Abstract
The retrospective study aims to confirm/disprove the relationship between selected parameters and their change during the treatment and retention phase, and the repeated opening of extraction spaces in patients treated with four premolars extraction. Material: The sample comprised 42 patients.
We assessed 141 quadrants in which extraction spaces were completely closed at the end of therapy. The patients were divided into two groups: one with spaces remained closed during the retention phase, the other without closed spaces.
The mean length of the retention phase was 7 years. Method: The following parameters were assessed (using documentation made prior to the treatment, at the time of appliance removal, and during the retention phase): Little's Irregularity Index of lower anterior segment, overbite, overjet, occlusal contacts, inclination of canines to occlusal plane, position of upper and lower incisors.
We recorded NS-ML angle at the beginning of therapy. According to orthopantomograms taken at the time of appliance removal we assessed the presence of third molars and whether they are fully developed or not.
Conclusion: We did not find statistically significant relationship between the parameters measured and repeated opening of extraction sites.