Abstract
Aim: The aim of this study was to compare the effectiveness of four types of retainer wires and their ability to maintain the stability of the lower frontal section in the retention phase. Another goal was to determine the degree of failure of these wires, the time distribution of failure and also whether it is affected by increased tooth looseness after the end of therapy with a fixed apparatus.
Material and methods: The study included 50 patients (23 men, 27 women) in whom the lower fixed retainer was present and in whom the fixed apparatus was removed more than 5 years ago. Patients were divided into 4 groups according to the retainer wire used (6-strand .0175 ", 3-strand .0150", .016 x .022 "8-strand, 5-strand .0215").
Measurements of Little Irregularity Index (LI) and interpeak distance were measured on plaster models at 3 times - before treatment (T0), when removing the fixed apparatus and using a fixed retainer (T1) and at least 5 years after the end of treatment (T2). Individual failures of retainers and their time distribution were recorded from the documentation.
To verify the effect of wobble on failure, patients with an increased wobble value at time T1 (greater than 15) were selected and compared to patients with a normal wobble value (less than 15). Results: The efficiency of fixed retainers does not depend on the type of retainer used (p = 0.750).
A significant effect of retainer failure on the stability of the lower frontal section was demonstrated (p = 0.0002), however, the difference in the frequency of failures between individual wires was not demonstrated. Most failures occurred in the 1st and 5th year of retention (43.5% and 30.4%).
There were no changes in the peak peak distance during the retention phase different for each type of wire. No statistically significant effect of higher lower frontal tooth rot was found at removal of the fixed apparatus to the subsequent frequency of retention failures in the retention phase.
Conclusion: All examined wires have similar effectiveness in maintaining stability. The negative impact of failure on this stability is significant.
However, the increased twitching of the teeth at the end of the fixed apparatus therapy does not increase this amount of failure.