Wyniki wyszukiwania - BazTech

1

Wpływ nanocząsteczek srebra na ścieralność szkliwa ludzkich zębów

Marcinowicz K., Arkusz K.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

|

2018

|

Vol. 24, nr 1

8--17

PL

Celem pracy było określenie przewodnictwa jonowego ludzkich zębów oraz wpływu nanocząsteczek srebra (AgNPs) na ścieralność szkliwa zębów. Badania prowadzono przez 31 dni, odwzorowując proces szczotkowania ludzkich zębów w obecności: wody destylowanej, roztworu pasty do zębów oraz roztworu pasty wzbogaconej o nanocząsteczki srebra. Nanocząsteczki srebra o średnicy 30±5 nm wytworzono metodą biologicznej syntezy z liści magnolii. Analizę powierzchni szkliwa ludzkich zębów dokonano za pomocą elektrochemicznej spektroskopii impedancyjnej (EIS), pomiaru potencjału stacjonarnego (OCP) i skaningowej mikroskopii elektronowej (SEM). Uzyskane wyniki wykazały negatywny wpływ szczotkowania mechanicznego na szkliwo ludzkich zębów, które wraz z kolejnym dniem ulegało degradacji. Szczotkowanie w obecności roztworu pasty zmniejszyło proces ścierania szkliwa, dzięki jonom fluoru wnikającym w głąb ludzkiego zęba oraz substancjom antyściernym. Zastosowane nanocząsteczki srebra zmniejszyły ścieralność ludzkiego szkliwa i wnikając w strukturę hydroksyapatytu polepszyły jego właściwości ochronne.

EN

The aim of this work was to define the ionic conductivity of human teeth and the influence of silver nanoparticles (AgNPs) on human tooth enamel abrasion. Studies were conducted for 31 days by mapping process of mechanical brushing in the presence of: distilled water, an aqueous paste solution, an aqueous paste solution enriched with silver nanoparticles. Silver nanoparticles with diameter of 30±5 nm were prepared by the method of biological synthesis from the leaves of magnolia. The analysis of the enamel surface was performed using electrochemical impedance spectroscopy (EIS), open circuit potential measurement (OCP) and scanning electron microscopy (SEM). Obtained results showed a negative effect of mechanical brushing on human enamel, which the degradation is increasing day by day. Brushing with toothpaste decreased the enamel abrasion process through a fluoride ions penetration into the tooth and antifriction components. Silver nanoparticles reduced the dental micro-abrasion, penetrating the structure of hydroxyapatite improved protective properties of enamel.

2

Reconstructing seasonality using δ18O in incremental layers of human enamel : a test of the analytical protocol developed for SHRIMP IIe/MC ion microprobe

Krzemińska E., Sołtysiak A., Czupyt Z. J.

Geological Quarterly

|

2017

|

Vol. 61, No. 2

370--383

EN

A number of recent studies dealing with palaeoclimate and environmental reconstruction include the measurement of oxygen isotope composition of mammalian teeth. Some of them analyse a temporal sequence of the changes recorded in bioapatite from enamel layers representing the whole period of tooth development. Enamel samples display large intra-tooth δ18O variations that may reflect a seasonal fluctuation in the δ18O of local palaeoclimate parameters. The present paper provides an effective analytical protocol for sequential δ18O analysis of human teeth using SHRIMP IIe/MC ion microprobe. It is possible to follow the inner enamel layer along enamel-dentine junction on a high spatial scale in a range about 0.02 mm of spot diameter and 0.12–0.14 mm of the distance between spots. Using the methodology described herein, we can achieve an external precision for δ18O analysis <0.2‰ (1σ). The number of 60 to 90 single analyses covering the enamel layer between the incisal and apical ends is enough to obtain temporal resolution of less than one month and to document precisely seasonal fluctuation caused by local environmental and climate factors. The methodology of δ18O in situ measurements has been tested on human teeth from Tell Majnuna, a 4th millennium BCE cemetery in Northern Mesopotamia, which is a relatively arid area with high seasonal differences in precipitation and temperature. Observed pattern of δ18O variations is consistent with expected seasonal fluctuations, although the overall effect is blurred by some inertia in the enamel maturation.

3

Phenomenological evaluation of fatigue cracking of dental restorations under conditions of cyclic mechanical loads

Pieniak D., Niewczas A.M.

Acta of Bioengineering and Biomechanics

|

2012

|

Vol. 14, no. 2

9-17

EN

This paper deals with microcracks in dental filling material and hard tissues of the teeth treated conservatively. Human teeth, removed due to orthodontic or surgical reasons, were the subject of those research studies. The studies have been conducted in vitro with the application of mastication simulator. It has been indicated that the number of cracks and the degree of their expansion increase with the number of load cycles. The number of microcracks of the filling material on the masticating surface is lower than in the deeper layers; however, they are more extensive. After applying a specified long load series a progressive increase of microcracks in the restoration material and their expansion in the contact zone with the dentine have been observed. It has been demonstrated that on the masticating surface the number of microcracks and their expansion were proportional to the number of load cycles.