[The relationship between maxillary anterior impacted teeth and sagittal facial type].

Purpose: To investigate the relationship between impaction of maxillary anterior teeth and sagittal facial type and evaluate the dentofacial morphological characteristics of patients with maxillary teeth impaction.

Methods: Totally 90 patients with maxillary anterior teeth impaction were divided into 3 groups (one incisor impaction, one canine impaction and two canines impaction), and their cephalometric films were measured and analyzed. They were further divided into Class I, II and III facial types according to ANB and the constituent ratio were calculated. SPSS 17.0 software package was applied for Student's t test and chi-square test.

Results: SNA, A'-Ptm' and L1-NB were smaller than the normal value in the 3 groups. Convexity, L1-MP, ANB and Wits appraisal were smaller while AB plane angle, U1-NA and U1-NA were greater than the normal value in groups of one and two canines impaction; S'-Ptm', L1-NB were smaller while U1-L1 was greater than normal value in group of two canines impaction; Among the 3 groups, ANB and Wits appraisal were the smallest while AB plane angle was the greatest in group of two canines impaction. The sagittal facial type of 90 patients was mainly Class I (50%), but Class III in group of two canines impaction increased to 40%.

Conclusions: Impacted maxillary anterior teeth might result in short maxillary basal bone. One canine impaction has the greatest influence than one incisor impaction on sagittal position of jaws. Two canines impaction has the greatest impact on sagittal facial type and tends to be Class III facial type.