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Article
The Marginal Fitness of CAD/CAM All Ceramic Crowns Constructed by Two Types of Direct Digitization Techniques (An In Vitro Study)

Authors: Rana M. Khdeir رنا خضير --- Adel F. Ibraheem عادل فرحان ابراهيم
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2016 Volume: 28 Issue: 2 Pages: 30-33
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: In capturing a negative image, the digital impression secures a digital record for the purposeofdesigning and creating restorations. The introduction of scanning system presents a paradigm shift in the way of thedental impression procedure and encourages the accuracy of obtained restoration especially in the marginal areaas a result of producing accurate final impression The digital system offers many advantages over theConventional method.. The objective of this present in vitro study was to evaluate the marginal fitness of all ceramiccrowns fabricated by direct digital scanning of the prepared tooth using two types of intra-oral cameras (Bluecamcamera with strip light projection technique and Omnicam camera with video sampling technique).Materials and Methods: Sixteen sound upper first premolar teeth of comparable size were collected. Standardizedpreparation of all teeth samples were carried out to receive all ceramic crown restoration with deep chamferfinishing line (1mm), axial length (4mm) and convergence angle (6◦). The specimens divided in to two groupsaccording to the type of digital impression technique: Group A, eight prepared teeth scanned directly by Bluecamcamera; Group B, eight prepared teeth scanned directly by Omnicam camera. Then CAD/CAM all ceramic crownsconstructed for each tooth sample.Marginal discrepancy was measured at Sixteen points per tooth using digital microscope at (120X) magnification.Results: Independent sample t-test was used to identify and localize the source of difference among the groups. Itwas found that there is statistically non- significant difference in the marginal gap mean values between (group Aand group B).Conclusions: From the above result we can conclude that the two types of direct digitization techniques have thesame accuracy


Article
An Investigation of Object Shadows Utilization In 3D Shape Re-Construction Using Inexpensive Equipment
إستقصاء بيانات ظلال الأجزاء لإعادة بناء الشكل الثلاثي الأبعاد بأستخدام معدات رخيصة الثمن

Authors: Ghassan A. Al-Kindi --- Ali Abbar Khleif
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2010 Volume: 28 Issue: 4 Pages: 836-852
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

An approach for automatic 3D object re-construction using its shadow ispresented. The approach investigates the use of information inherited by thegenerated object shadows to re-construct the object geometry. An algorithm isdeveloped that make use of object height information for the directions associatedwith the incident light and the generated object shadows, hence, acquired heightfeatures represents the object features that have actually obstructed the incidentlight. The technique is tested using objects of different shapes. Close to realmeasurements are gained and the overall accuracy of the system is found to bewithin 0.75 mm using the adopted imaging hardware and setup. Obtained resultsconfirmed the validity of the proposed approach.

في هذا البحث تم تقديم خطوة نحو عملية إعادة بناء الأجزاء ثلاثية الأبعاد ذاتياًبأستخدام ظلال هذه الأجزاء. حيث تعتمد هذه الخطوة على استكشاف وأستخدام المعلوماتالمتأصلة في الظلال المتولدة للأجزاء من أجل إعادة بناء الشكل الهندسي لهذه الأجزاء. تمتطوير خوارزمية تعمل على الأستفادة من بيانات إرتفاع الجزء في الأتجاهات ذات العلاقةبالضوء الساقط وظلال الجزء المتولدة، حيث أن سمات الجزء المتولدة تمثل السمات التي تقاطعأو تعرقل إتجاه الضوء الساقط. تم أختبار التقنية على عدد من الأجزاء مختلفة الأشكال، وكانتالنتائج قريبة من الواقع بدقة مقدارها 0.75 ملم بأستخدام المكونات المادية والتهيأة لنظام الرؤيةالمعتمد في هذا البحث، كما أظهرت النتائج المستحصلة صحة المنهجية المقترحة.


