Polymer grafting is a technique to improve the morphology, chemical, and physical properties of the polymer. This technique has the potential to improve the existing conduction and properties of polymers other than charge transport; as a result, it enhances the solubility, nano-dimensional morphology, biocompatibility, bio-communication, and other property of parent polymer. A polymer’s physicochemical properties can be modified even further by creating a copolymer with another polymer or by grafting. Here in the various chemical approaches for polymer grafting, like free radical, click reaction, amide formation, and alkylation have been discussed with their importance, moreover the process and its importance are covered comprehensively with their scientific explanation. The present review also covers the effectiveness of the graft-to approaches and its application in various fields, which will give reader a glimpse about polymer grafting and its uses.

This in-vitro study evaluated and compared the flexural fatigue resistance for Hero Shapers, Hyflex CM, One Shape, Profile Vortex and Protaper Next rotary NiTi files. Method and materials: Total 25 rotary NiTi files allocated to each experimental group were tested in a simulated constructed apparatus with an angle of curvature 60°& radius of curvature 5 mm. Each experimental file was coated with EDTA gel and was placed in endodomotor handpiece with rubber stopper at support steel cylinder and its end between two shaping steel cylinders on the simulated apparatus. File was then rotated at 400 rpm, 2.5 N/cm torque and simultaneously digital stop watch was started. Time taken (in seconds) until the file got fractured was recorded. Results: Time taken to fracture ranged from 7 to 58 s in different groups. Analysis of variance show a statistically significant intergroup difference (p < 0.001). Tukey HSD test showed the significant differences. The Weibull modulus values ranged from 7.31 to 24.19. Conclusion: Cyclic flexural fatigue resistance was observed highest for Grp IV (Hyflex CM) and lowest for Grp I (Hero Shapers). Clinical significance: Hyflex CM rotary NiTi files can be used in curved root canals as they had superior resistance and long survival time which will be helpful in eliminating one of the reasons for file fracture (due to cyclic flexural fatigue) during the root canal treatment clinically where root canal possesses a sharp bend or curve.

Chlorofluorocarbons (CFCs) have been widely used in the printed circuit board industry for many decades. However, the growing concern regarding their ozone depleting properties has demanded a ban on these solvents and consequently brought forth the search for environmentally friendly alternatives. In printed circuit board technology, methyl chloroform and methylene chloride have been widely utilized as solvents for developing and stripping, respectively, radiation sensitive materials useful in creating fine line circuitry patterns. The solubility of unexposed and exposed T168 resist in selected solvents or solvent mixtures at various temperatures is described here. Results addressing the ease of removal of such solvent based resists using environmentally friendly alternatives are presented. Debonding of the polymer layer from the underlying substrate was observed by monitoring the deflection of the composite strip immersed in the solvent using a Fotonic Sensor accessory. Debonding time, identified as the necessary time to remove the photoresist from such surfaces, can vary with temperature, solvent, photoresist type or thickness, and exposure energy. © 1996 John Wiley & Sons, Inc.

A comparative evaluation of the efficiency of two retreatment file systems in removing Gutta-percha from the root canals. Forty mandibular premolar teeth with single roots were specifically collected and decoronated with diamond disc so that the root lengths were standardized.Working length (WL) determination was done and root canal preparation done using Hyflex CM rotary files which was followed with meticulous irrigation and obturation was performed with gutta-percha, by the lateral condensation technique. AH-Plus sealer was used. The specimens were then divided in a random manner into two groups, in which retreatment was performed using two retreatment systems, Mtwo and REndo. These were further subdivided into two subgroups groups, i.e. one group using root canal solvent and another without solvent. Retreatment will be considered accomplished when gutta-percha was fully removed from the canal and none could be observed on the retreatment instruments and the same was confirmed radiographically. Longitudinally sectioning was done to split the root in to two halves-Mesial & Distal and was observed for the remnants under scanning electron microscope with 40x and 100x magnification. Photographs of the specimens were taken using a digital camera and the area of the remaining obturating material was determined using the AutoCAD16 software.: The area of remaining guttapercha in mesial and distal half for all the samples were evaluated using the Autocad software(Version 2016) and the mean as well as standard deviation of each group were used for statistical analysis (SPSS 22.00 for windows; SPSS inc, Chicago, USA).Statistical analysis was done using factorial ANOVA and Tukey HSD Post Hoc test. Difference between two groups was determined using student t-test and the level of significance was set at p &#60; 0.05. The results revealed that Mtwo R file system was found to be a more efficient rotary system for endodontic retreatment when compared to REndo(p&#60;0.05) and use of solvent acts as an adjuct for retreatment in both file systems (p&#60;0.05).

Background: Cytomorphometry is the analysis of the morphometry of exfoliated cells. Studies on exfoliated gingival epithelial cells in chronic periodontitis were not evident on the literature search. In the backdrop of this information, we were inspired to conduct a cytomorphometric study. Aim: The aim of the study is to correlate the nuclear area (NA), cytoplasm area (CA), and the nuclear: cytoplasm ratio (N/C) in the gingival cells of healthy individuals, patients with chronic periodontitis, and chronic periodontitis patients who are tobacco chewers. Materials and Methods: Ninety subjects, aged 35–45 years, were categorized into three equal groups of 30 each. Group I had individuals with healthy gingiva, Group II patients with chronic periodontitis without any deleterious habits, while Group III patients with chronic periodontitis and tobacco chewing habit. Exfoliated gingival cells were stained with Papanicolaou stain. Analysis of cells was done using binocular light microscope under ×40 and i-progress ® image analyzer software. Results: There was statistically significant increase in CA in all the groups, but NA and N/C ratio did not show any statistical significant difference. When Group II was compared with Group III, we found significant correlation of CA with pocket probing depth and clinical attachment loss (CAL) in Group II. Similarly, we also found a correlation of CA and N/C with pocket depth and CA with CAL in Group III. Conclusion: The results suggest that molecular level changes occur in the cells. Cytomorphometry can be used to analyze the cellular changes in chronic periodontitis patients even before clinical signs manifest. Hence, it can be used as an investigative tool.