Envisioning Post-treatment Occlusions after Space Closure Using Temporary Skeletal Anchorage Devices

Space closure by miniscrew-assisted mesialization of an upper third molar and partial vestibular fixed appliance: A case report

This case report demonstrates how the use of skeletal anchorage and appropriate orthodontic biomechanics can be used to resolve even complex cases, reducing unwanted dental movements and allowing the use of a partial vestibular appliance. It describes the complete mesialization of the left upper third molar and space closure following extraction of tooth UR7, due to vertical fracture one year after previous endodontic therapy for caries. This therapeutic choice was conditioned by the need not to alter the good pre-existing interarch relationships, and above all by the patient's request to be treated conservatively, and therefore not to undergo prosthetic implant rehabilitation. The use of orthodontic miniscrews and the careful application of orthodontic biomechanics, based on both direct and indirect anchorage, enabled the treatment objectives to be achieved in a reasonable period of time with reduced treatment costs.

Factors associated with spontaneous mesialization of impacted mandibular third molars after second molar protraction

OBJECTIVES

To investigate factors associated with spontaneous mesialization of impacted third molars after second molar protraction to close the space caused by a missing mandibular first molar (L-6) or retained deciduous mandibular second molars with a missing succedaneous premolar (L-E).

MATERIALS AND METHODS

Panoramic radiographs of patients treated with mandibular second molar protraction to close the space due to missing L-6 or L-E (14 males, 36 females, mean age = 18.6 ± 4.4 years) were analyzed before treatment (T1) and after second molar protraction (T2). Factors associated with the amount of third molar mesialization were investigated using regression analyses.

RESULTS

Mandibular second molars were protracted by 5.1 ± 2.1 mm and 5.8 ± 2.7 mm, measured at the crown and root furcation, respectively. After second molar protraction, third molars showed spontaneous mesialization by 4.3 ± 1.6 mm and 3.8 ± 2.6 mm, measured at the crown and root furcation, respectively. Nolla's stage of the third molar at T1 (B = 0.20, P = .026) and second molar protraction time (B = 0.04, P = .042) were significantly associated with the amount of third molar mesialization.

CONCLUSIONS

Greater third molar mesialization was observed when Nolla's stage of the third molar was higher before treatment and when the second molar protraction time was longer.