Use of the DNA Checkerboard hybridization method for detection and quantitation of Candida species in oral microbiota

The DNA Checkerboard method enables the simultaneous identification of distinct microorganisms in a large number of samples and employs up to 45 whole genomic DNA probes to gram-negative and gram-positive bacterial species present in subgingival biofilms. Collectively, they account for 55%-60% of the bacteria in subgingival biofilms. In this study, we present the DNA Checkerboard hybridization as an alternative method for the detection and quantitation of Candida species in oral cavities. Our results reveal that DNA Checkerboard is sensitive enough and constitutes a powerful and appropriate method for detecting and quantifying Candida species found in the oral cavity.

Scientific output trends in oral health in Brazil

Objective. To describe dental research trends in Brazil (especially population-based oral health) in the early Twenty-first Century. Methods. The abstracts of studies presented at meetings of the Brazilian Society for Dental Medicine Research (Sociedade Brasileira de Pesquisa Odontologica) from 2001-2006 were assessed in terms of methodological design (aggregate or population-based and individual-based studies, observational and intervention studies, cross-sectional and longitudinal studies); general type (literature review, studies with human subjects, and laboratory studies); and classification into one of the 19 specialty categories recognized by the Brazilian Federal Dentistry Council. Of the 10 406 abstracts presented in this period, 5 203 (50%) were reviewed. Results. Concerning methodological design, 87.5% of the abstracts referred to individual-based studies, whereas 12.5% were of aggregate studies. Concerning the general category, 41.7% referred to studies with human subjects. The remaining abstracts (58.3%) described in vitro (31.1%) or in vivo (23.6%) laboratory research and literature reviews (3.6%). Concerning the Council`s specialty categories, only five had a frequency higher than 10.0%: esthetic dentistry, periodontics, endodontics, pediatric dentistry, and population-based oral health. Conclusions. Brazil`s scientific output in the field of oral health for the period 2001-2006 was balanced, with increasing interest in the area of population-based oral health.

Detection of Paraquat in Oral Fluid, Plasma, and Urine by Capillary Electrophoresis for Diagnosis of Acute Poisoning

FAPESP

Balancing the role of the dental school in teaching, research and patient care; including care for underserved areas

Inequalities within dentistry are common and are reflected in wide differences in the levels of oral health and the standard of care available both within and between countries and communities. Furthermore there are patients, particularly those with special treatment needs, who do not have the same access to dental services as the general public. The dental school should aim to recruit students from varied backgrounds into all areas covered by the oral healthcare team and to train students to treat the full spectrum of patients including those with special needs. It is essential, however, that the dental student achieves a high standard of clinical competence and this cannot be gained by treating only those patients with low expectations for care. Balancing these aspects of clinical education is difficult. Research is an important stimulus to better teaching and better clinical care. It is recognized that dental school staff should be active in research, teaching, clinical work and frequently administration. Maintaining a balance between the commitments to clinical care, teaching and research while also taking account of underserved areas in each of these categories is a difficult challenge but one that has to be met to a high degree in a successful, modern dental school.

Oral health in transition: the case of Indigenous peoples from Brazil

The objective of this paper is to summarise epidemiological information about the distribution of dental caries among Indigenous peoples in Brazil. The authors also present a case study of a specific group of Xavante Indians, one of the most numerous of Brazil`s Indigenous peoples, describing how their oral health has deteriorated over recent decades, and showing how an oral health programme is attempting to reverse the present trend of increase in caries. The programme at Etenheritipa Xavante village incorporated three principal components: educational, preventive, and clinical. From the beginning, the programme included epidemiological record keeping for monitoring the level of caries in the population. Transversal studies of the condition of oral health among the Xavante of Etenheritipa were undertaken in 1999, 2004, and 2007. In the period from 2004 to 2007 the DMFS values in the 11-15 age cohort had a significant reduction in caries experience. The mean DMFS score fell from 4.95 in 2004 to 2.39 in 2007 (p<0.01). An increase in the percent of individuals who were free from caries was also noted: in 1999, 20% of adolescents 11-15 had no caries; in 2007, the proportion had risen to 47%. The Xavante case is a prime example of the transition in oral health that is taking place among the Indigenous peoples of the Americas, and it highlights the importance of oral health promotion through preventive measures such as access to fluoridation and basic care in reducing the inequality between Indians and non-Indians.

Dressing liposomal particles with chitosan and poly(vinylic alcohol) for oral vaccine delivery

Liposomes have been used as adjuvants since 1974. One major limitation for the use of liposomes in oral vaccines is the lipid structure instability caused by enzyme activities. Our aim was to combine liposomes that could encapsulate antigens (i.e., Dtxd, diphtheria toxoid) with chitosan, which protects the particles and promotes mucoadhesibility. We employed physical techniques to understand the process by which liposomes (SPC: Cho, 3: 1) can be sandwiched with chitosan (Chi) and stabilized by PVA (poly-vinylic alcohol), which are biodegradable, biocompatible polymers. Round, smooth-surfaced particles of REVs-Chi (reversed-phase vesicles sandwiched by Chi) stabilized by PVA were obtained. The REVs encapsulation efficiencies (Dtxd was used as the antigen) were directly dependent on the Chi and PVA present in the formulation. Chi adsorption on the REVs surface was accompanied by an increase of zeta-potential. In contrast, PVA adsorption on the REVs-Chi surface was accompanied by a decrease of zeta-potential. The presence of Dtxd increased the Chi surface-adsorption efficiency. The PVA affinity by mucine was 2,000 times higher than that observed with Chi alone and did not depend on the molecule being in solution or adsorbed on the liposomal surface. The liberation of encapsulated Dtxd was retarded by encapsulation within REVs-Chi-PVA. These results lead us to conclude that these new, stabilized particles were able to be adsorbed by intestinal surfaces, resisted degradation, and controlled antigen release. Therefore, REVs-Chi-PVA particles can be used as an oral delivery adjuvant.

