Evaluation of Change in Surface Enamel Microhardness in Patients Undergoing Fixed Orthodontic Appliance Therapy - A Randomized Control Trial.

AIM: This study aims at determining the amount of enamel decalcification in terms of microhardness. MATERIALS AND METHODS: Twenty patients requiring treatment by extraction method for Class I malocclusion with bimaxillary protrusion were selected for the study. Twenty patients were randomly divided into control group and experimental group. In the control group (n = 40), extraction of permanent first premolars was done on day 1 of bonding to assess the Vickers hardness number (VHN) of enamel surface, and in the experimental group (n = 40), extraction of the contralateral premolars was done on the 28th day after bonding to assess the VHN of enamel surface. The values are tabulated and analyzed by SPSS software. RESULTS: There is significant surface enamel dissolution of enamel crystals in the experimental group compared to the control group, and a statistically significant difference in VHN is evident between the control and experimental groups. The surface enamel dissolution (VHN) is not significant difference noted between mandibular and maxillary premolars of the control and experimental groups. CONCLUSION: The present study has demonstrated a higher level of surface enamel dissolution in the experimental group. There is a marked difference in the VHN between the control and experimental groups, which is statistically significant. The scanning electron microscopy study also confirms the presence of surface enamel demineralization following orthodontic bonding.

Antimicrobial Effect of Leaves of Phyllanthus niruri and Solanum nigrum on Caries Causing Bacteria: An In vitro Study.

INTRODUCTION: Solanum nigrum and Phyllanthus niruri are common herbs which are indigeneous to India. Solanum nigrum commonly called 'manathakkali Keerai' in Tamil, forms an indispensable part of South Indian diet. Phyllanthus niruri (keezhanelli in Tamil) is a widely used medicinal plant, the leaves of which have been used extensively in Ayurveda and native medicine to cure various liver ailments. The herbs Solanumnigrum and Phyllanthus niruri have been found to be effective against numerous enteropathogens in various in vitro studies. AIM: To assess and compare the antibacterial efficacy of the crude alcoholic extract of the leaves of Solanum nigrum and Phyllanthus niruri against five cariogenic organisms. MATERIALS AND METHODS: Standard strains of the micro-organisms were obtained from ATCC (American Type Culture Collection) and MTCC (Microbial Type Culture Collection) which comprised of Streptococcus mutans MTCC no. 890, Streptococcus oralis MTCC no 2696, Lactobacillus acidophillus MTCC no. 10307, Streptococcus sanguis ATCC no. 10556 and Streptococcus salivarius ATCC no. 13419. The organisms obtained were revived and lawn cultured on Trypticase Soy Agar-Blood Agar (TSA-BA) and de Man, Rogosa and Sharpe (MRS) agar media. The antibacterial effect of the dried and powdered leaves of Solanum nigrum and Phyllanthus niruri was tested using agar well diffusion method. The zones of inhibition obtained after incubation were measured and tabulated. The antibacterial activity for the two herbs was compared using the Mann-Whitney test. RESULTS: The antibacterial zones of inhibition obtained for the herb Solanum nigrum was in the range of 12.3-14.6 mm and ranged from 9.7-11.6 mm for the herb Phyllanthus niruri. When the zones of inhibition were compared for the herbs, Solanum nigrum showed significantly greater zones of inhibition compared to Phyllanthus niruri for the organisms Streptococcussanguis, Streptococcus salivarius, Streptococcus oralis and Streptococcus mutans (p-value<0.05). CONCLUSION: The alcoholic extract of leaves of Solanum nigrum and Phyllanthus niruri showed significant antibacterial activity against cariogenic organisms, with Solanum nigrum being more anti-cariogenic than Phyllanthus niruri.

Simulation of laser backscattering system for imaging of inhomogeneity/tumor in biological tissues.

BACKGROUND AND OBJECTIVES: The optical characteristics of biological tissues vary in health and diseases. By analysis of photons scattering process by Monte Carlo simulation (MCS) the inhomogeneities in tissues are to be identified and their images reconstructed. METHODS: Digital phantoms with goat's heart as a control tissue embedded with inhomogeneities adipose (high scattering) and spleen (high absorption) are simulated. The phantoms considered are - (a) simulation of the developed stage of inhomogeneity by inclusion of adipose and spleen tissues in control and (b) its onset stage by increasing the optical parameters by 10% at fixed locations in control tissue. These phantoms are scanned by simulated system, consisting of nine ports for photon injection and backscattered photons from each port are received by three ports located at 2, 4 and 6mm from the injecting port, placed in the direction of x-axis. By the data collected from the entire surface, by processing, three grey-scale images are constructed. For localization of inhomogeneities these images are scanned in terms of normalized backscattered intensity (NBI). RESULTS: The images obtained by MCS with 1 million photons, with error minimized, at respective ports, show the presence of inhomogeneities at various depths, which is further supported by the increase or decrease in the NBI compared to that of control for adipose or spleen, respectively. The increase or decrease is more at first port compared to others. The inhomogeneities located at 2mm below the surface are better identified by the receiving port located at 2mm on the surface. The same applies to inhomogeneities located at 4 and 6mm, respectively. CONCLUSION: The present simulated system not only shows the presence of inhomogeneties at various depths in tissue phantom but also presents their characteristics.

