adam, Author at IAOMT Library

Bacterial and human peptidylarginine deiminases: targets for inhibiting the autoimmune response in rheumatoid arthritis

Peptidylarginine deiminases (PADs) convert arginine within a peptide (peptidylarginine) into peptidylcitrulline. Citrullination by human PADs is important in normal physiology and inflammation. Porphyromonas gingivalis, a major pathogen in periodontitis, is the only prokaryote described to possess PAD. P. gingivalis infection may generate citrullinated peptides, which trigger anti-citrullinated peptide antibodies. In susceptible individuals, host protein citrullination by human PADs in the joint probably perpetuates antibody formation, paving the way for the development of chronic arthritis. Blockades of bacterial and human PADs may act as powerful novel therapies by inhibiting the generation of the antigens that trigger and sustain autoimmunity in rheumatoid arthritis.

By Mangat P, Wegner N, Venables PJ, Potempa J.|2019-06-17T00:23:40+00:00January 1st, 2010|Other|

Cytotoxicity of dental adhesives in vitro.

OBJECTIVES:
The purpose of this study was to evaluate the cytotoxic effect of six dental adhesives (Admira Bond, Clearfil Liner Bond 2V, ED Primer II, Fuji Bond LC, Gluma Comfort Bond, and NanoBond) applied to cell cultures.

METHODS:
The experiments were performed on two cell lines, rat pulp cells (RPC-C2A) and human lung fibroblasts (MRC5). Samples of the adhesives were light-cured and placed in culture medium for 24 hours. The extraction media was applied on the RPC-C2A and the MRC5 cells. Complete medium was used as a control. Cytotoxicity was evaluated with a modified sulforhodamine B (SRB) assay after 24 hours of exposure.

RESULTS:
The cell survival of RPC-C2A cells exposed to Fuji Bond LC, NanoBond, Clearfil Liner Bond 2V, ED Primer II, Admira Bond and Gluma Comfort Bond was 73%, 67%, 50%, 20%, 18% and 5% respectively, relative to the cell survival with the control medium. In the MRC5 cell line, the relative survival was 98%, 80%, 72%, 41%, 19% and 7% after exposure to NanoBond, Fuji Bond LC, Clearfil Liner Bond 2V, ED Primer II, Admira Bond and Gluma Comfort Bond, respectively.

CONCLUSIONS:
Different types of dental adhesives showed different cytotoxic effects on cells in vitro. The self-etch adhesives were superior in terms of cytotoxicity. The different cytotoxic effects of dental adhesives should be considered when selecting an appropriate adhesive for operative restorations.

By Koulaouzidou EA, Helvatjoglu-Antoniades M, Palaghias G, Karanika-Kouma A, Antoniades D.|2018-07-24T23:38:31+00:00January 1st, 2009|Other|

Effect of magnetic resonance imaging on microleakage of amalgam restorations: an in vitro study.

OBJECTIVES:
The technique of MRI, using powerful magnets, plays an important role in the diagnosis of diseases of the head and neck without any ionizing radiation. Because of the potential hazard imposed by the presence of ferromagnetic metals, patients with implanted metallic objects are excluded from MRI. However, amalgam restorations seem to be safe. The purpose of this study was to evaluate microleakage of amalgam restorations following MRI.

METHODS:
63 human freshly extracted premolars were divided into 3 groups based on 3 high-copper amalgams used to restore standard class V preparations on both buccal and lingual surfaces. Three different amalgam materials were used: Cinalux, GS-80 and Vivacap. The teeth were transferred into saline solution for 2 months at room temperature and then sectioned mesiodistally. MRI was randomly applied to one half of each section, and the other half was kept as a control. Following MRI, all specimens were immersed in a dye solution, sectioned and scored for any microleakage using a stereomicroscope.

RESULTS:
Differences in microleakage within each group following MRI were significant in the GS-80 and Vivacap groups but not in the Cinalux group. However, there was no significant difference between the three groups regarding the microleakage score.

CONCLUSIONS:
The results of this study suggest that MRI is not a completely safe technique in patients with amalgam restorations. It was shown that the main effect of fields led to the appearance of thermoelectromagnetic convection, which is responsible for the enhancement of the diffusion process, grain boundary migration and vacancy formation resulting in microleakage.

By Shahidi SH, Bronoosh P, Alavi AA, Zamiri B, Sadeghi AR, Bagheri MH, Javadpour S.|2018-07-30T22:24:01+00:00January 1st, 2009|Mercury|

Biocompatibility of dental materials.

