Maximum insertion torque loss after miniscrew placement in orthodontic patients: A randomized controlled trial

Area of Science:

• Orthodontics
• Biomaterials Science
• Dental Implantology

Background:

• Orthodontic miniscrews are widely used for anchorage in fixed orthodontic treatment.
• Understanding the mechanical stability of miniscrews post-insertion is crucial for predictable treatment outcomes.

Purpose of the Study:

• To compare torque recordings of immediately loaded orthodontic miniscrews from insertion to various post-placement timepoints.
• To evaluate torque variations at 2 weeks, 4 weeks, and removal time.

Main Methods:

• A parallel trial involving 47 patients and 74 miniscrews (2.0 mm diameter, 10 mm length).
• Miniscrews were placed inter-radicularly in the maxilla or mandible without pre-drilling and immediately loaded.
• Maximum Insertion Torque (MIT) was measured at baseline, 2 weeks, and 4 weeks; removal torque was assessed at the end of treatment.

Main Results:

• A significant association was found between maximum insertion torque and observation time.
• Mandibular and maxillary miniscrews showed a torque decrease of 26.9% and 30%, respectively, after 2 weeks.
• Torque values returned to baseline levels by 1 month, with an overall success rate of 79.7%.

Conclusions:

• Maximum insertion torque of orthodontic miniscrews experiences a loss within the initial 2 weeks.
• Torque stability is achieved by 1 month, with removal torque similar to initial insertion torque.
• Torque variation may be influenced by the miniscrew's insertion site and its intended anchorage purpose.