evidence base available to support initiatives and translational efforts. Concerted actions to accelerate this translation and implementation process are warranted; at the same time, policies that can help tackle the upstream determinants of oral health disparities are imperative. This article summarizes the proceedings from the symposium on the interdisciplinary continuum of pediatric oral health that was held during the 43rd annual meeting of the American Association for Dental Research, Charlotte, North Carolina, USA. This report showcases the latest contributions across the interdisciplinary continuum of pediatric oral health research and provides insights into future research priorities and necessary intersectoral synergies. Issues are discussed as related to the overwhelming dominance of social determinants on oral disease and the difficulty of translating science into action.

Early preventive dental visits are essential in improving children’s oral health, especially young children at high risk for dental caries. However, there is scant information on how these children enter the dental care system. Our objectives were as follows: (1) to describe how a population-based cohort of young Medicaid-enrolled children entered dental care; and (2) to investigate the influence of caregiver characteristics on their children’s dental care–seeking patterns.

Introduction: The prevalence of high levels of stress as well as its multilevel consequences is well documented amongst students in the health sciences, and particularly in dentistry. However, investigations of perceived stress amongst Spanish-speaking student groups are sparse. This study aimed to (i) describe the translation, adaptation and psychometric properties of a Spanish version of the Dental Environment Stressors questionnaire and (ii) to examine the perceived sources of stress and their associations with the students' study year and gender in two dental schools in Latin America. Materials and methods: All students officially registered in the dental schools of the University of San Sebastian (USS) in Chile and the Catholic University of Cordoba (CUC) in Argentina were invited to participate in the study. The DES30 questionnaire was adapted in Spanish using translation/back-translation, an expert bilingual committee, and consensus building. Cronbach's alpha was used to measure the instrument's internal consistency, and iterated principal factor analysis with promax rotation was employed to explore its underlying factor structure. Descriptive, bivariate and multivariate methods were used to examine the patterns of association between individual stressors, factor scores and students' characteristics. Results: Three hundred and four students comprised the study's analytical sample, with two-thirds of those being female. The DES30-Sp demonstrated good internal consistency (Cronbach's α = 0.89). A four-factor solution emerged and included 'academic workload', 'clinical training', 'time constraints' and 'self-efficacy beliefs' factors. 'Fear of failing a course or a year', 'examinations and grades' and 'lack of time for relaxation' were amongst the top individual-item stressors reported by students in both schools. Amongst this group of undergraduate dental students, those in Argentina, in higher study year, and females reported higher perceived stress. Conclusions: Increased workload, time constraints and some aspects of clinical training were the top stressors of approximately 300 Chilean and Argentinean dental undergraduates. Some variations between schools, males and females and study years were noted. The Spanish version of the DES30 questionnaire performed well, but future studies should evaluate the instrument's properties in larger and more diverse dental student populations. © 2012 John Wiley & Sons A/S.

Pathological shifts of the human microbiome are characteristic of many diseases, including chronic periodontitis. To date, there is limited evidence on host genetic risk loci associated with periodontal pathogen colonization. We conducted a genome-wide association (GWA) study among 1,020 white participants of the Atherosclerosis Risk in Communities Study, whose periodontal diagnosis ranged from healthy to severe chronic periodontitis, and for whom “checkerboard” DNA-DNA hybridization quantification of 8 periodontal pathogens was performed. We examined 3 traits: “high red” and “high orange” bacterial complexes, and “high” Aggregatibacter actinomycetemcomitans (Aa) colonization. Genotyping was performed on the Affymetrix 6.0 platform. Imputation to 2.5 million markers was based on HapMap II-CEU, and a multiple-test correction was applied (genome-wide threshold of p < 5 × 10−8). We detected no genome-wide significant signals. However, 13 loci, including KCNK1, FBXO38, UHRF2, IL33, RUNX2, TRPS1, CAMTA1, and VAMP3, provided suggestive evidence (p < 5 × 10−6) of association. All associations reported for “red” and “orange” complex microbiota, but not for Aa, had the same effect direction in a second sample of 123 African-American participants. None of these polymorphisms was associated with periodontitis diagnosis. Investigations replicating these findings may lead to an improved understanding of the complex nature of host-microbiome interactions that characterizes states of health and disease.

