El ve Döner Alet Kullanımı Sonrasında Apikalden Taşan Debris Miktarının ve Kalsiyum Hidroksit Uzaklaştırılmasının Değerlendirilmesi

Amaç: Bu çalışmanın amacı el ve döner alet kullanımından sonra kök kanal duvarlarında kalan kalsiyum hidroksit miktarının ve kalsiyum hidroksit uzaklaştırılması süresince apikalden taşan debris miktarının değerlendirilmesidir.Gereç ve Yöntem: Yirmi-dört çekilmiş üst çene kesici diş K-tipi eğeler ile prepare edildi ve kalsiyum hidroksit ile dolduruldu. Dört diş pozitif ve negatif kontrol olarak ayrıldı. Kalan dişler iki gruba ayrıldı: ana apikal eğe grubu ve ProTaper Universal döner alet grubu. Uzaklaştırma işlemleri boyunca yıkama solüsyonu olarak sitrik asit kullanıldı. Apikalden taşan debris toplandı ve gruplar arasında karşılaştırıldı. Daha sonra dişler dikey eksenleri boyunca ikiye ayrıldı, stereomikroskop kullanılarak fotoğrafları çekildi ve bilgisayar programı kullanılarak resimlerin analizi yapıldı. Veriler tek yönlü varyans analizi ile istatistiksel olarak analiz edildi.Bulgular: Her iki grupta kalsiyum hidroksit uzaklaştırma süresince ölçülebilir miktarda apikalden taşan debris gözlemlendi. İstatiksel analiz apikal olarak debris çıkışı ve uzaklaştırılan kalsiyum hidroksit bakımından teknikler arasında anlamlı farkın olmadığını gösterdi.Sonuçlar: Kalsiyum hidroksit uzaklaştırma süresince tekniğe bağlı olmaksızın apikal olarak debris çıkışı meydana gelmektedir. Kullanılan tekniklerden hiçbirisi kök kanal duvarlarından kalsiyum hidroksiti tamamen uzaklaştıramadı

Evaluation of Fit between Tooth and Band Surfaces when Different Orthodontic Cements are Used

The aim of this in vitro study was to compare three orthodontic band cements for gaps remained between tooth and band surfaces, at the cervical margin, which possibly caused after banding procedure. Sixty freshly extracted human mandibular third molars were randomly divided into 3 equal groups. Micro-etched molar bands were cemented to the teeth using each of the orthodontic band cements (Ketac Cem®, 3M Multi-Cure® and Transbond Plus®). The teeth were placed in preformed boxes (2.5X2.5X2.5 cm); crowns were on the bottom and perpendicular to the ground. Samples were capped with black colored plaster on a vibration machine. After hardening of the plasters, samples were removed from the boxes and were trimmed in the bucco-lingual dimension for evaluation. The mean of four parallel sections examined under a stere-omicroscope was noted as the score of that sample, for buccal and lingual sides, separately. Statistically analyses were performed by using analysis of variance and paired-samples t-test. When buccal and lingual gap formations were compared, Transbond Plus® and Ketac Cem® groups were found to have larger gaps in the lingual side than buccal at p<0.05 and p<0.01 level, respectively. Thus, buccal and lingual gaps of three cements were compared separately, and no statistically significant difference was determined among three investigated cement types at buccal and lingual sides. However no differences were found among different types of band cements, it is clear that large gaps were observed under molar bands at cervical margin; where it is not easily possible to clean. Further studies should be conducted to determine a favorable strategy to eliminate these gaps and maintain a gap-free adaptation and cementation between band and tooth structure

Phytochemical profile and some biological activities of three Centaurea species from Turkey

Purpose: To characterise the phytochemical profile of whole plants of Centaurea balsamita, C. depressa and C. lycopifolia with LC-ESI-MS/MS, and as well as their antioxidant, anticholinesterase and antimicrobial activities.Methods: Organic and aqueous extracts of the three Centaurea species were evaluated for DPPH free radical, ABTS cation radical scavenging and cupric reducing antioxidant capacity (CUPRAC). Acetyland butyryl-cholinesterase enzyme inhibition abilities of the extracts using petroleum ether, acetone, methanol and water were studied to determine anticholinesterase activity, while antimicrobial activity was determined by disc diffusion method using appropriate antimicrobial standards and organisms. The phytochemical components of the methanol extracts were assessed by LC-MS/MS.Results: The methanol extract of C. balsamita exhibited much higher DPPH free and ABTS cation radicals scavenging activities (with IC50 of 62.65 ± 0.97 and 24.21 ± 0.70 mg/ml, respectively) than the other extracts. The petroleum ether extracts of the plant species exhibited moderate inhibitory activity against butyrylcholinesterase enzymes while the acetone extract of C. balsamita showed good antifungal activity against Candida albicans. Quinic acid (17513 ± 813 μg/g, 63874 ± 3066 μg/g and 108234 ± 5195 μg/g) was the major compound found in the methanol extracts of C. balsamita, C. depressa and C. Lycopifolia, respectively.Conclusion: These results indicate quinic acid is the major compound in the three plant species and that Centaurea balsamita has significant antioxidant, anticholinesterase and antimicrobial properties. Further studies to identify the compounds in the extracts responsible for the activities are required.Keywords: Centaurea, LC-ESI-MS/MS, Anticholinesterase, Antioxidant, Antimicrobia

Robust Liu-type estimator for regression based on M-estimator

Hasan Ertas was supported by Cukurova University Academic Research Projects (FEF2013D15).The problem of multicollinearity and outliers in the dataset can strongly distort ordinary least-square estimates and lead to unreliable results. We propose a new Robust Liu-type M-estimator to cope with this combined problem of multicollinearity and outliers in the y-direction. Our new estimator has advantages over two-parameter Liu-type estimator, Ridge-type M-estimator, and M-estimator. Furthermore, we give a numerical example and a simulation study to illustrate some of the theoretical results

Effects of physical and morphological properties of roots on fracture resistance

OBJECTIVE: The aim of this study was to determine how physical and morphological properties affect the fracture resistance of roots, and which criteria are important for root specimen standardization in fracture resistance studies. MATERIALS AND METHODS: Seventy-five freshly extracted human canine teeth were selected. Crowns were sectioned from the cement–enamel junction and the root lengths were set at 16 mm. Then they were prepared up to ProTaper F3 file. Each root was numbered and data were obtained by measuring mesiodistal and buccolingual dimensions, volume, weight, and density. Tests for fracture strength were performed using an Instron Testing Machine (Instron Corp. MA, USA). The force was applied axially, angled at 45 degrees with a constant speed of 1 mm/min. For each sample, the force at the time of fracture was recorded in Newtons. Results were evaluated statistically using linear regression analysis. RESULTS: Volume and weight of the roots had more effect than mesiodistal or buccolingual dimensions on root fracture resistance. CONCLUSIONS: In root fracture resistance studies, volume or weight of the roots must be standardized when distributing roots to groups