Abstract: Objective To explore the relationship between the amount of maxillary central incisor retraction and the consumption of dental arch space. Methods Two hundred and three adult orthodontic patients with overjet and extraction of the maxillary first premolars were selected. Three-dimensional reconstruction of the cone-beam CT before and after treatment was established. The amount of maxillary central incisor retraction (X₁), intercanine width (X₂) and the amount of distal movement of canines were measured. The digital scanner was used to scan the maxillary plaster casts before treatment, and the crowding of the anterior segment of the maxillary arch was measured. The amount of the maxillary central incisor retraction, the change of intercanine width and the total amount of dental arch space consumption (Y) were analyzed using correlation analysis and linear regression analysis. Results The amount of maxillary central incisor showed strong positive correlation with the consumption of dental arch space (r=0.726,P＜0.001), while the change of maxillary canines width and the consumption of dental arch space showed negative correlation (r=-0.317,P＜0.001). The regression equation of maxillary central incisor retraction(X₁), intercanine width (X₂) and the total arch space consumption (Y) was Y=1.25X₁-0.494X₂-2.299. Conclusion For every 1 mm of maxillary central incisor retraction, the arch space required is 1.250 mm, and for every 1 mm reduction in the width between canines, arch space required is 0.494 mm.

Key words: maxillary central incisor, dental arch space, correlation, regression analysis