Objective: To quantify the impact of edentulousness on residual ridge volume, denture stomatitis (DS), as well as oral health behaviours among geriatric denture-wearers. Background: Residual ridge resorption (RRR) is the primary intraoral complication of complete edentulism, but individual variation among geriatric patients has been observed. Materials and methods: Data collection relied upon a 10-year retrospective chart review of all complete denture-wearing geriatric patients presenting at the Removable Prosthodontics Clinic, Dental School of Athens, between 1993 and 2002. Analyses relied on descriptive, bivariate, and multivariate methods based on ordinal logistic regression. Results: A total of 873 records of geriatric patients (age mean = 72; median = 70; range = 65-95) comprised our analytical sample. Subjects' mean (SD) time since edentulation was 7.7 (10.2) years. Eleven percent were diagnosed with temporomandibular disorder (TMD). While 28% of patients reported cleaning their dentures at least daily, 6% presented with denture stomatitis (DS). Each added year of edentulism increased the odds of mandibular RRR: OR (95% CI) = 1.05 (1.03, 1.07). Nightly denture wear was the strongest risk factor for DS. Finally, independent of age and sex, each year of being edentulous increased the odds of presenting with TMD: OR (95% CI) = 1.03 (1.01, 1.05). Conclusion: Time since edentulation was strongly associated with mandibular but not maxillary RRR, as well as TMD development. © 2010 The Gerodontology Society and John Wiley & Sons A/S.

Introduction: High levels of stress and burnout have been documented among dental students and practicing dentists, but evidence among dental residents and postgraduate students is lacking. Materials and methods: Ninety-nine postgraduate students enrolled in clinical, non-clinical and PhD programmes in the Athens University School of Dentistry completed the Graduate Dental Environment Stress (GDES) questionnaire and the Maslach Burnout Inventory. Perceived stress was measured in two domains, academic (GDES-A) and clinical (GDES-C) and burnout was measured using the scales of emotional exhaustion (EE), depersonalisation (DP) and personal accomplishment (PA). Analyses relied on descriptive, univariate and multivariate methods based on ANOVA and generalised linear models. Results: Participants' mean age was 30years; two-thirds were women and practised dentistry independently of their graduate studies. Residents in clinical programmes reported significantly higher levels of perceived stress compared to non-clinical and PhD students (P

Dental education is regarded as a complex, demanding and often stressful pedagogical procedure. Undergraduates, while enrolled in programmes of 4-6 years duration, are required to attain a unique and diverse collection of competences. Despite the major differences in educational systems, philosophies, methods and resources available worldwide, dental students' views regarding their education appear to be relatively convergent. This paper summarizes dental students' standpoint of their studies, showcases their experiences in different educational settings and discusses the characteristics of a positive academic environment. It is a consensus opinion that the 'students' perspective' should be taken into consideration in all discussions and decisions regarding dental education. Moreover, it is suggested that the set of recommendations proposed can improve students' quality of life and well-being, enhance their total educational experience and positively influence their future careers as oral health physicians. The 'ideal' academic environment may be defined as one that best prepares students for their future professional life and contributes towards their personal development, psychosomatic and social well-being. A number of diverse factors significantly influence the way students perceive and experience their education. These range from 'class size', 'leisure time' and 'assessment procedures' to 'relations with peers and faculty', 'ethical climate' and 'extra-curricular opportunities'. Research has revealed that stress symptoms, including psychological and psychosomatic manifestations, are prevalent among dental students. Apparently some stressors are inherent in dental studies. Nevertheless, suggested strategies and preventive interventions can reduce or eliminate many sources of stress and appropriate support services should be readily available. A key point for the Working Group has been the discrimination between 'teaching' and 'learning'. It is suggested that the educational content should be made available to students through a variety of methods, because individual learning styles and preferences vary considerably. Regardless of the educational philosophy adopted, students should be placed at the centre of the process. Moreover, it is critical that they are encouraged to take responsibility for their own learning. Other improvements suggested include increased formative assessment and self-assessment opportunities, reflective portfolios, collaborative learning, familiarization with and increased implementation of information and communication technology applications, early clinical exposure, greater emphasis on qualitative criteria in clinical education, community placements, and other extracurricular experiences such as international exchanges and awareness of minority and global health issues. The establishment of a global network in dental education is firmly supported but to be effective it will need active student representation and involvement. © 2008 Blackwell Munksgaard and The American Dental Education Association.

