Road and railway tunnels in cold regions are often affected by problems related to water leakage and freezing temperatures. Water leakage in a tunnel leads to ice growth when the temperature goes below freezing and creates favourable environment for fallouts of shotcrete and rock. This paper presents results and observations from laboratory freezing – thawing experiments on rock blocks covered ...

The aim of this study was to evaluate the integrity of the coronal seal of Temp-Bond and compare it to Cavit and IRM after post space preparation using S. faecalis as a microbial tracer. In addition, the affect of two methods of gutta percha removal on the apical seal of root canal fillings was also evaluated. Forty extracted human single rooted teeth were prepared chemomechanically and obturat...

BACKGROUND Various materials have been added to mineral trioxide aggregate to enhance its properties. This study was aimed to compare the sealing efficacy of MTA with and without nanosilver using bacterial leakage approach. MATERIAL AND METHODS Seventy canine teeth were prepared and obturated. Then, after apical resection, the root-end cavities were prepared by ultrasonic retrotips. Teeth wer...

This paper proposed a semi-theoretical model to quantitatively predict leakage rate of tubing and casing premium connections. The geometric parameters the sealing surface profile approximated by sinusoidal micro-convex were first obtained based on random normal distribution sampling method. With actual area prediction formula for elastic–plastic contact an axisymmetric body equivalent simulatio...

INTRODUCTION The apical constriction (AC) has been a traditional landmark as an end point of canal preparation and obturation. However, the morphology and incidence of this structure have not been definitively determined. The purpose of this study was to determine these factors by using a noninvasive technology, micro-computed tomography. METHODS Forty extracted maxillary molar palatal roots ...

his study evaluated the sealing ability of apical plugs fabricated with gray MTA Angelus sealer, CPM TM sealer and MBPc sealer. The root canals of 98 extracted single-rooted human teeth were instrumented with #5 to #1 Gates Glidden drills according to the crown-down technique until the #1 drill could pass through the apical foramen. The specimens were then prepared with K-files, starting with a...

AIM – The aim of this study was to evaluate marginal sealing ability of newly introduced Dyad Flow with total etch & self-etch adhesive system at the coronal and apical margins of class V resin composite restorations. MethodsA standard class V cavity (3 mm mesiodistal width, 3 mm occlusogingival height, and 1.5 mm axial depth) was prepared on the buccal surface of freshly extracted sound human ...