Scanning electron microscopic evaluation of root canal surfaces prepared with three rotary endodontic systems: Lightspeed, ProTaper and EndoWave

Background and Objectives: The purpose of this in vitro study was to  evaluate and compare the cleaning efficiency, preparation time, instrument deformation and fracture with LightSpeed (LS), ProTaper (PT) and  EndoWave (Ew) rotary instruments.Materials and Methods: A total of 45 freshly extracted human mandibular premolars were subjected for the study. They were divided into three groups, each group consisting of 15 teeth. Group 1: The canals were prepared with LS system; Group 2: PT rotary system, Group 3: Ew rotary system. All the groups were prepared according to manufacturerfs recommendation, using 5.25% sodium hypochlorite and 17%  ethylenediaminetetraacetic acid (dent wash, prime dent) alternately as an irrigants. Crowns of each tooth were removed with diamond disks at the level of cemento enamel junction. Canal length was determined by placing a size 10 K.file. The working length was 0.5 mm short of canal length. Two longitudinal grooves were prepared on the lingual and buccal surfaces of each root to facilitate vertical splitting with a chisel after canal  instrumentation. The sections were then observed under scanning electron microscope for presence or absence of debris and smear layer and the photographs were taken at coronal, middle and apical 1/3 with a magnification of ~200 and ~1000 respectively. The time taken to enlarge each canal was recorded in minutes and seconds. The instruments were examined after every use for deformation. The scores recorded were statistically analyzed using one.way analysis of variance and Mann.Whitney test.Results: There was statistically significant difference with regard to removal of debris and smear layer at coronal, middle and apical third for LS versus PT and LS versus Ew (P < 0.01). There was no significant difference  between PT and Ew. The mean preparation time for LS, PT and Ew was 1.76, 2.50 and 2.75 respectively. Interpretation and Conclusion: The study demonstrated that, LS instrumentation removed debris and smear layer effectively with shorter preparation time and Ew instrument showed deformation.Key words: Debris, EndoWave, instrument deformation, LightSpeed, nickel-titanium instruments, preparation time, ProTaper, scanning electron microscope analysis, smear laye

Biological Posts: Natural Alternatives in Restoring Smile

Traumatic injuries leading to severely mutilated anterior teeth are common in dentistry. These injuries may leave a severe impact when they affect  ndodontically treated teeth as strength of such teeth is compromised. Proper functional and esthetic rehabilitation of such badly broken teeth is a challenge. Dealing with the patient’s mental suffering and their impatience to regain the natural smile back makes the treatment even more challenging. An effective treatment plan including a suitable and cost-effective choice of post is very much necessary in such conditions. Biological posts obtained through extracted teeth from another individual represent an economic option and alternative technique for the functional recovery of extensively damaged teeth. All-ceramic crowns further add to enhanced esthetics. This paper presents a case where biological posts with composite core build up followed by all-ceramic crown adaptation have been used with successful outcom

Mutual Coupling Effects in Adaptive Antenna Arrays

Abstract attached as PD

A Review of Mutual Coupling in Phased Arrays

Abstract attached as PD

Pattern synthesis studies for planar and non-planar conformal arrays

Conformal arrays are the most general type of phased array,and can be defined as an array whose elements conform to the non-planar surface. They have applications in arrays for missiles, submarines,ships,high speed aircraft, and also in systems that require wide-angle coverage.In the present report, simulation study for the pattern synthesis of circular aperture, circular arrays,Hexagonal and cylindrical arrays is carried out. The beam patterns are generated for these planar and non-planar arrays using different amplitude distributions viz. uniform, Taylor,Dolph-Chebyshev. Villeneuve excitation. The concept of phase modes is also included in the code development for circular and cylindrical arrays.Results obtained are validated against those available in open literature

Pattern Synthesis Studies for Planar and Non-planar Conformal Arrays

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A comparative study of retention of complete denture base with different types of posterior palatal seals – an in vivo study

GS Chandu,1 BS Hema,2 Harsh Mahajan,1 Antriksh Azad,2 Ipsita Sharma,3 Anurag Azad4 1Department of Prosthodontics, Rishiraj College of Dental Sciences and Research Centre, Bhopal, Madhya Pradesh, India; 2Department of Conservative Dentistry, Rishiraj College of Dental Sciences and Research Centre, Bhopal, Madhya Pradesh, India; 3Department of Oral Pathology, RKDF Dental college and Research centre, Bhopal, Madhya Pradesh, India; 4Department of Oral and Maxillofacial Surgery, Bhabha College of Dental Sciences and Research Centre, Bhopal, Madhya Pradesh, India Aim: To evaluate retention of complete denture base with different types of posterior palatal seals. Material and methods: Ten male patients between the age group of 50 years to 60 years were selected for the study. After the primary and secondary impressions were taken, five casts were made including a cast without posterior palatal seal, a cast with single bead posterior palatal seal, a cast with double bead posterior palatal seal, a cast with butterfly shaped posterior palatal seal, and a cast with posterior palatal seal with low fusing compound by functional method. Results: It was observed that retention increased up to 108% in the posterior palatal seal with low fusing compound with functional method and the posterior palatal seal that was obtained by using functional method provided greater retention than a denture base without posterior palatal seal. Conclusion: It was concluded that the incorporation of a posterior palatal seal is important for obtaining optimum retention of the maxillary complete denture. Keywords: posterior palatal seal, denture base, complete denture, functional metho