A comparison of second premolar extraction and mini-implant total arch distalization with interproximal stripping

Abstract

Objective: The effect of total arch distalization using orthodontic mini-implants (OMIs) combined with interproximal stripping (IPS) and second premolar extraction was investigated in Class I malocclusion patients.

Materials and methods: A total of 66 consecutively treated Class I malocclusion (Class I molar relationship; 0 mm < overbite and overjet < 4.5 mm) patients ranging in age from 17 to 44 years who received single-phase treatment were included in this study. Pre- and posttreatment lateral cephalograms and dental casts were measured and compared statistically.

Results: In the distalization with IPS group, 3.6 mm and 3.8 mm of crowding in the upper and lower arches, respectively, were resolved, and 3.8 mm and 3.2 mm of upper and lower incisor retraction, respectively, were achieved simultaneously by the treatment. As a result of the second premolar extraction treatment, 3.9 mm and 3.6 mm of crowding in the upper and lower arches, respectively, were resolved, and 3.3 mm and 3.2 mm of incisor retraction, respectively, were achieved during treatment. There was no statistically significant difference in the amount of crowding and incisor retraction between the two groups.

Conclusions: Total arch distalization using an OMI with IPS did not yield a significantly different treatment result compared to second premolar extraction treatment.

Figure 1.

Cephalometric reference lines and measurements used for evaluating anterior-posterior dental changes. FH indicates Frankfort horizontal plane; FHv, vertical reference plane on the sella vertical to the FH plane: 1, FHv to the upper incisal tip; 2, FHv to the lower incisal tip; 3, FHv to the upper molar; and 4, FHv to the lower molar.

Figure 2.

Schematics showing different types of space closure in this study. (A) In group 1, the effects of IPS and total arch distalization using OMIs were synergistic in incisor positional change. (B) In group 2, the anterior and posterior teeth moved reciprocally during the space closure.