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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.


Article
The Influence of Different Fabrication and Impression Techniques on the Marginal Adaptation of Lithium Disilicate Crowns (A comparative in vitro study)

Authors: Shatha Saadallah شذى سعدالله --- Abdul Kareem J. Al-Azzawi عبدالكريم العزاوي
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2017 Volume: 29 Issue: 4 Pages: 20-26
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: The marginal adaptation has a key role in the success and longevity of the fixed dental restoration, which is affected by the impression and the fabrication techniques .The objective of this in vitro study was to evaluate and compare the marginal fitness of lithium disilicate crowns using two different digital impression techniques (direct and indirect techniques) and two different fabrication techniques (CAD/CAM and Press techniques).Materials and Methods: Thirty two sound upper first premolar teeth of comparable size extracted for orthodontic reason were selected in this study .Standardized preparation of all teeth samples were carried out with modified dental surveyor to receive all ceramic crown restoration with 1 mm deep chamfer finishing line, 4 mm axial length and 6 degree convergence angle. Half of the teeth were duplicated and poured in type IV dental stone to have sixteen dies and then these dies and the remaining teeth divided in to two groups according to the type of digital impression techniques (n=16) as follow: Group A: Indirect digital impression technique scanned by inEos X5 camera; Group B: Direct digital impression technique scanned by CEREC AC Omnicam camera. Each group was subdivided according to the technique of fabrication into two subgroups (n=8): Press technique using IPS e-max press (A1, B1); CAD/CAM technique using IPS e-max CAD (A2, B2).Marginal gaps were evaluated on the prepared teeth at four defined points on each aspect using digital microscope at a magnification of (280X). One way ANOVA and LSD tests were used to identify and localize the source of difference among the groups.Results: The results showed that indirect digital impression with IPS e-max CAD/CAM group A2 revealed the poorest marginal integrity with (55.93 μm ± 3.300). Group B2 and group A1 were next in line with(44.49 μm ± 6.840 and 37.74 μm± 5.433) respectively, while in the first group of restorations, the result of 29.9 μm ± 5.534 obtained with direct digital impression with pressable ceramic was clearly better.Conclusions: All the tested digital impression techniques showed clinically acceptable accuracy and intraoral scanning with pressable ceramic significantly enhanced the marginal fit


Article
Failures of Porcelain Laminate Veneers Using Different Techniques of Bonding, A Comparative Study

Authors: Safa Adnan Gaeed --- Prof. Ammar Atta-Allah Ali
Journal: Journal of Oral and Dental Research مجلة طب الفم والاسنان ISSN: 23106417 Year: 2017 Volume: 4 Issue: 1 Pages: 35-46
Publisher: Iraqi Association for Oral Research الجمعية العراقية لبحوث طب الفم

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Abstract


Article
Evaluation of Combined Sewer Network Design Using GIs and Multi Criteria Decision Making (MCDM)

Author: Zeena Adil Najeeb
Journal: AL-NAHRAIN JOURNAL FOR ENGINEERING SCIENCES مجلة النهرين للعلوم الهندسية ISSN: 25219154 / eISSN 25219162 Year: 2017 Volume: 20 Issue: 5 Pages: 1143-1153
Publisher: Al-Nahrain University جامعة النهرين

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Abstract

In this Research Geometric network modeled for combined sewer network pipe design were establish for AL-Nahrain University site by Arc map and GIS tools which is built within a feature dataset in the geodatabase. The geometric networks consist of lines and points which refer to the pips and junctions respectively. Data were collected for manholes location, flow direction, slop and elevations. Many influencing features were used in multi criteria decision making (MCDM) vie Super decision 2.0.8 software which be selected to fix the problem and find the alternative for two sewer networks. The first sewer network (A) considered the existing one and the second was the alternative one (B) , Bentley sewer Cad V8 have the ability to work with ArcGIS program as a part of it by export data as shape file from GIS then by scenario report form program that exam the part of network and find the alternative . The purpose of this research was to use this data GIS model, and developed it in future event by predicting some function like rainfall amount or adding population increasing density represent by both student and employers. As a result using (ANP) analysis this method allow to make consideration alternative we found the network(A) need to add some routs depending in the amount of person daily consumption with the amount of rain fall Intensity for the next years., judgment based on expert advice is obtained through pair-wise comparisons. Afterwards, the corresponding matrix is established, and sanity of the comparisons is checked by super decision software. Finally Existing network (A) shows highest benefit score and efficiency in this time for steady case depends on two criteria coast and optimum flow for person consumption.

