AAE Home > JOE > Abstracts > July 2002 Volume 28, Number 7
July 2002 Volume 28, Number 7
Depositions of Nitrogen on NiTi Instruments
Tripi, Bonaccorso, Rapisarda, Tripi, Condorelli, Marino, and Fragalà
The Demineralizing Effects of EDTA at Different Concentrations and pH
Serper and Çalt
Depositions of Nitrogen on NiTi Instruments
Teresa Roberta Tripi, DMD, Antonio Bonaccorso, DMD, Ernesto Rapisarda, DDS, Valeria Tripi, DMD, Guido Guglielmo Condorelli, DMD, Roberto Marino, DMD, and Ignazio Fragalà, DDS
This study was designed to obtain nitrogen-rich layers on the surfaces of endodontic files made of nickel-titanium (NiTi) alloy by chemical vapor deposition. Experimental samples (GT rotary instruments) were deposited by using two different methods. The first one was based on the reaction of wet NH3 with NiTi under high temperatures (300ºC). The second technique is a typical MOCVD (metal organic chemical vapor deposition) procedure that uses Ti(Et2N)4 as a titanium and nitrogen precursor. Control samples were not exposed to any process. The chemical composition of the surface layers of each sample was determined by means of X-ray photoelectron spectroscopy and X-ray diffraction measurements. The experimental instruments showed surface chemical composition that was different from that seen in the control group; samples treated with gaseous NH3 showed a surface nitrogen/titanium (N/Ti) ratio = 0.9; MOCVD instruments showed a surface N/Ti ratio of 2; control samples showed a N/Ti ration = 0.2; MOCVD of nitrogen ion of nickel-titanium files produced a higher concentration of nitrogen on the surface.
The Demineralizing Effects of EDTA at Different Concentrations and pH
Ahmet Serper, DDS, PhD, and Semra Çalt, DDS, PhD
The purpose of this study was to compare the effects of concentration and pH variations of EDTA on dentin demineralization. Twenty extracted, human permanent teeth with single canals were used in this study. Demineralizing effects of EDTA solutions at 10% and 17% concentrations at pH 7.5 and 9.0 were determined by measuring the amount of liberated phosphorus 1, 3, 5, 10, and 15 min after exposure. The results showed that the amount of phosphorus liberated from dentin was greater with increased EDTA concentration and increased time of exposure, and it was more effective at neutral pH than pH 9.0. The pH of the EDTA solutions did not display any significant alterations during the demineralization process.