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This paper reports two specific aspects of Si implantation in the molecular beam epitaxy grown p-type GaSb epilayer, namely, the evolution of nanoporosity and doping characteristics. The implantation is done with 100 keV Si ions at four different fluences, i.e., 5 × 1013, 1 × 1014, 5 × 1014, and 1 × 1015 ions/cm2. A field-emission scanning electron microscope (in-plane and cross-sectional view) shows a smooth nanoporous GaSb with a pore diameter of 10–20 nm for the higher fluences. The thickness of the porous film is enhanced from 235 nm (fluence: 1 × 1014 ions/cm2) to 515 nm (fluence: 1 × 1015 ions/ cm2). Development of smooth uniform porous GaSb using Si ion implantation is discussed from the viewpoint of displacement per atom and distribution of vacancies estimated through Stopping and Range of Ions in Matter simulation tool. Hall measurement shows conversion to n-type behavior after implantation and a variation in the sheet carrier concentration from 2.22 × 1014 to 8.52 × 1014 cm−2. There is a drastic change in the mobility with the onset of void formation by implantation.

The calcifying cystic odontogenic tumour (CCOT) is an uncommon benign neoplasm of odontogenic origin, which was first described by Gorlin. It has been shown to have extensive diversity in its clinical and histopathological features and its biological behaviour. Most of these cases present with cystic characteristics, but a few are of the solid type. Cystic variant of CCOT associated with odontoma is considered as rare variant. A case of calcifying cystic odontogenic tumour associated with odontoma is reported in an 11-year-old female patient. In this report, the lesion was very large extending from the midline up to the right tuberosity region and impeded the eruption of five permanent teeth. Through this article, the radiographic and histopathological features of this entity are discussed and the literature is reviewed.

Aim: This study aims to evaluate the flexural strength, hardness, and impact strength of heat-cured high-impact denture base resins with different polymer/monomer ratios. Materials and Methods: A total of 150 acrylic samples were prepared using high impact denture base resin (Travelon Hi). The samples were divided into five groups based on different powder/liquid ratios (g/ml) with 30 samples in each group. The P/L ratio in Group 1 (Ratio - 2.2:1) was the manufacturer's recommended ratio and was used as control. In Group 2, the ratio was 2.7:1, in Group 3, the ratio was 3.2:1, in Group 4, the ratio was 1.9:1, and Group 5 the ratio was 1.6:1. Each group with 30 samples was further subdivided into three different subgroups comprising 10 samples each, based on the properties to be evaluated, i.e., for flexural strength, hardness, and impact strength evaluation. The samples were tested for flexural strength, Vicker's hardness number (VHN) and impact strength. One-way ANOVA including post hoc-Tukey's tests was used to calculate the difference of means for quantitative variables and for intergroup comparison as well. Results: The results showed that the flexural strength values and VHN values showed a similar trend. The values decreased significantly as the ratio was increased or decreased from the control group. The results also showed that there was nonsignificant difference between the mean impact strength values for all the groups. Conclusion: For reinforced resins or high impact resins, the manufacturer's recommended polymer/monomer mixing ratio should be used to obtain the appropriate strength of the material.

Purpose: The purpose of this study was to evaluate the effect of incisal butt joint and incisal overlap design on the fracture resistance of ceramic veneers under two different loading conditions, i.e., 125° and 60° representing protrusive and intercuspal movements, respectively. Materials and Methods: Thirty-two maxillary central incisors were divided into two groups of sixteen specimens each and were prepared with incisal butt joint and incisal overlap design. Ceramic veneers were fabricated and cemented. Both the groups were further divided and mechanical testing to evaluate the fracture resistance were done using the universal testing machine. The values were recorded in Newton along with the assessment of the failure mode of both veneer and the tooth. Results: Unpaired t-test showed a significant difference (P < 0.05) with butt joint design having higher fracture resistance than palatal overlap design with the mean value of 409.50N at 60° angle and 473.37N at 125° angle. Paired t-test depicted a significant difference for both the designs at 125° than at 60° angle (P < 0.05). Chi-square analysis showed more number of intact veneers with butt joint design; however, there was no significant difference (P > 0.05). Failure mode of teeth showed more number of coronal fracture followed by cervical fracture and root fracture, but there was no significant difference between the two groups (P > 0.05). Conclusion: Butt joint design had higher fracture resistance than palatal overlap design. Under functional loads for both designs, fracture resistance was higher at 125° than at 60° angle.

