Characterization of dentine to assess bond strength of dental composites

This study was performed to develop alternating dentine adhesion models that could help in the evaluation of a self-bonding dental composite. For this purpose dentine from human and ivory was characterized chemically and microscopically before and after acid etching using Raman and SEM. Mechanical properties of dentine were determined using 3 point bend test. Composite bonding to dentine, with and without use of acid pre-treatment and/or the adhesive, were assessed using a shear bond test. Furthermore, micro gap formation after restoration of 3 mm diameter cavities in dentine was assessed by SEM. Initial hydroxyapatite level in ivory was half that in human dentine. Surface hydroxyapatites decreased by approximately half with every 23 s of acid etch. The human dentine strength (56 MPa) was approximately double that of ivory, while the modulus was almost comparable to that of ivory. With adhesive use, average shear bond strengths were 30 and 26 MPa with and without acid etching. With no adhesive, average bond strength was 6 MPa for conventional composites. This, however, increased to 14 MPa with a commercial flowable "self-bonding" composite or upon addition of low levels of an acidic monomer to the experimental composite. The acidic monomer additionally reduced micro-gap formation with the experimental composite. Improved bonding and mechanical properties should reduce composite failures due to recurrent caries or fracture respectively

Development of Antibacterial-releasing Dental Composites with High Strength and Dentine Bonding

The thesis aim is to develop a dental composite with (1) high conversion/ depth of cure to provide good strength, (2) water sorption to compensate shrinkage and promote antibacterial release, and (3) added re-mineralising components and acidic monomers to enhance bonding. Conversion/ shrinkage, depth of cure, water sorption, and antibacterial (polylysine & chlorhexidine) release into distilled water versus simulated body fluid were assessed using FTIR, ISO 4049 (scraping test), gravimetrical studies, and UV spectroscopy respectively. Flexural strength/ modulus was assessed up to 6 months of water storage. Similarly bonding to moist ivory and human dentine was assessed via a push out and shear bond test. Factorial analysis was used to analyze the data. The results showed that a major factor affecting the conversion, and shrinkage was sample thickness. Similarly a major factor affecting the depth of cure was duration of light cure. In water sorption studies the major factors enhancing water sorption were use of distilled water, and polylysine. The chlorhexidine release was enhanced by the use of distilled water, while a higher polylysine release percentage was seen with lower levels of drug in the filler phase. The strength and modulus were decreased with the addition of reactive fillers. Lastly, adhesion was improved with the use of adhesive, and acidic monomers. The materials produced could potentially reduce bacterial micro leakage, which is the most common reason for failure

Management and Complications of Arnold Chiari Hydrocephalus at Tertiary Health Care Center

Objective: to investigate the role of CT and MRI in diagnosis of Arnold chiari malformation of hydrocephalus and its treatment with VP shunt along with complications. Study Design: Prospective study Place and duration: Department of Neurosurgery, DG Khan Medical College from May 4, 2018 to May 4, 2019. Methodology: Fifty patients of congenital hydrocephalus who were not treated previously were selected. Detailed history about disease and clinical examination of patients was performed. Follow ups were done at neurosurgery OPD. SPSS software for data analysis was used and mean ± SD, frequency and percentages were calculated for variables. P value ≤0.05 was considered as significant. Results: Treatment in case of congenital hydrocephalus as VP shunt, intra-aneurysmal coiling, excision of meningomyelocele with VP shunt and suboccipital craniectomy + upper cervical laminectomy (scucl) were observed as 10%, 6%, 8% and 8% respectively.  Twelve percent of patients were not treated. Conclusion: CT and MRI are the main diagnostic tools for diagnosis of Arnold chiari malformation and VP shunt is the treatment of choice. Among complications of VP shunt infection of shunt and shunt block are the main complications

Extraction of Cerium (IV) Using Di–n-butylsulfoxide in Chloroform from Nitric Acid and Determination with Arsenazo (III) as Chromogenic Reagent

