scholarly journals Accuracy on Scanned Images of Full Arch Models with Orthodontic Brackets by Various Intraoral Scanners in the Presence of Artificial Saliva

2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Jihu Song ◽  
Minji Kim
Keyword(s):  
Artificial Saliva ◽  
Orthodontic Brackets ◽  
3D Analysis ◽  
Arch Models ◽  
Stl File ◽  
Reference Images ◽  
The Difference ◽  
Scanned Images ◽  
Ceramic Bracket ◽  
Maximum Discrepancy

Aim. This study aims to evaluate the accuracy of scanned images of 4 clinically used intraoral scanners (CS3600, i500, Trios3, Omnicam) when scanning the surface of full arch models with various kinds of orthodontic brackets in the presence of artificial saliva. Materials and Methods. Four study models were prepared; bonded with ceramic, metal, and resin brackets, respectively, and without brackets. Reference images were taken by scanning the models with an industrial scanner. Study models were then applied with an artificial saliva and scanned 10 times, respectively, with the above 4 intraoral scanners. All images were converted to STL file format and analyzed with 3D analysis software. By superimposing with the reference images, mean maximum discrepancy values and mean discrepancy values were collected and compared. For statistical analysis, two-way ANOVA was used. Results. Omnicam (1.247 ± 0.255) showed higher mean maximum discrepancy values. CS3600 (0.758 ± 0.170), Trios3 (0.854 ± 0.166), and i500 (0.975 ± 0.172) performed relatively favourably. Resin (1.119 ± 0.255) and metal (1.086 ± 0.132) brackets showed higher mean maximum discrepancy values. Nonbracket (0.776 ± 0.250) and ceramic bracket (0.853 ± 0.269) models generally showed lower mean maximum discrepancy values in studied scanners. In mean discrepancy values, the difference between scanners was not statistically significant whereas among brackets, resin bracketed models (0.093 ± 0.142) showed the highest value. Conclusion. Intraoral scanners and brackets had significant influences on the scanned images with application of artificial saliva on the study models. It may be expected to have similar outcomes in an intraoral environment. Some data showed the discrepancy values up to about 1.5 mm that would require more caution in using intraoral scanners for production of detailed appliances and records.

scholarly journals Adhesion of Streptococcus mutans to Different Types of Brackets

2007 ◽  
Vol 77 (6) ◽  
pp. 1090-1095 ◽  
Author(s):  
William Papaioannou ◽  
Sotiria Gizani ◽  
Maria Nassika ◽  
Efterpi Kontou ◽  
Melachrini Nakou
Keyword(s):  
Stainless Steel ◽  
Streptococcus Mutans ◽  
Bacterial Species ◽  
Culture Technique ◽  
Orthodontic Brackets ◽  
Clinical Strain ◽  
Microbial Culture ◽  
Salivary Pellicle ◽  
Different Types ◽  
The Difference

Abstract Objective: To examine the difference in the adhesion of Streptococcus mutans to three different types of orthodontic brackets and the effect of the presence of an early salivary pellicle and Streptococcus sanguis on adhesion. Materials and Methods: Three adhesion experiments were performed using stainless steel, ceramic, and plastic orthodontic brackets. In the first experiment a clinical strain of S mutans adhered to the three different types of brackets (n = 6 for each). For the second, the brackets were treated with saliva before adhesion of S mutans (n = 6 per type of bracket). Finally, the third experiment concerned saliva coated brackets (n = 6 per type of bracket), but before S mutans, S sanguis bacteria were allowed to adhere. The bacteria were always allowed to adhere for 90 minutes in all the experiments. Adhesion was quantitated by a microbial culture technique by treating the brackets with adhering bacteria with trypsin and enumerating the total viable counts of bacteria recovered after cultivation. Results: There were consistently no differences in the adherence to stainless steel, ceramic, or plastic brackets. The presence of an early salivary pellicle and S sanguis reduced the number of adhering S mutans to all three types of brackets. Conclusions: Adhesion of bacteria to orthodontic brackets depends on several factors. The presence of a salivary pellicle and other bacterial species seem to have a significant effect on the adhesion of S mutans, reducing their numbers and further limiting any differences between types of brackets.

scholarly journals A COMPARISON OF HAZE REMOVAL ALGORITHMS AND THEIR IMPACTS ON CLASSIFICATION ACCURACY FOR LANDSAT IMAGERY