The article presents design, analysis and development of a hyperelastic material based pneumatically driven soft bendingtype actuator as a viable actuation concept for enabling steering and navigation in a mechanized endoscopic device. The applications extend to rehabilitation and other non-medical field as well. This work introduces polylithic construction of a soft actuator using multiple grades of silicone. Developments of two types of actuators are presented, viz. one using single material in a monolithic (homogeneous) design and other utilizing combination of materials of different shore hardness in a polylithic (heterogeneous) construction. The behaviors of the developed actuators are studied using FEM modeling techniques with non-linear material models. Experiments are conducted with various end-point loading and blocked-tip conditions and corresponding simulation results are compared. It is observed that actuator built with softer actuation channel on the periphery and harder core manifests better deformation stability and uncompromised force capability at slightly higher actuation pressure than in homogenous construction.

Photoplethysmography(ppg) is an unadorned optical technique. It is a technique for acquiring plethysmogram optically that helps in diagnosing the changes in the volume of blood within an organ in the whole body by detecting blood volume change in micro vascular bed of tissue that further helps to monitor/ analyze heart rate, depth of anesthesia, cardiac cycle and other circulatory functions. It works on the theory of transmission and reflection of green light through the skin as every pulse pressure affects the amount of green light that is transmitted and reflected. PPG is categorized into two types, one is done by having contact with the skin that is generally done using fitness bands, smartwatches and pulse oximeter and another one is contact less that is done via high-quality cameras that detects the changes in absorption and reflection of green light from skin that is not visible with the naked eyes. This technique of generating plethysmogram without any contact with the skin or through cameras is also known as Remote photoplethysmography (rPPG). Each peak in photoplethysmograph will represent a cardiac cycle. Keywords - Photoplethysmography, Artificial Intelligence, plethysmogram, Security, Biomedical Monitoring, Correlation, Reliability

Every Technology in the market has some flaws and some advantages. Similar is the case of IoT (that is known as Internet of things). As its name suggests Internet of Things means transferring data over network in between connected devices without any human interaction and providing a promising environment for the actions that are to be performed. In IoT environment human interaction is bare minimum so chances of human error are also bare minimum which will help in increasing accuracy in various applications where humans are not able to perform well, machines can perform much better. IoT nowadays has become a basic necessity for humans and in future it will be going to become as essential for everyone as water is for humans to survive. In this paper topic of discussion is about various applications of IoT in various sectors, It's Security and privacy concerns which will throw the light on how various attacks and flaws could be prevented and then future research trends will be discussed.

With the increasing concerns about the security of data, Blockchain a decentralised public ledger, linked block structure which verifies and stores data and follows trusted consensus algorithms which ensure synchronisation of data in a distributed peer to peer network acquired a lot of attention as well as discussions recently. As it makes sure a tamper-proof digital platform for decision-making processes to store and share data among different individuals, authorities and organisations who do not trust each other. This technology is considered as the future of data security and integrity and is expected to serve in a lot of new or existing potential application, so the motive of this paper is to present insights of blockchain's architecture, it's security background, and it elaborate the two versions of blockchain: permissioned and permission-less. and some of its applications. Moreover, the first decentralized cryptocurrency and a public ledger named bitcoin are also elaborated in this paper. Furthermore, we summarize some typical implementations in blockchain, the lifecycle of bitcoin and explore future research challenges that still need to be addressed in order to preserve privacy when blockchain is used.

