PERBEDAAN SIFAT MEKANIK KAWAT ORTODONTIK JENIS BAJA TAHAN KARAT AKIBAT PENGARUH STRUKTUR MIKRO (Studi in-vitro)

The orthodontist has chosen the stainless-steel as a wire of choice that has a great property in elastic deformity and formability. However, some stainless-steel orthodontic wire that was found has low formability. The degree of plastic deformation during the drawing process will affect the microstructure and then to the mechanical properties of the wire. The purpose of this study was to prove that the mechanical properties of the stainless-steel orthodontic wire affected by their microstructure. The microstructure was evaluated before and after being annealed at 1050oC, and the grain size was measured from the annealed samples. Six sample of two stainless-steel orthodontic wires (RMO and Wilcock) were used to determine their tensile strength by using the universal testing machine. The area of the surface fracture was measured to determine the ductility. The wire hardness was tested by using the Micro Vickers Hardness Tester. The results showe that the Wilcock wire has a smaller grain size, higher hardness number, and higher tensile strength, but lower in ductility. In conclusion, the Wilcock wires have a lower formability than the RMO wires

INFLUENCE OF POLISHING SYSTEM ON COLOR CHANGES FOR A NANOIONOMER RESTORATIVE MATERIAL AFTER IMMERSION IN A COFFEE-BASED SOLUTION

Objective: In this study, we aim to assess a polishing system’s influence on the color change of a nanoionomer after immersion in a coffee-basedsolution.Methods: The specimens were divided into four groups, of which three of them were polished using Sof-Lex XT, PoGo, or OptraPol. However, thesamples in the fourth group were unpolished. The color was then determined using a spectrophotometer and color changes were evaluated using aCIELAB system. The data were analyzed using one-way ANOVA and paired samples t-test systems.Results: While the lightness (L*) value significantly decreased (p<0.05) after the polishing procedure, the red-green coordinate (a*) and yellow-bluecoordinate (b*) values did not show any significant change for any of the groups. The samples that were polished using OptraPol demonstrated thesmallest color change after polishing; moreover, for this group, the color changes were significantly different from those that were observed for PoGoand Sof-Lex XT groups. After immersing into a coffee-based solution, there were significant changes observed for the L*, a*, and b* values (p<0.05) forall the groups that were studied. Importantly, the color changes that were observed for the OptraPol group were not statistically significant comparedto those that were observed for PoGo and the unpolished groups.Conclusion: The immersion of unpolished and polished nanoionomers in a coffee-based solution will result into color changes and the smallestvariations, in this case, occurred for the nanoionomer that was polished using OptraPol

Hardness of Demineralized Enamel with the Application of Toothpaste Containing Green Tea Extract

The aim of this study was to analyze the influence of toothpastes with or without green tea extract on the enamel hardness. Human teeth were used as specimens and surface enamel demineralization by soaking in 1% citric acid. Teeth that have been demineralized were applied with a toothpaste containing green tea extract with concentrations of up to 15% on the surface of the enamel teeth and then proceed with surface hardness measurement using Knoop system. The results showed that soaking the teeth (enamel) in a demineralized solution has significantly decreased the hardness of tooth enamel. Applications of toothpaste without (0%) and with green tea extract 5% or 10% or 15% on the demineralized enamel surface have increased the enamel hardness significantly. However, no significant differences were seen between the demineralized enamel and enamel applied with toothpaste containing green tea 5% or 10% or 15%. It was concluded that the application of toothpaste containing 5% green tea extract was able to increase the hardness of demineralized enamel.   &nbsp

Kekuatan Rekat Restorasi Komposit Resin pada Permukaan Dentin dengan Sistem Adhesif Self-Etch dalam Berbagai Temperatur

Single-step self-etch adhesive systems are the system that combine self etching primer and bonding agent into one step application. This system was developed as the effort to simplified in application prosedures and give a good bond strength of resin composites to dentin surface. The purpose of this study was to examine the bond strength of resin composites with two singlestep self-etch adhesives system (Xeno III and Clearfil Tri-S Bond) to bovine dentin at temperature of adhesive 3ºC, 22ºC and 30ºC. Adhesive was applied to dentin surface (bovine insisivus mandibular dentin) follow by resin composites bonded according to the manufacturer’s instructions. Tensile bond strength of 60 specimens were tested UTM (universal testing machine) after 24 hours storage in aquadest at 37 ºC. The results were analyzed using ANOVA test followed by Tukey’s test (p< 0,05). The bond strength of Xeno III was significantly diffrent from that of Clearfil tri-S Bond, 0,66±0,271, 2,70±1,528, 0,23±0,104 versus 2,07±0,272, 4,77±0,689, 4,39±1,205 MPa at temperature of materials 3ºC, 22ºC and 30ºC respectively. The bond strength of two single- step adhesives system (Xeno III and Clearfil Tri-S Bond) were highest at temperature 22ºC than other temperatures of materials.DOI: 10.14693/jdi.v15i3.3

