جستجوی مقالات مرتبط با کلیدواژه « interface » در نشریات گروه « پزشکی »
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Objectives
Implant-retained maxillofacial prostheses have proven to be more successful than conventional adhesive-retained prostheses. Implants enhance prosthesis stability and retention through retentive attachments. However, a faulty abutment-implant interface in terms of complete seating and passive fit could be responsible for mechanical and/or biological complications. This case report describes a simple imaging method to check this adaptation.
CaseIn our case, two shoulder type maxillofacial implants with 4 mm length and diameter were placed with 15 mm distance using a surgical guide. After completion of the healing course and making an impression, a metal bar attachment was made and tried on. In addition to using conventional methods to check the complete and correct seating of the suprastructure (bar attachment), a modified posterior-anterior radiograph with a 15-degree downward head tilt was taken. After confirming the seating of the attachment, the auricular prosthesis was made accordingly.
ConclusionUse of radiography to ensure the seating of intraoral implant-supported frameworks is common and accurate. However, there is no radiographic imaging method to check the fit of extraoral implant-supported substructures. This case report described a simple and effective radiographic technique for auricular implant supported by a substructure which is especially important in case of presence of thick skin around the implants, which compromises the accuracy of direct exploring.
Keywords: Maxillofacial Prosthesis, Bone-Implant, Interface, Radiography} -
BackgroundThis study was conducted to assess the accuracy of dose calculation near the air-phantom interface of a heterogeneous phantom for Acuros XB (AXB) and Anisotropic Analytical Algorithm (AAA) algorithm of a 6-MV flattening-filter-free beam, compared with film measurements.Materials And MethodsA phantom included air gap was specially manufactured for this study. In order to evaluate the dose near air gap-phantom interface, Eclipse treatment planning system equipped both AXB and AAA was used for the dose calculations. Measurements in this region were performed with radiochromic film. The central-axis dose (CAD) and off-axis dose (OAD) between calculations and measurements were analyzed for various field sizes and air gaps. The root-mean-square-error (RMSE) was used to evaluate the difference between the calculated and measured OAD. In order to quantify agreement between the calculated and measured dose distributions, the gamma analysis was performed with the 2%/2 mm and 3%/3 mm criteria.ResultsFor all fields traveling through 1 and 3 cm air gap, the maximum difference in the calculated CAD was -5.3% for AXB and 214.8% for AAA, compared to the measured CAD. For the RMSE between the calculated and measured OAD, the calculated OAD using AXB showed interval in the RMSE (from 4.4 to 12.7) while using AAA indicated broad (from 7.7 to 101.0). In addition, the gamma passing rates showed that AXB was higher agreement than AAA.ConclusionThis study demonstrated that AXB was more accurate in heterogeneous media near air-phantom interface than AAA when comparing the measured data.Keywords: Acuros XB, anisotropic analytical algorithm, heterogeneous media, FFF, interface}
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IntroductionThis study aimed to evaluate the dentin-sealer interface in three different sealers using scanning electron microscopy (SEM).
