Hyporheic exchange carries reactive solutes, which may include biological oxygen demand (BOD), dissolved oxygen (DO) and reactive dissolved inorganic nitrogen (Nr), into the sediment, where biochemical reactions consume DO. Here, we study the impact of streambed morphology, stream-reactive solute loads and their diel oscillations on the DO benthic uptake rate (BUR) due to hyporheic processes. O...

This study evaluated the enamel loss and composite remnants after debonding and clean-up. The tested null hypothesis is that there are no differences between different polishing systems regarding removing composite remnants without damaging the tooth surface. Brackets were bonded to 75 extracted human molars and removed after a storage period of 100 hours. The adhesive remnant index (ARI) was e...

BACKGROUND A prolonged life of fissure sealant has always been the target for preventing caries in vulnerable newly erupted teeth. The use of preparatory techniques including bur introduction to the fissures is considered among such improving steps. MATERIALS AND METHODS Ninety freshly extracted healthy maxillary premolar teeth were randomly selected for this investigation. Teeth were then di...

OBJECTIVES CO(2), Er:YAG and Nd:YAG lasers have been used in endodontic surgery. This in vitro study evaluated 1% Rhodamine B dye penetration using computer-assisted morphometry (ImageTool Software) of 108 endodontically treated human permanent canines. MATERIAL AND METHODS Teeth were divided into 9 groups according to the technique used: A: 90-degree apicoectomy with bur, root-end cavity pre...

Bur oak (Quercus macrocarpa Michx.) and chinquapin oak (Q. muehlenbergii Engl.) leaves were exposed to high temperatures at various photosynthetic photon flux densities under laboratory conditions to determine if species-specific responses to these factors were consistent with the distribution of these oaks in gallery forests in the tallgrass prairies of northeastern Kansas, USA. Measurements o...

Objective: The aim of this study was to compare the number of crack formation in retrograde cavities after preparation with ultrasound, Er,Cr:YSGG (erbium, chromium:yttrium, scandium, gallium and garnet) laser with different power and frequency settings and bur. Materials and methods: Root canals of 60 extracted human maxillary incisors were prepared, the apices were horizontally cut and class ...

This paper reviews existing studies and investigates thermal operational regimes of diamond bit during drilling operations. The operating temperature of the diamond core drill is studied under bench condition and an optimal thermal range are presented. Based on this study, it was noted that glazing of diamond tools is observed at temperatures less than 327°C, and normal wear of diamond tools is...

BACKGROUND The present study aimed at 3D analysis of adhesive remnants and enamel loss following the debonding of orthodontic molar tubes and orthodontic clean-up to assess the effectiveness and safety of One-Step Finisher and Polisher and Adhesive Residue Remover in comparison to tungsten carbide bur. MATERIALS AND METHODS Thirty human molars were bonded with chemical-cure orthodontic adhesi...

Friedel-Crafts alkylation of 4-tert-butylaniline with 2 equiv of benzhydrol affords bulky 2,6-bis(diphenylmethyl)-4-tert-butylaniline (Ar*NH2) in good yield, which can be readily synthesized on a tens of grams scale. The reaction of 6 equiv of Ar*NH2 with triphosgene generates the symmetric urea (Ar*NH)2CO, which, upon dehydration with a P2O5/Al2O3 slurry in pyridine, produces the sterically en...