Hydrogen is foreseen as a promising energy carrier that can control global warming by reducing CO2 emissions. However, hydrogen is associated with an embrittlement phenomenon that imparts substantial damage to the infrastructure by reducing the ductility, fracture strength, strength bearing capacity, etc., of metallic components. Therefore, understanding hydrogen-induced crack initiation mechanisms in metals are of prime importance. Greater insights into this critical phenomenon are expected if the hydrogen-induced crack initiation can be correlated with the local microstructure and corresponding stress-strain state towards their propensity for hydrogen accumulation. With this motivation, in this work, crack initiation is studied for the uncharged and hydrogen charged nickel specimens during in-situ tensile loading under the scanning electron microscope. By assuming the material to be elastic at low strains, a novel approach is implemented for generating the microstructural stress maps through strain and stiffness tensor extracted at each point in the region of interest on the specimen surface using high-resolution digital image correlation (HR-DIC) and Euler angles (given by electron backscattered diffraction data), respectively. Based on this analysis at low strain, the crack initiation sites for uncharged and hydrogen charged nickel specimens are correlated with microstructural maps of maximum Schmid factor, elastic modulus in the loading direction, hydrostatic stress, von Mises stress, and triaxiality factor. The analysis highlighted two independent factors responsible for hydrogen enhanced decohesion (HEDE) based intergranular failure observed only at the random grain boundaries, (i) strain localization due to hydrogen enhanced localized plasticity (HELP) mechanism of hydrogen embrittlement, and (ii) hydrostatic stress-based hydrogen diffusion to the crack initiation sites. These critical insights thus can help to design hydrogen embrittlement resistant metals. In addition, the novel experimental approach can be used to calibrate advance micromechanical models while providing quantitative estimate of the hydrogen distribution in realistic metallic microstructure responsible for hydrogen-assisted crack initiation with deformation.

Denture labelling is not a new concept in either prosthetic or forensic dentistry and its routine practice has been urged by forensic dentists internationally for many years. Prosthodontists are playing very important role in forensic dentistry as they are concerned with fabrication of various prosthesis which can serve as an important tool for identification. The main objective of this article is to discuss the various methods available for denture marking along with three case reports.

This article presents the design, fabrication and characterisation of an elastomeric flexible and stretchable strain sensor using a variable resistance fabric. This provides a viable alternative to the microfluid and nanoparticle based flexible strain sensors involving complex fabrication techniques. A nylon-spandex based stretchable fabric serves as the sensing element which is in turn embedded in an elastomeric substrate. The fabricated sensor is experimentally characterised for determining the linearity, hysteresis, stretchability and gauge factor. The Finite Element Method based simulations to predict the operational force range of the sensor corresponding to its strain sensing range has been validated with the experimental results. These sensors have a wide range of potential applications in the constantly developing field of compliant robotics and mechanisms. In future works, these sensors will be utilized in the biomechanical analysis of human movements to track the various joint parameters.

Hydrogen deteriorates the fatigue behaviour of metals by attacking their microstructure in different ways. For better clarity about hydrogen-based degradation of metals, it is vital to identify the microstructural configurations that promote fatigue crack initiation (FCI) in the presence of hydrogen. Intergranular regions in polycrystalline metals are more prone to hydrogen attack due to the prevailing atomic structure, elastic anisotropy, and plastic inhomogeneities causing increased hydrogen accumulation in this region. In this work, FCI is studied in a model material nickel in the uncharged and hydrogen charged state during in-situ strain controlled low cycle fatigue (LCF) testing under a scanning electron microscope (SEM). Crack initiation sites are characterized by investigating the elastic modulus in the loading direction as well as the maximum Schmid factor of the crack neighbouring grains extracted through the electron backscattered diffraction (EBSD) data. The crack frequency for the uncharged and hydrogen charged specimens is then analyzed using the difference in the elastic modulus ( Δ E ), the difference in the maximum Schmid factor ( Δ m ), and Δ E / Δ m ratio between the crack neighbouring grains. The comparison shows that for the hydrogen charged specimens, intergranular FCI sites show high values of Δ E / Δ m compared to the uncharged specimens. These findings provide a predictive model for hydrogen linked FCI in metals. In addition, the synergistic role of the Hydrogen Enhanced Local Plasticity (HELP) mediated Hydrogen Enhanced Decohesion (HEDE) mechanism responsible for FCI is also demonstrated.