PROPERTIES OF COMPOSITE RESIN ALKASIT AND ZIRCONIA-REINFORCED GLASS-IONOMER CEMENT IN DIFFERENT STORAGE

Background: The temperature and salivary pH in a person's mouth are highly dynamic (e.g., before, during, and after eating) and so restorations in a cavity must be resilient to these variable conditions. Temperature and immersion conditions affect the mechanical properties of a restoration. This study aimed to determine the effect of environmental conditions on diametral tensile strength (DTS) and surface microhardness of a resin composite with alkaline fillers or zirconia–reinforced glass ionomer cement (Zr-reinforced GIC). Method: Thirty specimens of a resin composite with alkaline fillers (Cention-N, Ivoclar-Vivadent, Lichtenstein) and 30 specimens with zirconia-reinforced GIC (Zirconomer, Shofu, Japan) were stored at different conditions (23°C and 37°C; with and without immersion in water) for 24 hours. DTS was tested with a Universal Testing Machine (AGS-X series, Shimadzu, Japan) and surface microhardness was tested with a Vickers Microhardness tester (HMV-G Series Micro Vickers Microhardness Tester, Shimadzu, Japan). Data were analyzed statistically using a one-way ANOVA test (and Shapiro-Wilk test. Result: The values of microhardness and DTS increased significantly both for the composite resin alkasite and zirconia-reinforced GIC with increasing temperature in the groups without immersion. However, there was a significant decrease in microhardness and DTS after immersion in distilled water at 37°C for both the composite resin alkasite and zirconia-reinforced GIC. Conclusion: It can be concluded that storage conditions affect the microhardness and DTS of resin composite Alkasite and Zirconia-reinforced GI

PENGARUH KONSENTRASI FLUOR DAN pH PASTA GIGI TERHADAP PELEPASAN ION LOGAM DARI PERMUKAAN LOGAM PADUAN: EFFECT OF FLUORIDE CONCENTRATIONS AND pH OF TOOTH PASTE ON METAL IONS RELEASED FROM ALLOYS SURFACE

It was reported that fluoride in prophylactic agents can be detriment the oxide layers of CoCr and NiCr alloys used as dental restorations. The aim of this study was to determine the effect of fluoride concentration and pH of some commercial toothpastes in Indonesia on the ions released from CoCr and NiCr alloys surface. 120 specimens of CoCr and NiCr alloys were used in this study (60 specimens for each alloy). All specimens were mounted in resin with one side opened. Each alloy divided into 4 groups, there were 15 specimens immersed into 3 kinds of each commercial tooth paste solution (ratio 1:3) and aquabides as control solution for 1, 6, and 13 days duration,. The metal ions released into tooth paste solutions and aquabides were analyzed by AAS tool. The result of study showed that metal ions released into 3 kinds of commercial toothpastes solutions and aquabides were nickel ions from NiCr alloy only, and it was significant (p<0,05) for each aging duration. Lower pH showed higher influence to ion release than fluoride concentrations, and CoCr alloy had a better passive layer than NiCr alloy

Caries-­preventive Effect of 1300ppm Fluoride and Carrageenan Containing Toothpaste

Various studies stated that the increase concentration of fluoride in toothpastes leads to the reduction of calcium loss in enamel. Objective: The purpose of this study was to test the difference between the effect of 1300ppm fluoride with carrageenan toothpaste and 1000ppm fluoride only toothpaste on roughness and hardness of enamel surface. Methods: Enamel specimens were obtained from 30 extracted human premolars. The enamel specimens were randomly assigned to one of the three groups, 1300ppm fluoride with carrageenan toothpaste, 1000ppm fluoride only toothpaste and toothpaste with no fluoride as a negative control. The samples were immersed in 1% citric acid with pH 4 for 150 seconds for demineralization, afterwards exposed to each toothpaste for 6 minutes. Results: The results demonstrated that toothpaste with 1300ppm fluoride with carregeenan has two times greater efficacy in triggering remineralization than toothpaste with 1000ppm fluoride only, with regards to surface roughness and hardness recovery in an in vitro caries model. Conclusion: The results suggested that treatment of enamel with toothpaste containing 1300ppm fluoride with carrageenan has high potential in inducing remineralization on enamel.DOI: 10.14693/jdi.v20i1.12

