STATEMENT OF THE PROBLEM Demineralization of enamel adjacent to orthodontic appliances frequently occurs, commonly due to insufficient oral hygiene. PURPOSE The aim of this study was to compare two microabrasion techniques on improving the white spot lesions as well as subsequent enamel discoloration. MATERIALS AND METHOD Sixty extracted premolar teeth without caries and hypoplasia were sel...

The BishopTuff is a giant silicic ignimbrite erupted at 0·76Ma in eastern California, USA. Five pumice clasts from the late-erupted Bishop Tuff (Aeolian Buttes) were studied in an effort to better understand the preand syn-eruptive history of the Bishop magma body and place constraints on the timescales of its existence. This study complements and expands on a previous study that focused on ear...

Sangiran (Solo Basin, Central Java, Indonesia) is the singular Homo erectus fossil locale for Early Pleistocene Southeast Asia. Sangiran is the source for more than 80 specimens in deposits with (40)Ar/(39)Ar ages of 1.51-0.9 Ma. In April 2001, we recovered a H. erectus left maxilla fragment (preserving P(3)- M(2)) from the Sangiran site of Bapang. The find spot lies at the base of the Bapang F...

PURPOSE Surface roughness promotes adhesion and colonization of denture plaque. Therefore, it is important to know the effects of polishing and finishing on the surface roughness of various acrylic resin materials. OBJECTIVES To evaluate and compare the effects of different conventional lathe polishing techniques on heat cured acrylic resins in producing surface roughness. MATERIALS AND MET...

BACKGROUND: Hydrocarbon-degrading biofilms in the treatment of contaminated groundwaters have received increasing attention due to the role played in the so-called "biobarriers". These are bioremediation systems in which a microbial consortium adherent to a solid support is placed across the flow of a contaminated plume, thus promoting biodegradation of the pollutant. RESULTS: A microbial conso...

Background and Aim: Management of iron-induced tooth pigmentation is challenging. This study aimed to compare the efficacy of sodium bicarbonate powder and pumice flour for removal of iron-induced pigmentation from primary ante-rior teeth. Materials and Methods: In this in vitro, experimental study, 60 sound primary anterior teeth were collected. After cutting the roots and sealing the pulp ch...

Michael S. Ramsey (Y) 7 Jonathan H. Fink Department of Geology, Arizona State University, Box 871404, Tempe, Arizona 85287–1404, USA Fax: c602 965 1787 e-mail: ramsey6elwood.la.asu.edu Abstract Remote monitoring of active lava domes provides insights into the duration of continued lava extrusion and detection of potentially associated explosive activity. On inactive flows, variations in surface...

background: this study was conducted to determine the species of oral and non-oral microorganisms in dental laboratory pumice in order to undertake the necessary disinfection control protocols. methods: fourteen active and well-known dental laboratories of tehran entered our study. samples of pumice were collected from polishing containers in a completely sterilized and controlled condition. th...