Comparative Evaluation of Penetration Ability of Three Pit and Fissure Sealants and Their Relationship with Fissure Patterns

Statement of the Problem: Pit and fissure sealant placement is considered as an effective modality for prevention of caries on occlusal surfaces. Penetration, retention and lateral wall adaptation are the key factors in success of pit and fissure sealant restorations. Purpose: The purpose of this paper was to compare penetration ability and lateral wall adaptation of three commercially available pit and fissure sealants. Materials and Method: The present in-vitro study was done on 45 extracted sound human molars to evaluate the fissure pattern and assess the penetration ability of three commercially available sealants [Delton® FS Sealant (Dentsply DeTrey GmbH, Konstanz, Germany), Clinpro™ Sealant (3M™ ESPE™, Minnesota, USA) and GC Fuji VII Glass Ionomer Cement (GC Asia Dental Pte Ltd, Singapore)] on molars divided into 3 equal groups of 15 each, with further sectioning of each sample into 2 parts giving 30 samples per group. Following thermocycling and embedding of teeth in clear auto-polymerizing acrylic resin, sections were evaluated for fissure morphology, sealant penetration, unfilled space, lateral wall adaptation, and for presence of voids. Results: Penetrability of all the sealants studied was found to be significantly more in U-type fissure pattern (93.89%) followed by V-type (78.62%), IK-type (74.34%) and then in I-type (65.91). The depth of penetration of the GC Fuji VII Glass Ionomer sealant (85.82%) was found to be superior followed by unfilled resin sealant (Clinpro™ Sealant- 78.26%) and then by filled resin sealant (Delton® FS Sealant- 74.89%). Conclusion: U- type fissure pattern was more common than other fissure patterns and showed significantly higher penetrability of different type of sealants evaluated in the present study. GIC based sealant, due to significantly higher penetration depth than unfilled and filled sealants used in the present study, can be preferred over filled or unfilled resin sealants

Genomic characterization and epidemiology of an emerging SARS-CoV-2 variant in Delhi, India

Delhi, the national capital of India, experienced multiple severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreaks in 2020 and reached population seropositivity of >50% by 2021. During April 2021, the city became overwhelmed by COVID-19 cases and fatalities, as a new variant, B.1.617.2 (Delta), replaced B.1.1.7 (Alpha). A Bayesian model explains the growth advantage of Delta through a combination of increased transmissibility and reduced sensitivity to immune responses generated against earlier variants (median estimates: 1.5-fold greater transmissibility and 20% reduction in sensitivity). Seropositivity of an employee and family cohort increased from 42% to 87.5% between March and July 2021, with 27% reinfections, as judged by increased antibody concentration after a previous decline. The likely high transmissibility and partial evasion of immunity by the Delta variant contributed to an overwhelming surge in Delhi

Dispersion control of surface plasmons

Diese Arbeit zielt darauf ab, die Möglichkeiten zur Kontrolle von Oberflächen-Plasmonen durch unterschiedliche Nanostrukturierung zu erforschen. Im ersten Teil werden propagierende Oberflächenplasmonen an (geordneten und ungeordneten) nanoporösen Metallfilmen untersucht, die eine Rotverschiebung (bis zu 0,85 eV) der Dispersionsrelation mit zunehmender Porosität zeigen. Im zweiten Teil werden systematisch kollektive, lokalisierte Oberflächenplasmonen in Nanoantennenfeldern untersucht. Diese zeigen ebenfalls eine Rotverschiebung der Einzelpartikelresonanzen (von 800nm bis 1050nm) für ansteigende Partikelgrößen und Aspektverhältnisse. Darüber hinaus wurde eine dominante Gitterresonanz im nahen Infrarot bei Wellenlängen um 1400nm beobachtet, die aufgrund der kohärenten Fernfeldkopplung zwischen den periodisch angeordneten Nanoantennen entsteht. Werden lumineszierende Nanopartikel in der Umgebung der Nanoantennen platziert, so konnte eine 3,4 fache Erhöhung der Emission im Spektralbereich der Gitterresonanzen nachgewiesen werden.This thesis is aimed to explore the possibilities to gain control over the surface plasmon responses by different nanostructuring. In the first part propagating surface plamons which are supported by (ordered and disordered) nanoporous metal films are explored showing a red shift (up to 0.85 eV ) in the dispersion relation with increasing porosity. In the second part nanoantenna arrays, which support collective localized surface plasmons are systematically studied showing a red shift in single particle spectra (from 800nm to 1050nm) for increasing sizes and/or increasing aspect ratios. Furthermore a dominant surface lattice resonance in the near IR around a wavelength of 1400nm has been observed, which emerges due to the coherent far field coupling between the periodically arranged nanoantennas. Placing nanoparticles in the vicinity of the nanoantennas an up to 3.4 times enhancement of the nanoparticle-emission in the spectral range of the surface lattice resonance is observed.von Neha Sardan

