Biomedical subjects

Awlad Hossain

Publications and source records attributed to Awlad Hossain.

4 recordsLinked to original sources

PubMed2006

Surface texture and composition of titanium brushed with toothpaste slurries of different pHs.

OBJECTIVES: This in vitro study characterized the surface texture and composition of titanium brushed with toothpaste slurries of different pHs, and thereby elucidated mechanochemical interactions between the metal and abrasive material in dentifrice. METHODS: Two fluoride-free toothpastes, which contained crystalline CaHPO(4).2H(2)O and amorphous SiO(2) particles as abrasive, were mixed with acidic buffers to provide slurries of pH 6.8 and 4.8. Specimens were cast from CP Ti, mirror-polished, and then toothbrushed at 120strokes/min for 350,400 strokes under a load of 2.45N. Specimen surfaces were characterized by means of SPM and EPMA. The obtained data were compared with the already reported results of water-diluted alkaline slurries. SPM data of each paste were analyzed using one-way ANOVA, followed by post hoc Tukey test. RESULTS: Irrespective of toothpaste, neutral slurries, as with alkaline slurries, yielded a chemically altered surface with rough texture, whereas acidic slurries formed a chemically clean surface with relatively smooth texture. Mechanochemical polishing effect might be mainly responsible for the cleanness and smoothness. SIGNIFICANCE: Acidic slurry-induced smooth surface may minimize plaque formation. However, the augmentation of released titanium ions may be adverse to the human body. For evaluation of toothpaste abrasion effects on titanium, paste slurry pH should be taken into account.

Acids↗

PubMed2005

Effect of toothbrushing on titanium surface: an approach to understanding surface properties of brushed titanium.

OBJECTIVES: This in vitro study aimed to characterize the surface morphology and composition of tooth-brushed titanium casting and thereby to elucidate interactions between the metal and abrasive material in dentifrice. METHODS: Specimens were cast from CP Ti ingots and then mirror-finished. Two fluoride-free toothpastes containing crystalline CaHPO4.2H2O and amorphous SiO2 particles as abrasive were slurried with distilled water (15 g/30 mL). While toothbrushes were reciprocated at 120 strokes/min for 350,400 strokes, the specimens were brushed with the respective slurries under a load of 2.45 N. The brushed and non-brushed surfaces were characterized by means of SPM, EPMA, and XPS. SPM data were analyzed using one-way ANOVA, followed by post hoc Tukey test (p<0.01). RESULTS: Irrespective of toothpastes, toothbrushing had a significant influence on surface roughness. The CaHPO4.2H2O-containing paste produced much rougher surface than the SiO2-containing paste. Both the surfaces were chemically altered due to reactions with the respective abrasive materials. Abrading chips had dimensions of micron to submicron order. A number of chips were attached to abrasive particles. SIGNIFICANCE: The alterations of surface morphology and composition may affect biological responses of titanium in the oral environment. Dentifrice with lower abrasivity might be advisable for daily oral hygiene practice of patients with dental titanium devices.

Calcium Phosphates↗

PubMed2005

Surface composition and texture of titanium polished with colloidal silica suspension and chromic oxide slurry.

CP titanium was polished with a colloidal silica suspension and chromic oxide slurry under low and high pressures. The polished surfaces were characterized by means of EPMA and XPS. Irrespective of polishing pressure, colloidal silica suspension successfully created a mirror-like surface that was clean at EPMA level. However, XPS detected a small amount of silicon on the outermost surface. On the other hand, chromic oxide slurry under high pressure yielded a very uneven surface with numerous scratches. The EPMA and XPS results suggested the presence of chromium-containing species in the polished surface, which might include hydroxides as well as oxides. In addition, the level of oxygen concentration was noticeably raised, which probably resulted from the increase of surface oxide film thickness or the extension of oxide-to-metal transition zone.

Chromium Compounds↗

PubMed2004

Surface properties of electrochemically buffed titanium casting.

Electrochemical buffing, a combined process of electrochemical and mechanical polishing, was applied to titanium casting. Mixture of alpha-Al2O3 suspension (average grain diameter of 5 microm) and 5% KNO3 solution was used as abrasive slurry. Specimen and experimental wheel buff were respectively connected to the positive and negative poles of a DC source, whose potential ratings ranged from 0 V (MEP) to 10 V (ECB10). Surface roughness, hardness, color, and cleanness were investigated. ECB10 surface produced a gold color and attained a mirror finish, as its roughness value was only one-quarter that of MEP. High amount of aluminum was present in MEP surface. Its bond state entirely differed from that of alpha-Al2O3, hence indicating surface alteration due to chemical reactions with the abrasive material. At higher potentials, reaction products might be dissolved anodically, so that the surface was chemically clean to some extent. The surface also became rich in OH-.

Aluminum Oxide↗