research centers


Search results: Found 3

Listing 1 - 3 of 3
Sort by

Article
Dimensional accuracy of impression tec-hniques for the endosteal implants (An in vitro study): Part I

Authors: Nadira A Hatim --- Basim M Al–Mashaiky
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2007 Volume: 7 Issue: 9 Pages: 20-31
Publisher: Mosul University جامعة الموصل

Loading...
Loading...
Abstract

Aims: To detect the most accurate impression materials and technique to transfer single or multiple implants position from the master model to the stone dies by two methods of measurement. Materials and methods: Two master models (Cl III Kennedy with single implant Frialit–2, and Cl II free end saddle with double implants) were fabricated. Four impression techniques were used (direct, and indirect, each with one, and two steps) using condensation, addition (heavy and light consistencies) and addition (medium consistency) silicone impression materials. Five impressions were taken for each technique to produce a total number of 100 stone casts. A mechanical apparatus was carefully designed to allow constant repeatable position of stock impression tray to the master model, and to allow vertical removal of the impression tray that helps to standardize the path of removal. The measurements were performed by using digital caliber and optical micrometer microscope. Results: Showed that the direct (open tray) two steps technique was the accurate technique for transferring implant position to the laboratory cast. The two steps impression technique was the most accurate one than one step. There were no significant differences between single, and double implants. There was significant difference between the two methods of measurements in (Z) axis for both single and double implants case. Conclusion: The direct (open tray), two steps impression technique, and addition impression material is the most accurate technique. The numbers of dental implants had no significant effect on accuracy of stone cast.


Article
Dimensional accuracy of impression techniques for the endosteal implants (An in vivo study): Part II

Authors: Nadira A Hatim --- Basim M Al–Mashaiky
Journal: Al-Rafidain Dental Journal مجلة الرافدين لطب الأسنان ISSN: 18121217 Year: 2007 Volume: 7 Issue: 10 Pages: 131-137
Publisher: Mosul University جامعة الموصل

Loading...
Loading...
Abstract

Aims: To determine the most accurate impression techniques and materials to transfer the exactposition of a single implant to stone die to construct the prosthesis for selected clinical cases. Materialsand methods: Five clinical cases were selected with special criteria to construct implant (Frialit–2)prosthesis on a stone die with high accuracy according to the results of study. Four impressiontechniques were used (direct and indirect, each with one and two steps) using condensation, addition(heavy, medium and light consistencies) silicone impression materials. Ten impressions were taken foreach patient to produce a total number of 50 stone casts. The direct and indirect measurements wereperformed by using digital vernier. Results: The significant differences between the impressiontechniques at the three axes of dimensions (p ≤0.05) were applied clinically to construct the fixedprosthesis for each patient. The results of this study showed that the high dimensional change oflaboratory cast was related to indirect one step impression technique to transform the implant positionfrom patient mouth to laboratory cast. Addition curing (medium consistency) silicone impressionmaterial produced the lowest accurate stone die. Conclusions: The results of this study showed that thedirect two steps impression technique was the accurate impression technique for transformation ofimplant position from patient mouth to laboratory cast. Additional curing (light and heavy consistency)silicone impression material produced the most accurate stone die and gave a successful treatment tothe patient.


Article
Influence of Heat Treatment Conditions on Microstructure of Ti- 6Al-7Nb Alloy As Used Surgical Implant Materials

Authors: Abdulsalam K. Swadi --- Thair L. Alzubaydi --- Sami Abualnoun Ajeel
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2007 Volume: 25 Issue: suppl.of No.3 Pages: 431-442
Publisher: University of Technology الجامعة التكنولوجية

Loading...
Loading...
Abstract

The study involves mechanical deformation and heat treatment effect onthe microstructure of the Ti-6Al-7Nb alloy which is used as surgical implantedmaterials. The observed properties of (alpha-beta) Ti-based alloy are stronglydependent on their microstructures. These alloys are heat treated by solutiontreatment and aging (STA) as an effective strengthening method for (alphabeta)titanium alloys.Ti-6Al-7Nb alloy is hot rolled in the (alpha-beta) field and subjectedto solution treatment above and below its beta transformation temperature.The solution treatments are applied at three different temperatures (850oC,930oC and 950oC) for one hour to these treatments. The solution treatmentspecimens are water quenched (WQ), normalizing [air cooled (AC) andannealed,[ furnace cooled(FC)] and subsequently aged the quenched andnormalized specimens at 550oC for 4 hours.Changes in the microstructure were observed from heat treatmentaction using optical microscopy, Atomic Absorption Spectroscopy (AAS) andphases analysis by X-ray diffraction (XRD). The microstructure examinationresults for as received alloy indicate alpha grains within a b- transformedmatrix. The results also indicate that the grain size and percent of a /b for theheat treated specimens depend on heat treatment type and cooling media. Themicrostructure of specimens heat treated at 950oC with air cooled shows fineduplex (a /b) structures which have excellent properties for surgicalimplanted field applications.

تتضمن الدراسة تأثير التشكيل الميكانيكي والمعاملات الحراريه على التراكيب المجهريةالمستخدمة في الزوارع الجراحية. لوحظ بأن خواص سبيكة التيتانيوم (Ti-6Al-7Nb) لسبيكة) تعتمد بشدة على التراكيب المجهرية هذه. تعامل هذه السبائك بطريقة a / b ثنائية الطور (). يتم a / b المعاملة المحلولية والتعتيق كطريقة فعالة لتقوية سبائك التيتانيوم ثنائية الطور (درفلة هذه السبيكة على الساخن في منطقة (الفا- بيتا) وتجري لها معاملة محلولية فوق وتحتدرجة حرارة تحول الطور بيتا.(o ٩٥٠ م , o ٩٣٠ م , o استخدمت المعاملة المحلولية بثلاث درجات حرارية هي ( ٨٥٠ موبزمن قدره ساعة واحدة لجميع تلك المعاملات . تبرد هذه السبيكة بعد المعاملات اعلاه بثلاثاوساط تبريد هي التبريد السريع (تبريد بالماء) ، والمعادلة (تبريد بالهواء) والتلدين (تبريدلمدة اربعة ساعات للنماذج التي o داخل الفرن). يتم بعدها اجراء عملية التعتيق عند ٥٥٠ متم تبريدها (بالماء والهواء).لوحظ حصول تغيرات في البنية المجهرية بفعل هذه المعاملات بأستخدام المجهرأظهرت .(XRD) الضوئي، طيف الامتصاص الذري وتحليل الاطوار بأستخدام حيود الاشعةنتائج الفحص الدقيق للسبيكة (كما استلمت) على حبيبات الفا في ارضية بيتا .تبين النتائج ايضاًان نسبة وحجم حبيبات الفا / حبيبات بيتا للنماذج التي عوملت حرارياً بأنها تعتمد على نوعتلك المعاملة ووسط التبريد. تشير نتائج البنية المجهرية لنماذج السبيكة المعاملة حرارياً عند) الذي يمتاز بأفضل الخواص a / b وتبريد بالهواء الى وجود تركيب مزدوج دقيق( o ٩٥٠ مالتطبيقية في مجال الزوارع الجراحية.

Listing 1 - 3 of 3
Sort by
Narrow your search

Resource type

article (3)


Language

English (3)


Year
From To Submit

2007 (3)