scholarly journals Morphometric evaluation of multirooted artificial teeth used for endodontic training

2021 ◽  
Vol 50 ◽  
Author(s):  
Francine MONTAGNA ◽  
Francisco MONTAGNER ◽  
Tiago André Fontoura de MELO ◽  
Simone Bonato LUISI

Abstract Introduction Dental practice professionals encounter several urgency cases, mainly related to endodontic problems. To attend to these, professionals need extensive prior preclinical training, being one of the main difficulties the search for models that simulate dental morphology. Aim To compare the external morphometry of multirooted artificial teeth to literature. Material and method The artificial teeth (Upper First Premolar, Upper First Molar and Lower First Molar) were donated by the manufacturers: Fábrica de Sorrisos (FS) and IM do Brasil LTDA (IM), totaling 30 teeth. The total length of the tooth and root, height and buccal-palatal and mesial-distal dimensions of the crown were measured with a digital pachymeter. The data were placed in a spreadsheet and the statistical analysis was performed [ANOVA or Kruskal-Wallis and then, Dunnett's test (α=5%)]. Result The Upper Molar samples of the company Fábrica de Sorrisos presented all variables within the morphometric patterns described in the literature. The other dental groups presented statistically significant differences, maintaining or not a certain proportionality. Conclusion Of all the dental groups analyzed, the upper molar from the company Fábrica de Sorrisos was the only one that presented all the external morphometric aspects according to literature.

Complexity ◽  
2019 ◽  
Vol 2019 ◽  
pp. 1-16 ◽  
Author(s):  
Helbert Eduardo Espitia ◽  
Iván Machón-González ◽  
Hilario López-García ◽  
Guzmán Díaz

Systems of distributed generation have shown to be a remarkable alternative to a rational use of energy. Nevertheless, the proper functioning of them still manifests a range of challenges, including both the adequate energy dispatch depending on the variability of consumption and the interaction between generators. This paper describes the implementation of an adaptive neurofuzzy system for voltage control, regarding the changes observed in the consumption within the distribution system. The proposed design employs two neurofuzzy systems, one for the plant dynamics identification and the other for control purposes. This focus optimizes the controller using the model achieved through the identification of the plant, whose changes are produced by charge variation; consequently, this process is adaptively performed. The results show the performance of the adaptive neurofuzzy system via statistical analysis.


1992 ◽  
Vol 6 ◽  
pp. 305-305
Author(s):  
Mahito Watabe

The late Miocene Chinese hipparions are morphologically diversified showing similarity to both western Old World's and North American forms. Two Chinese taxa that are phylogenetically related to western Old World's forms are Hipparion fossatum (= H. forstende) from Baode (Shanxi) and H. hippidiodus from Qingyang (Gansu) and Baode. The former is related to H. mediterraneum and the latter to H. urmiense - platygenys from the Turolian localities in the western Old World. H. fossatum and H. hippidiodus are associated with the “dorcadoides” (open-land) and “mixed” faunas in northern China. Hipparion fossatum that is characterized by POF located close to the orbit co-occurs with large and morphologically specialized form, H. dermatorhinum in Baode (Loc.30). H. hippidiodus with reduced POF is discovered with smaller H. coelophyes in Loc. 43, 44 (Baode) and Loc. 115 (Gansu).The hipparions associated with the “gaudryi” (forest) fauna are characterized by well defined and small POF located far from the orbit. Those forms are: H. platyodus from Loc. 70; H. ptychodus from Loc. 73; H. tylodus from Hsi-Liang in Yushe - Wuxiang basins; and H. sefvei from Loc. 12 at Xin-an in Henan province. H. coelophyes from Baode (Loc.43 & 44) and Qingyang (Loc. 115) also show similar facial morphology to the these forms, although it has small size and shallow POF. Those forms are similar in facial and dental morphology to Hipparion sensu stricto and some species of Cormohipparion in North America.The assemblages of Chinese hipparions are composed of two groups whose members are phylogenetically similar to the forms from both western part of Eurasia and North America. The “gaudryi” fauna is considered younger than the other two on the basis of faunal analyses. The similarity in hipparionine taxonomy between northern China and North America in the latest Miocene is an evidences for possible faunal interchange(s) occurred during that period, as suggested by taxonomic analyses on carnivores and proboscideans in eastern half of Eurasia and North America.