2017 ◽  
Vol 23 (1) ◽  
pp. 55-71 ◽  
Author(s):  
Yang Xiao ◽  
Zhiyun Ouyang ◽  
Zhiming Zhang ◽  
Chaofan Xian
Keyword(s):  
Classification Accuracy ◽  
Near Infrared ◽  
Landsat Imagery ◽  
Spectral Response ◽  
Landsat Images ◽  
Haze Removal ◽  
Reference Images ◽  
The Difference ◽  
Spatially Varying

The quality of Landsat images in humid areas is considerably degraded by haze in terms of their spectral response pattern, which limits the possibility of their application in using visible and near-infrared bands. A variety of haze removal algorithms have been proposed to correct these unsatisfactory illumination effects caused by the haze contamination. The purpose of this study was to illustrate the difference of two major algorithms (the improved homomorphic filtering (HF) and the virtual cloud point (VCP)) for their effectiveness in solving spatially varying haze contamination, and to evaluate the impacts of haze removal on land cover classification. A case study with exploiting large quantities of Landsat TM images and climates (clear and haze) in the most humid areas in China proved that these haze removal algorithms both perform well in processing Landsat images contaminated by haze. The outcome of the application of VCP appears to be more similar to the reference images compared to HF. Moreover, the Landsat image with VCP haze removal can improve the classification accuracy effectively in comparison to that without haze removal, especially in the cloudy contaminated area

Ion Release and Galvanic Corrosion of Different Orthodontic Brackets and Wires in Artificial Saliva

2017 ◽  
Vol 18 (3) ◽  
pp. 222-227 ◽  
Author(s):  
Soodeh Tahmasbi ◽  
Tahereh Sheikh ◽  
Yasamin B Hemmati
Keyword(s):  
Galvanic Corrosion ◽  
Artificial Saliva ◽  
Potential Difference ◽  
Orthodontic Brackets ◽  
Saturated Calomel Reference Electrode ◽  
Ion Release ◽  
Microscopic Evaluation ◽  
Two Samples ◽  
Significant Difference ◽  
The Mean

ABSTRACT Introduction To investigate the galvanic corrosion of brackets manufactured by four different companies coupled with stainless steel (SS) or nickel–titanium (NiTi) wires in an artificial saliva solution. Materials and methods A total of 24 mandibular central incisor Roth brackets of four different manufacturers (American Orthodontics, Dentaurum, Shinye, ORJ) were used in this experimental study. These brackets were immersed in artificial saliva along with SS or NiTi orthodontic wires (0.016”, round) for 28 days. The electric potential difference of each bracket/ wire coupled with a saturated calomel reference electrode was measured via a voltmeter and recorded constantly. Corrosion rate (CR) was calculated, and release of ions was measured with an atomic absorption spectrometer. Stereomicroscope was used to evaluate all samples. Then, samples with corrosion were further assessed by scanning electron microscope and energydispersive X-ray spectroscopy. Two-way analysis of variance was used to analyze data. Results Among ions evaluated, release of nickel ions from Shinye brackets was significantly higher than that of other brackets. The mean potential difference was significantly lower in specimens containing a couple of Shinye brackets and SS wire compared with other specimens. No significant difference was observed in the mean CR of various groups (p>0.05). Microscopic evaluation showed corrosion in two samples only: Shinye bracket coupled with SS wire and American Orthodontics bracket coupled with NiTi wire. Conclusion Shinye brackets coupled with SS wire showed more susceptibility to galvanic corrosion. There were no significant differences among specimens in terms of the CR or released ions except the release of Ni ions, which was higher in Shinye brackets. How to cite this article Tahmasbi S, Sheikh T, Hemmati YB. Ion Release and Galvanic Corrosion of Different Orthodontic Brackets and Wires in Artificial Saliva. J Contemp Dent Pract 2017;18(3):222-227.

