Abstract Objective: To compare the high-cycle fatigue behavior of four commercially available NiTi orthodontic wires. Material and Methods: Twelve NiTi orthodontic wires, round, 0.016-in, three per brand, were selected and divided into four groups: G1 - Heat-activated NiTi, G2 - Superelastic NiTi, G3 - Therma-Ti, and G4 - CopperNiTi. The atomic absorption spectrometry method was used to determine the chemical composition of investigated NiTi wires. We also performed a fatigue test at three-point bending using a universal testing machine for 1000 cycles in a 35 °C water bath. For the first and thousandth cycle, the average plateau load and the plateau length were determined in the unloading area of the force versus displacement diagram. In addition, we calculated the difference between the average plateau load of the first and thousandth cycle (∆F), as well as the difference between the plateau length of both cases (∆L). Results: According to our results, there were no significant differences between the average plateau load of the first and thousandth cycles of each group (p>0.05) and in the plateau length of the first and thousandth cycles of the groups (p>0.05). Conclusion: There were no significant differences between the groups changing the superelasticity property after high-cycle fatigue.

RESUMO Objetivo: o objetivo do presente estudo foi avaliar o uso de dispositivos de ancoragem temporária (DATs) para a movimentação de caninos impactados, afastando-os das raízes dos dentes vizinhos, antes da colagem dos braquetes em todos os dentes, com o objetivo de minimizar os efeitos colaterais indesejáveis nesses dentes adjacentes. Métodos: a amostra consistiu de 34 caninos impactados por palatino, sendo 19 no grupo experimental e 15 no grupo controle. No grupo experimental, antes da colagem dos braquetes, os caninos impactados foram tracionados utilizando-se mini-implantes. No grupo controle, após o início do tratamento ortodôntico, a desimpacção dos caninos foi realizada com uma mola em cantiléver soldada a uma barra transpalatina. Ao fim do tratamento, os valores referentes à reabsorção radicular nos incisivos laterais e caninos foram medidos e comparados por meio de modelos tridimensionais reconstruídos a partir de TCFCs. Foram também registrados os escores relativos à dor sentida pelos pacientes, usando uma escala visual analógica (VAS); além do Índice de Sangramento à Sondagem (ISS) e do Índice Gengival (IG). O índice de sucesso clínico também foi calculado. Resultados: o volume de reabsorção radicular nos incisivos laterais no grupo controle foi significativamente maior do que no grupo experimental (p < 0,001). Ao fim do tratamento, não houve diferença significativa entre os dois grupos quanto aos escores relativos à VAS, ao IG e ISS. Conclusão: esses resultados sugerem que a desimpacção de caninos e a movimentação deles para a arcada dentária podem ser realizadas, com sucesso e com mínimos efeitos colaterais, por meio da ancoragem esquelética.

ABSTRACT Objective: The aim of this study was to evaluate the movement of impacted canines away from the roots of neighboring teeth before full-mouth bracket placement, performed by means of TADs to decrease undesired side effects on adjacent teeth. Methods: The study sample consisted of 34 palatally impacted canines, being 19 in the experimental group and 15 in the control group. In the experimental group, before placement of brackets, the impacted canine was erupted by means of miniscrews. In the control group, after initiation of comprehensive orthodontics, canine disimpaction was performed by means of a cantilever spring soldered to a palatal bar. At the end of treatment, volume of lateral incisors and canine root resorption were measured and compared by means of a CBCT-derived tridimensional model. Visual Analogue Scale (VAS) score, bleeding on probing (BOP) and gingival index (GI) were recorded. Clinical success rate was also calculated. Results: The volume of root resorption of lateral teeth in the control group was significantly greater than in the experimental group (p < 0.001). At the end of treatment, VAS score, GI and BOP were not significantly different between the two groups. Conclusion: Based on our results, it seems that disimpaction of canines and moving them to the arch can be done successfully carried out with minimal side effects by means of skeletal anchorage.