1989 ◽  
Vol 25 (1) ◽  
pp. 11-25
Author(s):  
D. J. Finney

SUMMARYObservations that are frequencies rather than measurements often call for special types of statistical analysis. This paper comments on circumstances in which methods for one type of data can sensibly be used for the other. A section on two-way contingency tables emphasizes the proper role of χ2 a test statistic but not a measure of association; it mentions the distinction between one-tail and two-tail significance tests and reminds the reader of dangers. Multiway tables bring new complications, and the problems of interactions when additional classificatory factors are explicit or hidden are discussed at some length. A brief outline attempts to show how probit, logit, and similar techniques are related to the analysis of contingency tables. Finally, three unusual examples are described as illustrations of the care that is needed to avoid jumping to conclusions on how frequency data should be analysed.


1899 ◽  
Vol 64 (402-411) ◽  
pp. 77-88 ◽  

In this research it was intended, by comparing the results obtained in dogs on a given diet with the same animals after the removal of the large intestine, to study more carefully the functions and any influence the absence of the large intestine might have on general metabolism. In one dog a little more than the middle third of the large intestine was removed, while in the other two dogs the total length of the large intestine, together with the cæcum, was extirpated. The dogs were fed after recovering from the operation on meat and biscuit, to which varying quantities of fat were added. The meat employed was preserved by sterilising minced meat in separate weighed out portions sufficient for each day.


1984 ◽  
Vol 41 (6) ◽  
pp. 985-988 ◽  
Author(s):  
A. H. El-Shaarawi ◽  
M. A. Neilson

Water samples were collected on Lake Ontario during April and November, filtered (0.45 μm), and immediately analyzed onboard ship for the nutrients soluble reactive phosphorus, nitrate-plus-nitrite, and ammonia. Replicates were stored in glass bottles at 4 °C and reanalyzed within 8 d. Statistical analysis showed that soluble reactive phosphorus decreased by 11 and 13% and nitrate-plus-nitrite by 7 and 6%, whereas ammonia increased by 75% on one cruise and decreased by 37% on the other.


2018 ◽  
Vol 4 (1) ◽  
pp. e000366 ◽  
Author(s):  
Joseph Alexander Nathan ◽  
Kevin Davies ◽  
Ian Swaine

ObjectiveTo determine whether there is an association between hypermobility and sports injury.MethodsA quantitative observational approach using a cross-sectional survey was adopted. Individuals were identified as hypermobile or not. All participants were asked to complete two questionnaires: one asking demographic information and the other injury-specific. Fisher’s exact test was used for statistical analysis.Results114 individuals participated in the study, 62 women and 52 men. 26% of the participants were hypermobile. There was no significant association between hypermobility and sports injury (p=0.66). There was a significant increase in joint and ligament sprain among the non-hypermobile (NH) group covering all sports (p=0.03). Joint dislocation was found exclusively among hypermobile individuals. The duration of injury in hypermobile individuals was higher than NH. The use of oral painkillers or anti-inflammatories in the semiprofessional group was greater than the general population.ConclusionHypermobility is relatively common among individuals, and there is a lot of anecdotal evidence associating it with increased rates of injuries. This project finds that NH individuals are more likely to sustain a ligament or joint sprain in sports. This is due to increased joint laxity and flexibility preventing injury. There were important limitations to this study which will be addressed in further work. These include assessing for pauciarticular hypermobility and focusing on one sport to investigate its association with sports injury in those who are hypermobile or not. It would also be important to focus on one specific joint, assessing its flexibility and association with injury.