A new and advantageous extraction procedure was developed for extraction of cerium (IV) from nitric acid with di-n-butylsulfoxide (DBSO) in perchloric acid. The extracted Ce (IV) was determined spectrophotometrically using 0.01 % solution of arsenazo-III in 3Mper-chloric acid. Various parameters such as equilibration time, metal ion concentration, effect of temperature and diverse ions on the extraction of the Ce (IV) were established. U (VI), Th (IV) and Pb (II) interfere whereas only phosphate and fluoride suppress the extraction among anions. The stoichiometric composition of the cerium complex withDBSO was determined by slope analysis and found to be 1:4. The process of extraction was found to be exothermic. Deionized water was the most appropriate solvent for back extraction of cerium. This method is easier and more sensitive than many of the reported procedures.KEYWORDS Cerium, extraction, DBSO, perchloric acid, arsenazo-II

Detection & Distinction of Colors using Color Sorting Robotic Arm in a Pick & Place Mechanism

Color sorting Robot is one of the useful, costless and fastest systems in Industrial applications to reduce manual working time and provides less human mistake when manual system is undertaken. The objective of this project is to design an efficient, microcontroller based system that pick up right color of objects and put it down at right place to optimize the productivity, minimizing the cost of the products and decreasing human mistakes. The controller used is a PIC Microcontroller (18F452) having high speed performance, low cost and 32 K bytes program memory. It communicates with color sensor TCS 3200 and various motor modules in real time to detect the right color object and to control the arm movement. Designed system can pick objects of 1kG weight and arm can rotate up to 3600 . Also, the use of easily available components reduces the manufacturing and maintenance costs. The design is quite flexible as the software can be changed according to specific requirements of the user. This makes the proposed system to be an economical, portable and a low maintenance solution for industrial applications

Sonographic Association of Cholelithiasis with Obstructive Jaundice in Adult Patients

Background: Cholelithiasis is the commonest cause of obstructive jaundice and for the investigation of cholelithiasis and obstructive jaundice ultrasound is a gold standard modality. Obstructive jaundice is generally due to biliary obstruction, which is a blockage of the common bile duct or any duct that carries bile from the liver to the gallbladder and then enters into the small intestine. Objective: To determine sonographic association of cholelithiasis with obstructive jaundice in adult patients. Methodology: A cross sectional study was conducted among 138 individuals. All were young adults within the age range of 18-35 years. Data was collected from Civil Hospital Gujranwala city, by using simple random sampling technique. The examination was done with Toshiba Xario 3.5-5MHz curvilinear transducer. Gallbladder scan was started with the patient in the supine position from both subcostal and intercostal approaches. It was analyzed through SPSS version 24.0 and presented through frequency and percentages. Results: Total 138 individuals were included in this study. Out of 138 subjects, 69 individuals with cholelithiasis out of 69, 24 individuals with obstructive jaundice. And other 69 individuals without cholelithiasis in which 26 subjects presented with jaundice. It was found that females (51.4%) were more commonly affected than males (48.6%).Conclusion: It was concluded that cholelithiasis is one of the main causes of obstructive jaundice and ultrasound can easily diagnose the cases of cholelithiasis. It was found that females were more commonly affected than males. Keywords: cholelithiasis, obstructive jaundice, jaundice, ultrasound. DOI: 10.7176/JHMN/72-04 Publication date:March 31st 202