Effect of Chlorhexidine Pretreatment on Bond Strength Durability of Caries–affected Dentin Over 2-Year Aging in Artificial Saliva and Under Simulated Intrapulpal Pressure

2011 ◽  
Vol 36 (6) ◽  
pp. 649-660 ◽  
Author(s):  
EH Mobarak
Keyword(s):  
Bond Strength ◽  
Failure Modes ◽  
Artificial Saliva ◽  
Water Control ◽  
Control Groups ◽  
Silver Precipitation ◽  
The Difference ◽  
Microshear Bond Strength ◽  
And Control ◽  
Composite Cylinders

SUMMARY Objective To evaluate the influence of 2% and 5% chlorhexidine (CHX) pretreatment on bond durability of a self-etching adhesive to normal (ND) and caries-affected (AD) dentin after 2-years of aging in artificial saliva and under simulated intrapulpal pressure (IPP). Methods One hundred twenty freshly extracted carious teeth were ground to expose ND and AD. Specimens were distributed into three equal groups (n=40) according to whether the dentin substrates were pretreated with 2% or 5% CHX or with water (control). Clearfil SE Bond (Kuraray) was applied to both substrates and composite cylinders (0.9 mm diameter and 0.7 mm height) were formed. Pretreatment and bonding were done while the specimens were subjected to 15 mm Hg IPP. After curing, specimens were aged in artificial saliva at 37°C and under IPP at 20 mm Hg until being tested after 24 hours or 2 years (n=20/group). Microshear bond strength was evaluated. Failure modes were determined using a scanning electron microscope (SEM) at 400× magnification. Data were statistically analyzed using three-way analysis of variance (ANOVA); one-way ANOVA tests, and t-test (p<0.05). Additional specimens (n=5/group) were prepared to evaluate interfacial silver precipitation. Results For the 24-hour groups, there were no significant differences among the ND groups and AD groups. For ND aged specimens, the 5% CHX group had the highest value followed by the 2% CHX and control groups, although the difference was statistically insignificant. For AD aged specimens, the 5% CHX group revealed statistically higher bond values compared to the 2% CHX and control groups. Fracture modes were predominately adhesive and mixed. Different interfacial silver depositions were recorded. Conclusions Two percent or 5% CHX pretreatment has no adverse effect on the 24-hour bonding to ND and AD. Five percent CHX was able to diminish the loss in bonding to AD after 2years of aging in artificial saliva and under simulated IPP.

Simulation-Based Tolerance and Assemblability Analyses of Assemblies With Multiple Pin/Hole Floating Mating Conditions

2005 ◽  
Author(s):  
Zhengshu Shen ◽  
Jami J. Shah ◽  
Joseph K. Davidson
Keyword(s):  
Tolerance Analysis ◽  
Virtual Manufacturing ◽  
Product Development Process ◽  
3D Analysis ◽  
Dimensional Problem ◽  
Press Fit ◽  
Simulation Based ◽  
The Difference ◽  
2D And 3D ◽  
Mating Conditions

Development of tolerance analysis methods that are consistent with the ASME and ISO GD&T (geometric dimensioning and tolerancing) standards is a challenging task. Such methods are the basis for creating computer-aided tools for 3D tolerance analysis and assemblability analysis. These tools, along with the others, make it possible to realize virtual manufacturing in order to shorten lead-time and reduce cost in the product development process. Current simulation tools for 3D tolerance analysis and assemblability analysis are far from satisfactory because the underlying variation algorithms are not fully consistent with the GD&T standards. Better algorithms are still to be developed. Towards that goal, this paper proposes an improved simulation-based approach to tolerance and assemblability analyses for assemblies with pin/hole floating mating conditions in mechanical products. A floating pin/hole mating condition is the one where the mating pin should be able to “float” within the mating hole, and thus press-fit is not necessary for the parts to assemble properly. When multiple pin/hole mating pairs are involved in a product, the feasibility of assembly needs to be analyzed. This paper will introduce a more complete method of analyzing assemblability for such assemblies. In most cases, a 3D (3-dimensional) problem can be simplified to 1D (1-dimensional) or 2D (2-dimensional) problem, with the loss of some accuracy. To make a comparison and find out how accurately 1D and 2D analyses can approximate 3D analysis, this paper will provide the variation algorithms for 1D, 2D and 3D simulations. The algorithms developed account not only for bonus/shift tolerances but also for feasibility of assembling. These algorithms are extendable to consider other different GD&T specifications. The assemblability criteria proposed is generally applicable to any assemblies with pin/hole floating mating conditions. Case studies are provided to demonstrate the algorithms developed. The comparison study shows quantitatively the difference in the results from 1D, 2D and 3D simulation based analyses.

scholarly journals CYTOTOXICITY OF IONS RELEASED FROM 17-4 PRECIPITATION HARDENING STAINLESS STEEL ORTHODONTIC BRACKETS IN ARTIFICIAL SALIVA

