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Article
Effect of zirconia surface treatments on the shear bond strength of veneering ceramic

Authors: Inas H. Kareem --- Haitham J. Al-Azzawi هيثم جاسم العزاوي
Journal: Journal of baghdad college of dentistry مجلة كلية طب الاسنان بغداد ISSN: 16800087 Year: 2014 Volume: 26 Issue: 3 Pages: 13-17
Publisher: Baghdad University جامعة بغداد

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Abstract

Background: The aim of the study was to investigate the effect of surface treatments of zirconia (grinding andsandblast with 50μm, 100 μm) on shear bond strength between zirconia core and veneering ceramic.Material and methods: Twenty-eight presintered Y-TZP ceramic specimens (IPS e.max ZirCAD, Ivoclar vivadent) werefabricated and sintered according to manufacturer’s instructions. The core specimens were divided randomly in to 4groups, group 1: no surface treatment, group2: zirconia specimens were ground with silicon carbide paper up to1200grit under water cooling, group3: zirconia specimens were ground and sandblast with 100 μm alumina, group 4:zirconia specimens were ground and sandblast with 50 μm alumina. Surface roughness of specimens were analyzedby surface profilometer, then veneering ceramic (IPS e.max ceramic, Ivoclar vivadent) was applied on thespecimens& fired according to manufacturer’s instructions. All specimens were subjected to shear force in a universaltesting machine at a crosshead speed of 1mm/min. The shear bond strength values were analyzed with one-wayANOVA; the fractured surfaces were examined with a stereo-microscope to observe the failure mode.Results: The mean of shear bond strength values in MPa were 24.75 for group 4, (17.72) for group 3, (17.68) for group2,(14.61) for group 1.The airborne-particle abrasion with 50μm group showed significantly higher bond strength thanother groups. The airborne-particle-abraded with 100 μm group was not significantly different from grinding group.Conclusion: With limit of this study, the sandblast with 50 μm alumina was enhance the SBS between zirconia&veneering ceramic, and zirconia-veneering ceramic bonding is not only influenced by surface roughness. But alsomay be other factors

الغرضمن ھذه الدراسھ لفحصتأثیر الطرق المختلفھ لمعاملھ السطح لماده الزركونیم على قوه الربط القصي بین ھیكل الزركونیم وقشره السیرامیك .تم تحضیر ثمان وعشرین عینھ من ماده الزركونیم (زركاد ,ایماكس ,ایفوكلار فیفادینت) حسب تعلیمات المصنّع،وتم توزیع العینات عشوائیاً الى اربع مجامیع:المجموعھ الاولى:لا توجدمعاملھ للسطح ، المجموعھ الثانیھ::شحذ(حك) العینات بأستخدام اوراق الحك(سیلكون كارباید) تدریجیا الى الحجم 1200 مایكرومیتر,المجموعھ الثالثھ :حك العینات ثم تخدیشھا بواسطھالالومینیوم اوكساید حجم ( 100 مایكرون)، المجموعھ الرابعھ: حك العینات ثم تخدیشھا بواسطھ الالومینیوم اوكساید حجم ( 50 مایكرون)، بعد عملیات الحك والتخدیش یتم فحصخشونھ سطح العینات بواسطھ جھاز قیاس خشونھ السطح(البروفایلومیتر)، ثم تم بناء ماده السیرامیك على جمیع العینات ثم تم صھر ماده السیرامیك حسب تعلیمات المصنّع،تم قیاس قوهاحادي الاتجاه، ثم تم فحص العینات بواسطھ المایكرسكوب(ستیریو مایكرسكوب) لتحدید نوع الكسر لكل ANOVA الربط باستخدام جھاز(الانسترون)،تم اجراء الاحصائي بواسطھعینھ.اظھرت النتائج ان معدل قوه الربط للمجموعھ الرابعھ( 24,75 ) میكاباسكال,وللمجموعھ الثالثھ( 17,72 ) میكاباسكال,وللمجموعھ الثانیھ ( 17,68 ) میكاباسكال،وللمجموعھ الاولى(14,61 ) میكاباسكال، قوة الربط للمجموعھ الرابعھ مجموعھ الحك ثم التخدیش ب 50 مایكرون) كانت اعلى من المجامیع الاخرى,واظھرت النتائج انھ لایوجد فرق بین المجموعھالثالثھ(مجموعھ الحك ثم التخدیش ب 100 مایكرون) والمجموعھ الثانیھ(مجموعھ الحك فقط).ضمن حدود ھذه الدراسھ فان عملیھ التخدیش ب 50 مایكرون بعد عملیھ الحك تزید قوه الربط بین ھیكل الزركونیم و قشره السیرامیك,وقد اظھرت الدراسھ ان قوه الربط بین المادتین لاتتأثر فقط بخشونھ سطح الزركونیم .


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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