Comparative Analysis on the Precision Fit of Dental Prosthesis between the Variously Fabricated Copings of Nickel-Chromium Alloy, Titanium and Zirconia Ceramic

2007 ◽  
Vol 330-332 ◽  
pp. 1373-1376
Author(s):  
S.W. Lee ◽  
J.W. Kim ◽  
S.H. Hwang ◽  
Dong Hoo Han ◽  
H.S. Moon
Keyword(s):  
Comparative Analysis ◽  
Zirconia Ceramic ◽  
Chromium Alloy ◽  
Marginal Fit ◽  
Mean Values ◽  
Nickel Chromium ◽  
Dental Prostheses ◽  
The Mean ◽  
Alloy Titanium ◽  
Alloy Cast

Precision fit of dental prostheses were compared between the four experimental groups of cast Ni-Cr alloy, cast titanium, milled titanium and milled zirconium by measuring and comparing the mean values of the marginal, axial, occlusal and overall coping-die gaps. The overall, axial and occlusal fit was most precise with the cast Ni-Cr alloy prosthesis. The biologically critical marginal fit was the most precise with the milled zirconium, thus suggesting that the copy-milled zirconia ceramic could serve as an alternative to the cast-metal prosthesis. The statistical variables, such as the groups and the regions, were in association with and had an interaction effect on the adaptability of the prostheses. The marginal gaps correlated with the axial gaps in the cast Ni-Cr alloy and milled titanium groups

scholarly journals Comparative analysis of morphological characteristics of beech leaves from the European provenance trial

2019 ◽  
pp. 145-174
Author(s):  
Marina Nonic ◽  
Dijana Cortan ◽  
Tatjana Batalo ◽  
Mirjana Sijacic-Nikolic
Keyword(s):  
Comparative Analysis ◽  
Genetic Variability ◽  
Morphological Characteristics ◽  
Climatic Conditions ◽  
Genetic Constitution ◽  
Provenance Trial ◽  
Morphological Markers ◽  
Mean Values ◽  
Leaf Characteristics ◽  
The Mean

The paper presents the results of the research conducted within the European provenance beech trial, in the Teaching Base of the Faculty of Forestry - Debeli Lug. To assess the inter- -provenance genetic variability of beech, using morphological markers, and comparative analysis of the results obtained in two successive years, 10 trees per each selected provenance were sampled. Thirty leaves were collected from each tree (total of 300 leaves per provenance per year). The inter-provenance differences of all morphological leaf characteristics were statistically significant and can be assumed to be the result of the genetic constitution of the provenances themselves. Based on the comparative analysis of the morphological characteristics of beech leaves from 13 different provenances in two research years, it was found that the mean values of most analyzed morphological characteristics were higher in 2017, compared to the results from 2016. Such results could be explained by the different climatic conditions that prevailed in the provenance trial in research years.

Analysis of the Effect of Cyclic Fatigue on the Flexural Strength of a Ceramoceramic System Used in Dental Prostheses

2018 ◽  
Vol 930 ◽  
pp. 43-47
Author(s):  
Cristiane Fonseca de Carvalho ◽  
Cláudio Luis de Melo-Silva ◽  
Tereza Cristina Favieri de Melo-Silva ◽  
Fábio Amaral de Araújo ◽  
Jefferson Fabricio Cardoso Lins
Keyword(s):  
Flexural Strength ◽  
Ceramic Coating ◽  
Cyclic Fatigue ◽  
Bending Test ◽  
Mean Values ◽  
Three Point Bending ◽  
Cyclic Stresses ◽  
Dental Prostheses ◽  
Before And After ◽  
The Mean

The aim of this study was to analyze the flexural strength of ceramics based on yttria-stabilized zirconia (YTZP) , used in the manufacture of dental prostheses infrastructure before and after aging with cyclic fatigue in moisture. The samples were made by pre-sintered blocks of ZirkonTransluzent (Zirkonzahn GMHB) from YTZP ceramics with and without feldspathic ceramic coating, divided into groups: G1 = YTZP control; G2 = YTZP aged; G3 = YTZP + feldspathic; G4 = YTZP + aged feldspathic. The samples were submitted to a three-point bending test with a speed of 0.5 mm / min. The mean values of the flexural strength values were G1 = 645 MPa (DP ± 124), G2 = 681 MPa (DP ± 129), G3 = 904Mpa (DP ± 157) and G4 = 954Mpa (DP ± 243). The values of groups G1 and G2; G3 and G4 were statistically similar, depending on the presence or absence of coating. Cyclic stresses did not affect the flexural strength of the material

scholarly journals COMPARATIVE ANALYSIS OF SOME HEAVY METALS LEVELS IN LEAVES, PEELS AND TUBERS OF CASSAVA PLANTED ALONG EAST-WEST ROAD RIVERS STATE