PERBEDAAN SIFAT MEKANIK KAWAT ORTODONTIK JENIS BAJA TAHAN KARAT AKIBAT PENGARUH STRUKTUR MIKRO (Studi in-vitro)

<p>The orthodontist has chosen the stainless-steel as a wire of choice that has a great property in elastic deformity and formability. However, some stainless-steel orthodontic wire that was found has low formability. The degree of plastic deformation during the drawing process will affect the microstructure and then to the mechanical properties of the wire. The purpose of this study was to prove that the mechanical properties of the stainless-steel orthodontic wire affected by their microstructure. The microstructure was evaluated before and after being annealed at 1050^oC, and the grain size was measured from the annealed samples. Six sample of two stainless-steel orthodontic wires (RMO and Wilcock) were used to determine their tensile strength by using the universal testing machine. The area of the surface fracture was measured to determine the ductility. The wire hardness was tested by using the Micro Vickers Hardness Tester. The results showe that the Wilcock wire has a smaller grain size, higher hardness number, and higher tensile strength, but lower in ductility. In conclusion, the Wilcock wires have a lower formability than the RMO wires.</p

Analisa Difraksi Sinar-X pada Baja Tahan Karat Austentitik dan Feritik (Uji Laboratorium)

X- rays with wavelength in the range 0,5 to 2,5 Å, have a very short wavelength compare to the visible light wavelength in order of 6000 Å. Therefore, x-rays can be used for determination of the finest structure of materials by using the x-rays diffraction method. A solid crystalline consist of atoms were orderly arrangement and when a beam of x-rays strikes at that crystalline, the atom act as a center of diffraction. Since x-rays are electromagnetic waves with the wavelength penetrated into the distance between planes of atoms, the x-ray diffraction can be seen regarding using the Bragg'slaw (χ = 2d sin θ).Austensitic stainless steel could be transformed from γ phase (FCC) to α phase (BCC) by shear induced mechanism. It was proved that the austensitic stainless steel have a metastable properties in room temperature and can be changed by plastic deformation. The ferritic stainless steel have more stable, and it was different from austensitic stainless steel. The crystal structure of ferritic stainless steel will not change by plastic deformation. The transformation on austensitic stainless steel can be determined by x-rays diffraction method. The diffraction pattern produced have peaks of γ phase (FCC) and α phase (BCC). However, the ferritic stainless steel only produced diffraction peaks of α phase (BCC). Therefore the different of austensitic stainless steel and ferritic stainless steel could be seen in the diffraction pattern.The purpose of this study is to determine the x-rays diffraction pattern of austensitic and ferritic stainless steel by powder method.</p

Pengaruh Perlakuan Panas pada Sifat Mekanis Kawat Ortodonti Jenis Baja Tahan Karat (Studi Pustaka)

  Kawat ortodonti adalah bagian dari alat yang digunakan untuk memperbaiki posisi gigi-gigi di dalam mulut, dan merupakan kawat yang memiliki sifat tertentu. Kawat ini dapat terbuat dari logam paduan baja tahan karat 18-8 atau logam lainnya. Dari semua jenis kawat ortodonti, kawat baja tahan karat 18-8 merupakan kawat termurah, aman bagi manusia, memenuhi syarat-syarat teknis ortodonti, namun kawat ini lebih kaku dan kelenturannya paling rendah dibanding dengan kawat ortodonti jenis lainnya. Mengingat bahwa sifat kekakuan dan kelenturan kawat serta sifat mudah dibentuk merupakan faktor utama yang harus diperhatikan dalam alat ortodonti, maka perlu dilakukan upaya untuk mengatasi kelemahan yang ada pada kawat tersebut. Hal ini dapat dilakukan dengan pemanasan pada suhu rendah dan waktu tertentu terhadap kawat yang dimaksud. Perlakuan panas ini bertujuan untuk menghilangkan tegangan yang ada di dalam kawat pada waktu proses pembuatannya, sehingga dapat memperbaiki sifat dari kawat.