Teeth movement following orthodontic treatment with four second premolar removal and its impact on facial esthetics

Abstract

Objective To investigate the movement distance and moving pattern of incisors and molars after orthodontic treatment with four second premolar removal in the slight dental protrusion patients.Methods 26 patients treated in Dept.of Orthondontics,Hua Xi Dental Hospital were recruited into this studdy .The moving distance and pattern of incisors and first molars were measured relative to the post-treatment occlusal plane, palatal plane and mandibular plane on the X-ray cephalometries.Results In the upper arch,the anterior segnemt took up 50.4±11.5% of the extraction space,while in the lower arch it was 46.2±10.7%.the rotation center of the upper central incisor located at -4.28～11.96 mm apical to the apex point,while the lower central incisors located 0.85～25.25 mm apical to the apex.All the molars were moved bodily.Conclusions The slight bimaxillary dental protrusion patients can be successfully treated with four second premolar removal.Following the treatment,the position and inclination of the upper incisors would be properly maintained.Profile esthetics and smile fullness would be achieved as well. Key words: Second premolar; Extraction; Teeth movement; Esthetics