Laminin-derived peptide AG73 regulates migration, invasion, and protease activity of human oral squamous cell carcinoma cells through syndecan-1 and beta 1 integrin

Squamous cell carcinoma is a prevalent head and neck tumor with high mortality. We studied the role played by laminin alpha 1 chain peptide AG73 on migration, invasion, and protease activity of cells (OSCC) from human oral squamous cell carcinoma. Immunohistochemistry and immunofluorescence analyzed expression of laminin alpha 1 chain and MMP9 in oral squamous cells carcinoma in vivo and in vitro. Migratory activity of AG73-treated OSCC cells was investigated by monolayer wound assays and in chemotaxis chambers. AG73-induced invasion was assessed in Boyden chambers. Invasion depends on MMPs. Conditioned media from cells grown on AG73 was subjected to zymography. We searched for AG73 receptors related to these activities in OSCC cells. Immunofluorescence analyzed AG73induced colocalization of syndecan-1 and beta 1 integrin. Cells had these receptors silenced by siRNA, followed by treatment with AG73 and analysis of migration, invasion, and protease activity. Oral squamous cell carcinoma expresses laminin alpha 1 chain and MMP9. OSCC cells treated with AG73 showed increased migration, invasion, and protease activity. AG73 induced colocalization of syndecan-1 and beta 1 integrin. Knockdown of these receptors decreased AG73-dependent migration, invasion, and protease activity. Syndecan-1 and beta 1 integrin signaling downstream of AG73 regulate migration, invasion, and MMP production by OSCC cells.

Presence of periodontopathic bacteria in coronary arteries from patients with chronic periodontitis

In this study the presence of periodontopathic pathogens in atheromatous plaques removed from coronary arteries of patients with chronic periodontitis and periodontally healthy subjects by PCR was detected. Our results indicate a significant association between the presence of Porphyromonas gingivalis and atheromas, and the periodontal bacteria in oral biofilm may find a way to reach arteries. (C) 2010 Elsevier Ltd. All rights reserved.

Noninvasive Evaluation of Oral Lesions Using Depth-sensitive Optical Spectroscopy

BACKGROUND: Optical spectroscopy is a noninvasive technique with potential applications for diagnosis of oral dysplasia and early cancer. In this study, we evaluated the diagnostic performance of a depth-sensitive optical spectroscopy (DSOS) system for distinguishing dysplasia and carcinoma from non-neoplastic oral mucosa. METHODS: Patients with oral lesions and volunteers without any oral abnormalities were recruited to participate. Autofluorescence and diffuse reflectance spectra of selected oral sites were measured using the DSOS system. A total of 424 oral sites in 124 subjects were measured and analyzed, including 154 sites in 60 patients with oral lesions and 270 sites in 64 normal volunteers. Measured optical spectra were used to develop computer-based algorithms to identify the presence of dysplasia or cancer. Sensitivity and specificity were calculated using a gold standard of histopathology for patient sites and clinical impression for normal volunteer sites. RESULTS: Differences in oral spectra were observed in: (1) neoplastic versus nonneoplastic sites, (2) keratinized versus nonkeratinized tissue, and (3) shallow versus deep depths within oral tissue. Algorithms based on spectra from 310 nonkeratinized anatomic sites (buccal, tongue, floor of mouth, and lip) yielded an area under the receiver operating characteristic curve of 0.96 in the training set and 0.93 in the validation set. CONCLUSIONS: The ability to selectively target epithelial and shallow stromal depth regions appeared to be diagnostically useful. For nonkeratinized oral sites, the sensitivity and specificity of this objective diagnostic technique were comparable to that of clinical diagnosis by expert observers. Thus, DSOS has potential to augment oral cancer screening efforts in community settings. Cancer 2009;115:1669-79. (C) 2009 American Cancer Society.

Flow injection amperometric determination of hydrogen peroxide in household commercial products with a ruthenium oxide hexacyanoferrate modified electrode

Hydrogen peroxide was determined in oral antiseptic and bleach samples using a flow-injection system with amperometric detection. A glassy carbon electrode modified by electrochemical deposition of ruthenium oxide hexacyanoferrate was used as working electrode and a homemade Ag/AgCl (saturated KCl) electrode and a platinum wire were used as reference and counter electrodes, respectively. The electrocatalytic reduction process allowed the determination of hydrogen peroxide at 0.0 V. A linear relationship between the cathodic peak current and concentration of hydrogen peroxide was obtained in the range 10-5000 mu mol L(-1) with detection and quantification limits of 1.7 (S/N = 3) and 5.9 (S/N = 10) mu mol L(-1), respectively. The repeatability of the method was evaluated using a 500 mu mol L(-1) hydrogen peroxide solution, the value obtained being 1.6% (n = 14). A sampling rate of 112 samples h(-1) was achieved at optimised conditions. The method was employed for the quantification of hydrogen peroxide in two commercial samples and the results were in agreement with those obtained by using a recommended procedure.