Influence of impacted maxillary central incisor on craniofacial structure and its orthodontic treatment

Abstract

Objective To explore the influence of impacted maxillary central incisor on craniofacial structure and its orthodontic treatment. Methods A total of 63 subjects with impacted upper central incisors were selected and categorized into the mixed (n=32) and permanent dentition group (n=31). By using the lateral cephalograms of each subject, 15 angular and 6 linear measurements were made. The cephalometric data were analyzed and compared to data of its corresponding control group with normal occlusion. Results Among the etiological factors of all 63 cases with impacted upper incisors, supernumerary teeth, dentigerous cyst or odontoma, mechanical trauma and idiopathic factors comprise of 6.3%, 6.3%, 12.4% and 73% respectively. Cephalometric analysis demonstrated a more retruded position of "A" point with decreased SNA and ANB angle in incisor impaction group. Dental compensations followed the decreased ANB angle with more proclined upper incisor and more upright lower incisor. In early stage of root development (stage 7 and 8 of Nolla's method), 12 out of 13 incisors were tracted successfully, whereas in late stage( stage 9 and 10), 7 out of 15 incisors were extracted. Conlusions Upper central incisor impaction adversely influences maxillary development. Early orthodontic treatment can improve successful rate and gain a better root morphology.

Keywords

• Impacted tooth ，
• Central incisor，
• Orthodontics，
• Cephalometry，
• Dental age，