The Efficacy And Angle Of Molars In Different Distalization Distance

This study measured the distalization efficacy and three-dimensional angle variation of the molars,to investigate the effect of predicted distalization distance on tooth movement. Collected and superimposed digital study models of molar distalization. A total of 32 maxillary second molars were divided into 1∼2 mm group (n=14), 2∼3 mm group (n=10), and 3∼4 mm group (n=8) according to the predicted movement. The efficacy and the variation of inclination and torque were measured. The upper second molar efficacy of 1∼2 mm group was (66.94±14.45)%, 2∼3 mm group was (80.64±12.94)%, 3∼4 mm group was (79.88±16.03)%, and the efficacy of 2∼3 mm group was significantly greater than the 1∼2 mm group (P<0.05). Upper second molars tilted distally by (3.44±3.10)° in 1∼2 mm group, (4.26±3.57)° in 2∼3 mm group, (9.58±5.24)° in 3∼4 mm group, and the distal inclination of 3∼4 mm group was significantly greater than the other groups (P<0.05). No significant torque change was observed in all above groups (P>0.05). The molar distalization efficacy was lowest at the initial 1∼2 mm, highest at 2∼3 mm, and slightly decreased at 3∼4 mm. And significant distal inclination was noticed in the upper second molars when predicted distalization distance exceeded 3 mm.