Beta-titanium arch wire (TMA)

Beta-titanium (TMA) arch wire

1. Al-noor University college TMA - ti a,w Aisha Muwafaq

2. Beta-titanium (TMA) archwire Introduction Pure titanium can exist in two phases: Alpha phase represents low temperature (below 885 °C ) beta phase represents high temperature (above 885 °C ) Charles J. Burstone and Dr. Goldberg developed the β- Titanium when they combined Molybdenum with pure titanium. Beta titanium (TMA) wire has been proven to be highly useful in orthodontic treatment because of its intermediate stiffness between stainless steel and the nickel titanium memory alloys. In addition, it is highly formable and has approximately twice the springback or range of action of an equivalent stainless steel wire. One of the unique characteristics of TMA is its ability to be welded without soldering, to produce effective joints that do not weaken the mechanical properties of the wire.

3. COMPOSITION Molybdenum - 11.3% Tin - 4.3% Zirconium 6.6% Titanium - 77.8 % Indication TMA has indications for all stages of treatment. Because of its intermediate stiffness between stainless steel and the nickel-titanium memory alloys, it is especially beneficial as a main working archwire. TMA has good flexibility and springback characteristics along with predictable forces for consistent control .

4. A ll Stage - TMA is recommended for t0oth alignment, space closure mital and curve of Spee. We oller prefomed Reverse Curve TMA and Reverse Curve TMA with "T" Loops . Intermediate Stage - TMA is recommended for carly tonque control with moderate forces. TMA alio provides complete manipulanion of the wire for dimensional control. Indications include use as an ideal retraction arch while exerting more-constant mnderate forces over a longer perind of time. Final Stage TMA is used as a detailing wire with moderate force

5. Advantages Biocompatibility. torsional strength . stress constancy . physiological compatibility . Shape memory . dynamic interference . wear resistance hysteresis . A high variety of products is now available on the market . good spring back . good formability . Weldability. absence of nickel makes it useful for patient allergic to nickel . T.M.A's moderate forces are moderate less trauma for ,the patient and increases patient comfort.

6. Disadvantages High coefficient of friction: Therefore it is disadvantageous in sliding mechanics. Physical properties Biocompatibility Corrosion resistance High spring-back Low stiffness High formability The ability of direct welding.

7. Mechanical properties TMA has a modulus of elasticity that is less than that of stainless steel and about twice that of nitinol . A beta-titanium wire can therefore be deflected almost twice as much as stainless steel wire without permanent deformation . Beta-titanium wires also deliver about half the amount of force as do comparable stainless steel wire . The former configuration has the added advantage of full bracket engagement and a resultant greater torque control than the smaller stainless steel wire.

8. The good formability of beta-titanium-wire allows stops and loops to be bent into the wire. Helices that are commonly used with stainless steel to lower the load deflection rate of the appliance may not be necessary with beta-titanium wires because of their low modulus of elasticity and high spring back. This helps to simplify appliance design by eliminating the need to place loops and helices in the wire. It is possible to attach stops, hooks, and active auxiliaries by welding to beta-titanium wires, thereby increasing the versatility of the wire. Overheating of the wire causes it to become brittle.

9. The mechanical characteristics of orthodontic archwires are very important in achieving clinical succes. The forces developed by orhodontic archwires should be kept at minimal levels in oder to preserve the periodontal health and to avoid the unwanted secondary effects. The forces developed by TMA archwires are depended on many factors, including size, diameter and shape. In adult patients, the size of TMA wires are always chosen in smaller diameters, especially in those with periodontal problems and alveolar loss. Conclusion TMA is an excellent choice for auxiliary springs and for intermediate and finishing archwires TMA is recommended for early torque control with moderate forces.TMA also provides complete modification of the wire for dimensional control . TMA is unsuitable for applications that require a flexible wire. Another drawback of TMA wires is their high surface roughness, which produces high friction between the archwire and bracket

10. Reference Burstone CJ, Goldberg AJ (February 1980). "Beta titanium: a new orthodontic alloy". American Journal of Orthodontics. JUVVADI, Shubhaker Rao, et al. Physical, mechanical, and flexural properties of 3 orthodontic wires: an in-vitro study. American journal of orthodontics and dentofacial orthopedics, 2010, 138.5: 623-630.‏ SZUHANEK, CAMELIA; FLESER, T.; GLAVAN, FLORICA. Mechanical behavior of orthodontic TMA wires. WSEAS Trans Biol Biomed, 2010, 7.3: 277-86.‏ BETA TITANIUM ( TMA) Source: Burstone, AJO-DO:1980 feb