A 24-month retrospective study of preformed metal crowns: the Hall technique versus the conventional preparation method.

PURPOSE: Conventional and Hall Technique (HT) Preformed Metal Crowns (PMCs) are used for treatment of carious primary molars. The aim was to evaluate the clinical and radiographic success of conventional and HT PMCs in a postgraduate dental setting. METHODS: A retrospective study using patients' electronic case-notes and radiographic images of carious primary molars treated with either conventional or HT PMCs was conducted to assess clinical and radiographic success/failure. A Kaplan-Meier curve was used to assess PMC survival. RESULTS: 187 PMCs (110 HT and 77 conventional) in 65 children (34 females and 31 males) at 6, 12, 18 and 24 months were assessed. At 24 months, the success rates of conventional and HT PMCs were 97.6% and 93.5%, respectively. Two HT (perforated/abscessed) and four conventional (abscessed) PMCs failures occurred. There was no significant difference in success/failure (p = 0.362) at 12 months, but the HT was more successful at 24 months (p = 0.002) with similar survival times for both methods. CONCLUSION: HT and conventionally placed PMCs, when placed in a postgraduate paediatric dentistry setting, were clinically and radiographically very successful at 6, 12, 18 and 24 months post operatively with a slightly higher success of the HT at 24 months.

Oral health status of pre-school children of incarcerated mothers in United Arab Emirates prison nurseries and oral health knowledge and attitudes of their caregivers.

AIM: To evaluate the oral-health of preschool-children of incarcerated-mothers at nine United Arab Emirates (UAE) prison-nurseries and assess the oral-health knowledge and attitudes of the prison nurseries' caregivers. STUDY DESIGN: Cross sectional comparative study. METHODS: A total of 128 and 254 preschool children formed the study and control groups respectively. All were examined clinically for dental caries using the dmft score and oral health and hygiene status indices. Knowledge and attitudes of all caregivers (n = 45) at prison nurseries were assessed using an interview questionnaire. RESULTS: The prevalence of caries was not significantly different between the two groups with 89.9% [mean-dmft 4.97 (± 3.61)] in the study group and 92.1% [mean-dmft 4.48 (± 3.60)] in the controls. Oral-hygiene in the control group was better with 18.2% having good oral-hygiene compared to 6.2% in the study-group. Oral-health knowledge and attitude of the caregivers of prison nurseries were not satisfactory. CONCLUSIONS: Despite the non-significant difference in the caries prevalence between the study and control groups, oral hygiene and care level of vulnerable-children of incarcerated-mothers were significantly poorer. Prisons' caregivers had poor knowledge and attitude of dental health matters.

In-Doped ZnO Hexagonal Stepped Nanorods and Nanodisks as Potential Scaffold for Highly-Sensitive Phenyl Hydrazine Chemical Sensors.

Herein, we report the growth of In-doped ZnO (IZO) nanomaterials, i.e., stepped hexagonal nanorods and nanodisks by the thermal evaporation process using metallic zinc and indium powders in the presence of oxygen. The as-grown IZO nanomaterials were investigated by several techniques in order to examine their morphological, structural, compositional and optical properties. The detailed investigations confirmed that the grown nanomaterials, i.e., nanorods and nanodisks possess well-crystallinity with wurtzite hexagonal phase and grown in high density. The room-temperature PL spectra exhibited a suppressed UV emissions with strong green emissions for both In-doped ZnO nanomaterials, i.e., nanorods and nanodisks. From an application point of view, the grown IZO nanomaterials were used as a potential scaffold to fabricate sensitive phenyl hydrazine chemical sensors based on the I-V technique. The observed sensitivities of the fabricated sensors based on IZO nanorods and nanodisks were 70.43 µA·mM-1 cm-2 and 130.18 µA·mM-1 cm-2, respectively. For both the fabricated sensors, the experimental detection limit was 0.5 µM, while the linear range was 0.5 µM-5.0 mM. The observed results revealed that the simply grown IZO nanomaterials could efficiently be used to fabricate highly sensitive chemical sensors.

A Highly-Sensitive Picric Acid Chemical Sensor Based on ZnO Nanopeanuts.

Herein, we report a facile synthesis, characterization, and electrochemical sensing application of ZnO nanopeanuts synthesized by a simple aqueous solution process and characterized by various techniques in order to confirm the compositional, morphological, structural, crystalline phase, and optical properties of the synthesized material. The detailed characterizations revealed that the synthesized material possesses a peanut-shaped morphology, dense growth, and a wurtzite hexagonal phase along with good crystal and optical properties. Further, to ascertain the useful properties of the synthesized ZnO nanopeanut as an excellent electron mediator, electrochemical sensors were fabricated based on the form of a screen printed electrode (SPE). Electrochemical and current-voltage characteristics were studied for the determination of picric acid sensing characteristics. The electrochemical sensor fabricated based on the SPE technique exhibited a reproducible and reliable sensitivity of ~1.2 µA/mM (9.23 µA·mM-1·cm-2), a lower limit of detection at 7.8 µM, a regression coefficient (R²) of 0.94, and good linearity over the 0.0078 mM to 10.0 mM concentration range. In addition, the sensor response was also tested using simple I-V techniques, wherein a sensitivity of 493.64 µA·mM-1·cm-2, an experimental Limit of detection (LOD) of 0.125 mM, and a linear dynamic range (LDR) of 1.0 mM-5.0 mM were observed for the fabricated picric acid sensor.