2021 ◽  
Vol 9 (8) ◽  
pp. 1-13
Author(s):  
Isaac Eguarkhide Ogah ◽  
Ekpete A. Ozioma
Keyword(s):  
Heavy Metals ◽  
Comparative Analysis ◽  
Mean Values ◽  
Cassava Leaves ◽  
Safe Limit ◽  
The Mean ◽  
Rivers State ◽  
The Impact ◽  
Mean Concentration ◽  
East West

Introduction: Pollution of the environment by heavy metals has caused serious environmental problems, which threatens the existence of various ecological system, agriculture and human health. This study assessed the comparative analysis of some heavy metals levels in leaves, peels and tubers of cassava planted along East-West Road Rivers State. Materials/Methods: Cassava leaves and tubers samples were collected from farmlands along East-West road (SX, SY and SZ communities, in Emohua, Tai, and Ahoada West LGA respectively), Rivers state, Nigeria. The samples were monitored for heavy metals levels to assess the impact of automobiles on cassava peels, leaves and tubers using Solar Thermo Elementary Atomic Absorption Spectrometer, ModelSG 71906. Metals studied were Lead (Pb), Nickel (Ni), Chromium (Cr), Cadmium (Cd), and Arsenic (As). Results: The mean concentration of Ni present in leaf was 2.81±0.104 mg/kg, tubers recorded 2.23±0.073 mg/kg and peels 3.20±0.06 mg/kg. The highest concentration (4.064±0.035 mg/kg) of Ni was observed in peels while the least concentration (1.80±1.023 mg/kg) was recorded in the tubers. The mean values of Pb in leaves, tubers and peels were 2.22±1.023 mg/kg, 1.80±1.023 mg/kg and 2.64±0.32, highest concentration was recorded in tubers. Arsenic values were 0.16±0.020 mg/kg > 0.51±0.021 mg/kg > 0.38±0.203 mg/kg in peels, tubers and leaves respectively. The values of As were above WHO safe limit of 0.1mg/kg. Also, the mean values of cadmium in leaves, tubers and peels were 0.054±0.570 mg/kg, 0.046±0.057 mg/kg and 0.16±0.609 mg/kg respectively. The highest concentration (0.138±0.109 mg/kg) was in the tubers. Finally, chromium was found to be present in all the cassava samples (leaves, peels and tubers). The mean concentration of chromium (Cr) was 3.58±0.023 mg/kg, 2.76±0.005 mg/kg and 3.83±0.203 mg/kg in leaves, tubers and peels respectively. Conclusion: From the findings, heavy metals were found in the samples and thus, crops should be cultivated far away from major roads.

Comparison of Plantar Arch Index Calculated from Ink and Electronic Footprints

2013 ◽  
Vol 583 ◽  
pp. 125-128 ◽  
Author(s):  
Mirela Toth-Tascau ◽  
Cosmina Vigaru ◽  
Oana Pasca ◽  
Dan Ioan Stoia ◽  
Flavia Bălănean
Keyword(s):  
Image Processing ◽  
Comparative Analysis ◽  
General Purpose ◽  
Mean Values ◽  
Geometric Characteristics ◽  
The Mean ◽  
Processing Software ◽  
Image Processing Software ◽  
Arch Index ◽  
Total Contact Area

The general purpose of this study was to assess the accuracy of geometric characteristics of electronic footprints acquired with Zebris FDM force platform based on comparison with corresponding characteristics of conventional ink footprints. The paper presents a comparative analysis of contact areas and plantar arch index calculated from simultaneously acquired ink and electronic footprints. The areas of the three main regions of the footprints have been determined using common image processing software. The plantar arch index was calculated based on Cavanagh method. The comparative analysis evidences the differences between the geometric characteristics. The total contact area is slightly overestimated in case of the electronic footprints. The electronic footprints overestimate fore-foot and rear-foot areas and underestimate mid-foot area. The mean values of AI in case of ink footprints generally have greater values than in case of electronic footprints.

scholarly journals Use of base metal casting alloys for implant framework: marginal accuracy analysis

