Document Type: Original Article

Authors

1 Orthodontic Research Center, Dept. of Orthodontics, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran.

2 Post graduate Specialist in Orthodontics, Member of Orthodontic Research Center, Dept. of Orthodontics, School of Dentistry, Shiraz, University of Medical Sciences, Shiraz, Iran.

Abstract

Statement of the Problem: Orthodontists often find challenges in treating the anterior open bite and maintaining the results.Purpose: This retrospective study was aimed to evaluate the stability of corrected open bite in the retention phase during permanent dentition.Materials and Method: A total number of 37 patients, including 20 males and 17 females, with the mean age of 18±2.1 years at the beginning of the treatment were studied after correction of the anterior open bite. Overbites of the patients were measured from their lateral cephalograms before (T1), at the end (T2) and at least 3 years after the end of the treatment in the presence of their fixed retainers (T3).The mean overbite changes and the number of patients with open bite, due to treatment relapse, at T3 were calculated. The relationship between the pre-treatment factors and the treatment relapse was assessed at T1 and T2. Also the effects of treatment methods, extraction and adjunctive use of removable appliances on the post-treatment relapse were evaluated.Results: The mean overbite change during the post-treatment period was -0.46±0.7 mm and six patients (16.2%) had relapse in the follow-up recall. Cephalometric Jaraback index showed statistically significant, but weak correlation with overbite changes after the treatment (p= 0.035; r= -0.353). No significant difference was found between the extraction and non-extraction groups (p= 0.117) the use and the type of the removable appliances (p= 0.801).Conclusion: Fixed retainers alone are insufficient for stabilizing the results of corrected open bite. The change of overbite in the retention phase could not be predicted from cephalometric measurements. Extraction and use of adjunctive removable appliance did not have any effect on the treatment relapse.