Methods and Materials: Thirty extracted human single-rooted teeth were prepared using ProTaper rotary files and were randomly divided into three groups (n=10) including BC Sealer, AH-Plus and Dorifill. The root canals were filled with cold lateral condensation technique and stored for 7 days in 100% humidity at 37°C. Cross sections were prepared from the coronal, middle, and apical sections of the roots. Then SEM images were taken and the width of gaps was measured by software. Sectional images were evaluated by two endodontists. Data were analyzed using two- and one-way ANOVA and Kruskal-Wallis tests.ResultsThe mean gap width was significantly lower in coronal area in BC Sealer group compared to Dorifill (P=0.043) and likewise in AH-Plus group compared to Dorifill (P=0.018). There was no significant difference between BC Sealer and AH-Plus group in this area (P=0.923). No significant difference was detected in apical and middle zones among three sealers (P=0.367 and 0.643, respectively). Dentin-sealer interface showed no significant difference in three sealers in the apical area (P=0.051), but dentin-BC Sealer interface was better than AH-Plus in middle and coronal areas, and both outperformed Dorifill (P=0.001).ConclusionBC Sealer and AH-Plus had less gaps than Dorifill in coronal area. In addition, BC Sealer had better dentin interface in middle and coronal area compared to AH-Plus, and both performed better than Dorifill. Reverse relationship was observed between the mean gap width and dentin-sealer interface quality.Keywords: Endodontic Sealer, Interface, Gap, Root Sealer, Scanning Electron Microscopy} -
Backgroud: Protein-protein interaction, plays a key role in signal transduction in signaling pathways. Different approaches are used for prediction of these interactions including experimental and computational approaches. In conventional node-edge protein-protein interaction networks, we can only see which proteins interact but ‘structural networks’ show us how these proteins interact which can give us so much information about the network. Structural networks help us understand the molecular basis of cellular functions and regulatory mechanisms in signaling pathways. In this study, we aimed to construct a structural network for a part of cAMP signaling pathway which has PKA (cAMP-dependent protein kinase catalytic subunit alpha) as the hub.Materials And MethodsA part of cAMP signaling pathway was selected from kegg database and interactions of PKA as hub protein with some of its partners were achieved using Hex8.00 software. The interfaces of the resulted complexes were predicted by KFC2 server.ResultsHex8.00, as a docking software, gave us the complexes from the interaction of PKA with 15 proteins of its partners. For each complex, the KFC2 server gave us the amino acid composition of the interfaces. Using this amino acid composition, we draw a structural network which shows the binding sites on PKA surface.ConclusionWe have constructed a structural network for cAMP signaling pathway which shows how PKA interacts with its partners. This network can be used for understanding the mechanisms of signal transduction and also for drug design purposes.Keywords: structural network, cAMP signaling pathway, interface}
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بیان مساله: با کاربرد صحیح سایلن (Silane) بدون نیاز به اچ کردن سطوح سرامیکی با اسید هیدروفلویوریک، اتصال (Bond) مطلوب کششی بین سرامیک و رزین حاصل می گردد. با توجه به اهمیت اتصال سرامیک به رزین کامپوزیتی در دندانپزشکی، امروزه بررسی بیشتر روش کاربردی صحیح سایلن با آزمونهای مناسب تر دیگر ضروری به نظر می رسد.هدفمطالعه حاضر با هدف مقایسه Interfacial Fracture Toughness سطوح سرامیکی صاف و خشن باندشده با روش صحیح کاربرد سایلن به یک رزین انجام شد.روش بررسیدر این مطالعه تجربی، 80 دیسک سرامیکی به قطر 10 و ضخامت 2 میلیمتر تهیه گردید. به منظور Surface Treatment از چهار روش مختلف 1) پالیش سطوح سرامیکی تا 1 میکرون،Gritblast (2 با ذرات آلومینای 50 میکرون، 3) اچینگ با اسید 10% HF به مدت 2 دقیقه و Gritblast (4 و اچینگ استفاده شد. (در هر گروه 20 نمونه مورد بررسی قرار گرفت). دیسک های سرامیکی داخل رزین PMMA قرار داده شدند و در ناحیه Adhesive، توسط نوار تفلون پوشانده شدند. یک سوراخ گرد به قطر 3 میلیمتر با زاویه 90 درجه روی نوار تفلون پانچ شد. سطوح سرامیکی Expose مانده، توسط روش بهینه شده کاربرد سایلن، Treat شدند و بعد از کاربرد یک Unfilled Resin، رزین استوانه ای به قطر 4 و طول 11 میلیمتر بر روی آن ساخته شد؛ سپس نمونه ها در دو محیط نگهداری مختلف (گروه: A آب مقطر 37 درجه سانتیگراد به مدت 24 ساعت و گروه: B آب مقطر 37 درجه سانتیگراد به مدت 30 روز) قرار گرفتند (GIC) Interfacial Fracture Toughness با سرعت 1 mm/min اندازه گیری شد. نحوه شکست با استفاده از استریومیکروسکوپ و سطوح شکست با استفاده از میکروسکوپ الکترونی بررسی گردیدند. به منظور تحلیل داده ها از آنالیز واریانس یک طرفه و آزمون Independent-Samples t استفاده شد.