OBJECTIVE To study and compare the effects of dental amalgam and composite restorations on human dental pulp. MATERIALS AND METHODS One hundred sound premolars scheduled for orthodontic extraction were divided equally into two groups: group A, teeth restored with silver amalgam, and group B, teeth restored with composite resin. Each group was equally subdivided into two subgroups [extracted a...

A novel sponge composed of a poly (lactic acid) composite skeleton covered with bonelike apatite (b-HA) was produced via a particleleaching technique combined with a biomimetic processing. The sponge has a large porosity of w75% with large-sized pores and shows mechanical ductility. After incubation of human osteoblasts for 7 days, numerous cells attached to the surface of the skeleton, which w...

PURPOSE To investigate the biocompatibility of hydroxyapatite composite (hydroxyapatite, plaster of Paris, and chitosan) impregnated with gentamicin, fosfomycin, imipenem, or amphotericin B. METHODS The interactions of the extract from each drug against osteoblast were tested using the methylthiotetrazole test. RESULTS Extracts from all drugs showed good biocompatibility at concentrations v...

We study the applicability of composite fermion theory to electrons in twodimensional parabolically-confined quantum dots in a strong perpendicular magnetic field in the limit of low Zeeman energy. The non-interacting composite fermion spectrum correctly specifies the primary features of this system. Additional features are relatively small, indicating that the residual interaction between the ...

When confined to two dimensions and exposed to a strong magnetic field, electrons screen the Coulomb interaction in a topological fashion; they capture and even number of quantum vortices and transform into particles called 'com-posite fermions' [1–3]. The fractional quantum Hall effect [4] occurs in such a system when the ratio (or 'filling factor', ν) of the number of electrons and the degene...

BACKGROUND The aim of the study was to evaluate, in vitro, the surface roughness of two composite resins submitted to simulated toothbrushing with three different dentifrices. MATERIALS AND METHODS Totally, 36 samples of Z350XT and 36 samples of Empress Direct were built and randomly divided into three groups (n = 12) according to the dentifrice used (Oral-B Pro-Health Whitening [OBW], Colgat...

Copper matrix composite reinforced by 1wt.% TiB2 particles was prepared using in situ reaction of Cu-1.4wt.% Ti and Cu-0.7wt.% B by rapid solidification and subsequent heat treatment for 1-20 hrs at 900ºC. High-resolution transmission electron microscopy (HRTEM) characterization showed that primary TiB2 particles were formed in liquid copper. Heat treatment of as-solidified samples led to ...

This work was presented in part at the meeting ofthe American Society of Human Genetics, San Diego, Calif., October 1977. Dr. Mellman and Dr. Willard are recipients of traineeships from the National Institutes of Health (T01-GM 02299). Dr. Mellman's present address is Laboratory of Cellular Physiology and Immunology, The Rockefeller University, New York 10021. Received for publication 18 May 19...

Influence of the stacking sequences of hybrid composites on the tensile strength, flexural strength, inter-laminar shear strength (ILSS) and impact energy was investigated. The hybrid glass-basalt-carbon/polyester composite laminates were processed by hand lay-up procedure at room temperature. The fracture surface of the composite laminates after the tension and flexural test was examined by sc...