HOW IMPORTANT ARE THE IMPLANT INCLINATION AND THE INFRASTRUCTURE MATERIAL USED IN IMPLANT SUPPORTED FIXED PROSTHESES?

Objectives: The aim of this study is to evaluate the stress , which is caused by the fixed prosthesis under oblique forces around dental implants and bone by using different infrastructure materials and different inclusions, by 3-dimensional finite element analysis method. Materials and Methods: The 3D finite element models of the mandible, dental implants and prostheses were prepared. The anterior and posterior implants were designed 10 mm in length and 4.3 mm in diameter. The anterior implant was placed parallel to each model. Posterior implant designed to make inclinations those mesial 17, distal 17, buccal 17, lingual 17. Implant supported fixed restorations were divided into 3 main groups according to the infrastructure materials. These materials were; chromium-cobalt, zirconia, polyetheretherketone (PEEK). In each model, a total of 500 N oblique force was applied from the buccal tubercle crests to the buccolingual direction at an angle of 30 degrees to the long axis of the tooth. Maximum principal stress and minimum principal stress values in the bone models were taken. In addition, maximum von Mises stress values were obtained from implants and substructure materials. Results: When the stress findings in the mandible during oblique loading were evaluated, it was found that the stresses on the cortical bone were higher than the stresses on the trabecular bone. It was observed that the highest stress values occurred in the implants. Conclusions: It is thought that chromium-cobalt and zirconia-based ceramic bridge restorations are more positive in terms of stress distribution than PEEK-based ceramic bridge restorations

A study into the changes in ALS1 adhesion gene levels in Candida albicans cells isolated from various soft lining materials in different time periods

Bu çalışmada; in vitro hızlandırılmış eskitme işlemi uygulanmış ve uygulanmamış dört farklı yumuşak astar maddesinin C. albicans hücreleri ile 12 ve 24 saat süreyle inkübasyonunun ardından, bu yumuşak astar maddelerinin yüzeylerinden izole edilen hücrelerdeki ALS1 geni mRNA ekspresyonunun kantitatif olarak araştırılması amaçlanmıştır. Çalışmada; oda sıcaklığında polimerize olan akril esaslı yumuşak astar maddesi olarak Visco Gel, ısıyla polimerize olan akril esaslı yumuşak astar maddesi olarak Vertex Soft, oda sıcaklığında vulkanize olan silikon esaslı yumuşak astar maddesi olarak Dentusil ve ısıyla vulkanize olan silikon esaslı yumuşak astar maddesi olarak Molloplast-B kullanılmıştır. Her bir maddeden 40 ar adet olmak üzere toplam 160 adet örnek hazırlanmıştır. Her bir maddeden hazırlanan örneklerin 20 tanesine Atlas UV2000 Hızlandırılmış Hava Koşullandırma Test Cihazında hızlandırılmış eskitme işlemi uygulanmıştır. Ardından her bir yumuşak astar maddesinden hazırlanan eskitme işlemi uygulanan ve uygulanmayan 10 ar tane olmak üzere toplam 20 örnek 12 saat, diğer 20 tane örnek ise 24 saat süreyle C. albicans hücreleriyle inkübe edilmişlerdir. Örneklerin yüzeyinde oluşan biyofilm kütlesi kazınmış ve mRNA ları izole edilmiştir. Bu mRNA lar cDNA ya çevrilmiş ve Real-time PZR ile kantitatif analizleri yapılmıştır. In vitro hızlandırılmış eskitme işlemi uygulanmamış ve uygulanmış maddelerde ortalama gen ekspresyonları incelendiğinde en az gen ekspresyonu Dentusil maddesinde bulunmuştur. Eskitilmiş maddelerin ortalama değerleri incelendiğinde Molloplast-B maddesinde diğer maddelere göre istatistiksel olarak anlamlı miktarda fazla gen ekspresyonu görülmüştür (p<0.05). Bu araştırma sonucunda yumuşak astar maddesi türünün, maddenin kullanım süresi ve C. albicans hücreleriyle inkübasyon sürelerinin ALS1 geni ekspresyonu üzerinde etkili olduğu görülmüştür.The aim of this study was to investigate the quantitative expression of ALS1 gene mRNA isolated from the surface of the soft lining materials, after the incubation of four different soft lining materials subjected to a process of in vitro accelerated aging and of the ones not subjected with C. albicans cells for 12 and 24 hours. In this study, Visco Gel (room temperature curing acrylic based soft lining material), Vertex Soft (heat-cured acrylic based soft lining material), Dentusil (room temperature vulcanized silicone based soft lining material) and Molloplast-B (heat-vulcanized silicone based soft lining material) were used . 40 specimens from each material were prepared so as to obtain totally 160 specimens. Of 40 specimens, 20 were subjected to accelerated aging process by using Atlas UV2000 Accelerated Air Conditioning Test Device and the other 20 were not subjected to aging process. 10 of the 20 specimens which were subjected to accelerated aging were incubated with C. albicans for 12 hours and the other 10 specimens were incubated with C. albicans for 24 hours. And 10 of the 20 specimens which were not subjected to accelerated aging were incubated with C. albicans for 12 hours and the other 10 specimens were incubated with C. albicans for 24 hours. The biofilm layer occured on the surfaces of the specimens were excavated and mRNAs were isolated. The mRNAs were converted into cDNA and quantitative analyses were performed with real-time PCR. When the average gene expressions obtained from the in vitro accelerated aging process applied and not applied materials were evaluated, the least gene expression was found in Dentusil. The most statistically significant gene expression was observed in the Molloplast-B, when the average values of the materials were evaluated (p<0.05) . As a result of this study, we observed that the types of soft lining materials, duration of the material usage and the incubation period of C. albicans influenced the expression of ALS1 gene

