Diagnostic accuracy of cone-beam computed tomography in detecting secondary caries under composite fillings: An in vitro study

Purpose: The aim of this in vitro study was to assess the diagnostic performance of cone-beam computed tomography (CBCT) in the detection of secondary carious lesions under composite resin fillings applied to different types of cavities. Materials and Methods: Occlusal cavities (O) (n=18), occlusal cavities with mesial or distal component (MO/DO) (n=30), and mesial–occlusal–distal cavities (MOD) (n=30) were prepared in seventy eight extracted human posterior teeth. In half of the cavities in each group, artificial secondary caries lesions were simulated. All cavities were restored by using composite resin. All specimens were embedded in silicone and they were positioned to have approximal contacts. CBCT imaging was done and data were evaluated two times with two week interval by two observers, using a five-point confidence scale. Intra- and inter-observer agreements were calculated with Kappa statistics (κ). The area under (Az) the receiver operating characteristic (ROC) curve was used to evaluate the diagnostic accuracy. Results: Intra- (κ =0.89) and inter-observer (κ = 0.79) agreements were found to be excellent. Az values were highest for the O restorations which is followed by the MOD and DO/MO restorations. Az values for MOD and DO/MO restorations were very low and no statistically significant difference was found. Sensitivity for DO/MO restorations and specificity for MOD restorations were found to be the lowest values. Conclusion: Diagnostic performance of CBCT was higher in O composite restorations than MOD and DO/MO restorations for secondary caries detection. The use of alternative imaging methods rather than CBCT may be useful for evaluating secondary caries under composite MOD and DO/MO restorations

On mappings that preserve Fermat-Torricelli points

Let (Delta) be the set of all triple points ({ A, B, C }) in (mathbb{R}^n) such that the largest angle of the triangle (ABC) is less than (frac{2pi}{3}) . In this paper we proved that if a mapping (f:mathbb{R}^n rightarrow mathbb{R}^n) preserves the Fermat-Torricelli points of the triangles in (Delta), then is an affine transformation

On the Mappings Preserving the Hyperbolic Polygons of Type B Together With Their Hyperbolic Areas

In this paper, we present new characterizations of Möbius transformations and conjugate Möbius transformations by using the mappings preserving the hyperbolic polygons of type B together with their hyperbolic areas

A New Proof of the Lester’s Perimeter Theorem in Euclidean Space

An injection defined from Euclidean space  n-space E^n to itself which preserves the triangles of perimeter 1 is an Eucldean motion.   J. Lester gave two different proofs for this theorem in Euclidean plane [1] and Euclidean space [2]. In this study a new technique is developed for the proof of this theorem which is valid in both Euclidean plane  and Euclidean space

Investigation of the prevalence and main features of skull-base anomalies and characteristics of the sphenoid sinus using cone-beam computed tomography

Objectives: This study aimed to define the prevalence and characteristics of skull base anomalies and the features of sphenoid sinus pneumatization (SSP). Materials and Methods: Five hundred cone-beam computed tomography scans were evaluated retrospectively for the presence of fossa navicularis magna (FNM), canalis basilaris medianus (CBM), sphenoid emissary foramen (SEF), and/or Onodi cells (OC). Patterns of the SSP and sphenoid sinus mucosa dimensions (SSMD) were also recorded. Results: The prevalence of FNM, CBM, SEF, and OC was 26.0%, 22.4%, 47.4%, and 18.4%, respectively. Two hundred sixty-two (52.4%) sellar-type SSP were defined, followed by post-sellar 191 (38.2%), pre-sellar 31 (6.2%), and conchal 16 (3.2%) types. The frequency of SSMD less than 1 mm, 1-3 mm, and greater than 3 mm was 40.6%, 38.4%, and 21.0%, respectively. An SEF was detected more frequently in females, while SSMD greater than 3 mm was more frequent in males. An FNM was more prevalent in the 18-29 and 30-39 age groups and SEF was significantly less frequent in patients over 60 years of age compared to other age groups. A sinus mucosa larger than 3 mm was more common in the younger than 18 year group. The frequency of post-sellar-type pneumatization was lower in patients younger than 18 years. Conclusion: Skull-base anomalies are common and may be detected incidentally during imaging procedures. The sphenoid sinus, its variations, and pneumatization patterns should also be taken into consideration in imaging procedures performed for various purposes

