Changes in third molar position as a result of first premolar extractions and orthodontic therapy in a group of egyptian adolescents

ABSTRACT

One of the concerns of orthodontic patients nowadays is whether premolar extraction will prevent third molar impaction and obviate the need for their surgical removal. The aim of this study was to investigate changes in third molar position as a result of first premolar extractions and or-thodontic therapy in Egyptian adolescents. Pre and post treatment panoramic and lateral ce-phalometric radiographs of 38 orthodontically treated patients were used in this study. All patients had Angle Class I malocclusion with moderate crowding. According to the treatment modality, the patients were divided into 2 groups. Group I comprised the radiographs of 20 patients who were treated by premolar extraction, while Group II comprised the radiographs of 18 patients who were "treated non-extraction. Relevant anatomjcal landmarks were traced on both the pre and post treatment panoramic radiographs. Angular and linear position of upper and lower 3rd molars were measured. Then, the amount of movement of upper and lower third molars were computed. Statistical analysis was used to compare between the 2 groups. The results of the study revealed that premolar extractions led to a statistically significantly greater increase in the space available for upper and lower third molars, as well as a statistically significantly greater improvement in the inclination and vertical position of upper third molars. These effects might contribute to the eruption process of upper and lower 3rd molars and prevent their impaction