Article
Studying Curve Interpolator for CNC System
دراسة استكمال المنحني لنظام مكائن السیطرة الرقمیة

Authors: Maan Aabid Tawfiq --- Laith A. Mohammed --- Abbas M. Jabber Al-Fnzi
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2009 Volume: 27 Issue: 11 Pages: 2205-2222
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

This thesis focuses on developing algorithm to calculate best length linesegments in (u) and (w) directions. By of tool paths for free form surfaces basedon the required accuracy of the manufactured part, which is represented bymathematical curves and surfaces. Bezier method was used to apply the proposedalgorithms. The proposed algorithms consist of two parts; the first part is tocalculate the better length line segment in (u) direction between cutter contactpoints (CC), the second part is to calculate the better line segment in (w) directiondepending on the type of surface, cutter radius, tolerance and height scallop beinggiven. The algorithms are applied in production field such as design of extrusiondies using three types of curve interpolation such as approximation cubic Bezier,interpolator Bezier and compound-CRHS profile die. In this paper, themanufactured parts are machined using a 3-axis CNC milling machine. Themachining operations are simulated using SURFCAM software depending on thedifferent interpolation techniques mentioned. An evaluation test is applied to thethree interpolation methods based on Finite Element Method (FEM) usingANSYS 9.0 software to expect the strain and force required to extrude billetthrough the dies which are designed using the three mentioned interpolationmethods. The G-code programs have been implemented on 5-axis CNC machine(Okuma VH-40-HS dynamic machine), the sample material is (cibatool) and themachining process is achieved without a lubricant at the Protoshop Oy inHelsinki/Finland.

و (u) يركز هذا البحث على تطوير خوارزمية لحساب أفضل طول قطعة مستقيم في اتجاهمسار العدة للسطح يعتمد على الدقة المطلوبة للجزاء المصنع, اي هو ممثل بواسطة الاقواس .(w)والسطوح الرياضية. طريقة بيزر هي الطريقة المستخدمة لتطبيق الخوارزمية عليها. الخوارزميةبين (u) المقترحة تتكون من جزأين, الجزاء الاول هو حساب افضل طول قطعة مستقيم في اتجاه(w) الجزاء الثاني حساب طول قطعة المستقيم الامثل في اتجاه ,(cc) نقاط تماس عدة القطع(height scallop) بالأعتماد على نوع السطح وكذلك على نصف قطر عدة القطع والتجاوز والمعطى. الخوارزمية المقترحة تم تطبيقها في مجال الأنتاج ( تصميم قوالب البثق) بواسطة استخدام(cubic Bezier, interpolator Bezier and ثلاثة انواع مختلفة من الأقواس المستكملة هيفي هذا البحث الاجزاء المصنع هي مشغلة .compound-CRHS extrusion profile die)3- وذلك لغرض أستكمال الطرق axis ذات ثلاثة محاور CNC بواسطة استخدام ماكنة تفريزخلال استخدام هذه الماكنة. تم (gouging) وتحليلها ومقارنتها. حيث تم ايجاد طريقة تتجنب حدوث 2206لمختلف الطرق المستكملة من اجل (SURFCAM) محاكاة عمليات التشغيل باستخدام برنامج يدعىللتقييم طرق (FEA) تقييم وتخميين السطوح قبل تشغيلها. تم أستخدام طريقة العناصر المحددةمن اجل التعرف على الانفعالات (ANASYS الاستكمال الثلاثة من خلال استخدام برنامج ( 9.0تم تطبيقه على (G-code) والقوى المطلوبة لبثق المعدن خلال القوالب المستكملة الثلاثة. ان برنامجالمادة التي تم تشغيلها هي , (Okuma VH-40-HS dynamic machine) ماكنة ذات خمس محاور.(Helsinki/Finland) في فنلندا (Oy) وأن التشغيل تم بدون سائل تبريد في مصنع ,(cibatool)


Article
COMPUTER AIDED SPUR GEAR DATA EXTRACTION BASED ON IMAGE PROCESSING TECHNIQUE
إستخلاص بيانات التروس العدلة المعان بالحاسوب بالأعتماد على تقنية معالجة الصورة

Author: Ali Abbar Khleif
Journal: Iraqi journal of mechanical and material engineering المجلة العراقية للهندسة الميكانيكية وهندسة المواد ISSN: 20761819 Year: 2011 Volume: 11 Issue: 1 Pages: 13-21
Publisher: Babylon University جامعة بابل

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Abstract

ABSTRACTThis paper proposed a computerized methodology of spur gears reconstruction and feature extraction using image processing technique. The methodology was prepared, by building a suitable logical program in Matlab environment, to process the captured gear image using mathematical and logical relationships for the purpose of spur gear data extraction required for 3D spur gear modeling which is include No. of teeth, tooth height, Pitch circle, … etc.The proposed system has been tested on different spur gears, and the extracted data shows reliable spur gear modeling, which generates accurate and efficient model and provides substantial saving in time and cost of production.