Dental Composites with Calcium / Strontium Phosphates and Polylysine

PURPOSE: This study developed light cured dental composites with added monocalcium phosphate monohydrate (MCPM), tristrontium phosphate (TSrP) and antimicrobial polylysine (PLS). The aim was to produce composites that have enhanced water sorption induced expansion, can promote apatite precipitation and release polylysine. MATERIALS AND METHODS: Experimental composite formulations consisted of light activated dimethacrylate monomers combined with 80 wt% powder. The powder phase contained a dental glass with and without PLS (2.5 wt%) and/or reactive phosphate fillers (15 wt% TSrP and 10 wt% MCPM). The commercial composite, Z250, was used as a control. Monomer conversion and calculated polymerization shrinkage were assessed using FTIR. Subsequent mass or volume changes in water versus simulated body fluid (SBF) were quantified using gravimetric studies. These were used, along with Raman and SEM, to assess apatite precipitation on the composite surface. PLS release was determined using UV spectroscopy. Furthermore, biaxial flexural strengths after 24 hours of SBF immersion were obtained. RESULTS: Monomer conversion of the composites decreased upon the addition of phosphate fillers (from 76 to 64%) but was always higher than that of Z250 (54%). Phosphate addition increased water sorption induced expansion from 2 to 4% helping to balance the calculated polymerization shrinkage of ~ 3.4%. Phosphate addition promoted apatite precipitation from SBF. Polylysine increased the apatite layer thickness from ~ 10 to 20 μm after 4 weeks. The novel composites showed a burst release of PLS (3.7%) followed by diffusion-controlled release irrespective of phosphate addition. PLS and phosphates decreased strength from 154 MPa on average by 17% and 18%, respectively. All formulations, however, had greater strength than the ISO 4049 requirement of > 80 MPa. CONCLUSION: The addition of MCPM with TSrP promoted hygroscopic expansion, and apatite formation. These properties are expected to help compensate polymerization shrinkage and help remineralize demineralized dentin. Polylysine can be released from the composites at early time. This may kill residual bacteria

Synthesis, structural and photo-physical studies of transition metal complexes with Mannich bases derived from 2-mercaptobenzimidazole

Two Mannich base ligands, [1-(di-n-butylamine-N-methyl)mercapto-1H-benz-imidazole] (L1) and [1-(diphenylamine-N-methyl)mercapto-1H-benzimidazole] (L2)have been synthesized and further reacted with Co(II), Ni(II), Cu(II) and Zn(II) ionsto afford their respective complexes. The progress of the reaction was monitored by thin layer chromatography. The structural elucidation of Mannich base ligands and their metal complexes was done by Fourier Transform Infrared (FTIR), UV-Visible, Nuclear Magnetic Resonance spectroscopy (1H NMR & 13C NMR) and Atomic absorption spectroscopy (AAS) / Inductively coupled plasma emission spectroscopy (ICPES). FTIR and NMR studies supported the monoanionic bidentate coordination mode of L1 and L2 while tetrahedral geometries of metal complexes were proposed on the basis of AAS/ICP, magnetic moment and electronic spectroscopic data. The synthesized compounds were also investigated for their luminescent behavior which exhibited broad emission bands indicating charge transfer nature of the involved transitions.               KEY WORDS: Metal complexes, Mannich bases, 2-Mercaptobenzimidazole, Luminescence Bull. Chem. Soc. Ethiop. 2018, 32(3), 481-490.DOI: https://dx.doi.org/10.4314/bcse.v32i3.

Antibacterial activity studies of Co(II), Ni(II), Cu(II) and Zn(II) complexes with Mannich base ligand

ABSTRACT. A Mannich base ligand (L) was prepared by reacting 2-mercaptobenzimidazole, diphenylamine and benzaldehyde. This ligand (L) was further used for the preparation of four metal complexes with Co(II), Ni(II), Cu(II) and Zn(II) ions. The reactions were monitored by TLC. The synthesized compounds were structurally characterized using FTIR spectroscopy, UV-Visible spectroscopy, 1H- and 13C-NMR spectroscopy, ICP-OES/atomic absorption spectroscopy. It has been observed that the ligand (L) behaved in a monoanionic bidentate mode and the geometry of resulting complexes was tetrahedral. Conductivity analysis revealed their non-electrolytic nature. Antibacterial activity of the synthesized compounds was assessed through an agar well diffusion method against four strains of Gram-negative bacteria. L-Zn(II) complex showed best activity at all four concentrations against the four strains of Gram-negative bacteria.               KEY WORDS: Metal complexes, Mannich bases, 2-Mercaptobenzimidazole, Antibacterial activity Bull. Chem. Soc. Ethiop. 2019, 33(3), 485-492.DOI: https://dx.doi.org/10.4314/bcse.v33i3.