Photoinitiated polymerization of 2-hydroxyethyl methacrylate by safranin T / triethanolamine in aqueous solution: a kinetic study

This study involves the polymerization of 2-hydroxyethyl metharylate [HEMA] [1-M], photoinitiated by safranin T [ST] / triethanolamine [TEOHA] system in the pH range 6.0â€"9.0. The kinetics of the reactions during the initial stages of polymerization [tilde 5% HEMA conversion, within 150 s] has been evaluated to avoid the effects of any volume changes in the solution. The concentration of HEMA in polymerized solutions has been determined spectrometrically at 208 nm with a precision of +/- 3%. The apparent first-order rate constants [kobs] for the polymerization of HEMA by ST in the presence of 0.010 M TEOHA range from 2.57-6.08 [1 M], 2.14-5.44 [2 M] and 1.79-4.81x10[-4] s[-1] [3 M] at pH 6.0-9.0. The second-order rate constants for the interaction of TEOHA with HEMA [1-3 M] range from 1.79-6.08x10[-2] M[-1] s[-1] at pH 6.0-9.0. This indicates that the reactivity of TEOHA radicals increases with an increase in pH of the solution. The viscosity of HEMA solutions exerts an influence on the rates of polymerization and the values of kobs show a linear relation with inverse of solution viscosity. This could be due to the quenching of the ST excited triplet state with an increase in the viscosity of the solution

review of the effect of various ions on the properties and the clinical applications of novel bioactive glasses in medicine and dentistry

Bioactive glass is a novel material that dissolves and forms a bond with bone when exposed to body fluids. Bioactive glasses are silicate-based, with calcium and phosphate in identical proportions to those of natural bone; therefore, they have high biocompatibility. Bioactive glasses have wide-ranging clinical applications, including the use as bone grafts, scaffolds, and coating materials for dental implants. This review will discuss the effects of ions on the various compositions of bioactive glasses, as well as the clinical applications of bioactive glasses in medicine and dentistry

Amalgam waste disposal in dental hospitals of Peshawar

The study was done to find out the methods for dispensing the dental amalgam and its disposal in three dental teaching hospitals of Peshawar according to American Dental Association [ADA] Standard and International Standard Organization Standard [ISO]. A specially designed questionnaire was sent for this study. The results showed that none of the dental teaching hospital in Peshawar follows the ADA and ISO standard for the disposal and recycling the amalgam waste. Only 9% claimed using the chair side traps and install amalgam separator at chair side, 64% used the hand mixing alloy / mercury procedure. Number of amalgam fillings done and removed by three dental hospitals per month were 2027 and 267 respectively. It was concluded that total amalgam waste Was 3.204 kg in three dental hospitals in one year, and proper measures should be taken for the dispensing and disposal of amalgam

Particle size variations in the glass component of glass-ionomer dental cements

Glass polyalkenoate cements [glass ionomer cements] are widely used in restorative dentistry and now a day the material of choice for bone cements. The aim of the study is to examine the variations produced by exposure to acid for dental Glass Ionomer Cement [GIC] glass particles of different composition. It also involves the study of the effect of replacing Ca by Sr in glass ionomer glasses on the particle size distribution. This study was carried out in a Malvern Mastersizer/E. This uses LASER-diffraction and was in reverse-Fourier mode [0.1-80 micro m]. Ultrasound was used to break up any agglomerates. Also, some samples were treated as above but instead of particle size analyser, the slurries were centrifuged and the glass washed and dried to constant weight to determine mass loss. The mass loss for LG26Sr in acid washing was comparatively greater whereas LG26 showed less mass loss. When statistically evaluated LG series and AH2 were found to differ significantly p=0.008. There was, however, no significant difference between other combinations of glasses in acid was treatment. The pseudocement formation in all the glasses suffered significant mass loss p=<0.008. By changing the different chemical composition of glass ionomer glasses the mass loss was substantially greater during the cement formation process as compare to acid washing.

To investigate the in-vitro effect of areca nut aqueous extract on reconstituted human epithelium model

To investigate the in vitro effect of areca nut aqueous extract on reconstituted human epithelium model by assessing the morphology of the tissue on formalin fixed paraffin embedded section. Aqueous extract of areca nut, and Phosphate Buffered Saline [as control] was applied to the surface of the buccal epithelium and gingival epithelium. The morphology of the stratified oral epithelial model was examined at 24 and 48 hours by using formalin fixed paraffin embedded tissue. It was found that after 24 hours areca affected the morphology of the tissue by causing intercellular spacing and vacuolation. After 48 hours these changes were more marked and there was disorganization of prickle cell layer. This study has confirmed that aqueous extract of areca nut caused significant histological changes in the tissue examined.

