Eğri kanallarda farklı preparasyon tekniklerinin değerlendirilmesi ile ilgili bir araştırma
Evaluation of Different Preparation Techniques in Curved Root Canals: an In Vitro Study In this study, the effects of Conventional Filing, Stepback, Stepdown, Crowndown, Roane, Ultrasonic and Sonic Instrumentation techniques were compared in curved canals in vitro. One hundred forty mesial root canals with curvatures of 25 to 50 degrees in freshly extracted human mandibular molars were randomly divided into seven instrumentation groups of 20 root canals each. After the roots were embedded in clear casting resin, the plastic blocks were sectioned horizontally at coronal, middle and apical levels and photographed before and after instrumentation. The amounts of dentin removed, the centering ratio, the directions and lengths of transportation and the final shapes of the instrumented canals were compared by using a computer with a digitized tablet. Conventional Filing Methods, Sonic Instrumentation and Roane Technique removed more dentin than the other techniques while Ultrasonic removed less dentin. In all seven techniques, the orijinal canals were transported mesially at coronal levels.distally in middle and mesially at apical level. There was a trend for Crowndown, Roane and Stepdown Techniques to remain centered in the canals.79 The greatest transportation was occured with Conventional Filing Methods and Sonic Instrumentation Techniques. The majority of canals in the Crowndown, Roane and Stepdown group were round whereas the majority in the Conventional Filing Methods were irregular.v
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