Differences of Cytotoxicity of Orthodontic Bands Assessed by Survival Tests inSaccharomyces cerevisiae

Abstract

The aim of this study was to evaluate the cytotoxicity induced by orthodontic bands through survival tests on Saccharomyces cerevisiae, a microorganism that presents several genetic and biochemical characteristics similar to human cells. Three groups of bands were evaluated: silver soldered (SSB), laser soldered (LSB), and bands without any solder (WSB). Yeast cells were directly exposed to the bands and indirectly, when a previous elution of the metals in artificial saliva was performed. The negative control was composed of yeast cells or artificial saliva not exposed to any kind of metal. In the direct exposure experiments, all tested groups of bands induced a slight reduction in yeast viability compared to the control. This effect was more intense for the SSB, although not statistically significant. For the indirect exposure experiments, the SSB induced a statistically significant decrease in cell viability compared to the LSB. There were no significant differences between the survival rates of the negative control and the LSB group in both direct and saliva tests. SSBs were cytotoxic, whilst LSBs were not, confirming that laser soldering may be a more biocompatible alternative for use in connecting wires to orthodontic appliances.

Cytotoxicity evaluation of orthodontic miniscrews

“…The use of S. cerevisiae as a model organism offers some advantages, since it is easy and cheap to manipulate, and provides a large amount of quantitative data from well-controlled experiments with shorttime results. Previous studies have used this yeast model to evaluate the cytotoxicity induced by different orthodontic materials 28,29 . However, the results should be extrapolated to clinical practice with caution.…”

“…The mean and standard deviation of the colony forming units per mL (CFU/mL) counts from three independent repeats of each treatment were compared with the negative control (yeast without exposure to miniscrews) to verify the occurrence of significant survival differences in a semi-log curve. As already assumed in previous published reports 24,28,29 , a significant difference in yeast survival is considered when there is at least one log of difference (considering the standard deviation) between treatments and negative controls in terms of CFU/ml, which is an accepted indication of cellular toxicity in S. cerevisiae,…”

Potencijalna toksičnost titanija

“…Ovo je svojstvo neophodno za osiguravanje sigurnog liječenja pacijenata. Materijali koji se ugrađuju u ljudsko tijelo nazivaju se biomaterijalima te moraju biti netoksični i inertni kako ne bi reagirali s okolnim tkivom [10][11][12] .…”

“…Studije in vivo korisne su u objašnjavanju kako se ortodontski materijali ponašaju u svom stvarnom okruženju, ali je interpretacija rezultata otežana zbog mnogih čimbenika koji nisu pod eksperimentalnom kontrolom 25 Njegova stanična struktura i funkcionalna organizacija ima mnogo sličnosti sa stanicama organizama viših razina 11,30,31 . Velika količina gena (30 - 45 %) koji su uključeni u ljudske bolesti ima ortologe kvasca, odnosno funkcionalne homologe 12,22,30,32 . Yang i Pon proveli su istraživanje o učincima iona metala otpuštenih iz zubnih legura na rast stanica i na funkciju respiratorne aktivnosti mitohondrija kvasca.…”

In Vivo Biocompatibility, Mechanical, and Antibacterial Properties of Cements Modified with Propolis in Different Concentrations

“…However, there is a lack of studies on the biocompatibility of propolis-modified GICs, an important factor for the safety of new biomaterials. 2,[16][17][18][19] Furthermore, the GIC must have satisfactory physical-mechanical properties and capacity to resist masticatory functions. 5,20 However, GIC has some clinical disadvantages, such as solubility and sensitivity to dehydration during the gelification process, low wear resistance, and deficient antibacterial action 21 therefore, researchers have added substances to GIC with the purpose of improving its inherent properties.…”