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    Comparing static, dynamic and impact loading behavior of biomimetic porous dental implants with conventional dental implants (3d finite element analysis)
    (2020) Çulhaoğlu, Ahmet Kürşad; Terzioğlu, Hakan
    Background: Porous structures instead of bulk structures have been suggested for implants because porous structures have elactic modulus similar to natural bone and allow bone tissue ingrowth. But there are limited studies to simulate porous implants with different amount of porosity at different locations The purpose of this study was to evaluate the stress distribution levels at cortical and spongious bone tissue that occurred around commercially available dental implants and four different biomimetic implant design with various porous parts and porosity amounts.Methods: 3-dimensional finite element analysis was conducted using mathematical models of unilateral 3-unit cantilever fixed partial dentures (FPD) subjected to vertical and oblique rotated static, dynamic and impact occlusal loads. Vertical load of 300 N was applied to the model over the central fossa of the crowns. Oblique load of 50 N were applied per tooth over the functional palatinal tubercule at an angle of 45 °.Results: Impact loading conditions create excessive stress values at distal dense titanium implants (1030 MPa). This was more than the ultimate tensile strength of dense titanium alloy Ti-6Al-4V (930 MPa). It might be summarized as fully porous and middle section porous implants showed lower stress values at distal implant for all loading conditions.Conclusion: The location of porosity is more critical than the amount of porosity for stress distribution. The distributions of stress at implants and surrounding bone mainly depended on the location of the porosity. Impact loading is a critical parameter for implant-supported prosthesis. Observance and prevention of impact loading should be considered for designing biomimetic porous implants. The porous biomimetic implant design with porous middle sections was the most successful design to decrease impact loading stress.
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    Comparison of Microleakage and Fracture Strength of Veneering Techniques for Polyetheretherketone Cores
    (AVES, 2023) Kiliçarslan, Mehmet Ali; Çulhaoğlu, Ahmet Kürşad; Çakirbay Taniş, Merve; Kiliçarslan, Müge; Ocak, Mert
    Objective: This study aimed to compare both microleakage and fracture strengths of polyetheret-herketone crowns manufactured via conventional composite layering and different computer-a-ided design and computer-aided manufacturing veneering techniques on polyetheretherketone cores. Materials and Methods: In total, 40 cores with 0.7-mm thickness were milled from polyethe-retherketone discs and separated into 4 groups: layering with composite resin, computer-aided design and computer-aided manufacturing-fabricated lithium disilicate veneer, computer-aided design and computer-aided manufacturing-fabricated hybrid ceramic veneer, and computer-a-ided design and computer-aided manufacturing-fabricated feldspathic veneer. Then, all cores were air abraded and an adhesive has applied to these surfaces. After the cores were connected to veneers, thermomechanical aging was applied in a chewing simulator. Evaluation of microlea-kage and fracture strength was performed via micro-computed tomography analysis and univer-sal test machine, respectively. One-way analysis of variance was used to detect any statistically significant differences between test groups. Also, failure modes and the correlation between mic-roleakage and fracture strength data were analyzed statistically. Results: Statistical analyses between the groups showed significant differences for both micro-leakage and fracture strength values. The lowest microleakage was in the computer-aided design and computer-aided manufacturing-fabricated hybrid ceramic veneer group (0.02 ± 0.01 mm3). The highest microleakage was in the layering with composite resin group (0.56 ± 0.21 mm3). The lowest fracture strength values were in the computer-aided design and computer-aided manuf acturing-fabricated feldspathic veneer group (620.58 ± 114.02 N). The highest fracture strength was in the computer-aided design and computer-aided manufacturing-fabricated lithium disili-cate veneer group (1245.82 ± 197.75 N). Also, there was no correlation between the microleakage and fracture strength groups. Conclusion: The use of computer-aided design and computer-aided manufacturing-fabricated lithium disilicate and hybrid ceramic veneers can be an alternative to layering when its other advantages are considered. © 2023, AVES. All rights reserved.