Heavy metals accumulation in fruits and vegetables grown on sewage sludge and that of river water

In this study the crops cultivated on the application of sewage sludge were investigated. The crops grown included lady finger [okra], round gourd, smooth luffa, spinach, pumpkin, red pepper, green pepper and the fruits [pomegranate, mango, lemon, java plum, guava, banana, melon]. Results showed that sewage irrigation significantly increased total heavy metal contents in different organs [leaf, peel and pulp] of the crops in comparison to river water. The sewage water carried a very high load of Pb, Fe, Cu, Zn, Mg, Ca and other heavy elements. Maximum concentration in lady's fmger was for Mg followed by Zn, Cu, Ca, Fe, Pb and Co. There was significant increase in Mg concentration in leaf at 73.20 mg ke. Concentrations of Zn, Cu, Ca, Fe, Pb and Co were lower varying from 0.30 to 1.0 in leaf, 0.50 to 1.60 in peel and 0.70 to 1.70 in pulp. The accumulation of heavy metals by other vegetables was similar except spinach which showed high content of Fe at 39.0 mg kg-' in leaf. Plants fed on sewage water produced fruits showing heavy metals accumulation. It appeared that the metals accumulated and distributed between tissues in nearly the same proportion as in the vegetables. The river water fed vegetables and fruits, however, showed lesser accumulation of the heavy metals

Role of different ingredients of tooth pastes and mouthwashes in oral health

Many different kind of ingredients are incorporated in toothpastes and mouthwashes to keep the oral health in a perfect condition. We have different kinds of toothpastes and mouthwashes available in the market like anti-cavity, extra-whitening and toothpaste for sensitive teeth, toothpastes with stripes, clear and even liver flavored toothpaste for dogs. Modern type of toothpaste contains abrasives which help to scour off bacterial films and fluorides to harden the teeth against caries and have thickeners that stay on the toothbrush. The role of detergents is to remove the fatty films, and water softeners to make the detergents work better. The sweeteners play the role as a non-nutritive which may help stop the attraction of bacteria. Different kind of ingredients incorporate such as detergents and phosphates to prevent the awful taste. A variety of mouthwashes are available in the market according to the different oral conditions like antibacterial mouthwash, whiting mouthwash, fluoride mouthwash and bad breath mouthwash which have a strong enough flavor to hide the bad tastes of decaying bits of previous meals. Both mouthwashes and toothpastes contain active and inactive ingredients which have their own importance and will be recommended according to their different oral conditions

Effect of erythropoietin on cell lines using methyithiazol tetrazolium assay

To investigate the effect of erythropoietin on cellular proliferation in SCC-25, TR146 and FIBS cells lines. This observational study was carried out at Department of Oral Pathology Barts and the London Queen Mary School of Medicine and Dentistry Queen Mary, University of London in tye year 2004-2005. This study focuses on the effects of Erythropoietin on 3 cell lines [SCC-25, TR146 and FIBS] when applied for 24 hours respectively, Methylthiazol tetrazolium [MTT] assay was carried out using a range of erythropoietin concentrations [1, 10, 25 units]. Serum free medium was used as a control. In this study erythropoietir significantly increased the cell proliferation of SCC-25 and FIBS with 1 and 10 unit/ml but had no effect on TR146 cells, While 25 unit erythropoietin showed very little effect in increase cell viability in both SCC-25 and FIBS. This study has confirmed that all the concentration of erythropoietin used had effect on SCC-25 and FIBS cell viability but erythropoietin had no effect on TR146 cell viability

expression of erythropoietin and erythropoietin receptor in oral squamous cell carcinoma

The objective of this study is to analyse the in vitro expression of Erythropoietin and Erythropoietin Receptor in pathological biopsies of oral squamous cell carcinoma. The biopsy samples of oral squamous cell carcinoma provided by Barts and the London NHS trust hospital. The samples were taken from buccal mucosa, lip, lateral border of tongue, tonsilor region, oropharynx and nasal columnella. These samples were cut to form the formalin fixed, paraffin embedded tissue blocks, and immunohistochemistry was performed on each sample, which later on viewed under microscope. In this study erythropoietin staining was present in all the specimens of oral squamous cell carcinoma studied. Within the tumors Erythropoietin staining showed a differential pattern that was related to the differentiation of the tumour. In poorly differentiated tumours, erythropoietin was present in all the tumour cells spread throughout the tissue. In well differentiated tumours, erythropoietin staining was only present in the prickle cell layer. Erythropoietin receptor staining within the tumours showed a differential staining too. In the poorly differentiated tumours, erythropoietin receptor was only present in the muscle plus adjacent inflammatory cells and was absent in the tumour islands. In the well differentiated tumours some islands showed weak staining in the prickle cell layer, while the surrounding inflammatory infiltrate was positive. This study has confirmed that oral squamous cell carcinoma express both erythropoietin and erythropoietin receptor. Erythropoietin staining showed a differential pattern that was related to the differentiation of tumour. Erythropoietin receptor was expressed in salivary gland ducts and serous but not in mucous acini. These findings suggest that more studies are needed to explore the functional significance of erythropoietin and erythropoietin receptor in oral squamous cell carcinoma and in salivary glands

