1 Associate Professor, Orthodontic Department, Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran

2 Assistant Professor, Orthodontic Department, Faculty of Dentistry,Tabriz University of Medical Sciences, Tabriz, Iran

3 Postgraduate Student, Prosthodontic Department, Faculty of Dentistry, Hamadan University of Medical Sciences, Hamadan, Iran

4 Postgraduate Student, Radiology Department, Faculty of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran

5 Assistant Professor, Endodontic Department, Faculty of Dentistry, Zanjan University of Medical Sciences, Zanjan, Iran Sources of support:Tabriz University of Medical Sciences



Introduction: Third molar impaction is usually related to lack of space for eruption. The aim of this study was to assess third molar angulation following extraction and non extraction orthodontic treatment.
Methods: This study was carried out on pretreatment and post treatment panoramic and cephalometricradiographs of 70 CL I malocclusion patients. Thirty-five patients (24 female and 11 male) with mean age of 16.3±1.8 years had been treated with extraction of four first premolars (extraction group) and thirty-five patients (27 female and 8 male) with mean age of 16.9±2.6 years had been treated without extraction (nonextraction group). In each group, upper and lower third molar angulation, on pre and post treatment radiographs were assessed. Changes in third molar angulations from pretreatment to post treatment in each group were assessed with Mann- Whiteny U test. Changes in two groups were compared with Wilcoxon test.
Results: statistical analysis revealed some degree of improvement in third molar angulation in both groups. changes of upper left third molars in extraction group and upper right and lower left third molars in non extraction group were statistically significant. The changes of third molar angulation between two groups were not statistically significant.
Conclusion: Extraction of first premolars during orthodontic treatments does not influence unerupted third molar angulation.