Synthesis, Characterization and Biocidal Activities of Some Schiff Base Metal Complexes

Some new mixed ligand complexes (1-5) of type ML''B (M(II)=Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); HL''= o-vanillidene-2-aminobenzothiazole; B= 1,10-phenanthroline) and Schiff base metal complexes of types (ML₂") (6-10) and (M₂L") (11-15) (HL"= o-vanillidene-2-amino-N-(2-pyridyl)-benzene sulfonamide) were synthesized and characterized by elemental analysis and spectral (IR, ¹H NMR and ¹³C NMR) studies. The free ligands and their metal complexes have been screened for their in vitro biological activities against bacteria, fungi and yeast. The metal complexes show more potent activities compared with Schiff base ligands.     

Back-scattered and secondary electron images of scanning electron microscopy in dentistry: a new method for surface analysis

Abstract Objective. A scanning electron microscope (SEM) is a popular tool for investigating the root canal surface to visualize dentinal tubules, the smear layer and various root canal filling materials in endodontics. Most of the SEM micrographs taken in endodontic research are in secondary electrons (SE) mode, in which the topographic view of a subject can be demonstrated without giving any information about the real structure. Back-scattered electron (BSE) images are also used, which reveal some information about the internal structure while providing no topographic details. The aim of this study was to investigate the possibility of using back-scattered (BSE) and secondary electron (SE) mode of scanning electron microscopy (SEM) together for obtaining detailed information about biomaterials in relation to dental structures. Materials and methods. Mesiobuccal roots of four permanent maxillary molars were cleaned and shaped with rotary instruments. Two samples were obturated with gutta-percha and sealer. After 2 weeks, gutta-perch was removed using rotary instruments and chloroform. In the other phase of the study, white mineral trioxide aggregate was mixed and packed into five glass tubes and exposed to blood, deionized water, synthetic tissue fluid and egg white. All the samples were prepared for visualization under SE and BSE modes of SEM to observe the characteristics of material remnants and surface structures. Results. BSE mode illustrated different grey scale views which made it possible to differentiate dentin chips from filling material remnants on the surface of root canal dentin. In addition, SE mode focused on image topography, while a BSE detector showed new texture formation on the surface of white mineral trioxide aggregate exposed to proteinaceous fluids such as blood or egg white. Conclusions. Mapping BSE and SE micrographs helped us to better understand the structure of materials on the surface of root canal dentin and MTA. Moreover, analysis of structure of materials on the surface of root canal dentine and MTA can be performed better by mapping of BSE and SE micrographs.     

Role of Arthrocentesis in the Management of Acute Closed Lock of TM Joint: A Pilot study

The following study was conducted in Meenakshi Ammal Dental College on 32 patients. The objective of our study was to assess the efficacy of arthrocentesis for the management of acute closed lock of TMJ. All patients presented with a history of sudden and persistent difficulty in mouth opening and associated TMJ pain. A total of 27 female and 5 male patients were treated using arthrocentesis and lavage under local anesthesia. Patients were assessed for pain and jaw function using visual analogue scales, VAS I (Fig. 4b), VAS II (Fig. 4c), respectively and mouth opening MMO (Fig. 4a) for a period of 6 months. Our results showed satisfactory relief in pain and improved mouth opening in 30 patients. The results proved that arthrocentesis is a very useful technique for treatment of acute closed lock of TMJ. However to arrive at a definitive conclusion a long term evaluation is required.Open in a separate windowFig. 4a Maximum mandibular opening. b Pain. c Jaw function     

Accuracy of a Mitral Valve Segmentation Method Using J-Splines for Real-Time 3D Echocardiography Data