Variations in powder/liquid ratio of a restorative and luting glass lonomer cement in dental clinics

A survey was conducted to ascertain the variations practiced in powder/liquid [P/L] ratio of Glass lonomer Cement [GIC] used as restorative and luting material in dental clinics of Karachi. It has been observed that in the use of GIC brands, 33% [Fuji 2] and 36% [Gold Label 2] of the dentists, did not follow the recommended P/L ratios for restorative purposes. Similarly, 67% [Fuji 1] and 29% [Gold Label 1] did not follow the recommended ratios for luting purposes. The wide variations practiced in P/L mixing ratios against the recommended ratio for restorative purpose [[tilde]1:2] and that for luting purpose [[tilde]1:1 to 2:1] may affect the performance characteristics of the material

Prevalence of periodontal disease in Gadap region Karachi

Periodontal disease is the most common infectious disease affecting the supporting tissues of the teeth. If untreated it may result in tooth loss. The prevalence and severity is higher in low - income groups, probably because of the higher percentage of gingivitis and periodontitis. Oral health condition, especially periodontal disease is an excessive burden on the people of Pakistan. However oral diseases are preventable and an inadequate application of preventive measures and inappropriate oral health care delivery systems have resulted in ineffective control of these problems. This present study comprised of 536 patients both males and females belongings to Gadap region; were examined at Dept. of Periodontology, Baqai Dental College, Baqai Medical University, Karachi. A history form was filled by students of 3rd year of dentistry under supervision of a supervisor. An intra oral examination was done on each patient and the data was collected. High number of chronic gingivitis patients were observed in 10-30 years age group. The male to female ratio shows that male patients are the highest in all age group. The number of patients suffering from chronic gingivitis was 331, which was the highest among all disease group. Persistent presence of periodontal disease represents a risk factor for periodontal disease and may ultimately lead to tooth loss. Proper oral hygiene practices can prevent both gingivitis and advanced periodontal disease. All intervention programs leading to improve oral hygiene results in improvement in periodontal disease and will reduce the risk of future tooth loss

Folic acid and deficiency diseases

Folic acid is a water-soluble vitamin, which is involved in hematopoiesis and the synthesis of amino acids and DNA. It is widely used for the treatment of megaloblastic anemia. Tetrahydrofolic acid is the fully reduced form of folic acid and is the parent compound of a variety of coenzymes that serve as carriers of one-carbon groups in metabolic reactions. The daily use of supplemental folic acid periconceptionally significantly reduces the risk of neural tube defects. The genetic polymorphisms affecting the structure-function of folate-related enzymes have been associated with the increased risk of birth defects and chronic diseases including vascular diseases and different types of cancers. Therapeutic use of folic acid has been found to greatly reduce the prevalence of these diseases

Clinical analysis, metabolism and bioavailability of thiamine

Thiamine is a component of vitamin B-complex and is used in the treatment of beriberi. The active form of the vitamin is thiamine pyrophosphate [TPP] which serves as a co-enzyme in various biochemical reactions. It is commercially available in the form of vitamin B-complex and multivitamin preparations. The clinical analysis of the vitamin and its esters is carried out by spectrophotometric, fluorimetric, high performance liquid chromatographic and flow-injection turbidimetric methods. The rates of catabolism and loss of thiamine indicate that in the absence of the vitamin, functional and clinical abnormalities occur in humans within a few weeks period. Thiamine absorption takes place in the intestine by two parallel mechanisms, i.e., saturable active transport and simple diffusion. The bioavailability of thiamine can be assessed by determining maximal thiamine concentration [Cmax] and its time [tmax] in plasma and hemolysates, the area under concentration time curve [AUC], and thiamine excretion in 24-hr urine

