Transverse and torque dental changes after passive self-ligating fixed therapy: A two-year follow-up study

Area of Science:

• Orthodontics
• Dental Biomaterials
• Craniofacial Biology

Background:

• Self-ligating appliances are utilized for dental arch expansion.
• Limited evidence exists regarding the long-term stability of arch dimensions achieved with these appliances.
• Assessing stability is crucial for understanding treatment outcomes.

Purpose of the Study:

• To evaluate the stability of transverse arch dimensions and torque changes after orthodontic treatment using passive self-ligating appliances.
• To assess the long-term (2-year follow-up) stability of these changes.

Main Methods:

• Utilized 3-dimensional (3D) models of maxillary and mandibular arches from 32 subjects.
• Collected models at three time points: pre-treatment, immediately post-treatment, and 2 years post-treatment.
• Employed 3D software to analyze transverse arch dimensions and torque values.

Main Results:

• Significant increases in maxillary and mandibular arch widths, particularly at the premolar regions, were observed.
• A significant positive correlation between increased transverse diameters and torque gain was noted.
• No significant changes in arch perimeter or depth were found.
• A slight but significant constriction in transverse diameters occurred during the 2-year follow-up, with torque values remaining stable.

Conclusions:

• Passive self-ligating appliances effectively increase transverse arch dimensions and torque.
• A tendency towards constriction of transverse arch dimensions, especially in premolar regions, was evident during the 2-year retention period.
• The findings highlight the need for careful monitoring of arch stability post-treatment.