2004 ◽  
Vol 12 (4) ◽  
pp. 337-343 ◽  
Author(s):  
Stefania Carvalho Kano ◽  
Gerson Bonfante ◽  
Raquel Hussne ◽  
Aline F. Siqueira
Keyword(s):  
Base Metal ◽  
Metal Casting ◽  
Chromium Alloy ◽  
Cobalt Chromium ◽  
Mean Values ◽  
Casting Alloys ◽  
Nickel Chromium ◽  
Plastic Cylinder ◽  
Silver Palladium ◽  
Vertical Gap

The original protocol for implant prosthesis recommends the use of a gold framework for acrylic and ceramic prosthesis. However, due to its high cost, the use of alternative alloys is desired. This study compares the marginal accuracy of pre-made cylinders versus plastic cylinders cast with two different base metal casting alloys. Five samples each of (1) plastic cylinder cast in cobalt-chromium alloy, (2) plastic cylinder cast in nickel-chromium alloy, and (3) silver-palladium pre-made cylinder (control) were examined for marginal accuracy according to: (A) vertical gap; (B) horizontal gap and (C) horizontal gap depth at the abutment/cylinder interface. Data were submitted to statistical analysis (ANOVA and Student-Newman Keuls, p<0.05). Mean values for vertical, horizontal and gap depth were 4.13µm, 14.5µm and 6.93µm for pre-made cylinder, 23.18µm, 33.2µm and 88µm for Ni-Cr cast cylinder and 25.6µm, 51.8µm and 114.54µm for Co-Cr cast cylinder. No statistically significant differences were found between cast groups (1 and 2), but significant better fit was obtained with pre-made metal cylinders when compared to cast cylinders with Ni-Cr and Co-Cr alloys, for all analyses.

scholarly journals Comparative analysis of the leaf anatomy of Echinacea purpurea and E. pallida

2018 ◽  
Vol 26 (2) ◽  
pp. 77-84
Author(s):  
T. N. Belaeva ◽  
A. N. Butenkova
Keyword(s):  
Comparative Analysis ◽  
Vascular Bundle ◽  
Echinacea Purpurea ◽  
Botanical Garden ◽  
Stomatal Index ◽  
Lower Epidermis ◽  
Southeastern Part ◽  
Stomatal Complex ◽  
Mean Values ◽  
The Mean

This article contains a comparative analysis of the anatomical structure of the rosette and stem leaves of Echinacea purpurea and E. pallida. The plants were grown on the experimental site of the Siberian Botanical Garden, located in the southeastern part of Tomsk (Western Siberia). Temporary preparations of the leaves were prepared by cutting them on a freezing microtome MZ-2. Photographs of leaf microscopy and microscopic measurements were made on a light microscope. Anomocyte type of stomatal complex is characteristic for the studied species. Leaves of the studied species are amphistomatic, rosette leaves of E. purpurea are hypostomatic. The stomatal index of E. purpurea was 1.5 (stem leaves, upper epidermis) and 24.4–25.5 (lower epidermis). In the leaf blade of E. purpurea, the signs are revealed as mesomorphic (the presence of relatively large dorsoventral leaves, moderate development of integumentary, conducting and mechanical tissues) and a xeromorphic-heliomorphic structure. A complex of xeromorphic-heliophytic features of the E. pallida leaf has been identified, which increase its drought resistance; the mean values of the stomatal index of the upper and lower epidermis were 24.8–28.7. There are 10 characteristics that have significant differences in mean values when comparing leaves of E. purpurea and E. pallida: the size of the stomata of the lower epidermis, the thickness of the mesophyll of the leaf, its layers and the leaf laminae free of the vascular bundle, the area of the vascular bundle and their constituents.

Influence of Nd: YAG Laser Parameters on Tensile Behaviour, Microhardness and Surface Roughness of Ni-Cr Alloy for Dental Prostheses

2015 ◽  
Vol 766-767 ◽  
pp. 539-545
Author(s):  
K. Gurusami ◽  
Karibeeran Shanmuga Sundaram ◽  
R. Vijay
Keyword(s):  
Surface Roughness ◽  
Test Method ◽  
Laser Shock Peening ◽  
Tensile Behaviour ◽  
Laser Shock ◽  
Yag Laser ◽  
Mean Values ◽  
Dental Prostheses ◽  
The Mean ◽  
Shock Peening

