Separation of electrically neutral non-metallic inclusions from molten steel by pulsed electric current

Effect of a pulsed electric current on the distribution of Al2O3 inclusions in liquid steel is explored; these inclusions ranged in size from microns to nanometres. When no electric current was applied the inclusions were randomly distributed in the steel. However, when an electric current was applied the inclusions were found in highlypopulated regions near the various interfaces. Moreover, this process applies to a wide range of inclusion diameters, in contrast to conventional inclusion removal methods which tend to apply to larger (>20 μm) particles only. Consequently, the application of pulsed electric current provides a method of removing inclusions from the steel and thereby, improving the mechanical, physical and corrosion resistance properties of the steel

Recent Trends in Dental Forensics

Teeth are the most robust tissues of the human body, and usually most resistant to post-mortemdecay. The dental patterns tend to be highly individualized and are therefore very useful for identification ifappropriate records are available for comparison. For these reasons, dental evidence remains important inforensic cases after accidents, crime or prolonged exposure to the environment. Routine antemortem dentalrecords are applied for storage and retrieval of such information but unfortunately not always available. Thesame is true for DNA typing, which is an increasingly useful approach with decreasing cost of analysis. Thispaper aims to review some of the new developments, particularly in biochemical forensic tools and methodsthat can be applied also for dental samples. No new tool will solve all cases, and it remains necessary to applyan array of techniques for post-mortem identification. It is also very important to use established protocols forefficiency and quality assurance in forensic investigation. Some challenges are highlighted for forensicapplication in Indonesia

Dental Forensics: Bitemark Analysis

Forensic odontology (dental forensics) can provide useful evidence in both criminal and civil cases, and therefore remains a part of the wider discipline of forensic science. As an example from the toolbox of forensic odontology, the practice and experience on bitemark analysis is reviewed here in brief. The principle of using visible bitemarks in crime victims or in other objects as evidence is fundamentally based on the observation that the detailed pattern of dental imprints tend to be practically unique for each individual. Therefore, finding such an imprint as a bitemark can bear a strong testimony that it was produced by the individual that has the matching dental pattern. However, the comparison of the observed bitemark and the suspected set of teeth will necessarily require human interpretation, and this is not infallible. Both technical challenges in the bitemarks and human errors in the interpretation are possible. To minimise such errors and to maximise the value of bitemark analysis, dedicated procedures and protocols have been developed, and the personnel taking care of the analysis need to be properly trained. In principle the action within the discipline should be conducted as in evidence-based dentristy, i.e. accepted procedures should have known error rates. Because of the involvement of human interpretation, even personal performance statistics may be required from legal expert statements. The requirements have been introduced largely due to cases where false convictions based on bitemark analysishave been overturned after DNA analysis.DOI: 10.14693/jdi.v15i2.7

EFFECT OF WHITE TEA EXTRACT IN VITRO AGAINST CARIOGENIC AND PERIODONTAL BACTERIA

Objective: This work aimed to evaluate the in vitro antimicrobial properties of white tea maceration extract against pathogenic oral bacteriaStreptococcus mutans (serotype F), Porphyromonas gingivalis (strain ATCC 33277), and Actinobacillus actinomycetemcomitans (phenotype A); theproperties of this product were also tested against non-pathogenic Streptococcus sanguis (ATCC 10556) for comparison.Methods: A maceration extract was made from white tea collected from West Java, and the infusion was prepared at concentrations of 5–80%. Theselected strains of each microbial species were cultured under anaerobic conditions, and equalized standard dilutions of the cultured bacteria wereused for testing. Dilution and diffusion tests were conducted to quantify the antimicrobial properties of white tea extract (WTE) against the bacteria.Results: The dilution test results showed a minimum inhibitory concentration of 40% of WTE against S. mutans, P. gingivalis, andA. actinomycetemcomitans and 80% against S. sanguis. The minimum bactericidal concentration was 80% for all tested bacterial strains.Conclusion: The diffusion test results showed higher inhibition with increasing extract concentration; however, the difference between concentrationsof 40% and 80% was small or negligible, except for A. actinomycetemcomitans. These results imply the clear, acute antimicrobial effect of WTE againstthe tested oral anaerobic pathogens in vitro. Considering that these effects were concentration dependent and that white tea has the highest contentof antimicrobial phenolic compounds among all grades of (green) tea, white tea or WTE may be useful for inhibiting the growth of pathogens involvedin the development of caries and/or periodontal disease

TUMOR SUPPRESSION IN ONCOGENESIS OF ORAL SQUAMOUS CELL CARCINOMA

Oral cancer is relatively uncommon in the industrialized world but accounts for about 5% of all cancer deaths worldwide, and up to 40% of all malignancies in South and South-East Asia. The present paper aims to review the role and signifivance of tumor suppressor genes in the genetic and molecular pathways to oral squamous cell carcinoma (SCC), which is the most common form of oral cancer and frequently associated with poor prognosis. The high incidence of SCC in betel quid users is due to the severe chemical insult resulting in multiple alterations of oncogenes and tumor suppressing genes. Of the latter, SCC in betel quid users is more often associated with alterations in P16 and pRb (typically at least 60% of the cases) than in p53 (typically less than 20%). However, in most parts of the world SCC is mostly attributed to smoked tobacco and alcohol, which inflict a synergistic effect when used in combination. The characteristic prevalent alterations are common (50 to 100%) in the tumor suppressor gene p53. Potential applications of the genes, corresponding expressed proteins and related other markers are discussed in brief.

