Diş hekimliği fakültelerinde kullanılan farklı diş ünitlerinin su ünitlerinin su sistemlerinin geri akım kontaminasyonu açısından değerlendirilmesi

Amaç: Farklı diş koltuk sistemlerine bağlı gerikaçış engelleyici sistemlerin etkinliğinin uzun dönem araştırılması ve farklı branşlara göre gerikaçış sonucu ortaya çıkabilecek çapraz enfeksiyon riskinin belirlenmesidir. Gereç ve Yöntemler: Dişhekimliğinin birbirinden farklı üç branşından çalışma grubu oluşturulmuştur. Bu farklı üç gruptan elde edilen materyaller bakteri varlığı açısından değerlendirilerek gruplar arasındaki farklılık mikrobiyolojik açıdan incelenmiştir. Bulgular: Üç grupta da birçok bakteri kolonisinin izole edildiği görülmekle birlikte üreyen mikroorganizmaların çoğunun çevreden ve ağız florasından sıklıkla izole edilen bakteri kolonileri olduğu görülmüştür. Sonuç: Diş ünit sistemlerinin kontaminasyonu engelleyici sistemlerle donatılmasının son derece önemli olduğu görülmüş, bununla birlikte uzun zamandır kullanılan diş ünit sistemlerinin sıklıkla kontrol edilmesi ve gerektiğinde yenilenmesi sonucuna ulaşılmıştır

Z(2) structure of the stopping power for electron beams

4th Conference on Elementary Processes in Atomic Systems -- JUN 18-20, 2008 -- Cluj Napoca, ROMANIAWOS: 000263586200031The target atomic number (Z(2)) dependence of the collision stopping power for electron beams have been investigated for the purpose of determining primary mechanisms in stopping of electrons in elemental matter. The stopping powers of target elements with atomic numbers Z(2) = 1-92 for the electrons have been evaluated on the basis of Gumus method. The variation of the stopping power depending on energy of electrons and type of target has been studied to obtain the elements with the strongest stopping force property for electron beams. A strong Z(2) oscillation in the collision stopping power has been observed whereas the mass collision stopping powers are found to be decreasing with increasing atomic number of the target. It is also found that the electron slowing down in matter mainly depends on the atomic density of target and initial energy of electrons. (c) 2008 Elsevier B.V. All rights reserved.Babes Bolyai Univ, Fac Phys, Hungarian Acad Sci, Inst Nucl Re

Effect of Surface Modifications of Abutment Screws on Reverse Torque Values: An In Vitro Study

Purpose: To investigate the reverse torque values of abutment screws subjected to various surface modifications. Materials and Methods: Sixty abutment screws were divided into two groups of 30 each: with thermomechanical cycling (240,000 cycles) and without thermomechanical cycling. Each group was then divided into three subgroups according to surface treatment: nontreated (NT, n = 10); anodic oxidation (AO, n = 10); and diamond-like carbon (DLC) coating (DLC, n = 10). All abutment screws were tightened to 30 Ncm using a digital torque meter. The reverse torque values of the abutment screws with and without thermomechanical cycling were then measured. The percentage of deviation (PERDEV) for reverse torque values was calculated. Two-way analysis of variance followed by Tukey Honest Significant Difference test were used for intergroup comparisons. Results: Significant differences were found among the PERDEV values of the groups based on thermomechanical cycling and surface treatment (P < .001 for each). A significant interaction was found between surface treatment and thermomechanical cycling (P < .001). Conclusion: Reverse torque values of abutment screws were found to be higher after surface treatments. The abutment screws with AO exhibited the lowest torque value loss in groups with and without thermomechanical cycling

An Alternative Method For Constructing An Obturator Prosthesis For A Patient With A Bilateral Cleft Lip And Palate: A Clinical Report

The design of esthetic and effective dental prostheses for bilateral cleft lip and palate patients is a challenge for prosthodontists because the prostheses must serve more than one purpose. The goals to be attained by prosthetic intervention are preventing food and liquid leakage into the nose, improving speech intelligibility, a more esthetic appearance, and achieving the general satisfaction of the patient. The framework design of the obturator prosthesis is of great strategic importance for patients with a cleft lip and palate. The reduction in the mass of the obturator prosthesis increases stabilization and retention and also contributes to an easier adaptation to the prosthetic restoration. In this report, a 22-year-old woman was successfully treated with a fixed partial denture and a bar-retained obturator with palatal coverage

Calculation of the electronic stopping cross-sections of compounds for low energy protons by using molecular orbitals

22nd International Conference on Atomic Collisions in Solids -- JUL 21-26, 2006 -- Tech Univ Berlin, Berlin, GERMANYWOS: 000245959300025The modified Firsov model has been applied to the calculation of the electronic stopping cross-section of compounds for low energy protons by using molecular orbitals. We used the Symmetry Adapted Linear Combination of Atomic Orbitals representation of molecular orbitals, instead of Floating Spherical Gaussian Orbitals. We used Gaussian and Slater type orbitals as a basis set of atomic orbitals. By applying this method, the electronic stopping cross-sections of compounds have been calculated by considering compounds as a whole, without separating core and bond orbitals of compounds and the concept of molecular fragments. (c) 2006 Elsevier B.V. All rights reserved

Effect of repeated ceramic firings on the marginal and internal adaptation of metal-ceramic restorations fabricated with different CAD-CAM technologies

Statement of problem The use of computer-aided design and computer-aided manufacturing (CAD-CAM) for metal-ceramic restorations has increased with advances in the technology. However, little is known about the marginal and internal adaptation of restorations fabricated using laser sintering (LS) and soft milling (SM). Moreover, the effects of repeated ceramic firings on the marginal and internal adaptation of metal-ceramic restorations fabricated with LS and SM is also unknown. Purpose The purpose of this in vitro study was to investigate the effects of repeated ceramic firings on the marginal and internal adaptation of metal-ceramic copings fabricated using the lost wax (LW), LS, and SM techniques. Material and methods Ten LW, 10 LS, and 10 SM cobalt-chromium (Co-Cr) copings were fabricated for an artificial tooth (Frasaco GmbH). After the application of veneering ceramic (VITA VMK Master; VITA Zahnfabrik), the marginal and internal discrepancies of these copings were measured with a silicone indicator paste and a stereomicroscope at ×100 magnification after the first, second, and third clinical simulated ceramic firing cycles. Repeated measures 2-way ANOVA and the Fisher LSD post hoc test were used to evaluate differences in marginal and internal discrepancies (α=.05). Results Neither fabrication protocol nor repeated ceramic firings had any statistically significant effect on internal discrepancy values (P>.05). Marginal discrepancy values were also statistically unaffected by repeated ceramic firings (P>.05); however, the fabrication protocol had a significant effect on marginal discrepancy values (P.05). Conclusions All groups demonstrated clinically acceptable marginal adaptation after repeated ceramic firing cycles; however, the LS and SM groups demonstrated better marginal adaptation than that of LW group and may be appropriate clinical alternatives to LW. © 2017 Editorial Council for the Journal of Prosthetic Dentistr