Torque efficiency of different archwires in 0.018- and 0.022-inch conventional brackets

Abstract

Objective: To compare the archwires inserted during the final stages of the orthodontic treatment with the generated moments at 0.018-and 0.022-inch brackets. Materials and Methods: The same bracket type, in terms of prescription, was evaluated in both slot dimensions. The brackets were bonded on two identical maxillary acrylic resin models, and each model was mounted on the orthodontic measurement and simulation system. Ten 0.017 × 0.025-inch TMA and ten 0.017 × 0.025-inch stainless steel archwires were evaluated in the 0.018-inch brackets. In the 0.022-inch brackets, ten 0.019 × 0.025-inch TMA and ten 0.019 × 0.025-inch stainless steel archwires were measured. A 15°buccal root torque (+15°) and then a 15°palatal root torque (-15°) were gradually applied to the right central incisor bracket, and the moments were recorded at these positions. A t-test was conducted to compare the generated moments between wires within the 0.018-and 0.022-inch bracket groups separately. Results: The 0.017 × 0.025-inch archwire in the 0.018-inch brackets generated mean moments of 9.25 Nmm and 14.2 Nmm for the TMA and stainless steel archwires, respectively. The measured moments in the 0.022-inch brackets with the 0.019 × 0.025-inch TMA and stainless steel archwires were 6.6 Nmm and 9.3 Nmm, respectively. Conclusion: The 0.017 × 0.025-inch stainless steel and -Ti archwires in the 0.018-inch slot generated higher moments than the 0.019 × 0.025-inch archwires because of lower torque play. This difference is exaggerated in steel archwires, in comparison with the -Ti, because of differences in stiffness. The differences of maximum moments between the archwires of the same cross-section but different alloys were statistically significant at both slot dimensions. To compare the archwires inserted during the final stages of the orthodontic treatment with the generated moments at 0.018-and 0.022-inch brackets. Materials and Methods: The same bracket type, in terms of prescription, was evaluated in both slot dimensions. The brackets were bonded on two identical maxillary acrylic resin models, and each model was mounted on the orthodontic measurement and simulation system. Ten 0.017 3 0.025-inch TMA and ten 0.017 3 0.025-inch stainless steel archwires were evaluated in the 0.018-inch brackets. In the 0.022-inch brackets, ten 0.019 3 0.025-inch TMA and ten 0.019 3 0.025-inch stainless steel archwires were measured. A 15u buccal root torque (+15u) and then a 15u palatal root torque (215u) were gradually applied to the right central incisor bracket, and the moments were recorded at these positions. A t-test was conducted to compare the generated moments between wires within the 0.018-and 0.022-inch bracket groups separately. Results: The 0.017 3 0.025-inch archwire in the 0.018-inch brackets generated mean moments of 9.25 Nmm and 14.2 Nmm for the TMA and stainless steel archwires, respectively. The measured moments in the 0.022-inch brackets with the 0.019 3 0.025-inch TMA and stainless steel archwires were 6.6 Nmm and 9.3 Nmm, respect...

Comparative analysis of real and ideal wire-slot play in square and rectangular archwires

“…The tip and torque values may vary between straight-wire systems, albeit by few degrees, and the advantages and disadvantages of these minor variations in prescription have been amply debated in the literature. [14][15][16] Although this is a valid issue from a theoretical perspective, in practice such small differences in torque can only be expressed if very precisely manufactured straight-wire components are available. 13 However, in the real world the archwire and bracket slot dimensions declared by manufacturers do not always correspond to the real measurements, and no information on the size tolerance of the materials on the market is provided.…”

Evaluation of torque moment in a novel elastic bendable orthodontic wire

“…Except for the ligation methods, several factors associated with torque moment are suggested, i.e. wire stiffness, play between the wire and bracket, bracket design, bracket material and so on [15][16][17][18][19][20] . In the present study, large size wires (0.019×0.025 inch wire) showed larger torque moment than small size wires (0.017×0.025 inch wire), because of the play.…”

“…Therefore, until the slot fills the wire, a considerable percentage of the torque built into the bracket is lost because of the play between the wire and bracket slot 12) . There are a number of reports in the literature in which the theoretical and/or measured torque moments between wire and bracket have been calculated [13][14][15][16][17][18][19][20] . Although there may be some discrepancies between in vitro and in vivo conditions, these studies could help in understanding the amount of third-order bends for wire-bracket-ligation combinations.…”

A randomized clinical trial of the effectiveness of 0.018-inch and 0.022-inch slot orthodontic bracket systems: part 2—quality of treatment

“…A potential for higher torque to be delivered by the 0.018-inch slot brackets has been shown in different experimental studies. (12)(13)(14) Nevertheless, these studies were laboratory-based and the influence of other factors in practice, such as intra-oral ageing of fixed appliances and the influence of saliva, among others, were not considered.…”