- Nickel release from orthodontic retention wires: the action of mechanical loading and pH
- Dental Materials
- Volume | Issue number
- 28 | 5
- Pages (from-to)
- Document type
- Faculty of Dentistry (ACTA)
Nickel (Ni) is a potent sensitizer and may induce innate and adaptive immune responses. Ni is an important component of orthodontic appliances (8-50 wt%). Due to chemical and mechanical factors in the oral environment, Ni is released from these appliances. Retention wires are in situ for a long period of time.
To quantitatively evaluate the influence of mechanical loading and pH on the nickel release from orthodontic retention wires.
Five different types of multi-stranded wires (Original Wildcat, Noninium, Lingual retainer, Dentaflex 3-s, Dentaflex 6-s), were submersed for 24 h in either 10 ml of distilled water or lactic acid, both submitted to cyclic loading in a 3-point bending test (0×, 1000×, 10,000×). The solutions were analyzed by Inductively Coupled Plasma Mass Spectroscopy (ICP-MS), and the data was statistically analyzed (ANOVA, p < 0.05).
Mechanical loading has a strong effect on the Ni release from orthodontic retention wires, especially in distilled water. Acidity has more impact on Ni release when compared to mechanical loading. Manganese-steel "Ni-free" wires released quantifiable amounts of Ni due to trace elements of Ni within the wire.
All investigated wires release considerable amounts of Ni to which exposure may have biological implications.
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