Ceramic brackets and low friction : A possible synergy in patients requiring multiple MRI scanning

To investigate any advantages of low friction biomechanics in orthodontic patients with fixed appliances without producing metal artifacts during magnetic resonance imaging (MRI).

Frictional resistance generated by bracket-wire-ligature systems was analyzed via an experimental model that reproduced upper canine misalignment. Each sample was tested 10 consecutive times in a dry state; a total of 160 tests were carried out. We documented the frictional forces generated by a 0.012- and 0.014-inch superelastic nickel-titanium wire (SENT) with ceramic self-ligating brackets (SLB) with metal insert and ceramic monocrystalline brackets with nonconventional elastic ligatures (NCEL) in conjunction with various degrees of canine misalignment (1.5, 3.0, 4.5, and 6.0 mm). Comparisons between the frictional forces released by the two different bracket-wire-ligature systems were made by conducting 3-way analysis of variance (ANOVA) with Tukey HSD pairwise test (P < 0.005).

We observed no clinically relevant difference between the frictional forces released by ceramic SLB and ceramic brackets in conjunction with a 0.012- and 0.014-inch SENT. Statistically significant differences were apparent with a 0.012-inch SENT at 4.5 and 6.0 mm of canine misalignment, where the SLB revealed higher frictional forces.

Ceramic brackets with NCEL revealed frictional forces similar to those generated in conjunction with ceramic SLB, thereby helping to avoid metal artifacts in case of expected necessary MRI during orthodontic treatment with fixed appliances.