Present work aims to unveil the mechanism of hydrogen embrittlement (HE) in SA508 Grade 3 Class I low alloy reactor pressure vessel (RPV) steel. In-situ tensile and low cycle fatigue (LCF) tests are performed on specially designed specimens using tensile/fatigue testing stage under scanning electron microscope (SEM). Electrochemical hydrogen charging resulted in localized void formation at prior austenite grain boundaries (PAGBs) during tensile loading. Alongside the hydrogen induced weakening of PAGBs due to synergetic HELP (hydrogen enhanced localized plasticity) and HEDE (hydrogen enhanced decohesion) mechanisms of HE, fish-eyes formation around Al2O3–SiO2 type inclusions are the primary factors for hydrogen enhanced tensile properties degradation in subject RPV steel. During LCF loading, crack initiation and propagation is facilitated by long rod inter-lath cementite particles distributed along the bainitic ferrite lath boundaries in the un-charged specimen. In case of hydrogen charged specimen, the edge crack formed during LCF loading propagated through the specimen by cleavage. Predominantly plasticity (slip) driven transgranular crack propagation occurred in un-charged specimen. In contrary, hydrogen charging resulted in LCF crack to propagate in mixed intergranular and transgranular manner during early stages of propagation, whereas once the crack length exceeded 5 to 6 grains, cleavage type transgranular crack propagation was observed.

Dens evaginatus (DE) is a developmental disturbance that clinically appears as an accessory occlusal tuberculated cusp composed of enamel and dentin, enclosing a thin pulp tissue. It mainly involves the mandibular premolars. These cusp-like protrusions are susceptible to wear and fractures with subsequent pulp exposure leading to pulpal necrosis. In most cases, DE is discovered due to periapical inflammation in the absence of obvious clinical presentation of caries, trauma, or other pathologies, thus making it a diagnostic challenge. A case of nonvital tooth with an obscured DE in an 18-year-old male is reported here with a review of literature.

AlGaN/GaN high electron mobility transistor (HEMT) epi-structures were grown on SiC substrate using MOVPE. In this paper, the growth of high-quality AlGaN epi-layer in AlGaN/GaN HEMT is reported. The optimization was carried out to improve surface morphology and quality of the AlGaN epi-layer to get high 2DEG (two-dimensional electron gas) properties of the HEMT structure. For this optimization, AlGaN epi-layers were grown with different V/III molar ratio. It was found that both lower and higher V/III molar ratios result in the step flow surface morphology of AlGaN. However, a higher V/III molar ratio results in reduced surface roughness, improved quality of AlGaN, and excellent 2DEG properties of HEMT epi-structure.

Aim: The purpose of this study was to evaluate the accuracy of implant casts generated with splinted and nonsplinted impression techniques with multiple parallel and nonparallel implants. Materials and Methods: In this experimental study, two edentulous maxillary stainless steel models with seven implant analogs in the central incisor, canine, premolar, and first molar region simulating clinical condition were used (control groups). In one master model, implant analogs were placed parallel to each other, whereas in another model, analogs were placed with a tilt-to-longitudinal axis. Forty stone casts were made from each model using splined and nonsplinted technique using polyether with open-tray technique. Then, the difference in the distance between the master cast and experimental cast in three dimensions was measured by coordinate-measuring machine. One-way ANOVA, post hoc Bonferroni test, and unpaired t-test were used for data analysis. Results: Statistical comparisons were made using ANOVA test, post hoc test, and unpaired t-test. Splinted technique with parallel implants generated interimplant distance values closest to the master model, followed by nonsplinted technique with parallel implants, splinted technique with angulated implants, and nonsplinted technique with angulated implants. Conclusions: Splinted impression technique exhibited higher accuracy than the other technique studies in both parallel and angulated implants.