Patient-specific models of the heart’s mitral valve (MV) exhibit potential for surgical planning. While advances in 3D echocardiography (3DE) have provided adequate resolution to extract MV leaflet geometry, no study has quantitatively assessed the accuracy of their modeled leaflets vs. a ground-truth standard for temporal frames beyond systolic closure or for differing valvular dysfunctions. The accuracy of a 3DE-based segmentation methodology based on J-splines was assessed for porcine MVs with known 4D leaflet coordinates within a pulsatile simulator during closure, peak closure, and opening for a control, prolapsed, and billowing MV model. For all time points, the mean distance error between the segmented models and ground-truth data were 0.40 ± 0.32 mm, 0.52 ± 0.51 mm, and 0.74 ± 0.69 mm for the control, flail, and billowing models. For all models and temporal frames, 95% of the distance errors were below 1.64 mm. When applied to a patient data set, segmentation was able to confirm a regurgitant orifice and post-operative improvements in coaptation. This study provides an experimental platform for assessing the accuracy of an MV segmentation methodology at phases beyond systolic closure and for differing MV dysfunctions. Results demonstrate the accuracy of a MV segmentation methodology for the development of future surgical planning tools.     

In Vitro Characterization of Bicuspid Aortic Valve Hemodynamics Using Particle Image Velocimetry

The congenital bicuspid aortic valve (BAV) is associated with increased leaflet calcification, ascending aortic dilatation, aortic stenosis (AS) and regurgitation (AR). Although underlying genetic factors have been primarily implicated for these complications, the altered mechanical environment of BAVs could potentially accelerate these pathologies. The objective of the current study is to characterize BAV hemodynamics in an in vitro system. Two BAV models of varying stenosis and jet eccentricity and a trileaflet AV (TAV) were constructed from excised porcine AVs. Particle Image Velocimetry (PIV) experiments were conducted at physiological flow and pressure conditions to characterize fluid velocity fields in the aorta and sinus regions, and ensemble averaged Reynolds shear stress and 2D turbulent kinetic energy were calculated for all models. The dynamics of the BAV and TAV models matched the characteristics of these valves which are observed clinically. The eccentric and stenotic BAV showed the strongest systolic jet (V = 4.2 m/s), which impinged on the aortic wall on the non-fused leaflet side, causing a strong vortex in the non-fused leaflet sinus. The magnitudes of TKE and Reynolds stresses in both BAV models were almost twice as large as comparable values for TAV, and these maximum values were primarily concentrated around the central jet through the valve orifice. The in vitro model described here enables detailed characterization of BAV flow characteristics, which is currently challenging in clinical practice. This model can prove to be useful in studying the effects of altered BAV geometry on fluid dynamics in the valve and ascending aorta. These altered flows can be potentially linked to increased calcific responses from the valve endothelium in stenotic and eccentric BAVs, independent of concomitant genetic factors.     

Bacteriology of deep carious lesions underneath amalgam restorations with different pulp-capping materials--an in vivo analysis

Microorganisms remaining in dentin following cavity preparation may induce pulp damage, requiring the use of pulp-capping agents with antimicrobial activity underneath permanent restorations.

Objective

The aims of this study were to analyze the bacteriological status of carious dentin and to assess the efficacy of different base underneath silver amalgam restorations.

Material and Methods

This study was conducted on 50 patients aged 13 to 30 years. Sterile swabs were used to take samples after cavity preparation, which was assessed by microbiological culture to identify the microorganisms present. Following this, cavities were restored with silver amalgam, using one of the materials being investigated, as the base: calcium hydroxide (Group II), polyantibiotic paste (Group III), a novel light-cured fluoride-releasing hydroxyapatite-based liner (Group IV) and mineral trioxide aggregate - MTA (Group V). In Group I, the cavities were restored with silver amalgam, without any base. After 3 months, the amalgam was removed and samples taken again and analyzed for the microbial flora.

Results

Lactobacilli were the most commonly isolated microorganisms in the samples of carious dentin. Groups IV and V showed negative culture in the 3-month samples. There was no statistically significant difference between Groups I, II and III. There was no significant difference between Groups IV and V (p>0.05). Both Groups IV and V showed significantly better results when compared to Groups I, II and III (p<0.05).

Conclusions

The hydroxyapatite-based liner and MTA performed significantly better in terms of antibacterial activity than the other materials.