Thesis (M.Sc.)-Cairo University, 2023.

Bibliography: pages 84-104.

Aim: To Compare change in deformation of the nylon cap between three different implant analog angulations of OT equator smart box attachment for a two implant-retained mandibular overdenture when subjected to cycles 75 000 and 150 000 of chewing cycles equivalent to 6 months and 12 months). Methodology: A completely edentulous mandibular stone model was pictured via digital camera photo extra-oral lab to produce a picture image J software. then file STL was used to virtually plan for two-implant analogs in the canine area bilaterally. Three groups were planned; In group I (straight); two implants analog were installed parallel to each other with a zero-degree difference in implant analog angulations, In group II (Buccal inclination) the left implant analog socket (A) was straight, and right implant analog socket (B) hole was installed with a 25degrees buccal angulation and group III ( Distally inclined) the left implant analog socket (A) straight and right implant analog socket (B) with a 25degrees distal angulation. Simulation of the oral mucosa was carried out by preparing a 2mm cutback on the residual alveolar ridge extending between the retromolar pads bilaterally. The overdenture was then designed and a space for the attachments housing of the three different angulations were designed to be added in the fitting surface of the overdenture to facilitate the pickup procedure. Nine models and nine overdentures were 3D-printed to be used in the present study. For all groups, the implants were installed in the prepared sockets by using self-cure acrylic resin, and then the smart box OT equator attachment was attached to the implant analogs and then picked up in the fitting surface of the denture. The geometric center was identified and then the initial wear (baseline values) was recorded for all groups using the universal testing machine. Then all groups were subjected to 75000 cycles and 150000 cycles using the chewing simulator and then the changes in the diameter of each nylon cap was carried out using the electron microscope, the values were recorded at base line (new cap) after 75,000 cycle and after 150,000 cycle. The mean change in diameter of the left implant (A), and right implant (B) for each group was then tabulated and statistically analyzed. Shapiro Wilk and Kolmogorov test was use for normality exploration. One Way ANOVA was used for multiple comparisons followed by Tukey`s Post Hoc test. Repetitive One-Way ANOVA for different intervals followed by Tukey`s Post Hoc test. Paired -t-test was used to measure changes in wear before and after the different cycles. The significant level (P-value) was determined to be significant as P-value > 0.05. Results: After being subjected to 75,000 cycles (equivalent to 6 month) there was a statically significant difference in the change in diameter of the left implant nylon cap (A) between the three groups. Group II showed the greatest change in diameter (1.86±0.33), followed by group I (1.49±1.09), while for group III there was a negative change in diameter (-0.17±0.45) (P=0.02).While for the right implant nylon cap (B) there was no statically significant difference in the change in diameter between the three groups ; Group I showed the greatest positive increase in diameter (1.30±1.15), followed by group III (0.04±0.21) while group III showed a negative change in diameter (-0.32±0.22) (P=0.06). There was no statistically significant difference in the change of the diameter between the three groups of the left implant nylon cap (A) after being subjected to 150,000 (equivalent to 12 month). Group II (2.23±0.30) showing the greatest positive change followed by group I (2.20±1.63), and group III showing the least change ( 0.01±0.26) (P=0.059). Similarly for the right implant nylon cap (B) there was no statistically significant difference in the change of the diameter between the three groups ;Group I showing the greatest positive change (0.95±0.65) , followed by Group III ( 0.09±0.68), and the least change in diameter was recorded by group II ( 0.03±0.44) (P=0.1). Conclusion: Smart box OT equator attachment showed the greatest significant deformation ( wear) with straight parallel implants after chewing cycles equivalent to 6- and 12 months. The Smart box OT equator with 25 degrees distally inclined implant showed the least deformation(wear) after chewing cycles equivalent to 6 months. While after chewing cycles equivalent to 12-month the 25-degree buccally inclined implants showed the least deformation (wear).

الهدف: مقارنة التغييرات في القدرة على الاحتمال بين ثلاث زوايا تناظرية مختلفة للزرع لمرفق الصندوق الذكي لخط الاستواء OT لاثنين من أسنان الفك السفلي الزائدة المحتفظ بها عند إخضاعها لدورات مضغ تبلغ 75000 و150000 ما يعادل 6 أشهر و12 شهرًا. المنهجية: تم أخذ صورة عن طريق كاميرا ميكروسكوب نموذج حجر الفك السفلي عديم الأسنان بالكامل باستخدام صورة ميكروسكوبية مختبري خارج الفم لإنتاج صورة عن طريق سوفت وير Image J تم بعد ذلك استخدام ملف STL للتخطيط فعليًا لنظيرين مزروعين في منطقة بشكل ثنائي. تم التخطيط لثلاث مجموعات. في المجموعة الأولى (مستقيم)؛ تم تركيب غرستين تناظريتين بالتوازي مع بعضهما البعض مع اختلاف درجة الصفر في الزوايا التناظرية للزرعة، في المجموعة الثانية (ميل الشدق) كان التجويف التناظري للغرسة اليسرى (A) مستقيمًا، وتم تركيب فتحة التناظرية للزرعة اليمنى (B) مع زاوية شدقية 25 درجة والمجموعة الثالثة (مائلة إلى أقصى الحدود) المقبس التناظري للزرعة اليسرى (أ) المقبس التناظري المستقيم والأيمن (ب) مع زاوية بعيدة 25 درجة. تم إجراء محاكاة للغشاء المخاطي للفم من خلال تحضير قطع بمقدار 2 مم على الحافة السنخية المتبقية الممتدة بين الوسادات خلف الرحى بشكل ثنائي. تم بعد ذلك تصميم طقم الأسنان الزائد وتم تصميم مساحة لمبيت الملحقات للزوايا الثلاثة المختلفة ليتم تضمينها في السطح الملائم لطقم الأسنان الزائد لتسهيل عملية الالتقاط. تمت طباعة تسعة نماذج وتسعة أطقم أسنان ثلاثية الأبعاد لاستخدامها في هذه الدراسة. بالنسبة لجميع المجموعات، تم تثبيت الغرسات في التجاويف المجهزة باستخدام راتنجات الأكريليك ذاتية المعالجة، ثم تم ربط ملحق خط الاستواء للصندوق الذكي OT بنظيرات الزرع ثم تم التقاطه في السطح المناسب للجهاز.

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Text in English and abstract in English.