An accurate assessment of the computer skills of students is a pre-requisite for the success of any e-learning interventions. The aim of the present study was to assess objectively the computer literacy and attitudes in a group of Greek post-graduate students, using a task-oriented questionnaire developed and validated in the University of Malmö, Sweden. 50 post-graduate students in the Athens University School of Dentistry in April 2005 took part in the study. A total competence score of 0-49 was calculated. Socio-demographic characteristics were recorded. Attitudes towards computer use were assessed. Descriptive statistics and linear regression modeling were employed for data analysis. Total competence score was normally distributed (Shapiro-Wilk test: W = 0.99, V = 0.40, P = 0.97) and ranged from 5 to 42.5, with a mean of 22.6 (±8.4). Multivariate analysis revealed 'gender', 'e-mail ownership' and 'enrollment in non-clinical programs' as significant predictors of computer literacy. Conclusively, computer literacy of Greek post-graduate dental students was increased amongst males, students in non-clinical programs and those with more positive attitudes towards the implementation of computer assisted learning. © 2007 The Authors. Journal Compilation © 2007 Blackwell Munksgaard.

Chronic periodontitis (CP) is a common oral disease that confers substantial systemic inflammatory and microbial burden and is a major cause of tooth loss. Here, we present the results of a genome-wide association study of CP that was carried out in a cohort of 4504 European Americans (EA) participating in the Atherosclerosis Risk in Communities (ARIC) Study (mean age—62 years, moderate CP—43% and severe CP—17%). We detected no genome-wide significant association signals for CP; however, we found suggestive evidence of association (P < 5 × 10−6) for six loci, including NIN, NPY, WNT5A for severe CP and NCR2, EMR1, 10p15 for moderate CP. Three of these loci had concordant effect size and direction in an independent sample of 656 adult EA participants of the Health, Aging, and Body Composition (Health ABC) Study. Meta-analysis pooled estimates were severe CP (n = 958 versus health: n = 1909)—NPY, rs2521634 [G]: odds ratio [OR = 1.49 (95% confidence interval (CI = 1.28–1.73, P = 3.5 × 10−7))]; moderate CP (n = 2293)—NCR2, rs7762544 [G]: OR = 1.40 (95% CI = 1.24–1.59, P = 7.5 × 10−8), EMR1, rs3826782 [A]: OR = 2.01 (95% CI = 1.52–2.65, P = 8.2 × 10−7). Canonical pathway analysis indicated significant enrichment of nervous system signaling, cellular immune response and cytokine signaling pathways. A significant interaction of NUAK1 (rs11112872, interaction P = 2.9 × 10−9) with smoking in ARIC was not replicated in Health ABC, although estimates of heritable variance in severe CP explained by all single nucleotide polymorphisms increased from 18 to 52% with the inclusion of a genome-wide interaction term with smoking. These genome-wide association results provide information on multiple candidate regions and pathways for interrogation in future genetic studies of CP.

Background: Poor oral hygiene has been proposed to contribute to head and neck cancer (HNC) risk, although causality and independency of some indicators are uncertain. This study investigates the relationship of five oral hygiene indicators with incident HNCs. Methods: In a pooled analysis of 8925 HNC cases and 12 527 controls from 13 studies participating in the International Head and Neck Cancer Epidemiology Consortium, comparable data on good oral hygiene indicators were harmonized. These included: No denture wear, no gum disease (or bleeding)