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    Comparison of Stain Effects of Nicotine and Beverages on Different Cad-Cam Materials
    (2022) Gokdeniz, Burak; Demirel, Gülbike; Çulhaoğlu, Ahmet Kürşad; Kılıçarslan, Mehmet Ali
    Purpose: This study aimed to compare the effect of smoking cigarettes and drinking beverages and also polishing procedures on the discoloration of CAD/CAM materials. Materials and Methods: Resin nanoceramic (Lava Ultimate-RN), feldspar ceramic (CEREC Blocs Ceramics-FC) and lithium disilicate glass-ceramic (IPS e.max® CAD-LDC) specimens (5X5 X2 mm) were used for this study. Initially, baseline surface roughness (Ra) and color values (L*, a*, b*) of the specimens were measured with profilometer and chroma meter. Then the specimens were exposure nicotine, coffee and red wine. The first discoloration values of each specimen were measured. Then, all of the specimens were subjected to re-polishing procedures. Than, the surface roughness and color values of each specimen were measured. The specimens were subjected to the same staining process again. After exposure of the specimens to the staining agents, the second staining value was measured. Two-way analysis of variance (ANOVA) was used for normally distributed groups, and the Kruskal-Wallis test was used for non-normally distributed groups. Results: Statistically significant ?E* values were observed for RN (8.26±1.55) and FC (7.69±1.52) for nicotine in the first staining group. The maximum total color changes were observed in the nicotine group for all of the material specimens. Nicotine caused the highest color changes on the test materials than coffee and wine. Surface roughness did not show a statistically significant difference based on the staining agents for any of the materials within a group (p<0.05). Conclusions: It was observed that nicotine staining is far stronger than beverage staining.
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    DİŞ HEKİMLİĞİNDE UZMANLIK SINAVININ FARKLI EĞİTİM SEVİYELERDEKİ ALGI VE TERCİH DURUMLARININ DEĞERLENDİRİLMESİ
    (2021) Çulhaoğlu, Ahmet Kürşad; Kılıçarslan, Mehmet Ali; Deniz, Kaan Zülfikar
    Amaç: Bu çalışmanın amacı, diş hekimliği öğrencileri ile Diş Hekimliğinde Uzmanlık sınavına giren diş hekimleri tarafından busınav sistemi ile mevcut lisans eğitimlerinin ilişkisini değerlendirmek ve diş hekimliğinde uzmanlık amaç veya tercih alanlarınıanaliz etmektir.Gereç ve Yöntem: Ankara ve Kırıkkale diş hekimliği fakültelerinde öğrenim görmekte olan preklinik ve klinik öğrencileri ileuzmanlık sınavına giren mezun diş hekimleri üzerinde ankete dayalı bir araştırma yürütülmüştür. Bu amaçla hazırlanan ankettekatılımcıların sosyo-demografik dağılımları ile birlikte bu sınavı ve sınav göz önünde bulundurularak fakültelerinde aldıklarıeğitimleri değerlendirmelerine yönelik sorular mevcuttur. Ankete toplam 607 katılımcı katılmış, tüm soruları cevaplayan 577katılımcı araştırma değerlendirmesinde dikkate alınmıştır. Veri analizleri ANOVA ve Scheffe testleri ile ikili (karşılıklı) karşılaştırmayöntemleri ile yapılmıştır.Bulgular: Çalışma grubundaki katılımcıların % 9.98’inin uzmanlık dahil diş hekimliğindeki lisans üstü eğitimler hakkında tamolarak bilgisinin olduğu, % 49.1’inin kısmi bilgisinin olduğu ve % 40.92’sinin de hiç bilgisinin olmadığı tespit edilmiştir. Öncelikleeğitim düzeyleri ile uzmanlık isteme durumları analiz edildiğinde; preklinik öğrencilerinin % 91,5’inin, klinik öğrencilerinin %88.7’sinin ve ankete katılan mezun diş hekimlerinden %69.9’unun uzmanlık yapmayı istedikleri tespit edilmiştir. Sınavkapsamındaki derslere öğrencilerin motivasyon düzeyleri değerlendirildiğinde cinsiyetin ve eğitim düzeyinin motivasyon üzerindeistatistiksel bir farkı olmadığı ortaya konulmuştur. Tercih edilen uzmanlık branşlarında da ağız diş çene cerrahisi ile ortodontininöne çıktığı görülmektedir.Sonuç: Öğrenciler ile henüz uzmanlık eğitimine başlamamış diş hekimlerinin büyük bir çoğunluğu uzmanlık eğitimi yapmakistemektedir. Ancak öğrencilerin isteği, mezunlara göre daha fazladır. Fakültelerdeki teorik ve pratik müfredatın bu sınav ileuyumlu olduğu görülmektedir ve sınav konularının derse olan motivasyonu bir miktar arttırdığı tespit edilmiştir.
