Search Results

You are looking at 1 - 10 of 469 items for :

  • All content x
Clear All

Thermal behaviour of aryloxides of titanium(IV) of composition TiCln(OAr)4−n (wheren=0→3 and OAr=OC6But-4, OC6H4OMe-4 and OC6H2-Bu2 t-2,6−Me-4) has been studied by DTA and TG analysis. Multiple decomposition steps have been indicated by thermal weight losses which are both exothermic and endothermic as shown by DTA curves. Based upon the total % loss in weight; during entire decomposition titanium dioxide has been found to be the final residue in each case.

Restricted access

Abstract  

Heat capacity of titanium in the temperature range 1500 to 1900 K was measured by a pulse-heating system, operating in the millisecond time regime. The measurement technique is based on selfheating of a tube-shaped specimen from room temperature to melting in approximately 500 ms and measuring current through the specimen, voltage drop along a defined portion of the specimen, and temperature of the specimen every 0.5 ms. A total of 12 measurements on 3 tube-shaped specimens was made. The reproducibility between individual measurements was 0.4%, between different specimens 0.7%. The extended measurement uncertainty (at a confidence level of 95%) is estimated to be 3%.

Restricted access

Abstract  

The aim of this study was to evaluate physico-chemical properties and the healing capacity of surface treated titanium. Surface treatment combining sand-blasting, acid etching and alkaline etching (BIO surface) was evaluated together with machined titanium as a reference surface. Hydration, wetting angle, surface area and roughness parameters were evaluated for both surfaces. Stability of dental implants with both surfaces implanted in the tibia of dog was measured during the healing of twelve weeks. BIO surface exhibited lower wetting angle, larger surface area, higher degree of hydration and higher average roughness compared to machined titanium. Implants with the BIO surface maintained their stability during the whole healing period in contrast to those with machined titanium surface, which showed a statistically significant decrease in stability three and nine weeks after implantation.

Restricted access

Abstract  

Interaction of acid and acid+alkali treated titanium samples with simulated body fluid was studied. In case of alkali treated titanium, the dynamic arrangement of the test enabled the detection of primary calcium and phosphate ion adsorption from the solution and later apatite crystal growth (XRD). The induction time for crystal growth was 24.20.3 h. On acid-only treated titanium no crystal growth was detected. The calcium phosphate adsorption layer formed on the acid treated samples was detectable by XPS only, however it differed from that one formed on the acid+alkali treated samples. The adsorption layer formed on the acid+alkali treated samples contained larger amount of calcium, especially in the shortest exposure times. Charging of the apatite crystallites during the XPS measurement enabled the determination their Ca/P ratio separately from Ca/P ratio of the adsorption layers. XPS and EDS analyses indicated that the spherulitic crystallites consisted of carbonated hydroxyapatite with the Ca/P ratio close to that one of the stoichiometric hydroxyapatite. It is proposed that the adsorption layer formed spontaneously and immediately on the acid+alkali treated titanium can provide an ideal interface between the metal implant and the apatite cement line, the first structure formed by osteoblast cells during the formation of the new bone on foreign surfaces.

Restricted access

1. Introduction Titanium (Ti) and its alloys belong to a group of bioinert materials which are intended to be used in several clinical applications, especially for orthopedic and dental implants [ 1 , 2 ]. However, as

Open access

efficacy of the abovementioned three chemical agents on polished titanium (Ti) surfaces infected with Porphyromonas gingivalis , a typical representative of the bacterial flora associated with peri-implantitis. Materials and methods Preparation of Ti

Open access

Introduction Implantation is one of the most widely applied treatment options for tooth replacement. Titanium (Ti) and Ti alloys are the most common choices for dental implant materials because these materials are well tolerated by human tissues and

Open access
Acta Alimentaria
Authors: - Carvajal, S. Reverte, A. A. Carbonell-Barrachina, J. L. Giménez, and M. Carvajal
Restricted access

. 8 93 105 Pais, I. (1983): Titanium and plant response. Nutri. , 6, 3-131. Titanium and plant response

Restricted access