Two-dimensional ytterbium oxide nanodisks based biosensor for selective detection of urea.

Herein, we demonstrate synthesis and application of two-dimensional (2D) rectangular ytterbium oxide (Yb2O3) nanodisks via a facile hydrothermal method. The structural, morphological, compositional, crystallinity, and phase properties of as-synthesized nanodisks were carried out using several analytical techniques that showed well defined 2D rectangular nanodisks/sheet like morphologies. The average thickness and edge length of the nanosheet structures were 20 ± 5nm and 600 ± 50nm, respectively. To develop urea biosensor, glassy carbon electrodes (GCE) were modified with Yb2O3 nanodisks, followed by urease immobilization and Nafion membrane covering (GCE/Yb2O3/Urease/Nafion). The fabricated biosensor showed sensitivity of 124.84µAmM-1cm-2, wide linear range of 0.05-19mM, detection limit down to ~ 2µM, and fast response time of ~ 3s. The developed biosensor was also used for the urea detection in water samples through spike-recovery experiments, which illustrates satisfactory recoveries. In addition, the obtained desirable selectivity towards specific interfering species, long-term stability, reproducibility, and repeatability further confirm the potency of as-fabricated urea biosensor.

How does hybrid bridging core modification enhance the nonlinear optical properties in donor-π-acceptor configuration? A case study of dinitrophenol derivatives.

This study spotlights the fundamental insights about the structure and static first hyperpolarizability (ß) of a series of 2,4-dinitrophenol derivatives (1-5), which are designed by novel bridging core modifications. The central bridging core modifications show noteworthy effects to modulate the optical and nonlinear optical properties in these derivatives. The derivative systems show significantly large amplitudes of first hyperpolarizability as compared to parent system 1, which are 4, 46, 66, and 90% larger for systems 2, 3, 4, and 5, respectively, at Moller-Plesset (MP2)/6-31G* level of theory. The static first hyperpolarizability and frequency dependent coupled-perturbed Kohn-Sham first hyperpolarizability are calculated by means of MP2 and density functional theory methods and compared with respective experimental values wherever possible. Using two-level model with full-set of parameters dependence of transition energy (ΔΕ), transition dipole moment (µ(0)) as well as change in dipole moment from ground to excited state (Δµ), the origin of increase in ß amplitudes is traced from the change in dipole moment from ground to excited state. The causes of change in dipole moments are further discovered through sum of Mulliken atomic charges and intermolecular charge transfer spotted in frontier molecular orbitals analysis. Additionally, analysis of conformational isomers and UV-Visible spectra has been also performed for all designed derivatives. Thus, our present investigation provides novel and explanatory insights on the chemical nature and origin of intrinsic nonlinear optical (NLO) properties of 2,4-dinitrophenol derivatives.

[Molecular characteristic of methicillin-resistant Staphylococcus aureus strains isolated in Moscow clinics].

UNLABELLED: OBJECTIVES; Methicillin-resistant Staphylococcus aureus (MRSA) is a common pathogen of nosocomial infection. The goal of this work was to evaluate the clonality of hospital-acquired MRSA (HA-MRSA) circulating in Russian Federation and to compare different multiplex PCR techniques with SNP-based approach for MRSA typing. METHODS: Epidemiologically unrelated MRSA isolates (n = 62) from Moscow hospitals were selected for typing. Genomic DNA from clinical isolates was purified using the DNA express kit (Lytech Ltd, Russia). Staphylococcus chromosomal cassette mec (SCCmec) typing was performed by PCR using the previously described methods. Seven loci from five housekeeping genes (arcC162, arcC210, aroE132, gmk123, tpi241, tpi243 and yqiL333) were used for SNP-typing. Detection of particular nucleotides in selected loci was carried out in the thermocyclic primer extension reaction, followed by mass spectrometry of the products. Standard MLST procedure was performed as reference method. RESULTS: The majority of the MRSA isolates (93.6%) belong to world-wide disseminated clonal complex (CC) 8. Three isolates (4.8%) belong to CC 1. All ST 239 isolates were found to carry SCCmec type III; ST 8 isolates, SCCmec type IV. CONCLUSION: Among Russian MRSA CC 8 isolates carrying SCCmec IV type are predominant. SNP-typing is powerful toll for studies of molecular epidemiology of MRSA.