Bilateralfilteringsmoothsimageswhilemaintainingedges,byuseofanonsimilarcombinationofnearingimagevalues.Themethodislesstimeconsuming,local,andeasy.Itclubstogethergraylevelsorcolorsbasedonboththeirgeometricclosenessandtheirphotometricsimilarity,andprefersnearvaluestodistantvaluesinbothdomainandrange.Also,incontrastwithstandardfiltering,bilateralfilteringgeneratesnophantomcolorsalongedgesincolorimages,andreducesphantomcolorswheretheyappearintheoriginalimage.Aftersuccessfulprocessing,thiswillbeimplementedonGPGPUforfasterimplementations. Keywords:BilateralFiltering,Denoising,GPGPU(GeneralPurposeComputingforGraphicsProcessingUnit)

The success of fixed prosthodontic treatment depends upon precision and accuracy in every step involved in the procedure. A very critical aspect of this is making accurate impressions in terms of dimensional accuracy, tear strength etc. The impression materials at the margins of the preparation require substantial thickness in order to resist distortion. This goal is in terms achieved by adequate gingival retraction. This paper focuses on the evaluation of three different gingival retraction methods namely retraction cord, Magic Foam Cord and Expasyl using width and depth of gingival sulcus as criteria.

Aim: The aim of the study is to analyze the effect of different materials and techniques in current use on peripheral shaping of complete denture impression. Methods: The present study was conducted to compare and evaluate the maxillary border morphology produced using tissue conditioner as control and low fusing impression compound, Polyether, Pattern resin and periphery wax as border molding materials. The study was carried out on 15 denture wearer patients with well formed, rounded edentulous maxillary arch with adequate width and height. On each patient, border moldings were done, with tissue conditioner which was loaded on the borders of previous maxillary denture of the patient (control group), low fusing impression compound (Group 1), polyether (Group 2), Pattern resin (Group 3) and Peripheral wax (Group 4), respectively on special tray made for the patient. Sulcus width height and area was then measured for each group using stereomicroscope. Results and Conclusions: Based on the study it is concluded that the polyether was the best material for border molding which will give most accurate borders to a denture.

This study aimed at the design and fabrication of a modular soft robotic manipulator for use in Minimally Invasive Surgeries(MIS). A single segment of such manipulator was fabricated with soft silicone polymer and three Shape Memory Alloy (SMA) spring wires connected 120 apart were used as actuators. Prilimary experiments conducted on a couple of such segments connected one over the other showed very promising results. A single segment with only one wire actuated showed a bending angle of 41 while two segments connected end to end showed a bending angle of 84. The prototype is an improvement over all existing manipulation systems used in MIS in terms of bending angle, actuation time and recovery time and is capable of attaining complex orientations in 3D space.

Complications in and post conventional invasive procedures makes minimal invasive surgery well accepted in society. It causes less pain and scarring, faster recovery, and reduces operative trauma for patients. To overcome the difficulties of limited steerability and stiffness control of conventional scope, a continuously curving manipulator actuated by smart material named shape memory alloys (SMA) is proposed in this paper. The segmented scope consisted of a compression spring backbone and three SMA actuators to dynamically control the shape of each segment of the manipulator as and when required. A detailed study was carried out to simulate the constraints of the manipulator and fit it to a given random curve in a 3-dimensional (3D) space in the best possible way. The paper also includes testing of one segment of the prototype with bending angles and force produced during actuation. Actuation time and cooling time, which is issue using SMA practically, are also discussed briefly. The manipulator seems to be a promising device to be able to follow given random complex 3D trajectories and vary segment stiffness as and when required.

To plan and execute rehabilitation of a decimated dentition is probably one of the most intellectually and technically demanding tasks faced by any prosthodontist. Attachments are small interlocking devices, which are used to connect prosthesis and abutments that offer a variety of solutions to challenge of balance between functional stability and cosmetic appeal. This clinical report describes a multidisciplinary approach for complete oral rehabilitation of a patient with few remaining natural teeth using precision attachment (ceka Preci-Clix Radicular RC) for mandibular overdenture and semi precision attachment (ceka revax extracoronal and ceka vertix) for maxillary cast partial denture.