Effects of Chromium on Human Body

Chromium is widely used in medical and dental implants, appliances and tools, where sufficient content s of this chemical element can provide a protective corrosion-resistant oxide on the alloy surface. At low concentrations chromium is used for medical purposes, and it is also involved in natural human lipid and protein metabolism. However, at sufficiently high concentrations particularly hexavalent chromium is toxic and carcinogenic. The healthy risks can be expected regardless whether the chromium originates from external sources such as polluted drinking water or internally from corroding dental appliances. As the latter source is likely to provide chromium exposure only at low to modest concentrations, no acute effects are generally expected. The current paper aimed to briefly review the toxicology aspects of chromium in general and in oral exposure from applications, used in dentistry. It was concluded that most likely oral effects are chronic, including carcinogenic impact, but more studies are directed to investigation on the chronic effects of chromium release from dental appliances

EFFECTIVENESS OF LAWSONIA INERMIS LINNEAUS LEAVES INFUSION IN GINGIVITIS HEALING: EFEKTIFITAS INFUSA DAUN LAWSONIA INERMIS LINNEAUS TERHADAP PENYEMBUHAN GINGIVITIS

Gingivitis is one type of periodontal disease and it is chronic in nature. The main etiological factor of gingivitis is bacterialplaque. Untreated gingivitis can spread to underlying tissues and it can become periodontitis and produce tissuedestruction. One of the treatments for gingivitis is plaque removal, helped by antibacterial mouthrinsing to reducebacterial plaque. Lawsonia inermis L. leaves have been used by Indonesian villagers for healing skin wounds andreported to show antibacterial effect in vitro and in vivo. This study aimed to determine the effect of Lawsonia inermis L.leaves infusion in gingivitis healing. A total of 63 gingivitis patients devided into 5 groups were instructed to rinse with 3concentrations (50000 µg/mL, 10000 µg/mL, 5000 µg/mL) of Lawsonia inermis L. leaves infusion; 0.1% hexetidinesolution, and placebo as control. Papilla Bleeding Index (PBI) used in measurement for bleeding on probing. The resultshowed that decreasing of PBI in Lawsonia inermis L. leaves infusion at 10000 µg/mL concentratation (80%), wasstronger than hexetidine 0.1% (76%). In conclusion, Lawsonia inermis L. leaves infusion effective to reduce PBI betterthan hexetidine. In conclusion, Lawsonia inermis L. leaves is effective to treat gingivitis

EFFECT OF ANCHOVY (STOLEPHORUS SP.) APPLICATION ON RAT ENAMEL MICROHARDNESS AND APATITE CRYSTAL SIZE: AN IN-VIVO STUDY

ABSTRACTObjectives: The study aimed to investigate the in-vivo effect on the enamel microhardness, apatite crystal changes, and fluorapatite formation afterapplying acidic anchovy solution on rat teeth.Methods: A total of 16 Sprague-Dawley rats were divided into four groups including the untreated baseline group, demineralized distilled water(control) group, positive control (sodium fluoride) group, and anchovy treatment group. Anchovies were heated, powdered, and diluted withdemineralized water to a 5% solution. The test and control solutions were applied to rat mandibular incisors twice daily for 7 days. After exposure, theteeth were subjected to microhardness testing, scanning electron microscopy, and energy dispersive X-ray spectroscopy analysis to examine enamelsurface and fluoride retention, and X-ray diffraction (XRD) analysis on fluorapatite formation and changes in apatite crystal size.Results: Anchovy treated specimens showed increase in enamel microhardness to 390±29 Vickers hardness number, decrease in apatite crystal sizeto 19.14±1.24 nm, higher fluoride retention on enamel (5.88±0.32%), reduction of crystal size, and increase in fluoride retention correlated withincrease of enamel surface microhardness. Fluorapatite formation was demonstrated by the increased peaks at 2θ=32.67° and 33.87° in XRD analysis.Conclusion: In-vivo application of anchovy solution on rat enamel surface increased enamel surface microhardness and promoted fluorapatiteformation. The applied anchovy solution appears to show a clear beneficial effect as a topical fluoride agent.Keywords: Caries, Apatite, Anchovy, Calcium fluoride, Fluorapatite