Long-term iterative biomechanical analysis of an efficient mandibular dental arch distal tipping method with straight wire technique.

BACKGROUND

The efficient mandibular dental arch distal tipping method with straight wire (EDSW) technique is an effective method to release cross bite compared to conventional straight wire (SW) technique. The aim of this study was to investigate the biomechanical features of EDSW technique with a long-term iterative biomechanical analysis (LIBA) method.

MATERIALS/

METHODS

A finite element model encompassing the mandibular dentition, periodontal ligaments, SW appliance was constructed. As for the EDSW group, brackets on premolars were removed and the canine bracket was Tip-edged. The same Class III elastics were simulated for both groups. Long-term tooth movement was simulated with LIBA method on an iterative computational method using a supercomputer.

RESULTS

One thousand steps of iterative calculations were performed for each group. The lingual inclinations of the central and lateral incisors in the EDSW group were 3.40 mm and 17.49° and 3.24 mm and 15.22°, respectively, and those for the central and lateral incisors in the SW group were 2.06 mm and 11.49° and 1.93 mm and 10.27°, respectively. The distal tipping of the first molars in the EDSW (2.05 mm, 9.38°) is larger than SW group (1.13 mm, 5.26°).

CONCLUSIONS

Mandibular total arch distal tipping movement could be efficiently achieved with light elastic force during EDSW treatment for skeletal Class III patients compared to SW technique. The Tip-edged canine bracket could help increase the passive range of motion of the slot, which was conducive to the distal tipping of the canine compared to the conventional SW canine bracket.