البحث — المستودع الرقمي العراقي

نتائج البحث: 3 من أصل 3

كفاءة التنظيف لمبرد XP - endo Finisher بالمقارنة مع انظمة الارواء بالتردد الصوتي والتردد فوق الصوتي : دراسة خارج الجسم Cleaning Efficiency of Xp - Endo Finisher File In Comparison With Sonic And Ultrasonic Irrigation Systems (An In Vitro Study)

اسم المؤلف: مهند غازي عزاوي

اسم المشرف: جمال عزيز مهدي

الموضوع العام: طب الاسنان

السنة: 2016

الموضوع الدقيق: معالجة الاسنان

الدرجة: ماجستير

الجامعة: الجامعة المستنصرية

اللغة: الانكليزية

مكان الجامعة: بغداد

الصفحات الاولى:

المستخلص: This in vitro study was conducted to evaluate and compare the efficiency of XP - endo Finisher, EndoActivator sonic irrigation system and the NSK Varios ultrasonic irrigation system in removing dentin debris at three levels of root canals and to compare the percentage of dentin debris among the three levels for each irrigation system. Sixty freshly extracted upper molar teeth with straight palatal root canals were used in this study. All canals were prepared with ProTaper NEXT rotary files to size X4, 1mm from the anatomic apex with irrigation of 1 ml 2.0% NaOCl between the files. After that the samples were randomly distributed into three groups of twenty samples each, irrigated with 1 ml 2.0% NaOCl, followed by irrigant activation for 60 seconds with three different irrigation systems; group one, by using the XP - endo Finisher; group two, by sonic irrigation using the EndoActivator system; and group three, by ultrasonic irrigation using the NSK Varios, then all the groups received a final rinse of 5 ml 2.0% NaOCl. After the final rinse, the roots were split longitudinally into two parts and photographed with a professional digital camera. The digital images were then transferred into a computer and opened in Adobe Photoshop CC 2015 software and the canal was magnified 200x. The percentage of dentin debris remaining at the apical level (0 - 3mm), the middle level (3 - 6mm) and the coronal level (6 - 9mm) was calculated by dividing the number of pixels occupied by the dentin debris at each level by the number of pixels representing the entire canal area. Data were analyzed statistically by ANOVA and LSD at 1% and 5% significant levels. This study showed that cleaning the canal with the XP - endo Finisher or NSK Varios ultrasonic irrigation system resulted in significantly cleaner canals (P<0.01) than the EndoActivator sonic activation system at all canal levels. The XP - endo Finisher resulted in cleaner canals than the NSK Varios ultrasonic irrigation system at all levels, but the difference is not statistically significant (P>0.05). The apical level of all the canals showed a greater amount of dentin debris (P<0.01) compared to the middle and coronal levels, regardless of the irrigation device used.

تحليل القوى المستقرة لثلاثة انواع مختلفة من المواد الراتنجية بطريقة عملية وعددية Static Stress Analysis For Three Different Types of Composite Materials Experimentally And Numerically

اسم المؤلف: محمد وائل سعيد

اسم المشرف: حكمت عبد الرحيم الغراوي

الموضوع العام: طب الاسنان

السنة: 2016

الموضوع الدقيق: معالجة الاسنان

الدرجة: ماجستير

الجامعة: الجامعة المستنصرية

اللغة: الانكليزية

مكان الجامعة: بغداد

الصفحات الاولى:

المستخلص: t is important to analyze and compare the stresses induced in different composite material types during load application to know which type of composite will behave as preferred under the loading in the same circumstances. This study aimed at measuring and comparing the stress induced in Filtek ™ Z350 XT (3M ESPE) composite, Tetric EvoCeram ® (ivoclar vivadent) composite and BRILLIANT ™ NG (Coltène/Whaledent) composite experimentally and numerically.Experimental analysis included cavity preparation in the Brass block with a concave (U - shape) cavity which represent a proximal cavity preparation. This cavity was used as a mold for sample preparation. The internal line and point angles of the cavity (mold) were rounded and the dimensions of the cavity (mold) were 10mm × 10mm × 10mm (Total height of the box × Width of the top side of box × Length of the top side of box). The internal diameter of “U” was 5 mm at the base of the box. The mold was used to prepare forty five samples, fifteen samples for each type of composite material. So, three groups were prepared : Group A filled with Filtek ™ Z350 XT composite material, Group B filled with Tetric EvoCeram ® composite material and Group C filled with BRILLIANT ™ NG composite material.Electrical strain gauge (Tokyo Sokki, Japan) was embedded in composite material horizontally at the same level in each sample. Static load of 50 N was applied perpendicular to the center of the occlusal surface of composite restoration in each sample testing. The strain gauge was connected to a Wheatstone bridge with a signal amplifier which measures the strain during load application and gives the amplified signal from (0 to 4.8 volt) to LabJack data acquisition where a stream software give the final values of strain with the aid of a scaled equation of voltage. Then, the von Mises stress (effective stress) was calculated by using equations. Numerical analysis was done by using ANSYS 16.1 - (2015) (finite element tool) software that was used to create the 3 - Dimensional models represented the same materials and dimensions used experimentally. The physical characteristics of the composite models were inserted in the software which included Elastic modulus and Poisson’s ratio (?). Analysis was selected in a finite element method according to boundary conditions. A mesh size and an element size were estimated during the study. The stresses were calculated at static load of 50 N with the ANSYS 16.1 - (2015) software.The data were analyzed statistically by One - way ANOVA test and Least Significant Difference (LSD) test. One - way ANOVA test and LSD test results showed that there was a highly significant difference (P<0.001) presented between groups A and B, groups A and C and between groups B and group C. The Stress induced in BRILLIANT ™ NG composite after load application was the lowest stress value followed by Tetric EvoCeram ® composite and followed by Filtek ™ Z350 XT composite which was the highest stress value experimentally and numerically.

التسرب المايكروي لنوعين من القشرة الخزفية بوجود وعدم وجود الحشوة الراتنجية تحت جهاز التحميل الدوري Microleakage of Two Porcelain Laminate Veneers Materials With And Without Composite Filling Under Cyclic Loading

اسم المؤلف: ياسر علي النقيب

اسم المشرف: عمار عطا الله علي السعدي

الموضوع العام: طب الاسنان

السنة: 2016

الموضوع الدقيق: معالجة الاسنان

الدرجة: ماجستير

الجامعة: الجامعة المستنصرية

اللغة: الانكليزية

مكان الجامعة: بغداد

الصفحات الاولى:

المستخلص: Although investigators have evaluated the microleakage of porcelain laminate veneers, there is insufficient data regarding the durability of porcelain laminate veneers bonded to existing composite fillings. The aim of this study was to evaluate the microleakage of porcelain veneers restorations fabricated from two types of CAD/CAM ceramic blocks bonded to teeth with or without composite class V composite filling.Forty eight sound, crack - free human maxillary first premolar extracted for orthodontic reasons were selected for this study. Teeth were divided randomly into.2 main groups, which further divded into 2 groups (12 sample each). Group A1 : IPS e.max CAD veneers with standardized class V composite filling, Group A2 : IPS e.max CAD veneers, Group B1 : VITA Suprinity veneers with standardized class V composite filling, Group B2 VITA Suprinity veneers. The class V cavities was restored with nanofilled composite (Filtek™ Z350 XT, 3M ESPE). Standard veneer preparations were made using Ceramic veneer burs system (Keramikveneers. de, Komet). All the veneers were milled by CAD/CAM technology (CEREC MC XL, inLab SW 15, Sirona Dental Systems) Composite fillings (groups A1 and B1) were sandblasted with alumina oxide.Porcelain veneers were cemented in place using light - cured resin cement (Rely Veneer Cement, 3M ESPE), Then the specimens were stored at 37? in distilled water for 2 weeks. Then mechanical load cycling (50,000 load cycle of 49 N at 2.5 Hz) and thermocycling procedure (500 cycles of 5 - 55 Co with 20 sec dwell time) were done. The specimens’ crowns were immersed in 2% methylene blue dye for two days, then mounted in clear acrylic before sectioning with a 0.35 mm microtome. Microleakage percentage were recorded using stereomicroscope and ImageJ program. Results were checked for normality of distribution (Kolmogorov - Smirnov test and Shapiro - Wilk test), and were analyzed with twoway ANOVA and independent samples t - tests. Two way ANOVA shows the significant effect of type of ceramic restoration and the highly significant effect of composite filling, however, the interaction between the main factors was non - significant. The results showed that the lowest mean of microleakage percentage was recorded for group A2 (4.6058% ± 1.5091) which considered statistically significant compared to group B2 (6.105%±1.456), and statistically highly significant compared to group A1 (6.6075%±1.3259) while group B1 recorded the highest mean of microleakage percentage (7.3158%±1.38713). In conclusion, the type of ceramic restoration and the presence of class V filling both had significant effects on microleakage of porcelain veneers. IPS e.max CAD veneers had significantly lower microleakage percentages compared to VITA Suprinity veneers. The presence of class V composite filling within the cervical finishing line of porcelain veneers had a highly significant higher microleakage percentage compared to groups without composite filling.