Aim: The purpose of this study was to evaluate the accuracy of implant casts generated with splinted and nonsplinted impression techniques with multiple parallel and nonparallel implants. Materials and Methods: In this experimental study, two edentulous maxillary stainless steel models with seven implant analogs in the central incisor, canine, premolar, and first molar region simulating clinical condition were used (control groups). In one master model, implant analogs were placed parallel to each other, whereas in another model, analogs were placed with a tilt-to-longitudinal axis. Forty stone casts were made from each model using splined and nonsplinted technique using polyether with open-tray technique. Then, the difference in the distance between the master cast and experimental cast in three dimensions was measured by coordinate-measuring machine. One-way ANOVA, post hoc Bonferroni test, and unpaired t-test were used for data analysis. Results: Statistical comparisons were made using ANOVA test, post hoc test, and unpaired t-test. Splinted technique with parallel implants generated interimplant distance values closest to the master model, followed by nonsplinted technique with parallel implants, splinted technique with angulated implants, and nonsplinted technique with angulated implants. Conclusions: Splinted impression technique exhibited higher accuracy than the other technique studies in both parallel and angulated implants.

The absence of external ear may be due to congenital, traumatic, or surgical causes. Many case reports only describe impression techniques to record details of the defect side and the natural ear. The purpose of this case report is to explain in detail simple clinical and laboratory procedures involved in fabrication of ear prosthesis.The use of three-part mold helps in the application of pigmented silicone in specific areas. The use of direct adhesive fixation provides the best esthetic result and if properly used the most satisfactory form of treatment.The patient was satisfied with the life-like appearance of the prosthesis. The use of direct adhesive fixation gave the patient a sense of security and improved his confidence.The technique described is economical, and additional steps of implant placement are avoided. The esthetics of the prosthesis made by hand carved clay pattern provides good details.The technique describes the method of direct adhesive fixation of the prosthesis giving it a life-like appearance. The confidence of the patient is also restored.

For a successful fixed partial prosthodontics, obtaining an accurate impression for making an accurate cast is of prime importance. In the present study the three fixed prosthodontic impression procedures, multiple mix impression technique, matrix impression system and dual arch impression technique; have been compared in terms of dimensional accuracy. An articulated acrylic resin typodont prepared with reference points was used as a master model. Addition silicon impression materials in various consistencies were used for making impressions. The coordinate measurement machine (Lloyd, Germany) was used for three dimensional measurement of master model and stone casts with an accuracy of 0.0001 mm. As per statistical analysis, all the impressions had a tendency to be oversized in horizontal dimensions and undersized in vertical dimensions. Dual arch impression technique used with flexible disposable plastic tray has found to be less dimensionally accurate as compared to multiple mix impression technique and matrix impression system whereas the other two techniques were comparable to each other.

Advancement of technology and rapid Internet made information to travel over the world in an easy and economical way. This has made people to anguish about their privacy. Steganography is a technique that thwarts unauthorized users to have access to the crucial data. There are various steganographic methods that users can use to hide and mix information within other information that make it arduous to recognize by unauthorised users. This paper gives an overview of LSB technique of steganography and further we proposed and implemented a unique algorithm to base steganography which is an enhanced and improved technique better in all aspects. The paper further compares our proposed enhanced technique with the existing LSB technique on various parameters to show effective and satisfactory results.