یافته هامقدار میانگین Interfacial Fracture Toughness به شرح زیر بود:1) گروه A: 4) 379.4±127.8 J/m2±SD، 3) 364.5±169.8، 2) 304.5±109.2، 317.1±114.82) گروه B: 4) 639.9±489 J/m2±SD، 3) 629.3±182.6، 2) 648±185.1، 255.6±134.4بین میانگین میزان GIC گروه های A1 تا A4 اختلاف معنی داری وجود نداشت. (p<0.05) اما میانگین میزان GIC در گروه B1 به طور معنی داری با گروه های B2،B3 و B4 اختلاف داشت (p<0.05)؛ همچنین افزایش قابل ملاحظه ای در میزان GIC در گروه های اچ شده و Gritblastشده بعد از 30 روز نگهداری در آب مقطر 37 درجه سانتیگراد وجود داشت. (p<0.05) نحوه شکست به طور غالب به صورت Interfacial و یاCohesive در رزین بود.نتیجه گیریروش آزمون اندازه گیری Fracture Toughness مورد استفاده در این تحقیق می تواند برای ارزیابی ناحیه Adhesive در سیستم های سرامیک- رزین مناسب باشد و در صورت استفاده از روش مناسب کاربرد سایلن، گیر میکرومکانیکال با Gritblast نمودن سطوح سرامیکی بدون نیاز به اچ کردن سطوح سرامیکی با HF کافی است.
کلید واژگان: سرامیک های دندانی, رزین, سایلن, چغرمگی}Statement of Problem: In a previous study it was reported that a durable resin-ceramic tensile bond could be obtained by an appropriate silane application without the need for HF acid etching the ceramic surface. Evaluation of the appropriate application of silane by other test methods seems to be necessary.PurposeThe purpose of this study was to compare the interfacial fracture toughness of smooth and roughened ceramic surfaces bonded with a luting resin.Materials And MethodsCeramic discs of 10 mm in diameter and 2 mm in thickness were prepared. Four different surface preparations (n=10) were carried out consisting of (1) ceramic surface polished to a 1µm finish, (2) gritblasted with 50µm alumina, (3) etched with 10% HF for 2 min, and (4) gritblasted and etched. The ceramic discs were then embedded in PMMA resin. For the adhesive area, the discs were masked with Teflon tapes. A circular hole with diameter of 3 mm and chevron-shaped with a 90° angle was punched into a piece of Teflon tape. The exposed ceramic surfaces were treated by an optimised silane treatment followed by an unfilled resin and then a luting resin cylinder of 4mm in diameter and 11 mm in length was built. Specimens were stored in two different storage conditions: (A): Distilled water at 37°C for 24 hours and (B): Distilled water at 37°C for 30 days. The interfacial fracture toughness (GIC) was measured at a cross-head speed of 1 mm/min. The mode of failure was examined under a stereo-zoom microscope and fracture surfaces were examined under Scanning Electron Microscope.ResultsThe mean interfacial fracture toughness values were Group A: 1) 317. 1±114. 8, 2) 304. 5±109. 2, 3) 364. 5±169. 8, and 4) 379. 4±127. 8 J/m2±SD. Group B: 1) 255. 6±134. 4, 2) 648. 0±185. 1, 3) 629. 3±182. 6 and 4) 639. 9 ±489. 0 J/m2±SD. One way Analysis of Variance showed that there was no statistically significant difference in the mean interfacial fracture toughness for groups A1-A4 (P>0. 05). However, the mean interfacial fracture toughness for group B1 was significantly different from that for groups B2, B3 and B4 (P<0. 05). Independent-ٍٍٍSamples T-Test results showed that there was a significant increase in the GIC mean value for groups B2 and B3 after 30 days water storage (P<0. 05). The modes of failure were predominantly interfacial or cohesive within the resin.ConclusionsThe fracture toughness test method used in this study would be appropriate for analysis of the adhesive zone of resin-ceramic systems. From the results, it can be concluded that micro-mechanical retention by gritblasting the ceramic surfaces could be sufficient with no need for HF acid etching the ceramic surfaces when an appropriate silane application procedure is used.Keywords: Dental ceramics, Luting resin, Silane, Fracture toughness, Interface}
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