2018 ◽  
Vol 9 ◽  
pp. 71
Author(s):  
Tjokro Prasetyadi ◽  
Bambang Irawan ◽  
Miesje Karmiati Purwanegara ◽  
Bambang Suharno ◽  
Sugeng Supriadi
Keyword(s):  
Stainless Steel ◽  
Cell Viability ◽  
Precipitation Hardening ◽  
Artificial Saliva ◽  
Nickel Content ◽  
Orthodontic Brackets ◽  
Assay Method ◽  
Cytotoxicity Test ◽  
Significant Difference

Objective: 17-4 precipitation hardening (PH) stainless steel has a low nickel content, which can reduce the risk of allergic reactions. It also has good mechanical properties against the stress caused by the archwire slot brackets in orthodontic treatments. The main focus of this study to evaluate the metal ions released into artificial saliva from different orthodontic brackets with the same 17-4 PH stainless steel and to examine the in vitro cytotoxicity of the metal.Methods: Material properties were analyzed by energy dispersive spectroscopy. The 3-(4,5-dimethylthiazol-2-y1)2,5-diphenyltetrazolium bromide (MTT) assay method was used to examine the cytotoxicity of Gemini and Synergy brackets.Results: The cytotoxicity test on all the orthodontic brackets showed a mean cell viability value above 80% in each immersion group, which means that this material is not cytotoxic to the human immortalized keratinocyte cell line.Conclusions: The results showed cell viability in the extracts of both groups of brackets, and there was no statistically significant difference between the groups (p>0.05).

scholarly journals Avaliação da Diminuição da Força de Ativação de Elásticos Correntes de Diferentes Cores: Estudo in Vitro

2020 ◽  
Vol 24 (4) ◽  
pp. 396-401
Author(s):  
Larissa Gomes ◽  
Renata Almeida-Pedrin ◽  
Victor Ladewig ◽  
Victor Didier ◽  
Joel Santiago ◽  
...  
Keyword(s):  
Artificial Saliva ◽  
Statistical Tests ◽  
Significance Level ◽  
Oral Environment ◽  
The Mean ◽  
The Difference ◽  
Continuous Use ◽  
Elastomeric Chains ◽  
Calculated Analysis

O objetivo deste estudo consistiu em comparar a degradação de força de cinco cores diferentes de elásticos corrente, a fim de buscar parâmetros clínicos para o uso desses elásticos nas terapias ortodônticas. Foram avaliados 10 segmentos com 6 elos de elásticos corrente de força média da marca Morelli, das cores preto, cinza, azul, rosa e transparente, provenientes de embalagens seladas e dentro do prazo de validade. Os elásticos foram distendidos até o dobro de seu comprimento e mantidos por dispositivos simples com duas pontas de metal, simulando o uso contínuo dos elásticos por parte dos pacientes. Esses dispositivos foram submersos em saliva artificial a 370C dentro de recipientes mantidos em estufa.  As forças dos segmentos de elásticos foram mensuradas com um dinamômetro ortodôntico de precisão ao início e nos intervalos de 1, 7,14, 21 e 30 dias após a imersão, e a média de força para cada grupo e tempo foi calculada. A Análise de variância (ANOVA) a dois critérios (tempo e grupos) e o teste de Tukey foram utilizados para a análise dos dados. Em todos os testes estatísticos foi adotado um nível de significância de 5%. Todas as cores de elásticos degradaram com o tempo, sendo a porcentagem média de degradação após 1 dia de 40,4%; 7 dias 48,2%; 14 dias 56,8%; 21 dias 65% e 81% após 30 dias. Entretanto, há diferença de degradação de força entre as cores dos elásticos. Os elásticos Transparente e Azul apresentaram menor degradação da força, sendo que após 30 dias o elástico Transparente se mostrou mais efetivo, seguido do Azul, Cinza, Preto e Rosa. Mesmo com a diferença na degradação de força entre as cores dos elásticos, esses dados não apresentam relevância clínica se utilizados por até 14 dias, após esse período seria melhor a utilização do elástico Transparente.   Palavras-chave: Ortodontia. Látex. Elasticidade   Abstract The aim of this study was to compare the force degradation of five different colors of elastomeric chains, in order to achieve clinical parameters for the use of these elastics in orthodontic therapies. The sample was composed by 10 segments with 6 links (medium force) for each color of elastomeric chain (Morelli); black, gray, blue, pink and transparent, from sealed packages and within the expiration date. The elastics were stretched twice their length and maintained by simple devices with two metal tips, simulating the continuous use of the elastics by the patients. These devices were submerged in artificial saliva at 370C to simulate the oral environment. The  elastic segments strengths were measured with a precision orthodontic dynamometer at the beginning and at intervals of 1, 7, 14, 21 and 30 days after immersion, and the mean strength for each group and time was calculated. Analysis of variance (ANOVA) with two criteria (time and groups) and the Tukey test were used for data analysis. In all statistical tests, a significance level of 5% was adopted. All the  elastics colors degraded over time, with the average  degradation percentage after 1 day being 40.4%; 7 days 48.2%; 14 days 56.8%; 21 days 65% and 81% after 30 days. However, there is a difference in force degradation among the  elastics colors. The Transparent and Blue elastics showed less force degradation, and after 30 days the Transparent elastic was more effective, followed by Blue, Gray, Black and Pink. Even with the difference in force degradation among the  elastics colors, these data are not clinically relevant they are used for up to 14 days, after that period it would be better to use the Transparent elastic.   Keywords: Orthodontics. Latex. Elasticity

