A prospective randomized study of different retainer types.

BACKGROUND AND AIM: In recent years, fixed lingual retainers have been gaining importance in relapse prevention. The aim of this prospective, randomized study was to compare different types of fixed retainers used for stabilization of the lower anterior segment with respect to detachment rate, relapse, periodontal and oral hygiene problems, as well as subjective patient discomfort. PATIENTS AND
METHOD: Two types of fixed, customized canine-to-canine retainers (attached to six teeth) with wire diameters of 0.0215" and 0.0195" as well as one type of prefabricated canine-and-canine retainer (bonded to two teeth) were investigated in a total of 103 patients. Some retainers were inserted under dry field conditions using a rubber dam, and the others under relatively dry conditions using cotton rolls. In addition, two types of composite, Heliosit and Concise, were compared.
RESULTS: The canine-and-canine retainer displayed an 18% detachment rate, a value significantly lower than the 29% determined for the 0.0195" canine-to-canine retainers. The 0.0215" canine-to-canine retainer had the highest detachment rate (53%). The 37% detachment rate with dry field bonding was slightly higher than the 32% with relatively dry field bonding. Comparison of the composites showed a significantly higher detachment rate for Heliosit (73%) than for Concise (27%). Plaque accumulation increased with all retainer types in the course of the study, but with no significant inter-group differences. Tooth position with canine-to-canine retainers showed a good degree of stability. The canine-and-canine retainer induced frequent relapse of incisors not bonded to the retainer. In view of their higher rate of subjective discomfort, canine-and-canine retainers were given a significantly poorer rating than their canine-to-canine counterparts.