The question of whether and to what extent dental materials may be hazardous to patients, the environment, and dental personnel has become of increasing public concern. The very emotional discussion in the public media about amalgam has significantly contributed to this dispute. In addition, reports about potential health risks in relation to other dental materials, such as resins and dental alloys, have generated an increased public and professional interest in this topic. One consequence of this tendency is that dental materials are now the subject of special regulations and directives in almost all countries of the world, intended to guarantee efficiency, safety, and quality and to make sure that only biocompatible materials are brought on the market. Basically, manufacturers are responsible for the safety and quality of their medical devices. It is, however, the responsibility of the dentist to fulfill distinct assignments in this context: The dentist is thus responsible for choosing the most suitable material for each specific indication in an individual patient. Furthermore, the dentist is the primary contact person for patients who have questions about the biocompatibility of the applied materials and is therefore an important part of the market surveillance system, with the responsibility to report adverse effects to the relevant authorities.

By Schmalz G, Arenholt-Bindslev D.|2018-07-30T21:44:14+00:00January 1st, 2009|Mercury|

Effectiveness of ozone against endodontopathogenic microorganisms in a root canal biofilm model.

AIM:
To assess the antimicrobial efficacy of aqueous (1.25-20 microg mL(-1)) and gaseous ozone (1-53 g m(-3)) as an alternative antiseptic against endodontic pathogens in suspension and a biofilm model.

METHODOLOGY:
Enterococcus faecalis, Candida albicans, Peptostreptococcus micros and Pseudomonas aeruginosa were grown in planctonic culture or in mono-species biofilms in root canals for 3 weeks. Cultures were exposed to ozone, sodium hypochlorite (NaOCl; 5.25%, 2.25%), chlorhexidine digluconate (CHX; 2%), hydrogen peroxide (H(2)O(2); 3%) and phosphate buffered saline (control) for 1 min and the remaining colony forming units counted. Ozone gas was applied to the biofilms in two experimental settings, resembling canal areas either difficult (setting 1) or easy (setting 2) to reach. Time-course experiments up to 10 min were included. To compare the tested samples, data were analysed by one-way anova.

RESULTS:
Concentrations of gaseous ozone down to 1 g m(-3) almost and aqueous ozone down to 5 microg mL(-1) completely eliminated the suspended microorganisms as did NaOCl and CHX. Hydrogen peroxide and lower aqueous ozone concentrations were less effective. Aqueous and gaseous ozone were dose- and strain-dependently effective against the biofilm microorganisms. Total elimination was achieved by high-concentrated ozone gas (setting 2) and by NaOCl after 1 min or a lower gas concentration (4 g m(-3)) after at least 2.5 min. High-concentrated aqueous ozone (20 microg mL(-1)) and CHX almost completely eliminated the biofilm cells, whilst H(2)O(2) was less effective.

CONCLUSION:
High-concentrated gaseous and aqueous ozone was dose-, strain- and time-dependently effective against the tested microorganisms in suspension and the biofilm test model.

By Huth KC, Quirling M, Maier S, Kamereck K, Alkhayer M, Paschos E, Welsch U, Miethke T, Brand K, Hickel R.|2019-02-09T19:59:28+00:00January 1st, 2009|Other|

Exposure to high fluoride drinking water and risk of dental fluorosis in Estonia.

The purpose of this study was to assess exposure to drinking water fluoride and evaluate the risk of dental fluorosis among the Estonian population. The study covered all 15 counties in Estonia and 93.7% of population that has access to public water supplies. In Estonia groundwater is the main source for public water supply systems in most towns and rural settlements. The content of natural fluoride in water ranges from 0.01 to 7.20 mg/L. The exposure to different fluoride levels was assessed by linking data from previous studies on drinking water quality with databases of the Health Protection Inspectorate on water suppliers and the number of water consumers in water supply systems. Exposure assessment showed that 4% of the study population had excessive exposure to fluoride, mainly in small public water supplies in western and central Estonia, where the Silurian-Ordovician aquifer system is the only source of drinking water. There is a strong correlation between natural fluoride levels and the prevalence of dental fluorosis. Risk of dental fluorosis was calculated to different fluoride exposure levels over 1.5 mg/L.

By Indermitte E, Saava A, Karro E.|2018-07-23T18:43:42+00:00January 1st, 2009|Fluoride|

Dietary carbohydrates and dental-systemic diseases.