Zirconium applications at restorative dentistry

Sabit protezler restoratif diş hekimliğinin önemli bir bölü- münü teşkil etmektedir. Metal destekli seramik restorasyonların yapısındaki metal alt yapının; restoras-yonun yarı geçirgenliğini azaltarak estetik sakıncalara yol açması, lokal doku reaksiyonuna ve korozyon toksisitesine sebep olabilmesi gibi dezavantajlarından ötürü günümüzde yüksek dirençli tam seramikler geliştirilmiştir. Yüksek gerilme direncine sahip olması, biyolojik uyumluluğu ve translüsent olması gibi avantajlarından ötürü zirkonyumdan üretilen tam seramik restorasyonların diş hekimliğinde kullanımı gün geçtikçe yaygınlaşmaktadır. Bu derlemede zirkonyum materyalinin özellikleri, restoratif diş hekimliğinde kullanıldığı yerler hakkında genel bilgi verilmektedir.Fixed denture consists a significant part of restorative dentistry. In the structure of the metal supported ceramic restorations of metal substructure; lead to aesthetic drawbacks with reducing restoration’s semi-permeability, lead to local tissue reactions and corrosion toxicity may cause disadvantages that because of the nowadays highresistance all ceramics have been developed. All-ceramic restorations made from zirconium for use in dentistry is spreading day by day because of the advantage of having high tensile strength, biocompatibility and being translucent. In this review, general information is given about zirconium material’s properties and places where used in restorative dentistry

Investigation on the Potential Use of Polypropylene Mesh for the Reinforcement of Heat-Polymerized PMMA Denture Base Resin