Enzymatic antioxidants and its role in oral diseases.

Antioxidants are substances that when present at very low concentration inhibits the oxidation of a molecule. It has the capacity to nullify the ill effects of oxidation caused by free radicals in the living organisms. The unpaired electrons of these free radicals are highly reactive and neutralize the harmful reactions of human metabolism. Protection of the body against free radicals is provided by some enzymes which come under a distinctive group, concerned solely with the detoxification of these radicals. Superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase are the key enzymatic antioxidants of this defense system by which the free radicals that are produced during metabolic reactions are removed. This review highlights the mechanism of action of enzymatic antioxidants SOD, GPX and catalase and its role in oral disease.

Antimicrobial effect of herbal dentifrices: An in vitro study.

AIM: This study was taken up to compare the antimicrobial effect of few herbal dentifrices against cariogenic organism such as Streptococcus mutans and Lactobacillus acidophilus. MATERIALS AND METHODS: This study was an in vitro model using the well method of microbial culture. Colgate total was used as the positive control and distilled water as the negative control. Dentifrices were prepared in 1:1 dilution using sterile distilled water. The standard strains were inoculated and incubated for 4 h. They were then lawn cultured. Wells were made using a standard template, and the dentifrices were placed in these wells Kruskal-Wallis test and Mann-Whitney test were used for statistical analysis. RESULTS: In case of S. mutans, the maximum antimicrobial effect among the six dentifrices was shown by Babool followed by Colgate Herbal. For L. acidophilus, the antimicrobial zone exhibited by all the six dentifrices were similar to the positive control. CONCLUSIONS: Babool and Colgate Herbal have more inhibitory effect against S. mutans than the other dentifrices of the group. Dabur Red, Colgate Herbal, and Himalaya are efficient against L. acidophilus.

Reconstruction of optical scanned images of inhomogeneities in biological tissues by Monte Carlo simulation.

The optical imaging of inhomogeneities located in phantoms of biological tissues, prepared from goat's isolated heart as control tissue and embedded with spleen and adipose tissues representing tumors, by Monte Carlo simulation, is carried out. The proposed scanning probe consists of nine units. Each unit is equipped with one photon injection port and three ports arranged in a straight line to collect backscattered photons emerging from various depths, and one port, placed coaxially to the source on the opposite side of the phantom, to collect the transmitted component. At each position of the grid, superposed on the tissue phantom, photons are introduced through source port into the phantoms and backscattered and transmitted photons are collected by respective ports. Based on the data collected from the entire grid surface the respective gray-level images are reconstructed. The inhomogeneity located at certain depth (2, 4, 6mm) is visualized in three images formed by the backscattered data collected by three ports. Increase or decrease in normalized backscattered intensity (NBI) observed in their scans corresponds to that of high scattering (adipose) or absorbing (spleen) inhomogeneity compared to that of control tissue and also their location as determined by NBI variation as received at various ports. The images constructed from the transmitted data are associated with decrease in intensity. The scans of these images through their centers show that normalized transmitted intensity (NTI) attains its maximum value when the inhomogeneities are at depth 6mm. These scans are of higher amplitude for spleen compared to that of adipose tissues. Thus the data received by backscattering and transmission complement each other in identifying the location and type of inhomogeneities.

Prediction of anthropometric measurements from tooth length--A Dravidian study.