Comparison of two digital intraoral radiography imaging systems as a function of contrast resolution and exposure time

BACKGROUND To compare the image quality of two different digital imaging systems; one photostimulable phosphor plate system (PSP) and a direct digital radiography system with CMOS imaging sensor; via evaluating contrast resolution among four different exposure times. METHODS Endodontically treated incisor teeth embedded in paraffin blocks are aligned next to a 99.5% Al wedge and exposed for 0.8, 0.1,0.125 and 0.16 seconds using both the CMOS and PSP systems. Using ImageJ software, 5 isometric and isogridded ROI from each root filling area and isometric ROI from the Al stepwedge were calculated. RESULTS Evaluation of the total of 120 images displayed that PSP system produced significantly higher contrast resolution (P0.05). CONCLUSIONS The contrast resolution was higher using the PSP system. It can be estimated that, filling material will be more obvious under lower doses using PSP

Yüksek Sıcaklığa Maruz Pomza ve Silis Dumanı Katkılı Betonların Mekanik ve Fiziksel Özelliklerine Kür Yaşının Etkisi

Bu çalışmada, ince öğütülmüş pomza (İÖP) ile çimentonun ağırlıkça %5, %10, %15 ve %20 oranlarında yer değiştirilmesiyle elde edilen betonların yüksek sıcaklık sonrası mekanik ve fiziksel dayanımları üzerine kür yaşının etkisi incelendi. Ayrıca, elde edilen pomzalı betonların mekanik ve fiziksel özellikleri üzerine silis dumanı (SD) ilavesinin etkisini belirleyebilmek amacıyla, kontrol numunesi dışındaki tüm serilere çimento ile ağırlıkça %10 oranında yer değiştirecek şekilde SD ilave edildi. 28 ve 365 günlük kür sürelerini tamamlayan numuneler laboratuar tipi fırında 400, 600 ve 800 °C sıcaklıklara kadar ısıtıldı ve bu sıcaklıklarda 1 saat bekletildi. Numuneler sıcaklığa maruz kalmadan önce birim ağırlık, porozite, kılcal su emme ve basınç dayanımı deneylerine tabi tutuldu. Elde edilen bu deney verileri sıcaklık sonrası veriler ile kıyaslanarak kür süresinin numunelerin dayanımı üzerindeki etkisi belirlendi. Sonuçlar, taramalı elektron mikroskobunda (SEM) yapılan incelemeler ile desteklendi. Yapılan çalışma neticesinde, pomza katkısının erken kür yaşlarında betonun dayanımını düşürdüğü ancak ilerleyen kür yaşlarında dayanım artışına neden olduğu belirlendi. Ayrıca, ilerleyen kür yaşlarında silis dumanı katkılı numunelerin 400 °C’nin üzerindeki yüksek sıcaklıklarda 28 günlük numunelere göre daha fazla dayanım kaybı gösterdikleri tespit edildi

Nazal septum deviasyonu ve konka bulloza ilişkisinin konik işinli bilgisayarli tomografi ile değerlendirilmesi