2015 ◽  
Vol 5 (2) ◽  
pp. 114
Author(s):  
Chiu-Fan Hsieh ◽  
You-Qing Zhu

<p class="1Body">This study analyzes the influence of design parameters on the dynamics of straight bevel gears by constructing a model that allows variation in the shaft angle, pressure angle, and backlash. According to the statistical analysis, the order of influence of these parameters on weight is shaft angle &gt; pressure angle &gt; backlash. When the shaft angle is 90°, the statistical results show the drive is stable and the stress fluctuation level is low. The pressure angle, on the other hand, can affect the gear’s dynamic property by influencing the driving component force on the gear and the component force on the shaft. The results for the shaft and pressure angles are used to determine the appropriate backlash. Overall, the analysis not only provides designers with an important reference but explains the dominance in the market of gear designs with a 90° shaft angle and a 20° pressure angle.</p>


1941 ◽  
Vol 1 (1) ◽  
pp. 26-41 ◽  
Author(s):  
Simon Kuznets

This paper deals with the relation between statistical analysis as applied in economic inquiry and history as written or interpreted by economic historians. Although both these branches of economic study derive from the same body of raw materials of inquiry—the recordable past and present of economic society—each has developed in comparative isolation from the other. Statistical economists have failed to utilize adequately the contributions that economic historians have made to our knowledge of the past; and historians have rarely employed either the analytical tools or the basic theoretical hypotheses of statistical research. It is the thesis of this essay that such failure to effect a close interrelation between historical approach and statistical analysis needs to be corrected in the light of the final goal of economic study.


Author(s):  
João Felipe Besegato ◽  
Gabriela Dos Santos Ribeiro Rocha ◽  
Marlene De Sousa Amorim ◽  
Fabio Martins Salomão ◽  
Daniel Poletto ◽  
...  

Objective: to measure pH values of bleaching agents that are indicated to intracoronal bleaching technique in different time intervals. Methods: Each group (G) received five samples (n=5): G1 – distilled water (AD); G2 – hydrogen peroxide (H2O2) 30%; G3 – sodium perborate (PbS) + AD; G4 – PbS + H2O2 30%; G5 – sodium percarbonate (PcS) + AD; and G6 – PcS + H2O2 30%. pH values were stated using a digital pHmeter, in different time intervals: immediately after handling (T0), 24 hours (T1) and 168 hours after handling (T2). The results were submitted to statistical analysis through Kruskal-Wallis and Mann Whitney tests, in this order, allowing multiple comparisons among the groups. To verify the effect of time in each group, Friedman test was applied. Results: In the evaluation of the effect of time in each group, it was observed that G2 presented acid behavior, while the other groups exhibited values close to neutrality or alkaline. Conclusions: H2O2 30% was the only agent that showed acidic behavior in every evaluation time. Meanwhile, PcS + H2O had the highest pH values.


2001 ◽  
Vol 15 (4) ◽  
pp. 296-301 ◽  
Author(s):  
Carolina Covolo da COSTA ◽  
Luiz Cesar da COSTA FILHO ◽  
Marina Lara SÓRIA ◽  
Ana Paula Rorato MAINARDI

The purpose of this study was to compare the effectiveness of plaque control performed with electric and manual toothbrushes. Fifteen children with primary dentition and 14 children with mixed dentition were divided in two groups and randomly assigned to utilize a manual or an electric toothbrush. In the first session, professional plaque removal was performed, and the children spent 24 hours without brushing their teeth. In the second session, plaque was disclosed and assessed on all facial and lingual surfaces. After that, all children brushed their teeth with the predetermined toothbrush. The next procedure was the disclosure and measurement of residual plaque. After a period of 7 days, the children switched the kind of toothbrush, and the same procedures were repeated. According to the statistical analysis of the results, there were no significant differences concerning plaque removal when the toothbrushes were utilized by children with mixed dentition. On the other hand, the electric toothbrush promoted significantly greater plaque removal on the lingual surfaces of teeth from children with primary dentition.


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