Biochemical Importance, Deficiency and Clinical Assay of Cyanocobalamin

The present review describes the biochemical importance of cyanocobalamin [vitamin B12] and its role in the biosynthesis of adenosylcobamide and methylcobamide co-enzymes which perform important functions in human metabolism. Cyanocobalamin deficiency is a significant public health problem particularly among the elderly. It has been reported that the prevalence of vitamin B12 deficiency may be as high as 30-40% among the elderly due to food B12 malabsorption. Various analytical methods have been used for the clinical assay of cyanocobalamin in biological samples. These include microbiological, radioisotope, spectrophotometric and chromatographic methods

levels of cytokines - the effect of betel quid/areca nut on oral epithelium

The objectives of this study were to investigate the in vitro effect of betel quid and its components on a stratified epithelium and to evaluate whether there was evidence of a site specific response to their effect. The reconstituted human buccal epithelium model and human gingival epithelium model used in the study which was prepared and supplied by Skin ethic Laboratories, Nice, France. It is a three-dimensional tissue culture model obtained by culturing transformed oral keratinocytes [TR146] derived from a buccal carcinoma and oral keratinocytes derived from healthy gingival. 50 micro ml of freshly prepared aqueous extract of paan, areca, lime, areca/lime mixture, tobacco and PBS [as control] was applied to the surface of the epithelium and the tissue incubated for upto 48 hours at 37 [degree sign] C in 5%. CO[2] in a humidified atmosphere. The tissue was used to access the viability by MTT assay. The culture medium was also collected at 4 and 48 hours and used for the measurement of cytokines /chemokines release using ELISA technique. In this study application of paan and its components caused up-regulation of cytokines and chemokines. On the buccal epithelium model after 4 hours of treatment lime caused increased release of IL-1 alpha [26.9 +/- 14.3 pg/ml] compared to PBS Control [9.5 +/- 4.5 pg/ml], IL-6 [24.9 +/- 8.4 pg/ml] compared to PBS control [8.2 +/- 1.8 pg/ml], IL-8 [437.5 +/- 227.8 pg/ml] compared to PBS control [194 +/- 58.1pg/ml] and TGF-beta after 24 hours [71.3 +/- 10.8 pg/ml] compared to PBS control [49.3 +/- 2.7 pg/ml]. In gingival epithelial model only paan caused increased IL-8 release [305.5 +/- 221.1 pg/ml] compared to PBS control [48.3 +/- 19.4] after 48 hours of treatment. Areca caused increased of IL-1 alpha [81.2 +/- 11.3 pg/ml] compared to PBS control [11.2 +/- 5.9 pg/ml] after 48 hours of treatment, whereas paan caused increased release of IL-6 [16.3 +/- 4.3 pg/ml] compared to PBS control [8.2 +/- 1.7 pg/ml], IL-8 [2333.7 +/- 1252.3 pg/ml] compared to PBS control [294.8 +/- 126.5pg/ml] and TGF-beta [35.8 +/- 0.9, 41.4 +/- 1.4 pg/ml] compared to PBS control [62 +/- 4.2] after 48 hours of treatment. Areca inhibited the viability of buccal epithelial cells. This study has confirmed that lime, areca and paan caused significant changes in cytokine release, viability and histology of the tissue. The release of pro-inflammatory cytokines may suggest that in the initial event of OSF these cytokines can act as a constant source of irritation to underlying tissue. The increase in TGF-beta release suggests that it may act on the underlying fibroblasts and result in increased collagen synthesis, a feature of OSF

Spectroscopic techniques in the development of glass ionomer cements

Glass ionomer cement [GIC] is a relatively recent development in the field of restorative materials in dental treatment. The setting of GIC is a complex process based on acid-base reaction and may vary with the composition of the ionomer. Various spectroscopic techniques have been applied to understand the nature and duration of the [BC setting process. The techniques include ultraviolet [UV] and visible spectroscopy, infrared [IR] spectroscopy, Fourier-transform infrared [FT-IR] spectroscopy. nuclear magnetic resonance [NMR] spectroscopy, Fluorescence Spectroscopy, kaman spectroscopy, mass spectroscopy. atomic absorption spectroscopy as well as electron probe microanalysis [FYMA] and have been presented in this article

Development of glass-ionomer cements as dental restorative materials

Physico-chemical adhesion with tooth sabstance has necessitated the production of polyacrylic acid based cements such as glass-ionomer cements [GICs] as dental restorative material. These materials undergo specific adhesion with hydroxyapatite and have been proved to possess properties that are satisfactory for a variety of clinical applications. In order to improve toughness, speed of setting and ressitance to dehydration, hybird materials are incorporated in the formulations to achieve desired ambient polymerization. FTIR, IR and Raman spectroscopic techniques have been used for observing the physico-chemical changes involved in the setting process. Different glass ionomer cement formulations used for this purpose have been presented