  • Küçük Resim
    Öğe
    Effects Of Remover Techniques On Stress Distribution Of Implant Supported Fixed Partial Dentures And The Surroundıng Bone: A Finite Element Analysis
    (2017) Özkır, Serhat Emre; Ünal, Server Mutluay; Çulhaoğlu, Ahmet Kürşad; Şeker, Emre
    Background & Aims: Implant retained restorations may be retrieved due to many reasons. However, implant retained restorations have many components which may be damaged during removal. The aim of this study is to observe stress concentrations in the surrounding bone, the implant and its components, during retrieval of a three-unit implant-supported fixed partial denture using two different removal techniques. Materials and Methods: One three-dimensional digital model of an implant-supported three-unit restoration was constructed. The implants’ dimensions were 3.7 mm x 10mm. A pull out force of 40 N was applied on a single support and on the connectors with a loop device. The stress values were calculated within the dental implant, abutment, abutment screw and surrounding bone. Results: The highest stress concentration was observed at the collar of the abutment during load on a single support (16.246 MPa). The stress concentrations at the cortical bone were lower than the stress concentration at implants, while the maximum stress concentration in bone structure was 1.175 MPa. The loop device technique was enabled to share the load through both implants and reduce the stress concentration levels (9.941 MPa). Conclusion: The pull-out force, did not show a great effect in bone structure. However, implant components were under higher stress and abutment screw was the weakest part of the system. During a crown removal, more attention is needed in order not to damage implant components rather than the bone.
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    Investigation of the Sodium Titanate Surface Behavior in Corrosive Oral Fluids by Comparing with Conventional Titanium Surfaces
    (2021) Çulhaoğlu, Ahmet Kürşad; Özgül, Özkan; Tekin, Umut; Önder, Ercüment
    Objective: Titanium (Ti) and Ti alloys are suitable options as implant material because they are biocompatible and form a corrosion protective titanium oxide layer. However, the oxide layer issensitive to corrosive ions such as fluoride (F) and hydrogen peroxide(H2O2) which are normally found in human mouth. Commercially produced toothpastes, mount rinses and cariostatic gels contain between0.1% and 1% content F concentration. Furthermore, H2O2 can be secreted during inflammatory reactions by bacteria in oral environment.The corrosion of dental implants and components can cause failure ofdental implant treatment. The aim of this study was to analyse the effects of different F and H2O2 concentrations on different treated Ti alloy(Ti6Al4V) in surfaces. Material and Methods: The effects of different F (0.5%, 2.5%) and H2O2 (0.1%, 10%) concentrations on differenttreated Ti6Al4V surfaces [electro-polished, roughed, fine-roughed andsodium titanate-treated (NaTi)] were analysed. Scanning electron microscopy and inductively coupled plasma with optical emission spectrometer provided quantitative bulk elemental composition for Tisamples. Results: Median corrosion values of Ti (mg/L) and V (mg/L)corrosion levels in 10% H2O2 and 2.5% F solutions were significantlyhigher than 0.1% H2O4, 0.5% F and control solutions. Median Ti corrosion values observed in electro-polished, roughed and fine-roughedgroups were statistically higher than NaTi treated surfaces. Conclusion: This study shows that low ion release on NaTi surfaces causesthe least amount of corrosion. Consequently, NaTi coating should beconsidered as the best alternative for protecting Ti surfaces from corrosion.
  • Küçük Resim
    Öğe
    Polieter Eter Keton (Peek) Ve Dental Kullanımı
    (2019) Çulhaoğlu, Ahmet Kürşad; Özkır, Serhat Emre; Türkkal, Fatoş
    Poliaril eter keton ailesinin yüksek ısı polimeri olanpolieter eter keton (PEEK) semikristalin birtermoplastiktir. Yüksek mekanik fiziksel özelliklere,aynı zamanda termal ve boyutsal stabiliteye sahipPEEK, birçok endüstri alanında metallere alternatifgörülen ender polimerlerdendir. Yüksek aşınmadirencine sahip olan ve kimyasal ajanlara karşıdayanıklı bir materyal olan PEEK, uygun biyomekaniközellikleri, uzun ömürlü oluşu ve biyouyumluluğu ile1990'ların sonunda özellikle medikal alanda,ortopedide metal bileşenli implantlara alternatif olarakkullanılmaya başlanmıştır. Kemiğe yakın elastik modülüile implant materyali olarak da kullanılan bu materyal,dental alanda özellikle de protetik diş tedavilerindekullanılmaya başlanmıştır. Bu derlemede PEEKmateryalinin yapısı, özellikleri ve dental kullanımalanları anlatılmıştır.