Nanotube material that has been synthesized for decades is Titanium Dioxide Nanotube (TDN) because it has high photocatalytic properties and produces free radicals that can whiten teeth. Tooth whitening materials that are used in the public is such as H2O2 with high concentrations so that they endanger the health of tooth enamel. Therefore, this research uses TDN as a natural teeth whitening agent with low H2O2 concentrations. TDN is obtained from natural materials, mineral sand which is chemically processed using sodium hydroxide in an autoclave for 24 hours. The amount of free radicals is determined by ESR and the effect of teeth whitening determined by immersing the teeth in a 3% TDN and H202 solution and then characterized by the UV-Vis PC 2401 Spectrophotometer. The results showed that TDN produced O2 − free radicals which could degrade tooth color up to turned brighter.

This research is focused on extraction titanium dioxide nanotubes from Tulungagung mineral sands using the hydrothermal method. Extraction is done by dissolving mineral sand into sulfuric acid solution and vacuums pump to obtain TiO2 precipitate. Furthermore, TiO2 precipitate were calcined at 600° C for 2 hours. TiO2 was dissolved in NaOH and stirred for 2 hours. The resulting solution was put into an autoclave and heated at 130° C for 24 hours to form nanotubes structure. The formed titanium dioxide nanotubes are neutralized using HCl and distilled water. TDN was dried using an oven and calcined at 600 ° C for 2 hours. Furthermore SEM, XRD characterization was carried out and analyze with Match! Software and rietveld. The analysis results showed that a single phase anatase TDN with a nanocrystalline size of 43,02 nm was formed based on rietveld analysis. Also the SEM images shows that the diameter of nanotubes are about 15,66-32,33 nm.

Abstrak Dolomit merupakan jenis batuan kapur yang tersedia melimpah di alam. Melalui proses kalsinasi sederhana dolomit dapat menghasilkan nanokristalin CaCO3/MgO yang memiliki manfaat dalam menghambat terjadinya erosi gigi serta menghambat pertumbuhan bakteri. Untuk itu dalam penelitian ini dilakukan kalsinasi dolomit pada suhu 700°C dengan tujuan untuk menghasilkan material nanokristalin CaCO3/MgO yang berpotensi sebagai material pencegah erosi gigi dan material antibakteri. Penelitian ini dilakukan dengan melakukan pembakaran pada batu kapur dolomit Bangkalan. Kemudian dihaluskan menggunakan mortar alu dan diayak menggunakan ayakan 200 mesh. Setelah itu serbuk dikalsinasi pada suhu 700°C dengan holding time 1 jam. Selanjutnya dikarakterisasi XRD untuk mengetahui struktur kristal dari CaCO3/MgO dari dolomit. Hasil penelitian menunjukkan bahwa kalsinasi dolomit pada suhu 700°C memiliki fasa optimum CaCO3/MgO dengan persentase 44,8% CaCO3 dan 38,1% MgO. Hasil analisis rietveld menunjukkan bahwa dolomit hasil kalsinasi memiliki ukuran kristal CaCO3 sebesar 10,95 nm dan MgO sebesar 46,54 nm yang termasuk ke dalam material nanokristalin yang berpotensi sebagai material pencegah erosi gigi dan material antibakteri yang baik dan ramah lingkungan.   Kata Kunci: Dolomit, Nanokristalin, CaCO3/MgO dan Rietveld.     Abstract Dolomite is a variety of limestone that is available in abundance in nature. Through a simple calcination process dolomite can produce nanocrystalline CaCO3 / MgO which effective in preventing tooth erosion and suppressing bacterial growth. For this reason, dolomite calcination at 700 ° C was conducted in this study in order to obtain CaCO3 / MgO nanocrystalline material which potentially able to prevent tooth erosion and antibacterial material. This study was done by conducting incineration on Bangkalan dolomite limestone. Then the dolomite was mashed using pestle mortar and sieved with a 200 mesh sieve. Afyer that, the powder was calcined at 700 degree celcius in an hour holding time. Next, XRD characterization was conducted to reveal the crystal structure of CaCo3/MgO from the dolomite. The results show that dolomite calcination at the temperature of 700 degree celcius produce an optimum of CaCO3/MgO phase with a percentage of 44.8% CaCO3 and 38.1% MgO. The results of the Rietveld analysis showed that calcined dolomite contain CaCO3 and MgO crystals with the dimension of 10.95 nm and 46.54 nm respectively which is a good and environmentally friendly nanocrystalline material that has the potential to prevent tooth erosion and antibacterial material. Keywords: Dolomite, Nanocrystaline, CaCO3/MgO and Rietvield.