BACKGROUND: Anthropometric measurement is essential for identification of both victims and suspects. Often, this data is not readily available in a crime scene situation. The availability of one data set should help in predicting the other. This study was hypothesised on the basis of a correlation and geometry between the tooth length and various body measurements. AIM AND OBJECTIVE: To correlate face, palm, foot and stature measurements with tooth length. To derive a regression formula to estimate the various measurements from tooth length. MATERIALS AND METHODS: The present study was conducted on Dravidian dental students in the age group 18 - 25 with a sample size of 372. All of the dental and physical parameters were measured using standard anthropometric equipments and techniques. RESULTS: The data was analysed using SPSS software and the methods used for statistical analysis were linear regression analysis and Pearson correlation. The parameters (incisor height (IH), face height (FH), palm length (PL), foot length (FL) and stature (S) showed nil to mild correlation (R = 0.2 ≤ 0.4) except for palm length (PL) and foot length (FL). (R>0.6). CONCLUSION: It is concluded that odontometric data is not a reliable source for estimating the face height (FH), palm length (PL), foot length (FL) and stature (S).

Combined effect of lime (Citrus aurantitolia) and drying on reducing bacteria of public health significance in Edible Oyster (Crassostrea madrasensis).

Combined effect of lime and drying on bacteria of public health significance in Edible Oyster (Crassostrea madrasensis) from Munambam coastal belt (Kerala, India) were studied (without depuration). Samples were examined for Total Plate Count (TPC), Staphylococcus aureus (hygiene indicator), Total coliforms, Faecal coliforms, Escherichia coli, (faecal indicator) Faecal Streptococci (faecal indicator), Salmonella, Vibrio cholera and Listeria monocytogenes. The fresh oyster meat though did not confirm to the specifications laid by National shellfish sanitation programme (NSSP), after treatment with lime with and without drying found to show significant reduction in counts and meet the required standards. Prevalence of faecal indicators in the fresh sample indicated faecal pollution in the area. The isolation of potentially pathogenic bacteria, V. parahaemolyticus in fresh sample indicates high risk of people consuming and handling oysters in raw and semi processed form and also it may lead to cross contamination. The present study indicates that treatment with natural organic product like lime and simple preservation technique, drying can effectively reduce the bacterial load. The study also revealed that TPC of water and soil collected from the site from where oysters were collected was less than from the meat.

Optical parameters of embedded abnormalities in tissues as determined by Monte Carlo simulation.

Photon propagation through tissue phantoms, made of heart, adipose, and spleen tissues was simulated by Monte Carlo procedure. To detect the presence of deep-seated abnormalities, phantoms of heart with adipose and spleen tissues embedded into it were created and simulations were performed to scan the tissue surface with a source and four detector model. Profiles drawn showed variation in parameters such as backscattered intensity in regions where adipose and spleen tissues were embedded. This study shows that depending on the type of embedded tissue the backscattered fraction as measured at 2 mm from the input fiber is altered. This is enhanced for adipose and decreased for spleen tissue. This is not only shown in scanned profiles on the surface but also in constructed images.

Digital analysis of changes by Plasmodium vivax malaria in erythrocytes.

Blood samples of malaria patients (n = 30), selected based on the severity of parasitemia, were divided into low (LP), medium (MP) and high (HP) parasitemia, which represent increasing levels of the disease severity. Healthy subjects (n = 10) without any history of disease were selected as a control group. By processing of erythrocytes images their contours were obtained and from these the shape parameters area, perimeter and form factor were obtained. The gray level intensity was determined by scanning of erythrocyte along its largest diameter. A comparison of these with that of normal cells showed a significant change in shape parameters. The gray level intensity decreases with the increase of severity of the disease. The changes in shape parameters directly and gray level intensity variation inversely are correlated with the increase in parasite density due to the disease.

Hapten inhibitors of the endogenous galactose binding lectins and anti-lectin antibodies inhibit primitive streak formation in the early chick embryo.

The early chick blastoderm expresses two endogenous galactose-binding lectins of 14 kDa and 16 kDa. We have studied the effect the lectin hapten inhibitors thiodigalactoside and the synthetic neoglycoprotein lactosyl-bovine serum albumin as well as polyclonal anti-lectin antibodies on the development of early chick embryos cultured in a defined medium. Controls consisted of maltose, maltosyl bovine serum albumin and rabbit IgG. Embryos treated at the onset of cell migration during early gastrulation underwent blastoderm retraction with decrease in surface area. In addition, they exhibited a lack of demarcation between the presumptive embryonic area (area pellucida) and the presumptive extraembryonic area (area opaca). These blastoderms also lacked a primitive streak, that is, the structure that forms in the area pellucida during gastrulation as cell migrate to form the endodermal and mesodermal layers of the embryo. Embryos treated at later stages of gastrulation showed development similar to that of controls in that they were able to undergo early organogenesis. The results suggest that lectin mediated mechanisms are essential for the migratory movements of early gastrulation and that, at late gastrulation, other mechanisms exist in the embryo to compensate for lectin function.