الخلاصةيقترح ھذا البحث طريقة معانة بالحاسوب لإعادة إنشاء التروس العدلة وأستخلاص السمات بأستخدام تقنية،(Matlab) معالجة الصورة. تم تھيئة ھذه الطريقة من خلال إنشاء برنامج منطقي مناسب ضمن بيئة الماتلابلمعالجة الصورة الملتقطة للترس باستخدام العلاقات الرياضية والمنطقية لغرض استخلاص بيانات الترساللازمة لنمذجة الشكل ثلاثي الأبعاد للترس والمتضمنة عدد أسنان الترس، إرتفاع السن، دائرة الخطوة، ... الخ.تم أختبار النظام المقترح على تروس عدلة مختلفة، وأظھرت البيانات المستخلصة معولية في نمذجةالتروس العدلة، من خلال توليد تصاميم دقيقة وكفؤة وبالتالي إستثمار زمن وكلفة الأنتاج


Article
The influence of CAD/CAM ceramic and heat processed composite inlays on the fracture resistance of premolars (An in-vitro study)

Authors: Huda A. Abdullah هدى عبد الله --- Inas I. Al-Rawi ايناس الراوي
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2012 Volume: 24 Issue: 4 Pages: 14-18
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: The aim of this in-vitro study was to identify the influence of intracoronal indirect adhesive techniques(heat processed composite (SR Adoro) andcomputer-aided design / computer-assisted manufacturing (CAD/CAM)ceramic (e Max CAD) inlays)on the fracture resistance of maxillary first premolars and to identify the modes offracture of all experimental groups.Materials and Methods: Forty sound freshly extracted upper first premolar teeth were selected then mounted inacrylic blocks, the teeth were divided into four groupsas follow:Group (A): tenintact teeth (control group).Group (B):ten teeth prepared with standardized MOD inlay cavity but not restored. Group(C): ten teeth prepared withstandardized MOD inlay cavity and restored with indirect heat processed composite (SR Adoro).Group (D): ten teethprepared with standardized MOD inlay cavity and restored with CAD /CAM ceramic material (e max CAD).Fracturestrength of the experimented teeth was measured by using universal testing machine (an axial compressiontest).Data were analyzed statistically by ANOVA and least significant difference tests.Results:Group (D) restored with CAD/CAM ceramic inlays showed more resistance to fracture than teeth restoredwith SR Adoro composite inlays group (C), but the values are statistically not significant, using One way ANOVA test ahighly significant differences (P < 0.01) were found among all groups.Conclusions:All CAD/CAM ceramic inlays and 80% of heat processed compositeinlays survived maximum biting forcefor posterior single tooth, so these two types of inlays provide good reinforcement in an extensive MOD cavities inpremolars,The fracture Mode of SR Adoro composite inlays seems to be 80% restorable while CAD/CAM ceramicinlays 90% of it are restorable type of fracture


Article
An in vitro evaluation of fit of the crowns fabricated by zirconium oxide-based ceramic CAD/CAM systems, before and after porcelain firing cycles and after glaze cycles

Authors: Sattar J. A. Hmedat ستار حميدات --- Adel F. Ibraheem عادل فرحان ابراهيم
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2013 Volume: 25 Issue: 1 Pages: 43-48
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: The objective of this in vitro study was to evaluate the vertical marginal fit of crowns fabricated withZrO2 CAD/CAM, before and after porcelain firing cycles and after glaze cycles.Materials and Methods: An acrylic resin model of a left maxillary first molar was prepared and duplicated to haveNickel-Chromium master die. Ten die stone dies were sent to the CAD/CAM (Amann Girrbach) for crownsfabrication. Marginal gaps along vertical planes were measured at four indentations at the (mid mesial, mid distal,mid buccal, mid palatal) before (Time 0) and after porcelain firing cycles (Time 1) and after glaze cycles (Time 2)using a light microscope at a magnification of ~100. One way ANOVA LSD tests were performed to determinewhether the mean and standard deviation of sub group Time 2.Results: The mean values of the ZrO2 CAD/CAM Time 0 were (6.77ƒÊm), Time 1(8.75ƒÊm) and Time 2(10.62 ƒÊm). Oneway ANOVA test revealed highly statistical significance(P<0.01). LSD test results showed that there is highly significantdifference between time (0) and time (2), while there is no any significant difference between time (0) and time (1),and between time (1) and time (2).Conclusions: Within the limitations of this study, it was concluded that the ZrO2 CAD/CAM demonstrated acceptablemarginal fit; The porcelain firing and the glaze firing cycles affected the marginal gap