scholarly journals The Impact of Different Types of Orthodontic Appliances and Its Location in Producing CT Scan Artefacts

2021 ◽  
Vol 50 (10) ◽  
pp. 3067-3075
Author(s):  
Mahmud Mohammed ◽  
Norma Ab. Rahman ◽  
Ahmad Hadif Zaidin Samsudin
Keyword(s):  
Stainless Steel ◽  
Image Quality ◽  
Orthodontic Brackets ◽  
Diagnostic Image Quality ◽  
Orthodontic Appliances ◽  
Diagnostic Image ◽  
Different Types ◽  
Polycrystalline Ceramic ◽  
The Mean ◽  
Ceramic Bracket

Fixed orthodontic appliances can produce metal artefacts in CT images which may degrade the diagnostic image quality. The study aimed to evaluate the artefacts based on the types and location of the metallic and non-metallic orthodontic brackets. This is an in-vitro cross-sectional study. Four different types of orthodontic brackets (stainless steel, titanium, monocrystalline, and polycrystalline ceramic bracket) were bonded consecutively in four different locations of the cadaveric skull. All scans were performed by a single operator using the same CT machine followed by a standard scanning protocol. Artefact intensity for all data sets was quantified by calculating the standard deviation (SD) of the grey values within the dataset by following a standard method. The One-way ANOVA Bonferroni test was used for the data analysis. The mean artefact score of the stainless steel bracket was significantly (p < 0.001) high in comparison with other types of the orthodontic brackets. Besides, the mean artefact score was significantly (p=0.002) low when orthodontic brackets were placed unilaterally. Stainless steel brackets produced a significant amount of noise in CT images which can degrade the diagnostic image quality. Thus, the polycrystalline ceramic bracket can be a better alternative of stainless steel brackets for patient need frequent CT scan.

scholarly journals A Digital Camera-Based Rotation-Invariant Fingerprint Verification Method

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Sajid Khan ◽  
Dong-Ho Lee ◽  
Asif Khan ◽  
Ahmad Waqas ◽  
Abdul Rehman Gilal ◽  
...  
Keyword(s):  
Feature Matching ◽  
Digital Camera ◽  
Reference Image ◽  
Digital Cameras ◽  
Scale Invariant ◽  
Image Capture ◽  
Verification Method ◽  
Reference Images ◽  
Binary Segmentation ◽  
The Difference

Fingerprint registration and verification is an active area of research in the field of image processing. Usually, fingerprints are obtained from sensors; however, there is recent interest in using images of fingers obtained from digital cameras instead of scanners. An unaddressed issue in the processing of fingerprints extracted from digital images is the angle of the finger during image capture. To match a fingerprint with 100% accuracy, the angles of the matching features should be similar. This paper proposes a rotation and scale-invariant decision-making method for the intelligent registration and recognition of fingerprints. A digital image of a finger is taken as the input and compared with a reference image for derotation. Derotation is performed by applying binary segmentation on both images, followed by the application of speeded up robust feature (SURF) extraction and then feature matching. Potential inliers are extracted from matched features by applying the M-estimator. Matched inlier points are used to form a homography matrix, the difference in the rotation angles of the finger in both the input and reference images is calculated, and finally, derotation is performed. Input fingerprint features are extracted and compared or stored based on the decision support system required for the situation.

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