Amaç: Çalışmada rastgele seçilmiş 100 hastadan alınmış konik ışınlı bilgisayarlı tomografi (KIBT) görüntülerinde, nazal septum deviasyonu (NSD) ile konka bulloza (KB) arasındaki ve bu anomalilerin maksiller sinüs patolojilerinin varlığı ile ilişkisinin değerlendirilmesi amaçlanmıştır.Gereç ve Yöntemler: Çalışmaya diş hekimliği fakültesi uygulama ve araştırma hastanesi arşivinde bulunan, rastgele seçilmiş 100 hastaya ait KIBT görüntüleri dahil edildi. Görüntüler üzerinde KB varlığı ve tipi, NSD varlığı ve miktarı ile maksiller sinüslerdeki mukozal değişiklikler değerlendirildi. İstatistiksel olarak bu anomalilerin birbirleriyle ve maksiller sinüslerde gözlenen mukozal değişikliklerle ilişkisi incelendi.Bulgular: NSD değerlendirilen hastaların % 66’sında, KB ise % 72’sinde gözlendi. Maksiller sinüs patolojileri değerlendirilen hastaların % 49’unda mevcuttu. KB tipleri arasında en sık lameller tip KB izlendi. NSD ve KB arasında istatistiksel olarak anlamlı ilişki tespit edildi ve bu anomalilerin maksiller sinüslerde gözlenen patolojilerle ilişkili olduğu gözlendi. NSD miktarı ile KB varlığı arasında ve NSD miktarı ile sinüs patolojileri arasında pozitif korelasyon saptandı.Sonuç: NSD ve KB oldukça sık karşılaşılan sinonazal anomaliler olup, birbirleriyle ilişkilidir. Bu anomalilerin maksiller sinüslerde gelişen mukozal değişikliklerle ilişkisi vardır. NSD miktarı arttıkça, KB ve maksiller sinüslerde patolojik değişim görülme oranı artmaktadır.ANAHTAR KELİMELER Konik Işınlı Bilgisayarlı Tomografi, Konka Bulloza, Nazal Septum Deviasyon

Corrosion Behavior of Reinforcing Steel Embedded in Concrete Produced with Finely Ground Pumice and Silica Fume

In this study, the mechanical and physical properties of concrete specimens obtained by substituting cement with finely ground pumice (FGP) at proportions of 5%, 10%, 15% and 20% by weight has been investigated, in addition to analyzing the corrosion behavior of reinforcing steels embedded in these specimens. Besides, with the purpose of determining the effect of silica fume (SF) additive over the corrosion of reinforcing steels embedded in concrete with FGP, SF has been entrained to all series with the exception of the control specimen, such that it would replace with cement 10% by weight. Corrosion experiments were conducted in two stages. In the first stage, the corrosion potential of reinforcing steels embedded in the concrete specimens was measured every day for a period of 160 days based on the ASTM C 876 standard. In the second stage, the anodic and cathodic polarization values of the steels were obtained and subsequently the corrosion currents were determined with the aid of cathodic polarization curves. In the study, it was observed that a decrease in the mechanical strength of the specimens and an increase in the corrosion rate of the reinforcing steel had taken place as a result of the FGP addition. However, it was determined that with the addition of SF into concretes supplemented with FGP, the corrosion rate of the reinforcing steel has significantly decreased

Effect of Elevated Temperature on the Mechanical Properties of Concrete Produced with Finely Ground Pumice and Silica Fume

This study investigated the effect of elevated temperature on the mechanical and physical properties of concrete specimens obtained by substituting cement with finely ground pumice (FGP) at proportions of 5%, 10%, 15% and 20% by weight. To determine the effect of silica fume (SF) additive on the mechanical and physical properties of concrete containing FGP, SF has been added to all series except for the control specimen, which contained 10% cement by weight instead. The specimens were heated in an electric furnace up to 400, 600 and 800 1C and kept at these temperatures for one hour. After the specimens were cooled in the furnace, ultrasonic pulse velocity (UPV), compressive strength and weight loss values were determined. The results demonstrated that adding the mineral admixtures to concrete decreased both unit weight and compressive strength. Additionally, elevating the temperature above 600 1C affected the compressive strength such that the weight loss of concrete was more pronounced for concrete mixtures containing both FGP and SF. These results were also supported by scanning electron microscope (SEM) studie