Examination Of Damage on Enamel Surface Due to Removal of Metal and Ceramic Brackets: A Review

During fixed orthodontic treatment, there is great possibility that the dental enamel could be damaged due to the process of debonding the bracket. Enamel cracks are one of the most common aspects that can develop or increase during debonding. This review aimed to conduct an examination of cracks in the enamel that occur both prior to and following metal or ceramic brackets being debonded.

Examination Of Damage on Enamel Surface Due to Removal of Metal and Ceramic Brackets: A Review

During fixed orthodontic treatment, there is great possibility that the dental enamel could be damaged due to the process of debonding the bracket. Enamel cracks are one of the most common aspects that can develop or increase during debonding. This review aimed to conduct an examination of cracks in the enamel that occur both prior to and following metal or ceramic brackets being debonded.

Modeling metal removal from workpiece surface during centrifugal rotation processing

The modeling and analysis the removal of metal process in centrifugal rotational processing of workpiece in abrasive medium are considered in this article. The single contact interaction process between abrasive particle and the workpiece surface is researched through three-dimensional modeling taking into account dry coefficient of friction. The contact interaction problem is solved through Ansys software and Archard code programmed to analyze the data. The removal of metal from the workpiece surface is researched when changing the technological parameters: friction coefficient, machining time, speed. The dependences between metal removal from the workpiece surface and technological parameters are constructed, from which reasonable parameters can be selected when machining the workpiece, allowing to achieve high accuracy. Experimental results have been confirmed by simulation results. Through this research, essential and important data sheets will be provided for actual production and testing activities. Consequently, time and money are saved in achieving the desired surface quality.

Ferrate(VI) Synthesis Using Fe(OH)3 from Waste Iron Electrolysis and Its Application for the Removal of Metal Ions and Anions in Water

Ferrate(VI) salt is an effective oxidant and coagulant for water treatment and removal of metal ions. This study demonstrates a new approach to processing metal ions and anions in water by Fe(VI) through Fe(III) obtained from the electrolysis of waste iron transformer. The electrolysis was successfully carried out in the Na2SO4 electrolyte using waste iron and zinc plates as anode and cathode, respectively. Fe(III) electrolysis results through the characterization of FTIR and XRD indicate compliance with Fe(OH)3 standards. Synthesis of ferrate was carried out by adding Fe(III) from electrolysis with NaOCl in alkaline conditions. The formed ferrate solution shows a purple color with a typical maximum wavelength of 505 nm. Furthermore, the ferrate obtained is used to remove metal ions (Fe(III), Cu(II), Zn(II), Mg(II), Pb(II)) and anions (sulfate, nitrate, and carbonate) in water with pH variations. Ferrate treatment filtrate was analyzed using AAS for metal ions, while sulfate, nitrate, and carbonate anions used UV-Vis spectrophotometry, turbidimetry, and titration methods. The results showed that ferrate effectively eliminates metal ions and anions in water with optimum pH 6. The mechanism of heavy metal removal by ferrate(VI) can be explained by ionic bonding and adsorption.