Article
Iterative Method of Data Transfer from CAD to CAM Systems for the Profile of Stamping Dies
طريقة تكرارية لنقل البيانات من انظمة التصميم المعان بالحاسوب الى انظمة التصنيع المعان بالحاسوب لنماذج قوالب الطبع

Authors: Ali Abbar Khleif --- Ahmed A. A. Duroobi --- Ali Mohammed
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2014 Volume: 32 Issue: 11 Part (A) Engineering Pages: 2714-2721
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

A proposal method for data transfer from CAD to CAM program has been investigated in the present work using iterative process for the stamping dies. The Bezier and B-spline equations forcurves and surfaces of n-degree had been derived as a matrix and formulated using MATLAB program, then a computer program had been constructed for the data transfer as a case study. The procedure of converting the profile of stamping dies from CAD program to CAM program without any geometrical distortion had been presented. The implementation of data transfer and the simulation using UGS(UniGraghics Solutions) program observed that the transformation of any complex profile shape from CAD to CAM program done without any distortion in final shape of the profile in CAM program. The present method matched the experimental result conformity and used in short time as compared with other methods.

تم تحقيق أسلوب مقترح لنقل البيانات من CAD إلى برنامج CAM في العمل الحالي باستخدام عملية تكرارية لقوالب الختم. معادلات بيزر وبي سبلاينللمنحنيات والأسطحمن الدرجة(n) تم اشتقاقها باستخدام برنامج MATLAB لبناء برنامج كمبيوتر لنقل البيانات كحالة دراسية. قدمت إجراءات تحويل نموذج قالب الختم من برنامج CAD لبرنامج CAM من دون أي تشويه في هندسية الشكل. بينت عملية نقل البيانات والمحاكاة باستخدام برنامج UGS بإمكانيه تحول أي نموذج شكليللأشكال المعقدة من برنامج CAD الى برنامج CAM دون أي تحريف في الشكل النهائي. الأسلوب الحالي يطابقالنتيجة التجريبية واستخدامها في وقت قصير بالمقارنة مع الطرق الأخرى.


Article
The influence of recent adhesive onlay fabrication techniques on the fracture resistance of endodontically treated premolars (An in vitro study)

Authors: Zainab Shaker Al-Taii زينب شاكر الطائي --- Inas I. Al-Rawi ايناس الراوي
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2014 Volume: 26 Issue: 2 Pages: 12-17
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: Endodontically treated teeth have low resistance to fracture against occlusal forces. The strengtheningeffect of bonded esthetic onlay restoration on weakened tooth has been reported. This study aimed to assess thefracture resistance of endodontically treated premolars restored with composite with and without cuspal coverageby using direct and indirect techniques. Indirect technique done by CAD/CAM system (computer aided design –computer aided manufacturer) and laboratory processing.Material and methods: Forty human extracted maxillary premolars of approximately comparable sizes were dividedinto four groups: Group (A): Ten endodontically treated teeth directly filled with Filtek Z250xt without cuspalcoverage. Group (B): Ten endodontically treated teeth prepared with onlay cavities and restored directly with FiltekZ250 XT. Group(C): Ten endodontically treated teeth prepared with onlay cavities and restored indirectly with FiltekZ250 XT. Group (D): Ten endodontically treated teeth prepared with onlay cavities and restored indirectly withParadigm MZ100 CAD/CAM blocks. Fracture strength of the samples was measured by using universal testingmachine (an axial compression test). Data were analyzed statistically by one way ANOVA test and least significantdifference test,Results showed that Group A has the lowest fracture resistance value than all experimental Groups and thedifference are highly significant. While Group B has a high significant fracture resistant value than the indirectlyrestored groups. Group C and Group D showed an approximate fracture resistant result (1.13KN and 1.07KNrespectively) and the difference is statistically not significant.Conclusion All CAD/CAM composite onlay, indirect Filtek z250 XT and direct cuspal coverage survived maximumbiting force for posterior single tooth, so these types of onlays provide good reinforcement in an extensive MODcavities in premolars The mode of fracture for Group D was 90% restorable which is higher than group C (80%)restorable and group B (30%) restorable type of fracture