The paper presents the results of tensile behaviour, microhardness, surface roughness and microstructure of Ni-Cr alloy surface treated using high power Q-switched Nd: YAG laser has been studied. The major clinical disadvantage of the Ni – Cr is their lack of adequate ductility and yield strength. These properties combined made finishing, polishing and burnishing of conventional base metal alloys rather difficult. The dumbbell shaped tensile and cylindrical specimens of Ni-Cr were cast with a phosphate bonded investment material, using an induction melting centrifugal casting machine. The microhardness values of the surface melted layers increased as compared with Ni-Cr as - cast condition. The results of experiment showed that the surface treatment process has improved the % elongation, and surface roughness and microhardness as compared with as-cast. The improvement of the mechanical properties may be attributed due to grain refinement imparted by laser shock peening. The microstructure and changes in crystal orientation presented in the surface layer of the laser treated material were analyzed by optical, SEM as well as XRD. The chemical composition of laser treated surface was determined by EDAX attached along with SEM. Vickers microhardness was measured as per ASTM E384 11el standard test method. The data were compared using ANOVA and post hoc –Tukey test. In our present study, the laser shock peening process shows, a substantial increase in surface roughness from Ra = 0.440 μm before LSP treatment to 1.781 μm and surface hardness of Ni-Cr was achieved by 53.5% the base material hardness (i.e. from284 HV to 436 HV) and the mean values of % elongation of Ni-Cr alloy was higher (double) than that of after laser shock peening. The mean values of UTS, YS, modulus of elasticity of Ni-Cr were significantly lower after LSP. The experimental results showed that the mean values of percentage elongation of Ni-Cr increased by 200 % after LSP. It is evident from the above experimentation, increase of ductility of Ni-Cr alloy facilities workability which could produce a reliable removable partial denture (RPD) metal framework for dental prostheses.

Articulatory Behavior Pre and Post Full-Mouth Tooth Extraction and Alveoloplasty

1980 ◽  
Vol 23 (3) ◽  
pp. 630-645 ◽  
Author(s):  
Gerald Zimmermann ◽  
J.A. Scott Kelso ◽  
Larry Lander
Keyword(s):  
Control Subject ◽  
High Speed ◽  
Tooth Extraction ◽  
Kinematic Parameters ◽  
Experimental Conditions ◽  
Mean Values ◽  
Articulatory Movements ◽  
The Mean ◽  
Experimental Subjects ◽  
Normal Speech

High speed cinefluorography was used to track articulatory movements preceding and following full-mouth tooth extraction and alveoloplasty in two subjects. Films also were made of a control subject on two separate days. The purpose of the study was to determine the effects of dramatically altering the structural dimensions of the oral cavity on the kinematic parameters of speech. The results showed that the experimental subjects performed differently pre and postoperatively though the changes were in different directions for the two subjects. Differences in both means and variabilities of kinematic parameters were larger between days for the experimental (operated) subjects than for the control subject. The results for the Control subject also showed significant differences in the mean values of kinematic variables between days though these day-to-day differences could not account for the effects found pre- and postoperatively. The results of the kinematic analysis, particularly the finding that transition time was most stable over the experimental conditions for the operated subjects, are used to speculate about the coordination of normal speech.

Comparative Study of Intranasal, Subcutaneous and Intravenous Administration of Desamino-D-Arginine Vasopressin (DDAVP)

1986 ◽  
Vol 55 (01) ◽  
pp. 108-111 ◽  
Author(s):  
M Köhler ◽  
P Hellstern ◽  
C Miyashita ◽  
G von Blohn ◽  
E Wenzel
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Factor Xii ◽  
Additional Advantage ◽  
Mean Values ◽  
Routes Of Administration ◽  
The Mean ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Factor Antigen

SummaryThis study was performed to evaluate the influence of different routes of administration on the efficacy of DDAVP treatment. Ten healthy volunteers received DDAVP intranasally (i.n.), subcutaneously (s.c.) and intravenously (i.v.) in a randomized cross-over trial. Factor XII and high molecular weight (HMW)-kininogen levels increased only slightly after DDAVP administration. The mean increase of factor VIII: C was 3.1 (i. v.), 2.3 (s. c.), and 1.3 (i.n.) - fold over baseline. Ristocetin cofactor (von Willebrand factor antigen) increased 3.1 (2.5), 2.0 (2.3) and 1.2 (1.2) - fold over baseline mean values after i.v., s.c. and i.n. DDAVP, respectively. The half-disappearance time of factor VIII and von Willebrand factor (vWF) after DDAVP ranged from five (factor VIII: C) to eight hours (vWF). The mean increase of fibrinolytic activity was more pronounced after i.v. DDAVP. The antidiuretic effect was moderate with no apparent differences between the routes of application. This study provides further evidence that both i.v. and s.c. DDAVP administration result in an appropriate and reliable stimulation of haemostasis. An additional advantage of s. c. administration is its suitability for home treatment.

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