IADR Abstract Archives

Force delivery of orthodontic Z springs: an in-vitro study

Objectives: Orthodontic Z springs are commonly used in removable orthodontic appliances to tip incisor teeth. A comprehensive search of literature was undertaken to define the force delivery characteristics of Z springs, but no such data was found. By defining the forces exerted by orthodontic Z springs, it was hoped that clinicians would find it easier to use forces of the right magnitude to optimise tooth movement.

Methods: This study compared the force delivery characteristics of double helical and non-helical Z springs manufactured from two different brands of commercially available orthodontic stainless steel wires, namely Remanium® (18/9) 0.5mm diameter wire and Unitek®(18/8) 0.51mm diameter wire. The Z springs were formed by hand and four sizes of each design type were formed for each brand. The mesiodistal widths of the Z springs used were 6,7,8 and 9mm respectively. Three springs in each width category were formed for each spring variant. The force delivery characteristics were tested using a Zwick 2010 Universal Material Tester® using a 50N load cell at a crosshead speed of 10mm/min for up to 2mm deflection. The data was analysed using ANCOVA (P<0.05).

Results: There were statistically significant differences between: the different wire types used, the double helical and non-helical Z springs and the width of springs. The Remanium® wires demonstrated a lower LDR as compared to the Unitek® wires (P <0.05). The double helical Z springs demonstrated a lower LDR as compared to the non-helical Z springs (P <0.05). As the mesiodistal width of the springs increased the LDR of the springs decreased (P <0.05).

Conclusion: The design of Z springs, the brand of wire used and the mesiodistal width of the spring will play a significant role in the LDR of the spring and therefore need to be considered in the clinical situation.


South African Division
2004 South African Division (Pretoria, South Africa)
Pretoria, South Africa
2004
0
Scientific Groups
  • Choonara, Sahide Ahmed  ( University of Pretoria, Pretoria, N/A, South Africa )
  • Zietsman, S. T.  ( University of Pretoria, Menlo Park, N/A, South Africa )
  • Botha, Stephanus J.  ( University of Pretoria, Pretoria, N/A, South Africa )
  • Becker, P J  ( SAMRC, , N/A, South Africa )
    • Oral Session
    Orthodontics