Article
A UNIFIED METHOD FOR B-SPLINE’S SURFACE MODELING (INNOVATIVE METHOD FOR DATA TRANSFORMATION FROM CAD TO CAM PROGRAMS)
طريقة موحدة لنمذجة السطوح( طريقة مبتكرة لنقل المعلومات من برنامج التصميم ))CAD)الى برنامج التصنيع (CAM)

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In present work, a unified method for geometric transfer from CAD to CAM program has been investigated using iterative process. The B-spline objects (curves and surfaces) of 3rd degree one patch matrix had been derived and formulated using MATLAB program to construct a computer program for the geometric transfer as a case study. The procedure of converting the sculpture surfaces from CAD program to CAM program without any geometrical distortion had been presented. The implementation of transfer data and the simulation using UGS program during transformation of any complex profile shape from CAD to CAM program is done without any distortion in final profile in CAM program. It was found that the results obtained by applying the present method which utilizes a less time as compared with the other methods are in a good agreement with the experimental results.

في العمل الحالي تم أجراء طريقة هندسية للنقل من برنامج CAD إلىCAM باستخدام طريقة معدلة .تم اشتقاق وصياغة مصفوفة لرقعة واحدة من الدرجة الثالثة لأجسامB-spline (المنحنيات والأسطح) باستخدام برنامج MATLAB لإنشاء برنامج حاسوبي لنقل البيانات الهندسية كدراسة للحالة. تم تمثيل إجراءات تحويل الأسطح النحتية من برنامج CAD إلى برنامج CAMبدون أي تشوه هندسي .تم تنفيذ نقل البيانات والمحاكاة باستخدام برنامجUGS أثناء تحويل لأي شكل معقد من برنامج CAD إلىCAM بدون أي تشوه في الشكل النهائي في برنامجCAM . وجد ان النتائج التي تم الحصول عليها مطابقة مع النتائج العملية بتطبيق الطريقة الحالية والتي تستغرق وقت اقل مقارنة مع الطرق الاخرى .


Article
A study to compare the internal fitness and marginal gap between single crowns and crowns within three-unite bridge of zirconia substructure fabricated by CAD-CAM system. (An In vitro study)

Authors: Auday M. Asady --- Haitham J Al azzawi هيثم جاسم العزاوي
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2017 Volume: 29 Issue: 1 Pages: 27-31
Publisher: Baghdad University جامعة بغداد

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Abstract

Purpose: the aim of this in vitro study was to compare the marginal gap and internal fitness between single crowns and the crowns within three-unit bridges of zirconium fabricated by CAD-CAM system.Materials and methods: A standard model from ivoclar company was used as a pattern to simulate three-units bridge (upper first molar and upper first premolar) as abutments used to fabricate stone models, eight single crowns for premolar and eight of three units bridges. Crowns and bridges fabricated by CAD-CAM system were cemented on their respective stone models then sectioned at the mid-point buccolingaully and misiodistaly and examined under stereomicroscope.Result: the marginal gap in premolar crowns and premolar within bridge were within the acceptable value 120μm, one –way ANOVA showed that there was significant differences in the internal gaps among the areas. Independent t- Test showed there was significant differences between the premolar crowns and premolar crowns within bridges in marginal opening and cusp tip (lingually and distally)Conclusion: the marginal and internal gaps were in the bridge higher than those in the crowns. The areas of sloped surfaces such as chamfer area, occlusal area and cusp tip had high gap values in comparison with areas of flat surfaces such as axial wall and when the surface area of abutment increased, the marginal and internal gaps of abutment was increase.

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