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ortho1_2012 I technique_ archwire 44 I Material Wires tested: Four different Upper 016X022 NiTi archwires were tested — NITINOL-SE (3M UNITEK); Copper- NiTi 35 (ORMCO); NEOSENTALLOY F 80 (DENTSPLY GAC International); Bio- force-SENTALLOY (anterior section) (DENTSPLY GAC International) Equipment Differential scanning calorimeter (DSC)formeasuringtheaustenitetrans- formation temperature (Af point) was performed using a SII-DSC6220 Seiko Instrument (Fig. 39) and a thermal ana- lyzer LN2 vessel was connected to DSC for cooling (Fig. 40). Oraltemperature Sublingual temperature is routinely usedasanindicatoroforaltemperature. It is approximately 37°C for most indi- viduals, while not forgetting that many factors have been shown to affect the temperature in the oral cavity. Temperature data should be considered during themanufactureandclinicaluseoftemperaturesen- sitive orthodontic materials like the nickel titanium wires. According to Moore12 if a single oral tem- perature were to be selected for the investigation of the in- vitro properties of orthodontic wires, 35.5°C would be more appropriate than 37°C. Results NITINOL SE With NITINOL SE the complete transformation to austenite (Af) occurs at about 60°C, which is considerably above the temperature of the oral environment. CopperNiTi35 A single peak on the heating DSC curve, which corresponds to the martensite to austensite trans- formationindicatesthattheAftemperature(29.1°C) is under oral cavity temperature for copper NiTi 35. NEOSENTALLOY NEOSENTALLOYhasacompletelyausteniticstruc- tureclosetothetemperatureoftheoralenvironment (32.7°C). There is also considerable hysteresis for the TTR in the forward and reverse directions for the complete transformation (martensite to austenite). Bioforce(anteriorsection) JustlikeNEOSENTALLOY,intheanteriorsectionof Bioforceweseethecompletetransformationoccur- ring very close to body temperature 32.5 °C. Summary SENTALLOY archwires were the first reported su- perelasticnickel-titaniumarchwireinorthodontics.5 They are body heat activated and are capable of producing excellent treatment results because they deliveralightandconstantforceforalongperiodof time; which is considered physiologically desirable for tooth movement. _ _References 1. Buehler WJ, Gilfrich JV, and Wiley RC. J. Appl. Phys., Vol. 34, 1963, p 1475. 2. Kauffman G, Mayo I. The Story of NITINOL: The Serendipitous Discovery of the Memory Metal and Its Application. Chem. Edu. 1997. Abstract, Volume 2, Issue 2 (1997), S1430–4171(97)02111-0 DOI 10.1333/ s00897970111a. 3. Andreasen GF, Hilleman TB. An evaluation of 55 cobalt substituted Nitinol wire for use in ortho- dontics. J Am Assoc, 1982, 1173–1375, 1971. 4. Kusy, Robert P. 1997: A review of contempo- rary archwires: Their properties and charac- teristics. The Angle Orthodontist: Vol. 67, No. 3, pp. 197–207. 5. Miura F, Mogi M, Ohura Y, and Hamanaka H. The super-elastic property of Japanese NiTi alloy use in orthodontics. Am. J. Orthod. Dentofac Orthop. 1986,90.1–10 . 6. Miura F. Reflections on my involvement in orthodontic research. Am. J. Orthod. Dentofac Orthop. 1993, 104. 531–538. 7. Teramoto A. SENTALLOY. The Inside History of Superelasticity. 2005 GAC Books. 8. Miyazaki S, Ohmi Y, Otsuka Y, Suzuki Y, 1982. Characteristic of deformation and transforma- tion pseudoelasticity in Ti-Ni alloys. Journal de Physique. Colloque C4 supplement au n12, tome 43, Decembre:255–260. 9. RyanR,etcols.Theeffectsonionimplantationon rate of tooth movement. An in vitro model. Am J Orthod. & Dentofac Orthop 1997.112:64–68. 10. BedollaV.andTeramotoA.Diferenciadefricción generada entre arcos de NiTi y NiTi con Nitróg- eno en comparación con acero en brackets estándar y de autoligado activo. Ortodoncia Actual 2008 Año 5 Vol;16,20–26 ( in Spanish). 11. Bradley T, Brantley WA, and Culbertson B. Dif- ferential scanning calorimetry (DSC) analyses of superelastic and non superelastic nickel- titanium orthodontic wires. Am. J. Orthod & Dentofac Ortop, 1996; 109: 589–597. Alberto Teramoto DDS, Orth. Cert., maintains a private practice devoted ex- clusively to orthodontics in Mexico City, Mexico. He received his certificate of orthodontics from the First Department of Orthodontics of Tokyo Medical and Dental University, Japan. Presently he is an assistant professor at the Universidad Tecnologica de Mexico and Editor in Chief of the journal Ortodoncia Actual. _contact ortho Fig. 39 (top) Fig. 40 (bottom)