In-vitro evaluation of the corrosion behavior of orthodontic brackets.
OBJECTIVE
The number of bracket systems for orthodontic therapy increases significantly. One major concern of newly developed orthodontic devices is aspects of corrosion and biocompatibility.


METHODS
In this study, nine bracket systems made of different material and from various design principles were tested with respect to their corrosion behavior. Electrochemical and static immersion tests with subsequent measurement of nickel ion release were performed. In addition surface alterations of the brackets after corrosion were documented by scanning electron microscopy. Studies of corrosion behavior were performed according to the DIN/ISO standard 10271 for corrosion testing of dental materials.


RESULTS
All systems showed traces of corrosion after electrochemical testing. However, after static immersion testing only minor corrosion defects could be documented and the measured nickel ion release was far below critical limits.


CONCLUSIONS
All tested systems seem to be biocompatible and applicable for orthodontic therapy. The measured nickel values are far below the daily dietary intake level. A static immersion test combined with the nickel ion release measurement seems to be more relevant for the determination of biocompatibility than the electrochemical testing.
Luft
S
S
University of Bonn, Bonn, Germany.
Keilig
L
L
Jäger
A
A
Bourauel
C
C
D001672:Biocompatible Materials / Q000737:chemistry; D003343:Corrosion; D003722:Dental Alloys / Q000737:chemistry; D055664:Electrochemical Techniques; D004577:Electron Probe Microanalysis; D007101:Immersion; D007477:Ions; D013058:Mass Spectrometry / Q000379:methods; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D009532:Nickel / Q000032:analysis; D016910:Orthodontic Brackets; D012464:Saliva, Artificial; D013499:Surface Properties
D001672:Biocompatible Materials; D003722:Dental Alloys; D007477:Ions; D012464:Saliva, Artificial; D009532:Nickel