Two contradictory hypotheses on the role of dietary carbohydrates in health and disease shape how dental-systemic associations are regarded. On one side, Cleave and Yudkin postulated that excessive dietary fermentable carbohydrate intake led-in the absence of dental interventions such as fluorides-first to dental diseases and then to systemic diseases. Under this hypothesis, dental and systemic diseases shared-as a common cause-a diet of excess fermentable carbohydrates. Dental diseases were regarded as an alarm bell for future systemic diseases, and restricting carbohydrate intake prevented both dental and systemic diseases. On the opposite side, Keys postulated the lipid hypothesis: that excessive dietary lipid intake caused systemic diseases. Keys advocated a diet high in fermentable carbohydrate for the benefit of general health, and dental diseases became regarded as local dietary side effects. Because general health takes precedence over dental health when it comes to dietary recommendations, dental diseases became viewed as local infections; interventions such as fluorides, sealants, oral hygiene, antimicrobials, and dental fillings became synonymous with maintaining dental health, and carbohydrates were no longer considered as a common cause for dental-systemic diseases. These opposing dietary hypotheses have increasingly been put to the test in clinical trials. The emerging trial results favor Cleave-Yudkin’s hypothesis and may affect preventive approaches for dental and systemic diseases.

By Hujoel P.|2018-07-23T18:27:20+00:00January 1st, 2009|Fluoride|

Bacterial diversity in persistent periapical lesions on root-filled teeth

BACKGROUND: The purpose of this study was to analyze the bacterial diversity in persistent apical lesions on root-filled teeth by using culture-independent molecular methods.

DESIGN: Twenty surgically removed apical lesions from therapy-resistant teeth were examined for the presence of bacterial DNA using PCR targeting the 16s ribosomal RNA gene, followed by cloning and sequencing.

RESULTS: Bacterial DNA was detected in 17 of the 20 samples (85%). A total of 236 clones were analyzed. Seven different bacterial phyla were represented and a total of 75 different bacterial taxa were identified; 36% of the species have not yet been cultivated. Commonly detected bacterial species included Fusobacterium spp., Prevotella spp., Tannerella forsythia, Porphyromonas endodontalis, Treponema denticola, Bacteroidetes spp., Peptostreptococcus spp., and Streptococcus spp.

CONCLUSIONS: A wide range of bacteria was identified in periapical lesions on therapy-resistant teeth. These bacteria may contribute in the etiology of periapical infection and impede healing of these lesions.

By Handal T, Caugant DA, Olsen I, Sunde PT.|2019-05-18T16:23:08+00:00January 1st, 2009|Other|

Cost and effectiveness in American Health Care.

Since silicofluorides aren’t used in other coun-tries and are associated with a significant increase in the fre-quency of seven different diseases, stopping their use should be combined with screening and treating children for high body burdens of other toxins. As this suggestion indicates, Americans urgently need to focus on national health policy, can improve health at virtually no cost by ending silicofluoride use, and – as soon as possible – consider ways to increase public financing of medical care.

By Masters RD.|2018-07-26T16:26:19+00:00January 1st, 2009|Fluoride|

Considerations on optimal fluoride intake using dental fluorosis and dental caries outcomes–a longitudinal study.

OBJECTIVES:
The “optimal” intake of fluoride has been widely accepted for decades as between 0.05 and 0.07 mg fluoride per kilogram of body weight (mg F/kg bw) but is based on limited scientific evidence. The purpose of this paper is to present longitudinal fluoride intake data for children free of dental fluorosis in the early-erupting permanent dentition and free of dental caries in both the primary and early-erupting permanent teeth as an estimate of optimal fluoride intake.

METHODS:
Data on fluoride ingestion were obtained from parents of 602 Iowa Fluoride Study children through periodic questionnaires at the ages of 6 weeks; 3, 6, 9, 12, 16, 20, 24, 28, 32, and 36 months; and then at 6-month intervals thereafter. Estimates of total fluoride intake at each time point were made by summing amounts from water, dentifrice, and supplements, as well as other foods and beverages made with, or containing, water. Caries data were obtained from examinations of children at ages 5 and 9 years, whereas fluorosis data were obtained from examinations of children only at age 9 years.

RESULTS:
The estimated mean daily fluoride intake for those children with no caries history and no fluorosis at age 9 years was at, or below, 0.05 mg F/kg bw for nearly all time points through the first 48 months of life, and this level declined thereafter. Children with caries had generally slightly less intakes, whereas those with fluorosis generally had slightly higher intakes.

CONCLUSIONS:
Given the overlap among caries/fluorosis groups in mean fluoride intake and extreme variability in individual fluoride intakes, firmly recommending an “optimal” fluoride intake is problematic.

By Warren JJ, Levy SM, Broffitt B, Cavanaugh JE, Kanellis MJ, Weber‐Gasparoni K.|2018-08-03T15:39:23+00:00January 1st, 2009|Fluoride|

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About Mangat P, Wegner N, Venables PJ, Potempa J.