The next generation ground-based giant telescope, the European Extremely Large Telescope (E-ELT), under development by the European Southern Observation (ESO) , will have nearly 1000 hexagonal segments of 1.45m across the flats. Fast processing of these segments with high form and edge specifications has proven to be a challenge. The Zeeko Precessions sub-aperture bonnet polishing plays an impo...

OBJECTIVES This study aimed to evaluate the color stability of bulk-fill and nanohybrid resin-based composites polished with 3 different, multistep, aluminum-oxide impregnated finishing and polishing disks. MATERIALS AND METHODS Disk-shaped specimens (8 mm in diameter and 4 mm in thickness) were light-cured between two glass slabs using one nanohybid bulk-fill (Tetric EvoCeram, Ivoclar Vivade...

AIM The purpose of this study was to investigate the effect of polishing systems on the microleakage of a nanofill, a nanohybrid, and a microhybrid composite in Class V cavities. METHODS AND MATERIALS Preparations were made at the cemento-enamel junction (CEJ) of 36 extracted human premolars. The teeth were randomly divided into three groups and restored with new resin composites according to...

The purpose of this study was: to determine whether polishing standardized proximal root surfaces with dental floss, Superfloss, wood and plastic interdental cleaners, using a polishing paste, produces any significant change on root surface roughness; and to determine the effectiveness of different number of strokes in polishing. 80 tooth specimens were prepared, 10 in each of 8 sample groups. ...

Laser-induced damage on optical surfaces is often associated with absorbing contaminants introduced by the polishing process. This is particularly the case for W optics. In the present study, secondmy ion mass spectroscopy (SIMS) was used to measure depth profiles of finishing-process contamination on fused silica surfaces. Contaminants detected include the major polishing compound components (...

OBJECTIVE To evaluate the surface roughness of IPS Empress 2 ceramic when treated with different finishing/polishing protocols. MATERIALS AND METHODS Sixteen specimens of IPS Empress 2 ceramic were made from wax patterns obtained using a stainless steel split mold. The specimens were glazed (Stage 0-S0, control) and divided into two groups. The specimens in Group 1 (G1) were finished/polished...

The microstructure of a mechanically finished calcium fluoride (CaF2) was studied by transmission electron microscopy (TEM). The (111) oriented surfaces of high-purity CaF2 single crystals were finished to a flat surface by ultra-precision mechanical polishing. A float polishing method—with 7-nm-diameter silicon dioxide powder, pure water, and a tin lap—was employed for the finishing. Prior to ...

Correspondence to: Célia Marisa Rizzatti-Barbosa Department of Prosthesis and Periodontology Piracicaba Dental School, State University of Campinas (UNICAMP) Avenida Limeira, 901. Areião CEP: 13414-018 Piracicaba São Paulo Brazil. Phone: 00 55 19 3412 5373 Fax: 00 55 19 3412 5218 E-mail: [email protected] Abstract The aim of this study was to evaluate the influence of polymerization metho...

PURPOSE The aims of this in vitro study were to evaluate morphological changes induced by glycine powder air-polishing on titanium surfaces, biofilm removal, and biocompatibility. MATERIAL AND METHODS Titanium grade IV discs were allocated into two groups: (1) discs without biofilm and (2) discs for Streptococcus mutans biofilm formation. Discs in each group were further subdivided into (a) n...

A generalized model is developed to quantitatively describe the smoothing effects from different polishing tools used for optical surfaces. The smoothing effect naturally corrects mid-to-high spatial frequency errors that have features small compared to the size of the polishing lap. The original parametric smoothing model provided a convenient way to compare smoothing efficiency of different p...