The aim of this study was to investigate the potential use of polypropylene (PP) hernia mesh as a reinforcement of PMMA denture base resin in comparison with metal and glass fiber meshes, with the expectation of enhancing the mechanical stability of the PMMA dentures in oral conditions. The control group with no mesh, the aluminum metal mesh (Al) group, the PP1 (PP mesh used on top) group, the PP2 (PP mesh used on both the top and bottom) group, the orthopedic casting tape with self-curing resin (DP0) group, and the flushed form (DPA) group were fabricated in a chromium mold. A total of 144 specimens were divided into three equal portions and subjected to: first, no treatment; second, thermal cycling only; and third, thermal cycling and chewing simulation. The flexural strength, maximum deformation, and flexural modulus were determined by a three-point bending test to compare mechanical properties. Fracture surfaces were evaluated by scanning electron microscopy. The obtained data were statistically analyzed by a two-way ANOVA test with Bonferroni corrections. The non-treated Al mesh reinforcement group exhibited the highest (82.66 ± 6.65 MPa) flexural strength, and the PP2 group treated with chewing simulation displayed the lowest (56.64 ± 4.59 MPa) flexural strength. The Al group showed the highest (7.25 ± 1.05 mm) maximum deformation and the PP2 group showed lowest (3.64 ± 0.28 mm) maximum deformation when both groups were not subjected to any treatment. The control group with no treatment exhibited the lowest (1556.98 ± 270.62 MPa) flexural modulus values, and the Al group with no treatment exhibited the highest (3106.07 ± 588.68 MPa) flexural modulus values. All the mesh groups displayed intact fractures. Any type of mesh used for reinforcement exhibited a significant change in all flexural properties (p < 0.001). The PP1 reinforcement group did not exhibit a significant change in mechanical properties when the effect of treatment was compared. Using PP hernia mesh on top enhanced the mechanical properties despite the weakening when it was used on both the top and bottom. The mechanical stability provided by the PP hernia mesh indicated it to be a promising candidate to be used for reinforcement

Effect of surface finishing on the colour stability and translucency of dental ceramics

Abstract Background The purpose of this study was to investigate the effects of staining solutions and surface finishing on the colour stability and translucency of hybrid ceramic (HC) and resin nanoceramic (RNC) materials. Methods Twenty four groups consisting of 10 specimens (240 specimens in total) were created out of HC and RNC, including six groups to be stored in distilled water served as the controls groups. The Vita Enamic technical set, Shofu polishers, medium and fine rubber wheels and Sof-Lex polishing discs were used as polishing instruments. Cola, tea, and coffee were used as staining solutions. The colour differences (∆E*) and translucency parameter (TP) were evaluated by a spectrophotometer. Data were analysed by a One-way Analysis of Variance (ANOVA) and Mann-Whitney U test. Results There was a statistically significant difference between the ∆E* values of the HC specimens in the coffee groups and the ∆E* values of the other HC groups (p 0.05). The TP values of the polished groups were higher than the Sof-Lex groups and the Shofu groups on both HC and RNC materials (p < 0.05). Conclusions Increased ∆E* values were observed in HC specimens stored in a coffee solution compared to the specimens stored in a tea or cola solution. Both of the RNC specimens stored in coffee and tea had higher ∆E* values than the RNC specimens stored in the cola. The TP values of both HC and RNC specimens stored in the coffee solution decreased

Investigation of CD40 gene rs4810485 and rs1883832 mutations in patients with recurrent aphthous stomatitis

WOS: 000393017400008PubMed ID: 27875792Objectives: Recurrent aphthous stomatitis (RAS) is a common painful disorder affecting oral health, mucosa and overall quality of life. The etiopathogenesis of RAS remains unclear. RAS shows a large genetic diversity among the patients. In present study, we investigated whether CD40 gene rs4810485 and rs1883832 are associated with RAS and its clinical findings in Turkish patients. Materials and methods: Genomic DNA obtained from 387 individuals (160 patients with RAS and 227 healthy controls) were used in the study. CD40 gene rs4810485 and rs1883832 mutations were determined by using polymerase chain reaction with the specific primers. Results: There was no statistically significant difference between the groups with respect to genotype and allele distribution (p > 0.05, OR 0.94, 95% CI 0.70-1.28, OR 1.01 95% CI 0.75-1.37, respectively). Additionally, there was no statistically significant difference in the combined genotype analysis of CD40 gene rs4810485 and rs1883832 mutations (p >0.05). Conclusions: According to our results, we found that CD40 gene mutations are not associated with RAS. We are convinced that CD40 gene mutations do not predispose to develop RAS in Turkish population. To our knowledge, this is the first study regarding CD40 gene rs4810485 and rs1883832 mutations investigated in RAS patients. (C) 2016 Elsevier Ltd. All rights reserved