في هذا البحث تم اعتماد تصميم شبكة التصريف الهندسية لمياه المجاري والامطار للابنية المضافة والابنية قيد الانشاء لموقع جامعة النهرين بأستخدام أدوات نظام المعلومات الجغرافي والتي تم بناءها بأستخدام قاعدة بيانات الجيؤيد وتتألف الشبكة من خطوط ونقاط والتي تشير الى أنابيب التصريف ونقاط التقاطع بالتتابع . البيانات التي تم جمعها من مواقع المنهولات هي أتجاه التصريف ,الميل,والمناسيب . العديد من المحددات المؤثرة تم اعتمادها بأستخدام برنامج افضل صانع قرار والذي اختير لتثبيت المعوقات وأيجاد البدائل للشبكة الحالية والشبكة البديلة المستقبلية. بالاعتماد على التحليل الشبكي للمعايير وهي افضل تصريف,الكلفة ,مقدار شدة الامطار,الكثافة السكانية حيث وجد ان الشبكة الحالية جيدة وكفوءة في الحالة الثابتة بالاعتماد على معياري الكلفة وأفضل تصريف اشارة الى الاستهلاك اليومي للفرد .


Article
A Comparitive Study of CNC Milling Cutting Path Strategies
دراسة مقارنة لستراتيجيات مسار القطع باستخدام مكائن التفريز المبرمجة

Authors: Ali Abbar Khleif علي عبار خليف --- Majeed Nemat مجيد نعمت محمد --- Hasan Nemah Khniefer حسن نعمه خنيفر
Journal: AL-NAHRAIN JOURNAL FOR ENGINEERING SCIENCES مجلة النهرين للعلوم الهندسية ISSN: 25219154 / eISSN 25219162 Year: 2017 Volume: 20 Issue: 1 Pages: 214-221
Publisher: Al-Nahrain University جامعة النهرين

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Abstract

This paper investigates the effect of cutter path used in the milling process on the produced surface roughness using two different tools. The cutting paths which are named as; one directional, zigzag , Morph, overlap spiral and spiral are considered as cutter path strategies. The cutter path strategies greatly influenc the surface finish of the work pieces. The objective of this study is to investigate the best cutting characteristics and effects of cutting path for aluminuim using end mill and ball mill tools. MASTER CAM software has been used in design and producing NC CODE. The results indicate that the raw tool path strategy and flat end mill tool gives minimum roughness value with (0.15µm), while the spiral tool path strategy and ball end mill tool gives minimum roughness value with (0.76µm).

يتناول هذا البحث تأثير مسار عدة القطع بالتفريز على مقدار الخشونة السطحية الناتجة باستخدام عدتي قطع مختلفة. تم أعتماد مسارات القطع المعروفة بالأتجاهي، المتعرج، خلال عملية دوران العدة، والمسار الحلزوني للعدة. تعتبر هذه المسارات مؤثرة جدا على مقدار الخشونة السطحية للمشغولات الناتجة. ان اهمية البحث تتضمن الحصول على افضل خصائص لمسار القطع لعينات من الألمنيوم باستخدام عدد قطع بالتفريز ذات نهايات مستوية وكروية. تم في هذا البحث استخدام برنامج (MASTER CAM) لغرض النمذجة والحصول على الرموز التشغيلية الخاصة بمكائن القطع المبرمج. بينت النتائج بان المسار الخام الاتجاه المنتج بواسطة عدة تفريز ذات نهاية مستوية يعطي اقل قيم للخشونة السطحية (0.15µm)، بينما يوفر المسار الحلزوني المنتج باستخدام عدة ذات نهاية كروية اقل قيمة للخشونة السطحية (0.76µm).

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