Bonded retainers seem to be an ideal solution for a long-term retention and the advantage lies in keeping an aesthetic and stable result without the need of cooperation from the side of the patient - the patient's responsibility. However, there can be some disadvantages: check-ups are necessary, there may occur fractures and loss of bond, higher calculus accumulation and recession is common, and last but not least - it can cause unexpected complications of fixed retainers (UCFR). The author describes several types of UCFR - Twist effect and X effect - and how they were studied on 3,500 patients. The prevalence of UCFR occurred in 1.1% and potential causes are showed here. But UCFR is of multifactorial origin where more aspects become important: type of wire, local anatomic condition and occusal forces.
Recognize unexpected complications of fixed retainers.
Define types of the complication.
Evaluate which kind of wire is the best one for retention.