The IL-1Ra gene variable number tandem repeat variant is associated with susceptibility to temporomandibular disorders in Turkish population

WOS: 000425109100031PubMed ID: 28612927BackgroundTemporomandibular joint disorders (TMD) are a group of disorders involving temporomandibular joint and related structures. Interleukine-1 receptor antagonist (IL-1Ra) is an important anti-inflammatory molecule that competes with other interleukin-1 molecules. This study was designed to investigate the possible association of the IL-1Ra VNTR variant with the risk of TMD in the Turkish population. MethodsPeripheral blood samples were collected from 100 patients with TMD (23 males, 77 females) and 110 healthy individuals (35 males, 75 females). Genotyping of IL-1Ra 86bp VNTR variant was evaluated by gel electrophoresis after polymerase chain reaction (PCR). ResultsOur results show that there is a statistically significant difference between TMD patients and control group with respect to IL-1Ra genotype distribution and allele frequencies. 1.2, 1.4, and 4.4 genotypes were more common in patients, while 2.2 and 3.3 genotypes were rarer (P<.000). Frequency of alleles 1 and 4 was higher in patient groups (P<.000), whereas alleles 2 and 3 had a lower frequency in patients with TMD (P<.000). ConclusionsThis is the first correlation study that evaluates the association between IL-1Ra gene VNTR variant and TMD. The VNTR variant related to IL-1Ra gene showed a strong pattern of association with TMD that may have a potential impact on disease counseling and management. Larger studies with various ethnicities are needed to establish the impact of IL-1Ra VNTR variant on risk of developing TMD

Effect of a functional variant of tumor necrosis factor-beta gene in temporomandibular disorders: A pilot study

WOS: 000456672300022PubMed ID: 30129153Background Temporomandibular disorders (TMD) are a group of conditions that cause chronic orofacial pain. The tumor necrosis factor beta (TNF-beta) is a proinflammatory cytokine that is involved in the various aspects of the inflammatory process including organization and maintenance, and in the arrangement of cells at the inflammation site. The purpose of this study was to evaluate the correlation between TNF-beta +252A/G (rs909253) variant and susceptibility to TMD in a Turkish cohort. Methods The study included 104 patients (26 males, 78 females) with TMD and 126 healthy controls (44 males, 82 females). The TNF-beta +252A/G variant analysis was based on Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP). Results There was no deviation from HWA for TNF-beta +252A/G variant in patient and control groups. There was significant difference in genotype and allele frequencies between patient group and control group in terms of TNF-beta +252A/G variant, respectively (P = 0.010, 0.015). A significant increase in the TNF-beta +252 AG genotype and G allele frequencies were observed in TMD patients compared to healthy controls. The individuals with GG genotype and G allele had an increased risk of developing TMD. A statistically significant association was observed when the patients were compared with the controls according to AA genotype vs AG+GG genotypes (P = 0.002, OR: 2.23, 95% CI:1.31-3.82). TNF-beta +252A/G genotype distribution was associated with chewing problems (P = 0.046). Conclusions In conclusion, our results provided evidence that TNF-beta +252A/G variant may contribute to TMD development in a Turkish cohort. Further studies are needed to confirm this observation

Examination of Natural Tooth Color Distribution Using Visual and Instrumental Shade Selection Methods

Aim: Although visual color determination is the most frequently applied method in dentistry, instrumental color analysis offers advantages like objectivity, measurability and rapidity. The aim of this study was to evaluate the natural teeth color in teeth without any restoration visually, and by using a computerized shade measuring and analyzing system in the population