Surface plasmons on ordered and bi-continuous spongy nanoporous gold

The dispersion relation and propagation of surface plasmons polaritons (SPPs) on nanoporous gold films is experimentally investigated and an increasing red shift of the SPPs is observed with rising porosity. This is caused by a less negative effective dielectric constant of the nanoporous metal films and is predicted by classical Bruggeman or specific two dimensional Maxwell-Garnett effective medium models. The dispersion relation data is supported with leakage radiation microscopy enabling the determination of the propagation length and losses of surface plasmons on these nanoporous films. These results demonstrate how the control of the nanoporosity of metal layers leads to designer plasmons in the visible and near infrared allowing the tuning of the SPP dispersion to match the requirements of certain applications

Occlusal characteristics and prevalence of associated dental anomalies in the primary dentition

Introduction: Morphological variations in primary dentition are of great concern to a pediatric dentist as it may pose clinical problems like dental caries, delayed exfoliation and also anomalies in the permanent dentition, such as impaction of successors, supernumerary teeth, permanent double teeth or aplasia of teeth. The present study was conducted to investigate the presence of dental anomalies in the primary dentition of 1000 schoolchildren in the 3–5 year-old age group in Faridabad. Materials and methods: One-thousand schoolchildren were examined using Type III examination (WHO, 1997) for primary molar relationship, occlusal characteristics, primate spaces, physiological spaces and other anomalies of teeth, including number and morphology. Results and conclusions: The prevalence of physiological spaces in maxillary and mandibular arches was 50.9% and 46.7%, respectively, whereas primate spaces were found in 61.7% of the children in the maxillary arch and 27.9% in the mandibular arch. The prevalence of unilateral anterior and posterior cross-bite was 0.1% and 0.8%, respectively, in the present study. The prevalence of hypodontia in the primary dentition was found to be 0.4% and the prevalence of fusion and gemination in the present study was 0.5%. Double teeth (fusion and gemination) and hypodontia were the most common dental anomalies found in the primary dentition in the present study

A randomized controlled clinical trial to evaluate and compare three chairside techniques of veneering stainless steel crowns

Background: With the increasing patient demands of esthetics in paediatric dentistry, pre-veneered stainless steel crowns (SSCs) have been made available commercially. However, they suffer from technique sensitivity, limited ability to crimp and associated higher costs. Aim: The present study was planned to clinically evaluate and compare the success of preformed SSCs in which esthetic modification was done using three different techniques of composite veneering. Materials and Methods: A total of 60 primary molars selected from patients between the age group of 4–9 years were randomly divided into three groups having 20 samples each: Group A (composite veneering done using the open face technique), Group B (composite veneering done after sand-blasting SSCs), and Group C (composite veneering done after preparing retentive grooves on SSCs). The patients were evaluated at 1, 3, 6, and 9 months as per evaluation criteria. Statistical Analysis: Kruskal–Wallis and ANOVA were used to compare means among three groups at different time intervals. Results: All 60 SSCs were retained at the end of the study, thereby demonstrating 100% success of SSCs. Open window technique of veneering significantly showed maximum retention of composite veneers; therefore, highest level of parental satisfaction. Overall, the most common fracture was of adhesive type seen at the metal composite interface. Conclusions: All the three techniques used provide a chairside and easy method for esthetic modification of the SSCs. The open window is the most successful of the three methods of veneering and may be clinically useful technique for dental practitioners and pediatric dentists

A Synergic Approach of Deep Learning towards Digital Additive Manufacturing: A Review

Deep learning and additive manufacturing have progressed together in the previous couple of decades. Despite being one of the most promising technologies, they have several flaws that a collaborative effort may address. However, digital manufacturing has established itself in the current industrial revolution and it has slowed down quality control and inspection due to the different defects linked with it. Industry 4.0, the most recent industrial revolution, emphasizes the integration of intelligent production systems and current information technologies. As a result, deep learning has received a lot of attention and has been shown to be quite effective at understanding image data. This review aims to provide a cutting-edge deep learning application of the AM approach and application. This article also addresses the current issues of data privacy and security and potential solutions to provide a more significant dimension to future studies

Sputter-deposited zirconium doped nickel-aluminide coatings for high-temperature oxidation-resistant applications

Zr-Ni3Al coatings were deposited over the Inconel-718 substrate using DC cosputtering. The deposition was carried out in a custom-designed chamber at a substrate temperature of 400 degrees C. The evolution of phases, microstructure, surface topography, and elemental composition were characterized using x-ray diffraction, field emission scanning electron microscopy (FESEM), atomic force microscopy, and energy dispersive spectroscopy (EDS), respectively, whereas the adhesion strength and the mechanical properties of the coatings were characterized using nanoindentation. The oxidation properties of the coatings were studied at 900, 1000, and 1100 degrees C in open air to determine the kinetics of oxidations. The results reveal that with the increase in Zr concentration in the host Ni3Al matrix, the adhesive strength and mechanical properties of the films increase. The highest hardness and Young's modulus of similar to 9.2 and similar to 150.3 GPa, respectively, are observed for 30 W Zr-Ni3Al coatings. Additionally, 1.51 at. % of Zr in Ni3Al coatings has shown the best oxidation resistance properties at all temperatures. However, an increase in the rate of oxidation has been observed with an increase in exposure temperature. The formation of different oxide layers after oxidation has been elucidated using FESEM and EDS after looking into the surface morphologies of the oxidized coatings