Introduction To overcome limitations of screw-retained prostheses, cement-retained prostheses have become the restoration of choice now a days. Selection of the cement hence becomes very critical to maintain retrievability of the prostheses. Aim The purpose of this study was to assess and compare the retention of base metal crowns cemented to implant abutments with five different luting cements. Materials and methods Ten implant analogs were secured in five epoxy resin casts perpendicular to the plane of cast in right first molar and left first molar region and implant abutments were screwed. Total of 100 metal copings were fabricated and cemented. The cements used were zinc phosphate, resin modified glass ionomer cement, resin cement, non-eugenol acrylic based temporary implant cement & non-eugenol temporary resin cement implant cement. Samples were subjected to a pull-out test using an Instron universal testing machine at a crosshead speed of 0.5mm/min. The load required to de-cement each coping was recorded and mean values for each group calculated and put to statistical analysis. Results The results showed that resin cement has the highest retention value 581.075N followed by zinc phosphate luting cement 529.48N, resin modified glass ionomer cement 338.095 N, non-eugenol acrylic based temporary implant cement 249.045 N and non-eugenol temporary resin implant cement 140.49N. Conclusion Within the limitations of study, it was concluded that non-eugenol acrylic based temporary implant cement and non-eugenol temporary resin implant cement allow for easy retrievability of the prosthesis in case of any failure in future. These are suitable for cement retained implant restorations. The results provide a possible preliminary ranking of luting agents based on their ability to retain an implant-supported prosthesis and facilitate easy retrieval.

A case of hemifacial hyperplasia that presented with muscular, skeletal, and dental hyperplasia along with lipomatous infiltration was described. Advanced imaging was useful in identifying the lipomatous infiltration present in the lesion, which raises the possibility of lipomatosis having a diverse presentation in hemifacial hyperplasia. As there was a scarcity of related literature in the field of dentomaxillofacial radiology, this report would make us familiar with its computed tomographic and magnetic resonance image findings.

This clinical report describes the fabrication of a two-piece obturator used to close the mandibular buccal defect. Two-piece obturator prosthesis was fabricated with clear heat cure acrylic resin to be used during the healing period following the marsupialization of odontogenic keratocyst which had lead to the loss of portions of the mandibular buccal region. The prosthesis fabricated in two parts was joined by the rare earth magnets. Retention was increased by lining the prosthesis with tissue conditioner material engaging the undercut.

Context: Most of the maxillary complete dentures do not adapt accurately to the cast because of the changes in the resin during polymerization. The amount of heat associated with processing of polymethyl methacrylate has been correlated with the adaptation of the processed denture base to its supporting tissues. Aims: This study conducted to determine the effect of different curing temperatures on the accuracy of fit of a complete maxillary denture and to compare with that of fiber-reinforced acrylic resins. Materials and Methods : An ideal maxillary rubber mould used to make an edentulous cast. Forty-eight stone casts made from the ideal rubber mould. Out of 48 identical stone casts, 44 stone casts with wax adapted processed using simple acrylic resin. The remaining four stone casts were processed using fiber-reinforced acrylic resin. However, processing time for 12 hrs was maintained constant for all the samples. The variable to investigate was the temperature. Therefore, four denture bases processed at each temperature from 60°C to 80°C with two-degree increments for a total of 44 samples using simple acrylic resin. Remaining four samples processed at 70°C using fiber-reinforced acrylic resin. A traveling microscope used to measure the discrepancy between each cast and its denture base. Statistical analysis used: Analyzed with Student's unpaired t test. Results : Minimum distortion was observed at 70°C. Maximum distortion was observed for the denture bases processed at 80°C. Amount of distortion increases as the processing temperature increases which was highly significant. Distortion was significantly high from 60 to 68°C in the decreasing order. Conclusion: This study verified the observation that maxillary complete denture base show the greatest discrepancy at the central portion of the posterior palatal seal region as the processing temperature increases.

Acrylic resin denture teeth often exhibit rapid occlusal wear, which may lead to decrease in the chewing efficiency, loss of vertical dimension of occlusion, denture instability, temporomandibular joint disturbances, etc. There are various treatment options available like, use of highly cross linked acrylic teeth, amalgam or metal inserts on occlusal surface, use of composite, gold or metal occlusal surface, etc. Several articles have described methods to construct gold and metal occlusal surfaces, however, these methods are time-consuming, expensive and requires many cumbersome steps. These methods also requires the patient to be without the prosthesis for the time during which the laboratory procedures are performed. This article presents a quick, simple and relatively inexpensive procedure for construction of metal occlusal surfaces on complete dentures.

