OBJECTIVE To investigate the effect of different dentin treatments on the microtensile bond strength of a self-etching primer and a simplified, total-etch adhesive system. METHODS Flat dentin surfaces were created on extracted human third molars. The surfaces were treated with one of the following conditioners: self-etching primer for 20 s (Clearfil SE Primer), 37% phosphoric acid for 15 s or...

Silica (SiO2) glass, an essential material in human civilization, possesses excellent formability near its glass-transition temperature (Tg > 1100 °C). However, bulk SiO2 glass is very brittle at room temperature. Here we show a surprising brittle-to-ductile transition of SiO2 glass nanofibers at room temperature as its diameter reduces below 18 nm, accompanied by ultrahigh fracture strength. L...

The objective of this study was to evaluate the effects of methods of acid application, wash times, and saliva contamination on the tensile bond strength of a composite resin to enamel Ninety human maxillary central incisors were used and the tensile bond strength was determined for the composite resin to enamel surfaces subjected to the following acid etch parameters. In the control group (A) ...

the marble slurry wastes (msw) produced by marble industry is left unattended in theenvironment which causes serious environmental problems. in order to evaluate its potential usage in normal1:2:4 concrete, this study was designed, where the partial replacement of cement with msw was examined.replacement of cement with msw from 0 to 100%, and also its usage as an additive material 10% and 20% b...

The purpose of this study was to evaluate the effects of two concentrations of poly (acrylic acid) (10 and 25%), three treatments (untreated, passive conditioning, and active conditioning), and two storage conditions (24 hours in 37 degrees C water and thermal cycling) on the in vitro tensile bond strength of three commercial glass-ionomer liners to human dentin. Bond strengths to untreated den...

Tensile bond strength and bond failure location were evaluated in vitro for two types of aesthetic brackets (non-silanated ceramic, polycarbonate) and one stainless steel bracket, using bovine teeth as the substrate and diacrylate resin as the adhesive. The results show that metallic bracket had the highest bond strength (13.21 N) followed by the new plastic bracket (12.01 N), which does not re...

In this work, the effect of rock bolt angle on the shear behavior of Rock Bridges is investigated using the particle flow code in two dimensions (PFC2D) for three different Rock Bridge lengths. Firstly, the calibration of PF2D is performed to reproduce the gypsum sample. Then the numerical models with the dimensions of 100 mm * 100 mm are prepared. The Rock Bridge is created in the middle of th...