Comparative evaluation of demineralization of radicular dentin with 17% ethylenediaminetetraacetic acid, 10% citric acid, and MTAD at different time intervals: An in vitro study.

BACKGROUND: The smear layer has the capability to protect the bacteria within the dentinal tubules from intracanal medicament. After removal of the smear layer from infected root canals, it allows disinfection of the entire root canal. The smear layer compromising the seal between the root canal sealer and root canal wall also decreases the penetration of irrigants into dentinal tubules. AIMS: This study compares the amount of phosphorous liberated and demineralization of the radicular dentin with 17% ethylenediaminetetraacetic acid, 10% citric acid and mixture of doxycycline, citric acid, and a detergent at different time intervals. MATERIALS AND METHODS: Extracted maxillary single-rooted teeth were prepared by using a combination of passive step-back and rotary 0.04 taper nickel-titanium files. Sodium hypochlorite 5.25% and sterile distilled water were used as an intracanal irrigant. The canals were then treated with 5 mL of one of the following solutions such as final rinse sterile distilled water, 5.25% sodium hypochlorite, 17% ethylenediaminetetraacetic acid (EDTA) or mixture of doxycycline, citric acid, and a detergent. The presence or absence of smear layer and the amount of erosion on the surface of the root canal walls at the coronal, middle, and apical portions of each canal were examined under a scanning electron microscope. STATISTICAL ANALYSIS: Data were analyzed by one-way analysis of variance (ANOVA) to determine whether there were significant differences between the groups. RESULTS: The results show that mixture of doxycycline, citric acid, and a detergent is an effective solution for the removal of the smear layer and does not significantly change the structure of the dentinal tubules. CONCLUSIONS: In this study, 10% citric acid shows the maximum amount of dimeneralization of radicular dentine followed by mixture of doxycycline, citric acid, and a detergent, and 17% ethylenediaminetetraacetic acid. When all the subgroups were compared, it was seen that the maximum amount of phosphorus liberation was performed by 10% citric acid >mixture of doxycycline, citric acid, and a detergent >17% EDTA at a different time interval.

Spectroscopic, Thermal, and Antimicrobial Studies of Co(II), Ni(II), Cu(II), and Zn(II) Complexes Derived from Bidentate Ligands Containing N and S Donor Atoms.

Two new heterocyclic Schiff bases of 4-amino-5-mercapto-3-H/propyl-1,2,4-triazole and 5-nitrofurfuraldehyde [HL(1-2)] and their cobalt, nickel, copper, and zinc complexes have been synthesized and characterized by elemental analyses, spectral (UV-Vis, IR, (1)H NMR, Fluorescence, and ESR) studies, thermal techniques, and magnetic moment measurements. The heterocyclic Schiff bases act as bidentate ligands and coordinate with metal ions through nitrogen and sulphur of the thiol group. The low molar conductance values in DMF indicate that the metal complexes are nonelectrolytes. The magnetic moments and electronic spectral data suggest octahedral geometry for the Co(II), Ni(II), and Zn(II) complexes and square planar for Cu(II) complexes. Two Gram-positive bacteria (Staphylococcus aureus MTCC 96 and Bacillus subtilis MTCC 121), two Gram-negative bacteria (Escherichia coli MTCC 1652 and Pseudomonas aeruginosa MTCC 741), and one yeast, Candida albicans, were used for the evaluation of antimicrobial activity of the newly synthesized compounds.

Cobalt, nickel, copper and zinc complexes with 1,3-diphenyl-1H-pyrazole-4-carboxaldehyde Schiff bases: antimicrobial, spectroscopic, thermal and fluorescence studies.

Two new Schiff bases of 1,3-diphenyl-1H-pyrazole-4-carboxaldehyde and 4-amino-5-mercapto-3-methyl/H-1,2,4-triazole [HL(1-2)] and their Cobalt, Nickel, Copper and Zinc complexes have been synthesized and characterized by elemental analyses, spectral (UV-vis, IR, (1)H NMR, Fluorescence) studies, thermal techniques and magnetic measurements. A square planar geometry for Cu(II) and octahedral geometry for Co(II), Ni(II) and Zn(II) complexes have been proposed. In order to evaluate the biological activity of Schiff bases and to assess the role of metal ion on biological activity, the pyrazole Schiff bases and their metal complexes have been studied in vitro antibacterial against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and antifungal against Aspergillus niger, and Aspergillus flavus. In most of the cases higher activity was exhibited upon coordination with metal ions.

Biological and Spectral Studies of Newly Synthesized Triazole Schiff Bases and Their Si(IV), Sn(IV) Complexes.

The Schiff bases HL(1-3) have been prepared by the reaction of 5-bromothiophene-2-carboxaldehyde with 4-amino-5-mercapto-3-methyl/propyl/isopropyl-s-triazole, respectively. Organosilicon(IV) and organotin(IV) complexes of formulae (CH(3))(2)MCl(L(1-3)), (CH(3))(2)M(L(1-3))(2) were synthesized from the reaction of (CH(3))(2)MCl(2) and the Schiff bases in 1 : 1 and 1 : 2 molar ratio, where M = Si and Sn. The synthesized Schiff bases and their metal complexes have been characterized with the aid of various physicochemical techniques like elemental analyses, molar conductance, UV, IR, (1)H, (13)C, (29)Si, and (119)Sn NMR spectroscopy. Based on these studies, the trigonal bipyramidal and octahedral geometries have been proposed for these complexes. The ligands and their metal complexes have been screened in vitro against some bacteria and fungi.

Metal-based biologically active compounds: synthesis, spectral, and antimicrobial studies of cobalt, nickel, copper, and zinc complexes of triazole-derived schiff bases.

A series of cobalt, nickel, copper, and zinc complexes of bidentate Schiff bases derived from the condensation reaction of 4-amino-5-mercapto-3-methyl/ethyl-1,2,4-triazole with 2,4-dichlorobenzaldehyde were synthesized and tested as antimicrobial agents. The synthesized Schiff bases and their metal complexes were characterized with the aid of elemental analyses, magnetic moment measurements, spectroscopic and thermogravimetric techniques. The presence of coordinated water in metal complexes was supported by infrared and thermal gravimetric studies. A square planar geometry was suggested for Cu(II) and octahedral geometry proposed for Co(II), Ni(II), and Zn(II) complexes. The Schiff bases and their metal complexes have been screened for antibacterial (Pseudomonas aeruginosa, Bacillus subtilis) and antifungal activities (Aspergillus niger, A. flavus). The metal complexes exhibited significantly enhanced antibacterial and antifungal activity as compared to their simple Schiff bases.