One of the most important steps is accurate impression making for fabrication of fixed partial denture. The two different putty-wash techniques that are commonly used are: (1) Putty-wash one-step technique, (2) putty-wash two-step technique. A uniform wash space is needed for an accurate impression. Nissan et al recommended the use of two-step technique for accurate impression making as there is uniform wash space for the light body material to polymerize. The aim of the present study was to compare the accuracy of stone casts obtained from different putty-wash impression techniques using various spacer thickness. The critical factor that influences the accuracy of putty-wash impression techniques is the controlled wash bulk which is absent in one-step putty-wash impression technique and with polyethylene spacer was used. How to cite this article: Chugh A, Arora A, Singh VP. Accuracy of Different Putty-Wash Impression Techniques with Various Spacer Thickness. Int J Clin Pediatr Dent 2012;5(1):33-38.

Short fatigue cracks, having dimension less than 1 mm, propagate at much faster rates (da/dN) even at lower stress intensity factor range (da/dN) as compared to the threshold stress intensity factor range obtained from long fatigue crack growth studies. These short cracks originate at the sub-grain level and some of them ultimately transit into critical long cracks over time. Therefore, designing the components subjected to fatigue loading merely on the long crack growth data and neglecting the short crack growth behavior can overestimate the component’s life. This aspect of short fatigue cracks become even more critical for materials used for safety critical applications such as reactor pressure vessel (RPV) steel in nuclear plants. In this work, the transition behaviour of short fatigue crack gowth into long fatigue crack is studied in SA508 Grade 3 Class I low alloy steel used in RPVs. In-situ characterization of initiation, propagation and transition of short fatigue cracks is performed using fatigue stage for Scanning Electron Microscope (SEM) in addition to digital microscopes fitted over a servo-hydraulic fatigue machine and correlated with the microtructural information obtained using electron backscatter diffraction (EBSD). SA508 steel having an upper bainitic microstructure have several microstructural interfaces such as phase and grain boundaries that play a significant role in controlling the short fatigue crack propagation. Specially designed and prepared short fatigue specimens (eletro-polished) with varying initial crack lengths of the order of tens of microns are used in this study. The transition of such short initial cracks into long cracks is then tracked to give detailed insight into the role of each phase and phase/grain boundary with an objective of establishing Kitagawa-Takahashi diagram for the given RPV steel. The behavior of the transited long cracks is then compared with the crack propagation behavior obtained using conventional CT specimens. The outcome of this research will enhance information on the integrity of the components made from RPV steel used in Indian nuclear power plants.

Nanostructured CdS thin films were deposited on glass substrates by chemical bath deposition technique. RBS and SEM analyses showed that the film surface was smooth, consisting of uniformly dispersed clusters. Absorption spectra of as prepared sample showed a blue shift in the absorption edge indicating quantum confinement effect. The band gap of the N + ion implanted samples decreased with increase in implantation fluence. Photoluminescence spectra showed a new peak (red band), in addition to the violet, blue and yellow emissions, due to surface states created during ion implantation. Raman peak appearing at 300 cm −1 for both as deposited and N + ion implanted samples was attributed to A 1 (LO) phonon of CdS. A new Raman peak which appeared at 250 cm −1 in the case of N + ion implanted samples was interpreted as E 1 (TO) mode resulting from the lattice disorder occurred due to ion implantation. The ratio of intensity of E 1 (TO) mode to that of A 1 (LO) mode showed conspicuous increase with increase in implantation fluence and the FWHM of both the modes increases with increase of implantation fluence.

The branch of Prosthodontics is not only a science but also an art of handling patients who present with limitations in continuing with normal procedures. An abnormally small mouth opening is called as microstomia. The common reasons for this condition include scleroderma, orofacial malignancies, surgery, burns and TMJ ankylosis. Impressions can be made for patients with restricted mouth opening with a sectional impression tray that can be assembled and disassembled in the mouth and reassembled outside the mouth. This article describes a sectional tray system for making preliminary and secondary impressions. Also an innovative technique of fabricating a sectional complete denture for a microstomic patient has been described.

(2004). Materials For Innovative Eco Products. Materials Technology: Vol. 19, No. 3, pp. 154-158.